Food packaging's materials: A food safety perspective
M.S. AlamriAkram A.A. QasemAbdellatif A. MohamedShahzad HussainMohamed A. IbraheemGhalia ShamlanHesham A. AlqahAli S. Qasha Department of Food Science and Nutrition, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). ⇑Corresponding author. E-mail address:firstname.lastname@example.org(A.A.A. Qasem).Peer review under responsibility of King Saud University. Abstract Food packaging serves purposes of food product safety and easy handling and transport by preventing chemical contamination and enhancing shelf life, which provides convenience for consumers. Various types of materials, including plastics, glass, metals, and papers and their composites, have been used for food packaging. However, owing to consumers’ increased health awareness, the significance of transferring harmful materials from packaging materials into foods is of greater concern. This review highlights the interactions of food with packaging materials and elaborates the mechanism, types, and contributing factors of migration of chemical substances from the packaging to foods. Also, various types of chemical migrants from different packaging materials with their possible impacts on food safety and human health are discussed. We conclude with a future outlook based on legislative considerations and ongoing technical contributions to optimization of food–package interactions. 1. Introduction Food packaging is used for diverse products, and food protection along the supply chain is largely based on the packaging (Brody et al., 2008). Without packaging, the handling of food products would be costly and inefficient (Robertson, 2006). Packaging also provides consumers initial product identity before deciding whether to purchase it. Also, consumer demand is changing and now includes such diverse packaging as active and intelligent packaging. These packaging systems interact and respond to the food-packaging environment, where they release some substances in or scavenge some from the packaging headspace and prolong the shelf life of food products (Robertson, 2006). Such innovative packaging is practiced in part to boost sales in a competitive environment. The packaging style and design may also enhance the product’s image and acceptability. Thus, the selection of packaging material is a consideration for consumers at the end of supply chain. The major objective of packaging is to protect and preserve foods from possible physical, chemical, microbiological, or other hazards that ultimately can impact their quality and safety (Lee, 2010). In the prediction of food shelf life, the design of food packaging is the main consideration. When selecting packaging materials, many factors should be considered, including cost, quality of products, and their ability to maintain product freshness. A few common materials used in food packaging are plastics, paper, glass, and metals. Among these, a wide variety of plastics are used in rigid or flexible food packaging. Packaging materials now include laminates, which were developed by systematically integrating materials with different inherent properties to improve the functionality of the final material. Diverse food packaging and container types are shown in Table 1. In general, various chemical substances are found in foods during different phases of the supply chain; these include micronutrients, flavorings, antimicrobials, antioxidants, pesticides, and mycotoxins. Also, additives such as plasticizers, monomers, and oligomers found in the packaging materials could transfer to the foods upon contact during processing or packaging; this transfer of chemical compounds between the food and packaging is termed “migration” (Arvanitoyannis and Bosnea, 2004). This interactive phenomenon could result in alterations in the quality and also the safety of the food, and flavor may change owing to sorption of aroma and the transfer of undesirable components from the packaging material to the food. Understanding the migration mechanism is crucial for estimating food deterioration when using synthetic polymer-based packaging. However, direct interaction between food and packaging is not necessarily detrimental, as the same principles that because unwanted interactions may also result in desirable outcomes. Table 1. Food packages and container types (Shaw, 2013). Packaging type Products type Application* Aseptic processing Egg (liquid/whole) and dairy Primary Bags Potato chips, apples, rice Primary Cans Soup Primary Paper (cartons, coated) Eggs, milk/juices Primary Flexible packaging Bagged salad Primary Trays Meat/fish pieces Primary Corrugated boxes Cereal carton boxes, frozen pizza Secondary Pallets Series of boxes on single pallet for carriage from producing plant to distribution station Tertiary Wrappers To wrap boxes for transport Tertiary *Primary packaging is main package used to hold food being processed; secondary packaging combines primary packages inside one box; tertiary packaging combines multiple secondary packages into one pack. An example of beneficial migration is the oxygen-scavenging films that directly absorb oxygen, prevent microbial growth, and remove undesirable flavors by sorption (Hotchkiss, 1997). The mass transfer has been variously described as a physical interaction in which chemical transfer occurs at the food–packaging interface, a chemical interaction possibly resulting from the corrosive action of food components on metallic packaging, or microbiological food contamination caused by contact with contaminated packaging material (Lee et al., 2008). Because the interaction between packaging material and food is influenced by many factors, a careful selection of packaging material is required to avoid negative effects on the quality, safety, and shelf stability of products. Product considerations should also include flavor sensitivity, color changes, and microbial activity. To design a suitable food-packaging system, type of polymer, method of preparation, and polymer content-to-food ratio are assessed to help define the interaction level of the food and the package. Also, processing methods as well as time and temperature during food storage should be considered (Hotchkiss, 1997). 1.1. Food interaction with packaging materials The interaction between food and its packaging is a crucial consideration, especially when the food comes in contact with the packaging material. It is during this contact that the intrusion of gases and volatiles, moisture, microorganisms and other low molecular weight compounds occurs (Arvanitoyannis and Bosnea, 2004). Such interaction between food and packaging materials is considered to be an interchange among food, packaging, and the environment and can impact food quality, safety, and/or package integrity. The main goal of food packaging is to protect food from external environmental factors, but food–packaging interactions also can compromise the quality and/or safety of foods. However, the mass transfer of additives from packaging to the foods is undesirable and can alter the food’s flavor. Other undesired phenomena include removal of some desirable flavors from the food to the packaging and the uptake or release of moisture by permeation. An interesting possibility is that food quality and safety could be enhanced via such package-to-food interactions. Recently for instance, diverse studies have been used in designing packaging with active component materials that scavenge oxygen, as opposed to acting as a simple barrier to permeation, to improve the stability of high-fat foods (Maloba et al., 1996). Packaging designed to enhance desirable interactions with the contained food are called “active packaging” (Labuza and Breene, 1989). The food and packaging interaction could be categorized into three types: migration, permeation, and sorption. Examples are the migration of contaminants or plasticizers from recycled plastic polymers, which is considered as a regulatory and safety issue, or the migration of food additives, which could enhance food quality; the permeation of different gases, such as oxygen or carbon dioxide, that may be beneficial for modified atmosphere packaging yet undesirable for carbonated beverages; and the sorption of aroma and flavor, which could change the organoleptic properties of foods. The key theories that reinforce these interactions are based on the Fickian theory of diffusion. The theoretical basis of migration, absorption, and permeation, while the interactions between polymeric packaging and aroma and flavors (Crank, 1975, Johansson, 1996). 1.2. Migration from packaging material to food The migration phenomenon in packaged foods may happen in two directions simultaneously, i.e., from packaging material to the food product and vice versa (Mousavi et al., 1998). In the former case, the molecularly diffused low-molecular weight substances such as additives and oligomers from the packaging films are transferred into the foods (Helmroth et al., 2020). In the latter scenario, the mass transfer of food color, aroma, flavor, and nutrients happens from the food product to the packaging and results in a strong impact on the organoleptic properties of foods (Lee et al., 2008). The polymer packaging and food interface suggesting chemical migration is diagrammed in Fig. 1. Fig. 1. Packaging polymer and solution interface with diffusion of additives and solvent (Ferrara et al., 2001). Migration is the transfer of chemical compounds from or to the packaging film that occurs upon contact with the food. We have considered mostly the transfer of chemical substances from packaging to food. The chemical substances can potentially come from packaging substrates (such as paper, cardboard, or plastics), but other packaging components (such as printing inks, adhesives, or coatings) could also be sources of chemical migrants. Factors that determine the extent of migration include the packaging polymer, physicochemical properties of the migrant, the food type, duration and temperature of storage, and the package-to-food proportion (because smaller packaging has a larger surface-to-volume ratio). The maintenance of food quality and safety is considered critical during the packaging process, in storage, during transportation, and in retail locations (Hron et al., 2012). Therefore, various levels of safety standards are practiced from country level (U.S. Food and Drug Administration) to regional level (European Food Safety Authority). Some certification programs, such as the Global Food Safety Initiative, have been introduced but are not yet in widespread use. Authorities have issued legislative directives about migration of chemicals into food (Arvanitoyannis and Kotsanopoulos, 2014). Health-related risks from the materials and chemicals used in food packaging should be carefully considered and thoroughly monitored. To prevent contact and potential migration of carcinogenic chemical compounds into foods, such carcinogens need to be eliminated (Claudio, 2012). Trace metals, one of the potential sources that can contaminate food products, may enter food chains from soil; agrochemicals; water used in food processing; food-processing equipment, containers, and utensils; and from packaging. Hazards related to the presence of trace metals in food has raised widespread health concerns. Chronic and acute symptoms including dizziness, nausea, diarrhea, vomiting, loss of appetite, sleeping disorders, and reduced conception rate may be indicative of heavy-metal toxicity. Trace metals have also been linked to cardiovascular ailments, suppressed growth, neurological and immune-system disorders, impaired fertility, increased spontaneous abortions, and higher death rates among infants (Yüzbaşi et al., 2003). 1.3. Mechanism of migration Substances migrating from food packaging to foods are highly complex. Diffusion phenomena are the main mechanism of migration where the macroscopic mass movement of molecules occur from higher to lower concentration gradients until an equilibrium is reached (Miltz et al., 1997, Simoneau, 2008). The rate of molecular diffusion is shown mathematically by Fick’s second law: dCp=dt ¼ Dðd2Cp=dx2Þ; whereCp: concentration (mg/g) of migrant in packaging material D: coefficient of diffusion (cm2/s) t(s): time of diffusion x: distance (cm) between food and packaging material (Silva et al., 2007). Although the mathematical models are under continuous development, their reliability is appreciable for measuring contamination from packaging chemicals. A complete understanding of the factors influencing the migration is well suited to improving quality control by determining the variables with the greatest impact. Such improved evaluation of chemical migration from package to food would help limit and control food contamination and improve food safety. 1.4. Types of migration1.4.1. Migration according to number of migrants There are two terms used for migration that should be not confused, overall migration and specific migration. Overall migration refers to the sum of the mass transfer of all releasing substances from a unit area of packaging material, and specific migration refers to the migration of a particular chemical species (Robertson, 2006). Both types of migration are considered important based on analytical objectives. 1.4.2. Migration related to foods nature Migration can be divided into three categories related to food systems–nonmigrating, volatile, and leaching system. In a nonmigrating system, very little mass transfer of pigments or some inorganic substances occurs as compared to the high molecular weight of packaging polymers. On the other hand, in a volatile migrating system, minor volatile aromatic compounds transfer to the package even without direct contact between the food and the packaging material, though contact could improve such migration. This type of migration is considered in dried products where less direct contact occurs between food and packaging material. Under such conditions the volatile substances migrate in three stages: diffusion or evaporation of migrant, desorption from a product, and adsorption onto the product. However, for a leaching type of migration system, the food must contact the packaging for the migrant transfer to occur. In this system, the mass transfer of a migrant is initiated with its diffusion from the package material, is followed by dissolution, and ends with dispersion into the food product. A common example of this system is the mass transfer of substance to fluid or semisolid foods from daily-use plastic packaging materials upon direct mutual contact (Lee et al., 2008). 1.4.3. Migration based on coefficient of diffusion The process of diffusion is the key determinant of the rate of diffusion, but diffusion estimation becomes challenging when the package is in contact with the food, which may alter the diffusion rate in the packaging material. This migration could be categorized into three clearly distinguishable categories. In the first category, the diffusion coefficient approaches zero, and thus there is a minimal migration potential. In the second category, the diffusion coefficient possesses a constant value and experiences no impact from the food component or storage time. However, in the last category, the diffusion of a substance remains insignificant unless the food is in direct contact with the packaging material (Aurela, 2001). 1.4.4. Contact migration In this category, as the name suggests, the migration of a substance happened from the packaging to the food only upon contact. For example, the transfer of additives from the cardboard pizza box to the pizza or transfer of monomers and plasticizers from a plastic tray, pouch, or wrapping to the foods (Karen et al., 2006). 1.4.5. Gas-phase migration In this type of migration, the substance permeates from the outer coating or printed layer of the package to the inner layer of the packaging material. The mass transfer of a particular substance happens through the medium of gas (Karen et al., 2006). 1.4.6. Penetration migration In penetration migration, a substance from the outer coated or printed layer of the packaging material migrates toward the inner layer or contacting side of the packaging material through the packaging material itself. The substance upon reaching to inner side of the package could migrate to the contained food either by contact or by gas-phase migration (Karen et al., 2006). 1.4.7. Set-off migration This type of migration is related to the mass transfer of inks, varnishes, and coatings from the outer printed side to the inner side of the packaging films by stacking (e.g., of printed cartons) or during reeling (e.g., winding printed wrappers into a reel). The set-off migration could be either visible or invisible depending on the specific substance. Substances clinging to the inner side by set-off migration could easily transfer either by gas-phase migration or by direct contact and could contaminate the packaged or wrapped food (Karen et al., 2006). 1.4.8. Condensation/distillation migration Although heat treatment of foods is used to improve their shelf stability, the transfer of substances may happen during processes of boiling or sterilization of pouched food or food in trays or cartons. Typically, the volatile components from the packaging or from distillation of moisture from steam released from aqueous foods migrates from package to food and vice versa (Karen et al., 2006). 1.5. Factors influencing migration phenomenon Given the complexity of migration phenomena, several factors could affect the process. The extent and the rate of migration is variously influenced. The primary factors include the following: 1.5.1. Nature of foods The nature and composition of the food are critical factors in migration evaluation. For example, foods with surplus fats reportedly display high levels of migration (Triantafyllou et al., 2007). Various food simulants have already been used to study the influence of food nature on migration. Many studies have been conducted to investigate the mass transfer of substances between packaging and food by applying solubility parameters that helped test the extent of migration during food production in real time. In this regard, different food simulants are recommended by different authorities in Europe and the U.S. (Table 2). Table 2. Listing of common food simulants used for migration testing (Franz, 2000, Rossi, 2000). Solvents used for migration testing Simulant category Distilled H2O Simulant A Aqueous acetic acid (3% w/v) Simulant B Aqueous ethanol (15% v/v) Simulant C Sunflower oil or rectified olive oil Simulant D 1.5.2. Type of contact Numerous studies have indicated that migration levels are associated with the type of contact (direct or indirect) between the food and the packaging. Specifically, direct contact between food and the packaging enhances the mass-transfer rate, and with indirect contact, the gas medium between the food and the packaging results in relatively slower migration (Anderson and Castle, 2003). 1.5.3. Duration of contact Mass transfer of specific substances of concern is largely dependent on the duration of contact of food with the package. Experimental data has shown that the mass transfer of a substance is proportional to the square root of the duration of contact between the food and packaging material (Arvanitoyannis and Bosnea, 2004). Other experimental evidence has shown that the log of the duration of equilibrium of a migrating substance is inversely correlated with temperature (Poças et al., 2011). 1.5.4. Temperature of contact The rate and extent of migration are directly influenced by the temperature of food at storage. At higher temperatures, migration rates increase as the equilibrium is rapidly established between the packaging headspace and the food (Triantafyllou et al., 2005). 1.5.5. Nature of packaging material The packaging material has a significant impact on the migration of a substance. Typically, the thickness and the plasticization of the packaging material affect the migration of specific additives. Thicker packaging slows migration, whereas thinner packaging allows greater migration (Nerin et al., 2007). However, the presence of recycled additives and ingredients did not present any discernible correlation with migration rates (Poças et al., 2011). 1.5.6. Migrant characteristics The nature of a migrating substance (or potential migrant) have significant impact on the migration extent and rate. Mass transfer of a highly volatile substance happens at a greater pace. However, substances with relatively higher molecular weights exhibit lower migration rates (Johns et al., 2000). The microstructure of the migrating substance also impacts its migration level. More specifically, the configuration of the migrating molecules (e.g., spherical vs branched and with or without side chains) affects migration differently; for instance, branched molecules exhibit lower migration rates (Maloba et al., 1996, Triantafyllou et al., 2005). 1.5.7. Migrant concentration in packaging Obviously, mass transfer of a migrating species occurs at a higher rate from the packaging to the food based on its concentration in the packaging material. It is also evident that a higher amount of migrants is found in the food matrix after a given time of storage under experimental conditions (Mariani et al., 1999). 1.6. Types of food packaging migrating compounds 1.6.1. From printing inks The packaging, besides providing containment for the foods, also delivers information about the brand and composition and provides nutritional labelling for the foods. High-performance plastic packaging materials are very effective for shelf stability of the product until expiry. Generally, the single layer of material used in packaging the food products also has printed inks to disseminate the product description to consumers. A food stored in such packaging could increase the probability of transfer of printing dyes or inks to the food and thus may pose a quality and safety challenge. Printable ultraviolet (UV)-curable inks and varnishes are commonly used in packaging and normally comprise three components: a monomer, an initiator, and a pigment. For application, the ink is exposed to a UV source where the photoinitiator is converted into a free radical that ultimately reacts with the added monomers and starts polymerization (Castle et al., 1997, Robertson, 2006, Samonsek and Puype, 2013). During polymerization, the developed polymers bind the base polymeric packaging irreversibly and entrap the pigments resulting in a fast and good-quality printed surface. Some other printing inks are composed of pigmented resins and an organic carrier or polar solvent. This type of ink requires adequate drying if solvent removal is necessary, and print quality is highly dependent on numerous factors. In the case of UV-cured inks, the unbalanced formulation of the monomers and photoinitiators and incorrect functioning of the UV source may result in excessive residuals of monomers or photoinitiators. Thus, a potential migration of these substances into a food matrix would alter the organoleptic properties of food and compromise the safety of the food. Additionally, the interaction of the migrating species with the food would initiate taints and possibly result in loss of quality and nutritional value (Johns et al., 2000, Boon, 2008, Bradley et al., 2013). Migration of benzophenone, a frequently used odorless photoinitiator, has been reported to generate alkyl benzoates, which contribute to undesirable flavors. Studies have reported the presence of printing inks in snacks and confectionary products well above the minimal detectable limits. Similarly, plasticizers, commonly used in packaging materials and in printing inks to provide functions such as flexibility, wrinkle resistance, and adhesion, are capable of contaminating foods by migrating from the packaging films. The presence of phthalates and other compounds such as tris(2-ethylhexyl) trimellitate, sulphonamides, and N-ethyl-toluene and N-methyl-toluene has been detected in printing inks. However, the chance of mass transfer of printing ink is relatively lower than that of the plasticizers used in the fabrication of packaging materials during direct contact with foods (Rasff, 2005, Boon, 2008, Bradley et al., 2013). 1.6.2. From adhesives Adhesives are the compounds that are used to seal the packaging and they can also migrate to the foods during packaging or storage. The adhesives commonly used in the packaging industry are hot-melt, cold-seal, pressure-sensitive polyurethanes and acrylics that are water- or solvent-based or solvent-free. The selection of adhesives must be based on the type of packaging and characteristics of the food product. For example, the use of a hot-melt adhesive is inappropriate for wrapping bars of milk chocolate. Also, special requirements apply in cases where aromatic volatiles are directly incorporated in cold seals to augment the food-product perception at the time of opening (Athenstädt et al., 2012, Sella et al., 2013). From a previous survey by adhesive manufacturers, a listing of more than 360 substances was compiled to indicate potential chemical migrants from adhesives into foods (Hoppe et al., 2016). A subsequent study focused on the chemical composition and level of migration of polyurethane-based adhesives. The migrating residuals (e.g., polyether, polyols, and cyclic reaction products derived from polyester polyols) were identified at concentrations of 10–100 μgdm−2 (Sella et al., 2013, Hoppe et al., 2016). The migrants from the inks of a printed packaging surface also can easily transfer to the layer of adhesives, especially when the packaging is stacked, and thus could ultimately migrate to the food matrix during the process of packaging. However, in the case of multilayer packaging systems such as laminates, the chances of potential contact migration of migrants are increased significantly. The multilayer laminates are complex packaging materials that are manufactured by layering of different polymeric with non-polymeric materials (e.g., metals) to achieve particular packaging characteristics. The existence of diverse components along with adhesives could greatly increase the likelihood of health problems while also making the identification and detection processes more difficult and complex (Athenstädt et al., 2012, Sella et al., 2013, Hoppe et al., 2016). 1.7. Plastic packaging 1.7.1. Plasticizers Most plasticizers are the esters of phthalic (phthalates) and adipic acids. Dioctyl phthalate, di-2-ethylhexyl phthalate and di-2-ethylhexyl adipate are systematically applied during the preparation of packaging material (Rahman and Brazel, 2004). The phthalates are cast off in sealing gaskets and cap-sealing resins for bottled food, polyvinylchloride (PVC) films, and some plastic packaging. Phthalates once used as plasticizers in polymeric packaging films are characterized by low molecular weight, thus facilitating the package-to-food migration. Numerous studies have reported plasticizers as potential migrants that could transfer to foods from the packaging (Pedersen et al., 2008). 1.7.2. Thermal stabilizers Thermal stabilizers are commonly incorporated in plastic materials, including PVC and polystyrene (PS) (Lau and Wong, 2000). Generally, epoxidized seed and vegetable oils (e.g., soybean oil–esterified soybean oil) is commonly used in a wide range of food-contact plastic-polymer films as heat stabilizers, lubricants, and plasticizers (Lau and Wong, 2000) From studies of the impact of the degree of purity on toxicity, it was found that residual ethylene oxide is highly toxic (Food Standards, 2012). 1.7.3. Slip additives Fatty acid-based amides are extensively used as additives in plastic packaging manufactured from polyolefins, PS, and PVC. Slip additives, which are directly incorporated into the plastic formulations, cause the emergence of surface bloom. These compounds are used to impart specific characteristics to the products. For example, they provide lubricating properties to the packaging materials to avoid sticking or conglomeration and also to reduce static charges (Cooper and Tice, 1995, Arvanitoyannis and Bosnea, 2004). 1.7.4. Light stabilizers These chemicals are used in plastic packaging materials (polyolefins) to enhance endurance for long-term applications. Light stabilizers are used in many applications to improve long-term weathering properties of plastic polymers such as polyolefins. Polymeric hindered amines (e.g., Chimasorb 944 and Tunuvin 622) are widely used in polyolefins as light stabilizers (Poças and Hogg, 2007, Grob, 2002). These amines are detected through sophisticated analysis based on ultra-performance liquid chromatography with detectors of dual wavelengths (UV and visible). The procedure provides dependable results, offering a chance to develop functional tools that could help verify compliance with legal limits (Noguerol-Cal et al., 2010). 1.7.5. Antioxidants When polymers are exposed to UV light and air, they could be degraded significantly owing to the oxidation reactions. Antioxidants can be applied to decrease the degree of oxidation and enhance stabilization of the polymers. Tinuvin P, Tinuvin 776 DF, Tinuvin 326, Tinuvin 234, Irganox168, Irganox 1010, Irganox 1330, and Irganox P-EPQ are the commonly used chemical antioxidants in plastic packaging materials (Nestmann et al., 2005). Also, vitamins such as A, C, and E and derivatives such as tocopherols, tocotrienols, and carotenoids can be added. Similarly, some metal ions (e.g., selenium) are crucial for the activity of antioxidant enzymes, and other phytochemicals, such as CoQ10, glutathione, and lipoic acid, are also considered good in controlling the oxidation of packaging materials. Additionally, mass transfer of synthetic antioxidants, such as butylated hydroxyanisole, butylated hydroxytoluene, tertiary butylhydroquinone, and propyl gallate have been reported to transfer between food matrix and packaging materials (Papas, 2012) 1.7.6. Solvents Various solvents are used in the preparation of solutions or in dispersions of the printing inks used in plastic packaging. The solvents are mainly low-molecular-weight organic compounds such as ethers, esters, alcohols, and ketones. These solvents are mostly evaporated from printed plastic packaging but may also disperse by distillation, penetration, or direct contact (Boon, 2008). However, some residue of the base solvent may remain entrapped in the packaging materials and later get transferred to the food upon direct contact or after release into the packaging headspace. The amount of solvent transferring to the food from packaging material is highly dependent on the concentration and distribution of the solvent (Robertson, 2006). Therefore, potential migration of residual solvent may pose a risk of changing the food organoleptic properties. 1.7.7. Monomers and oligomers Many monomers and oligomeric building blocks connect to produce polymers by various chemical reactions. Styrene is among monomers that are widely applied to produce PS, which is used in packaging that is in direct contact with foods. PS is used mostly as containment for a range of dairy products (ice cream, cottage cheese, yogurt), fruit juice and other drinks, poultry and other meat, bakery products, and fresh produce (Tawfik and Huyghebaert, 1998). Leibman (1975) reported that a styrene monomer may degrade into its respective oxide, which is characterized as a severe mutagenic and if metabolized in body can produce hippuric acid that could be excreted from the body in urine. Styrene exposure could result in organ toxicity and irritation of the skin, eyes, and lungs with simultaneous suppression of the activity of the central nervous system. Also, Tang et al. (2000) reported that the average identified level of styrene monomers in food packaging is 100–3000 ppm. 1.7.8. Isocyanates Isocyanates are commonly used to produce polyurethanes and are used in some adhesives for the preparation of food packaging. Also, aromatic amines, especially primary amines, are a subcategory of this class of compounds, and Miltz et al. (1997) reported their migration into foods from materials such as rubber, epoxy polymers, aromatic polyurethanes, and azo dyes. The toxic effects of isocyanates on human health have been extensively reviewed in other studies (Lau and Wong, 2000). The maximum level of isocyanates residues must be < 1.0 mg kg−1 in the final packaging material. However, only 12 isocyanates are approved for use in food packaging. 1.7.9. Vinyl chloride Under normal temperature and pressure conditions, vinyl chloride is a colorless gas. It is compressed into liquid under high pressure and has been used in the preparation of polyvinyl chloride-based packaging materials (Robertson, 2006). Vinyl chloride can leach from PVC bottles and food packaging and may modify the food organoleptic properties and also may result in toxicity. Because it is highly toxic, maximum allowed levels in food packaging have been in place since the 1970s (Castle et al., 1996). The Agency for Toxic Substances and Disease Registry (2006), a U.S. government agency, reported that records show the daily dietary exposure to vinyl chloride was <0.0004 μg kg−1 in the United States and United Kingdom in the 1970s and early 1980s. Many organizations, including the U.S. Food and Drug Administration, have established limitations regarding the maximum vinyl chloride content in food-packaging films and bottles. 1.7.10. Acrylonitrile The monomer acrylonitrile (AC) is used extensively as starting material in the production of plastics, resins, elastomers, and synthetic rubbers (National Industrial Chemical Notification and Assessment Scheme, 2000). It is also found in diverse polymeric materials used in manufacturing food packaging. For example, terpolymer consists of three or more AC monomers in combination with styrene and butadiene. AC/butadiene/styrene resins can be used as food-contact materials. The relative amounts of the resins used in the polymers may vary depending on different specific characteristics necessary for different products. However, AC monomer is toxic; Lickly et al. (1991) examined and evaluated the association of its residues in polymers by using various food simulants. 1.7.11. Polyethylene terephthalate oligomer Polyethylene terephthalate (PET) oligomers are used mainly in manufacturing of trays and bottles for packaging of various types of food (including fresh produce) and drink (including mineral water, juice, beer, carbonated beverages, and milk). It is a thermoplastic polyester produced by a condensation reaction (esterification) of ethylene glycol in the presence of terephthalic acid or its derivative as dimethyl terephthalate (Kim and Lee, 2012). PET is easy to mold for producing trays and dishes of various desired shapes, and due to its temperature resistance (∼220 °C), these containers can be used in heating or reheating of food. However, PET reportedly contains small amounts of low-molecular-weight oligomers (some dimers to pentamers). Additionally, the main volatile substance found in PET is acetaldehyde, which is of high significance owing to its effects on food odors, especially in cola-type beverages. Lau and Wong, 2000) detected these cyclic chemical substances in various beverages at levels of 0.06% and 1.0% depending on the type of PET (Nerín et al., 2013, Silano et al., 2008). 1.8. Metal packaging 1.8.1. Tin Tin-based cans are used in containing foods and various carbonated and noncarbonated drinks. Tin traces transfer into the foods contained in tin cans with or without any lacquering. Foods with higher concentrations of tin (e.g., ∼500 mg kg−1) reportedly can cause severe gastrointestinal ailments (Omori et al., 1973, Benoy et al., 1997). According to clinical trials, Boogaard et al. (2003) found that the threshold for an acute effect from tin starts after consuming a dose >730 mg kg−1. A thin layer of tin can help protect corrosion of metal cans. Although usually no lacquering is done for tin, especially when oxygen scavenging is desired, a lacquer coating is otherwise preferable because an uncoated can may lead to various interactions between the tin and the food matrix (Oldring, 2007). 1.8.2. Lead Despite its toxicity and although it is known to be a common contaminant in foods, lead is commonly used in metal food and beverage containers. Lead toxicity could damage the central nervous system and has negative impacts on various body organs in humans. Infants are especially prone to lead toxicity because of the greater retention of lead in their brains and bones. Even a subacute consumption of lead could result in mental retardation, convulsions, and encephalopathy in children (Skrzydlewska et al., 2003, Robertson, 2006). 1.8.3. Aluminum Al is used in preparation of laminate or multilayer food packaging or directly design cups and trays. It is used mostly in alloy form with other metals (such as Cu, Zn, Si, Mn, Mg, and Fe) to design food packaging. Small concentrations of Al are found in various plants and animals (Taylor, 1964). Unlike so many other vital elements that take part in the metabolism of animals, Al is not essential for the functionality of enzymes or any other metabolic process. High intake and increasing levels of Al in tissues have been associated with many disorders (such as dialysis encephalopathy, osteodystrophy, and microcytic anemia). Other than the recommended-maximum-dose Al intake from food and beverages, Al also migrates from cooking utensils and from storage or packaging. Because pure Al cannot be used to produce packaging materials, alloys of Al with Fe, Ag, Cu, Mn, and Zn are used instead. Therefore, elements other than Al could be present in foods upon corrosion of the cans used to contain the food (Rodushkin and Magnusson, 2005, Robertson, 2006). 1.8.4. Chromium Electrolytic Cr coating is widely used as a thin layer in tin-based cans to make them more stable against oxidative damage and to strengthen enamel adherence. Cr is characterized by relatively high toxicity and undesirable sensory properties. Also, in its hexavalent form (Cr(VI)), it could have a severe impact on living organisms owing to its having both carcinogenic and mutagenic properties (Skrzydlewska et al., 2003, Kim et al., 2008). 1.9. Paper packaging 1.9.1. Dioxins These form a class comprising a large number of synthetic polychlorinated compounds that include but are not limited to polychlorinated dibenzofurans and dibenzo-dioxins. Dioxins are used in paper-based packaging for food applications. Dioxins are reported as highly toxic and mutagenic organic compounds. The isomer called 2,3,7,8-tetrachlorodibenzo-para-dioxin is the most toxic among all the dioxins (Ackermann et al., 2006). 1.9.2. Benzophenone This organic compound is used in inks and lacquers as a photoinitiator and also is used as a wetting agent for dyes and pigments to improve their flowability. In general, 5%–10% of this compound is used once considered as photoinitiator in inks (Anderson and Castle, 2003). UV light is used to cure the printing inks for cardboard packaging thus online production process of finished packaging is relatively faster. However, because the benzophenones used in these inks may not get totally removed during this process, benzophenone could migrate to the inner sides of the cardboard components during stacking before forming the cardboard cartons or boxes. Also, the use of fiber recycled from cardboard may increase the probability of the presence and migration of benzophenones. The specific compound 4-methoxybenzophenone is also used but reportedly is carcinogenic and mutagenic (Muncke, 2009). 1.9.3. Nitrosamines Nitrosamines are commonly found in foods and beverages (Robertson, 2006). These amines are considered potential carcinogens and genotoxic. Nitrosamines are formed endogenously in the human body by reaction of amines with salivary nitrates or nitrites (Tricker and Preussmann, 1991). Nitrosamines could also come from waxed cardboard and paper. These materials contain morpholine and N-nitrosomorpholine, which contaminate food after migration from a surface upon contact during storage and the processes involved in packaging. 1.9.4. Chlorophenols and chloroanisoles Chlorophenols are organochlorides that have been industrially used for the production of biocides, fungicides, and herbicide intermediates (Kirwan et al., 2011). These compounds commonly transfer into food from packaging materials. Contamination of foods with these organochemicals results in the production of off-flavors and taints (Jelén, 2006). 1.10. Glass containment Chemical glass is resistant to water or water-based solutions and organic substances. Acidic solvents have very limited impact on the silica component, although other ingredients of glass could be attacked by these solvents. Autoclaving of glass within various solvents resulting in the leaching of traces of alkali and silica has been thoroughly investigated. However, this has almost no impact on the organoleptic properties of the foods. Similarly, minimum contamination of foods is reported for cadmium and lead, as these metallic components are rarely present in glass containers designed for food packaging. Although the rate of glass recycling has greatly increased, the amount of chemical migration in glass containment is still very low (Shaw, 2013). 1.11. Additive derivatives and monomers Other than the multiple above-mentioned types of possible food contamination, various derivatives of additives and monomers also could transfer to foods. In particular, direct contact between food and packaging material could result in migration of chemical substances and potentially contaminate the product. The environment also could contaminate the food if water and air quality are not properly monitored and thoroughly cleaned (Lau and Wong 2000). 1.12. Benzene and other volatiles For diverse food-contact plastics, organic components such as benzene or alkyl-benzene are typically produced at higher temperatures. For example, benzene is known to migrate into food from PET-, PVC-, and PS-based food packaging. Owing to its low molecular weight, it can easily diffuse through the package and contaminate foods. Therefore, the detection of benzene levels in plastic-based food packaging is necessary given its potential carcinogenicity (Anderson and Castle, 2003, Arvanitoyannis and Bosnea, 2004). 1.13. Environmental contaminants The surrounding environment could be a major source of food contamination if it is not hygienic. Numerous environmental contaminants, such as dust, microbes, insects, and naphthalene, can be transferred into foods and result in contamination. This may occur through damaged or absorbent packaging material with subsequent migration to the foods (Raloff, 2000). For example, concentration of naphthalene could rise significantly in the environment where naphthalene-based insect repellants are in use. Similarly, milk or milk-based drinks packaged in low-density polyethylene containers have shown increased concentration of naphthalene once stored in high-naphthalene environments. Also, during processing and supply cycles, the risks of packaging and hence food contamination may increase. Similarly, hydrogen peroxide, a widely applied sanitizer used in sterilizing polypropylene and polyethylene aseptic food packaging, could be a contaminant (Lau and Wong, 2000). 1.14. Other contaminants Besides the already-mentioned contaminants, there are various possible components that could migrate and contaminate foods. For instance, PVC-based food packaging contains the contaminant dioxin. Similarly, benzene, diphenyl thiourea (a heat-stabilizing agent) (Griffith, 1989), processing-aids additives (Satyanarayana and Das 1990), and diverse volatiles may migrate into packaged foods. Contamination of foods by diphenyl thiourea and its derivatives (e.g., aniline, diphenylurea, isothiocyanatobenzene) reportedly has been found in packaging materials (Lawson et al., 1996, Careri et al., 2002, Arvanitoyannis and Bosnea, 2004). 1.15. Conclusion and future outlook For a specific food product, a careful choice of packaging material should be made by considering the end-product components and all their possible interactions as well as the resultant impact on food quality and safety. For any food-packaging selection, the benchmark is compliance with valid legislation and regulations, which may demand measurement of global and specific migration to assess the safety of the packaging material. The potential for taints migration should be estimated by considering the following: 1.Is the packaging material optimized to reduce the chances of potential migration of available components? 2.The probability of migration of any potentially migrating component into the packaged food depends on the food composition, which determines the affinity of migrants toward the model food. For instance, the majority of migrating constituents that result in taints production includes hydrophobic elements, which pose serious challenges in packaging for high-fat foods. 3.The impact of the migrating compounds on the organoleptic properties of foods is affected by the flavor intensity of the foods. 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Free Curcumin Goes to the Brain and Beyond in a New Study
Highly bioavailable BCM-95® curcumin extract addresses Alzheimer’s disease beyond the brain. Kerala, India — A new study reveals Arjuna Natural Pvt, Ltd.’s CURCUGREEN® (BCM-95®) turmeric extract could potentially help lessen damage from Alzheimer’s disease on organs other than the brain. With the global population of seniors poised to double by 2050, concern about Alzheimer’s is something of high importance to a third of the world’s population, making its prevention and relief from its symptoms critical issues. Alzheimer’s disease is the cause of around two-thirds of dementia cases, worldwide. It is marked by progressive deficit in memory and cognitive ability, leading to deterioration of mood, motivation, language, immunity, and behavior. The majority of the focus on Alzheimer’s disease is on what it does to the brain. But the progress of the disease is not confined to the central nervous system. Alzheimer’s disease also involves damage to the peripheral organs, including the spleen, liver, lungs, kidneys, and brain stem. These co-pathologies are what make Alzheimer’s ultimately fatal. The new study, published in the June, 2021 issue of the science journal Antioxidants, built on ample previous studies demonstrating the powerful antioxidant, anti-inflammatory, and anti-amyloid properties of curcumin, the most concentrated source being from the turmeric rhizome (Curcuma longa). The study was conducted on male and female transgenic mice by Jayeeta Manna, PhD, Gary Dunbar, PhD, and Panchanan Maiti, PhD, at the Field Neurosciences Institute, Central Michigan University, US, and investigated how the highly bioavailable curcuminoid formulation, CURCUGREEN (BCM-95), can help prevent abnormalities in peripheral organs of sufferers of Alzheimer’s disease. In the study, the subject mice orally received the equivalent of 100 mg/kg of CURCUGREEN (BCM-95) for two months. Cellular changes in the spleen, liver, kidney, and lungs were investigated for cell death, amyloid deposition, pTau levels (nerve fiber markers of Alzheimer’s), pro-inflammatory and anti-inflammatory markers, and overall cell death/survival markers. Results showed that CURCUGREEN (BCM-95) reduced enlargement and degeneration of the spleen, inflammation in the kidney, lung damage, and damage to the liver, including enlargement of liver cells and inflammation of the central hepatic vein. The results also showed a reduction in cell death in all these areas. In the brain, CURCUGREEN (BCM-95) also decreased amyloid deposition, pTau, cell loss, and reductions in inflammatory markers. “We are encouraged by this suggestion that curcumin could help protect against secondary organ stress and cellular damage, and help against overall damage wrought by this undiscriminating disease,” says Benny Antony, PhD, Joint Managing Director for Arjuna and inventor of CURCUGREEN (BCM-95). One of the primary advantages of CURCUGREEN’s (BCM-95) curcuminoid compounds is the unusually high bioavailability. Curcuminoid compounds typically have poor solubility in most body fluids, limiting their bioavailability. However, free curcumin levels achieved with the bioavailable formulation of curcuminoids and essential oil of turmeric in CURCUGREEN (BCM-95) proved to be about 200 to 300 times more prevalent in the blood, brain, liver and kidney than levels reported for natural curcumin in other studies, demonstrating unprecedented bioavailability. “Cognitive health is emerging as one of the more serious health issues facing an aging population,” adds Antony. “But in the case of Alzheimer’s disease, the co-morbid damage to the rest of the body’s critical structures raises the stakes of prevention and mitigation quite literally to life or death status. At Arjuna, we believe that maintaining physical brain and body health naturally through safe and effective plant-based ingredients is a game-changer. Our highly bioavailable turmeric extract can be an important weapon in the campaign against this devastating, yet widely prevalent, disease.” About Arjuna Natural Pvt, Ltd.For more than a quarter of a century Arjuna Natural (Arjuna Natural Pvt., Ltd.) has been India’s leading manufacturer of standardized spice and botanical extracts for food supplement industries dedicated to ecofriendly and sustainable practices. Established in 1992, the company has grown rapidly, with customers in 64 countries and has an advanced research facility that works in collaboration with international universities on phytochemistry, pharmacokinetics, formulation, development, pre-clinical and toxicity studies. Arjuna Natural’s facilities comply with the highest world standards, are GMP-certified, and have ISO, NSF, Halal and Star-K kosher.
Amcor announces breakthrough healthcare lidding technology for combination products
• Developed in collaboration with leading healthcare company• Ideal for combination healthcare products, such as devices with an Active Pharmaceutical Ingredient• Technology leverages Amcor’s best-in-class innovation and R&D capabilities Amcor contact lens liddingZurich, Switzerland: Amcor, a global leader in developing and producing a diverse offering of responsible packaging solutions, today announced the launch of a proprietary healthcare lidding technology that will be utilized for combination products – those consisting of two or more regulated components (device, drug or biologic). This latest innovation from Amcor is based on a patented inert film development and laminate design. It provides a lidding solution that can withstand heat sterilization, the process of preserving and sterilizing items, while preventing drug uptake into the packaging. The packaging solution is ideal for combination healthcare products, such as devices with an Active Pharmaceutical Ingredient (API) that forms the basis of a medicine. It ensures machinability, integrity after sterilization, as well as a convenient peel opening for patients. The features of the new product complement Amcor’s existing healthcare portfolio, which range from lidding for demanding sterilization environments to high barrier overwraps protecting eye droppers and medications for the eye. Amcor collaborated with Johnson & Johnson Vision over the course of several years to develop the lidding technology for use with contact lenses. Each company contributed specific skills and perspective, notably Amcor’s expertise with film extrusion, lamination and conversion for healthcare, and J&J Vision’s expertise on ophthalmic device packaging requirements. Peter Konieczny, Amcor’s Chief Commercial Officer said: “We are bringing together industry-leading innovation and close customer relationships to develop the packaging solutions of the future. With this next-generation healthcare lidding technology we are opening a world of possibilities for products using active pharma ingredients. We look forward to extending this differentiated lidding technology to additional combination products in the future.” To find out more about Amcor’s innovative healthcare packaging solutions go to www.amcor.com/healthcare. About AmcorAmcor is a global leader in developing and producing responsible packaging for food, beverage, pharmaceutical, medical, home- and personal-care, and other products. Amcor works with leading companies around the world to protect their products and the people who rely on them, differentiate brands, and improve supply chains through a range of flexible and rigid packaging, specialty cartons, closures, and services. The company is focused on making packaging that is increasingly light-weighted, recyclable and reusable, and made using an increasing amount of recycled content. Around 47,000 Amcor people generate US$12.5 billion in sales from operations that span about 230 locations in 40-plus countries. NYSE: AMCR; ASX: AMC www.amcor.com
Spouted Pouches: TOMRA and Gualapack join forces for a ground-breaking, full-scale recycling trial
TOMRA and Gualapack work together to prove the recyclability of Gualapack’s first-of-a-kind monomaterial PP spouted pouch through all stages of treatment of a DKR rigid PP waste stream. In a context of full-scale sorting and recycling infrastructure, Gualapack’s first-ever monomaterial polypropylene spouted pouch was proven recyclable. The results of extensive testing, carried out on several sites during the course of 2020, demonstrate that sustainability through innovation is possible. Industry leaders TOMRA and Gualapack, both members of CEFLEX (the European platform for the Circular Economy of Flexible Packaging), joined forces to test how one of Gualapack’s innovative products, which combines monomaterial laminates and semi-rigid multi-layer components, could be automatically and effectively managed for recycling in the rigid PP (polypropylene) stream. Gualapack is the world leader in pre-made spouted pouches and a global player in the flexible packaging industry, manufacturing laminates, caps and pouches for baby food, snacks, pharmaceutical products and a wide range of other applications. The company is fully committed to sustainability, which in the past few years has been its greatest driver for growth and innovation. Michelle Marrone, Gualapack Sustainability Manager recalls, “It was 2018 when I first met Jürgen and TOMRA. At Gualapack, we were busy tackling the challenge of designing a monomaterial spouted pouch that had to resist hot-filling, pasteurization, and maintain its barrier properties 12 months on the shelf. But at the same time, I knew that to be monomaterial by design was not enough! It was equally important to prove our circularity by demonstrating that our pouch could be correctly identified as PP, sorted, processed and extruded on an industrial line.” As a passionate and trusted innovation leader with 50 years of experience in circular waste management, TOMRA provides technology-led solutions and contributes proven expertise, established processes and market knowledge, which enable Circular Economy solutions through advanced collection and sorting systems. “After development of the new pouches, and to determine whether these could be sorted with optical sorters, we added a significant amount of them to a combined separate source and mixed waste stream sorting plant for automated sorting, “explained Jürgen Priesters, SVP Business Development TOMRA Circular Economy. “The result was very good detection and accurate separation rate of all pouches. A subsequent washing and recycling trial showed that the Gualapack mono-material pouches could be easily recycled into standard products.” As a first step, different percentages of Gualapack pouches were added to rigid PP waste, which was then processed through TOMRA’s AUTOSORT®, a sensor-based sorting machine that confirmed pouches are well identified as a PP material, with over 80% redirected to the rigid PP stream. Then, a waste PP bale with 5% additional pouches and a bale without any pouches were compared, in a back-to-back trial that took them through all the steps of a standard recycling process. First shredded into flakes and hot washed with water and sodium hydroxide at 85 °C (185 °F), then post-sorted through a second AUTOSORT® FLAKE machine to further improve the quality of the material, the two bales were then extruded on an industrial scale extruder and pelletized back to PP. Results were surprisingly good, with ink and adhesives from the pouches not impacting on extrusion and affording high thermal stability without any odor or volatile issues. Furthermore, the pelletized materials were characterized by third party laboratories and declared comparable to PP copolymer grades suitable for injection molding. This key takeaway demonstrates that the Gualapack monomaterial pouches are well tolerated within a German DKR rigid PP stream and that TOMRA sorting systems, in real-life scenarios, are suitable infrastructure to correctly identify and sort monomaterial laminates, even in the presence of semi-rigid multi-layer structures. Furthermore, this is a successful example of design for recyclable packaging according to the CEFLEX D4ACE (design for a circular economy) guidelines. TOMRA TOMRA was founded on an innovation in 1972 that began with the design, manufacturing and sale of reverse vending machines (RVMs) for automated collection of used beverage containers. Today TOMRA provides technology-led solutions that enable a sustainable future with advanced collection and sorting systems that optimize resource recovery and minimize waste in the food, recycling and, mining industries. With the addition of a circular economy division in 2020, TOMRA is committed to playing a significant role in building and enabling a global circular economy framework. TOMRA has more than ~100,000 installations in over 80 markets worldwide and had total revenues of ~ 9.3 billion NOK in 2019. The Group employs ~4,500 globally and is publicly listed on the Oslo Stock Exchange (OSE: TOM). For further information about TOMRA, please see www.tomra.com Gualapack S.p.A. Gualapack is the world leader in pre-made spouted pouches and a global player in the flexible packaging industry. With Pouch5®, the first high-barrier recyclable monomaterial pouch for pasteurized baby-food, fruit purees and dairy snacks on the market, Gualapack has pioneered a trend which will be the future of flexible packaging for a Circular Economy.
Aerogels as porous structures for food applications: Smart ingredients and novel packaging materials
LaraManzoccoaKirsi S.MikkonenbcCarlos A.García-Gonzálezd aDipartimento di Scienze AgroAlimentari, Ambientali e Animali, Università di Udine, Via Sondrio 2/A, Udine, I-33100, Italy bDepartment of Food and Nutrition, P.O. Box 66 (Agnes Sjöbergin katu 2), University of Helsinki, FI-00014, Finland cHelsinki Institute of Sustainability Science, Faculty of Agriculture and Forestry, University of Helsinki, FI-00014, Finland dDept. Farmacología, Farmacia y Tecnología Farmacéutica, I+D Farma Group (GI-1645), Faculty of Pharmacy, and Health Research Institute of Santiago de Compostela (IDIS), Universidade de Santiago de Compostela, Santiago de Compostela, 15782, Spain https://doi.org/10.1016/j.foostr.2021.100188 Received 19 December 2020, Revised 17 February 2021, Accepted 19 February 2021, Available online 23 February 2021. 2213-3291/© 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Abstract Aerogels are nanostructured materials with low density, high surface area (>150 m2/g) and open porosity (typically 95–99.99 %). They are obtained by solvent removal from gels while preserving network structure. Hydrogels, organogels and even tissues can be optimal sources of aerogels with limitless customization of format and texture. Aerogels might be used for a range of advanced food applications: from smart ingredients controlling nutrient release to delivery systems for active compounds; from fat substitutes to novel biodegradable and intelligent food packaging materials. This review article summarizes recent developments of aerogels in food applications, analyzing research challenges and prospecting future markets. 1. Introduction The advent of nanostructured materials for food applications is rather recent and mainly focused on nanoencapsulation of ingredients (protection, masking, flavoring, tuned bioavailability), packaging and nanosensors (Ghanbarzadeh, Oleyaei, & Almasi, 2015; Pathakoti, Manubolu, & Hwang, 2017). The most common approaches used for these purposes are micro- and nanoemulsions as well as liposomes but there is still a broad room for food research on other nanostructured materials. Aerogels are defined as a special type of nanostructured material endowed with special physical features and obtained from a gel by removing the pore fluid (García-González et al., 2019). Solid, low bulk density and open porosity (mainly in the mesoporous range) stand out as specific physical properties that the material should fulfill to fit in the consensual definition of aerogel. Aerogel networks are formed by bonded particles or nanometric fibers that are loosely packed leading to high porosities (typically in the 95–99.99 % range) and very high specific surface areas (150 m2/g and above) (Fig. 1). These structures result in unique thermal and sound insulation properties and high loading capacities that are being exploited in many industrial fields (aerospace, buildings, petrochemical) and are under research in the recent years for environmental and biomedical applications (www.cost-aerogels.eu), including functional food and packaging (Lehtonen et al., 2020; Plazzotta, Calligaris, & Manzocco, 2018; Plazzotta, Calligaris, & Manzocco, 2018; Plazzotta, Calligaris, & Manzocco, 2020; Selmer et al., 2019). Fig. 1. SEM images of the microstructures of (a) alginate and (b) pectin aerogels obtained by supercritical drying, (c) cellulose aerogels by freeze-drying, and (d) silica-cellulose composite aerogels by ambient drying. Adapted from https://doi.org/10.1016/j.cej.2018.09.159, https://doi.org/10.1016/j.carbpol.2018.05.026, https://doi.org/10.1021/acsami.5b05841, https://doi.org/10.1007/s10853-016-0514-3 with permissions. Aerogels are obtained by the extraction of the solvent of wet gels (hydrogels or organogels) using a method that allows the preservation of the solid network structure, typically supercritical carbon dioxide (scCO2)-assisted drying being the gold-standard (Fig. 1a,b). Fig. 2 shows a schematization of the possible strategies to turn hydrogels into aerogels. Prior to supercritical drying, a solvent exchange may be needed depending on the gel solvent, as the solubility of water in supercritical CO2 is low but the solubility of ethanol or acetone is high (Şahin, Özbakır, İnönü, Ulker, & Erkey, 2017). Other drying techniques, such as ambient/oven drying or freeze drying, can also lead to aerogel structures in very specific cases (Fig. 1c,d). For ambient/oven drying, surface functionalization (mainly with silanes) or flexible gels followed by the sequential use of solvents with low surface tension (hexane, pentane, ethanol, acetone) may be needed to avoid the shrinkage or cracking of the dry gel due to capillary forces (Budtova, 2019). For freeze drying of hydrogels, the higher volume of water in the solid than in the liquid form results in solvent expansion upon solidification with severe porous damages usually leading to the formation of foams with large macropores, microchannels, cracks and loss of mesoporosity after sublimation (Fig. 3b) (Baudron, Gurikov, Smirnova, & Whitehouse, 2019; Rodríguez-Dorado et al., 2019). Despite these limitations, certain biopolymer-based aerogels, typically nanofibrous cellulose aerogels but also chitin aerogels, may be also obtained by atmospheric drying or freeze-drying (Budtova, 2019; Gao, Lu, Xiao, & Li, 2017; Jiménez-Saelices, Seantier, Cathala, & Grohens, 2017; Li et al., 2019; Nemoto, Saito, & Isogai, 2015). Fig. 2. Flow sheet (continuous line) and addition of materials (dashed line) to obtain aerogels and functionalized aerogels. Steps at which target molecule is impregnated or oil is absorbed are also shown. Fig. 3. Aerogel engineering strategies: (a) Shape preservation; visual appearance of starch, and pectin hydrogels and their corresponding aerogels. (b) Effect of drying technique; optical appearance of a whey protein hydrogel prepared at pH 7 and the corresponding alcogels, aerogels and cryogels (above). The microstructure of the whey protein aerogels (bottom left) and cryogels (bottom right) obtained by supercritical drying and freeze-drying differed significantly in morphology and textural properties (Sa=specific surface area determined from N2 adsorption-desorption analysis). (c) Customized morphology; aerogels monoliths with personalized shape, aerogel particles from the millimetric to the micrometric sizes and coated aerogels. Adapted from https://doi.org/10.1016/j.supflu.2013.03.001, https://doi.org/10.1016/j.carbpol.2011.06.066, https://doi.org/10.1016/j.supflu.2012.08.019, https://doi.org/10.1038/s41586-020-2594-0, https://doi.org/10.1016/j.cej.2018.09.159, https://doi.org/10.1016/j.powtec.2015. A limitless customization of the format, shape, size and texture of the aerogels is possible and is mainly carried out during the gelation step using different molds and gelation conditions (gel source concentration, cross-linker concentration, etc.) (Fig. 1, Fig. 3) (García-Gonzalez, Alnaief, & Smirnova, 2011). For the specific case of aerogel particles, the use of molds is usually replaced by technological combinations of the sol-gel processing with powder technologies (e.g., emulsion-gelation, spraying, prilling, inkjet printing, jet-cutting) or by postprocessing (grinding) (Auriemma et al., 2020; Ganesan et al., 2018). The size and texture of the aerogels can be also partially modulated during the solvent exchange step (solvent choice, direct or sequential procedure) or by post-processing (aerogel compression) (García-Gonzalez et al., 2011; Plappert, Nedelec, Rennhofer, Lichtenegger, & Liebner, 2017). Finally, aerogels with dual formats like core-shell aerogel particles and coated aerogel particles are also possible by technological combinations (Antonyuk, Heinrich, Gurikov, Subrahmanyam, & Smirnova, 2015; Auriemma et al., 2020; Bugnone, Ronchetti, Manna, & Banchero., 2018; Veronovski, Knez, & Novak, 2013). Most aerogels are inorganic or synthetic polymer-based, being often made of silica, metal oxides or polystyrenes (Du, Zhou, Zhang, & Shen, 2013; Gesser & Goswami, 1989). However, according to different authors (Kistler, 1931; Pierre & Pajonk, 2002, 1932; Zhao, Malfait, Guerrero‐Alburquerque, Koebel, & Nyström, 2018), not only inorganic polymerizing agents but all biopolymers are potential candidates to form aerogels. Namely, the second generation of aerogels eases the penetration of these materials in the food market since it comprises biopolymer-based aerogels, including food-grade polysaccharides and proteins (El-Naggar, Othman, Allam, & Morsy, 2020; García-Gonzalez et al., 2011; Nita, Ghilan, Rusu, Neamtu, & Chiriac, 2020). These new aerogel sources provided new opportunities for food applications due to their compatibility with human diet, absence of adverse health effects and peculiar physical properties. Aerogels can be used as edible delivery systems for nutraceuticals, nutritional supplements, flavors and other additives or as intelligent components for food packaging. Aerogels can be designed to serve as hosts or carriers of food ingredients and can increase the stability of the loaded ingredient, mask its odor and allow for a controlled or pH-triggered release after intake (Betz, García-Gonzalez, Subrahmanyam, Smirnova, & Koluzik, 2012; Del Gaudio et al., 2013; García-González, Jin, Gerth, Alvarez-Lorenzo, & Smirnova, 2015; Tkalec, Knez, & Novak, 2016). Food-grade aerogels can also contribute to an increased shelf life of the product by the encapsulation of labile or sensitive components (De Oliveira et al., 2020; García-González et al., 2021; Miranda-Tavares, Croguennec, Carvalho, & Bouhallab, 2014). The use of natural polymers can be also considered as an economical and environmentally-friendly approach to penetrate the food packaging sector. Finally, aerogels as nanostructured materials should be assessed regarding food safety, mainly with respect to the overproduction of reactive oxygen species inducing cell oxidative stresses (Eleftheriadou, Pyrgiotakis, & Demokritou, 2017; Fu, Xia, Hwang, Ray, & Yu, 2014; Pathakoti et al., 2017). Accordingly, the changes in physicochemical and biological properties of aerogels with respect to the bulk unprocessed counterpart should be critically studied in food systems. In this review article, the current state-of-the-art of aerogel processing for food applications is compiled for the first time. This work will firstly focus on different biopolymer-based aerogel sources obtained from hydrogels, organogels and tissues as the main sources of food-grade aerogels. Then, the evaluation of these aerogels for their potential direct uses as functional ingredients by themselves, as delivery systems and as fat replacers in food products, as well as their indirect food application in packaging are discussed. Finally, current gaps and challenges in aerogel research for food are identified, and future niche markets for food-grade aerogels are prospected. 2. Bio-based materials for aerogel preparation The preparation of aerogels intended for food applications is virtually possible from any bio-based material characterized by a tridimensional polymeric network. Table 1 compares the number of papers published on aerogels during the last two decades, in relation to specific materials that might be used for their preparation. The research was performed using not only Web of Science platform but also Food Science and Technology Abstracts ones to highlight current interest of food scientists towards aerogel materials. Data clearly unveiled that biomedical and environmental applications of aerogels are two important directions of current mainstream research. By contrast, research on aerogels intended for food applications is in its early steps and their full potential is still to be assessed. Following, the main bio-based materials that can be used for preparation of aerogels for food applications are discussed. Table 1. Number of articles on bio-based aerogels indexed in the Web of Science and the Food Science and Technology Abstracts platforms. Material Building blocks Biopolymer Number of papers Web of Science Food Science and Technology Abstracts Hydrogel Carbohydrates Cellulose 1129 13 Hemicellulose -Glucomannan 28 2 -β-glucan 10 2 -Xylan 4 – -Xyloglucan 4 – Alginate 231 2 Chitin 65 – Starch 91 6 Pectin 33 – Carrageenan 23 1 Garose 24 1 Gums -Gellan gum 1 – -Xanthan gum 6 2 -Guar gum 12 – -Locust bean gum – – Hyaluronan – – Aminoacids Gelatin 52 1 Collagen 24 – Whey proteins 8 4 Caseinate 2 2 Egg white 6 4 Phenols Lignin – – Nucleotides Polynucleotides – – Organogel Carbohydrates Ethylcellulose – 1 Chitin “wiskers” – – Aminoacids Proteins – – Tissues 1 103 Search criteria: “aerogel” AND “name of biopolymer”; “aerogel” AND “tissue”. Search date: 28/11/2020. 2.1. Hydrogels 2.1.1. Polysaccharide hydrogels At present, the majority of bio-based aerogels are obtained from polysaccharide hydrogels (Table 1). To this regard, the prospects of polysaccharide hydrogels for the production of aerogels have been discussed by different authors (Baudron, Taboada, Gurikov, Smirnova, & Whitehouse, 2020; García-Gonzalez et al., 2011; Zheng, Tian, Ye, Zhou, & Zhao, 2020). Nevertheless, applications relevant to the food sector are limited and mainly relevant to the use of cellulose and starch (Table 1) (Ivanovic, Milovanovic, & Zizovic, 2016; Mikkonen, Parikka, Ghafar, & Tenkanen, 2013; Ubeyitogullari & Ciftci, 2016). Beside them, other polysaccharides traditionally used as food thickeners or dietetic fiber, have the potential of networking, begetting gels which could be turned into aerogels. This possibility has been demonstrated with reference to hemicelluloses (Comin, Temelli, & Saldaña, 2012; Mikkonen et al., 2014; Parikka et al., 2017; Ubeyitogullari & Ciftci, 2020), pectin (White, Budarin, & Clark, 2010), alginates (Alnaief, Alzaitoun, García-Gonzalez, & Smirnova, 2011; Escudero, Robitzer, Di Renzo, & Quignard, 2009; Mallepally, Bernard, Marin, Ward, & McHugh, 2013), xanthan gum (Bilanovic, Starosvetsky, & Armon, 2016) and carrageenan (Manzocco et al., 2017). 2.1.2. Protein hydrogels Gelatin and collagen are certainly the most studied proteins for aerogel preparation, being particularly suitable not only as drug carriers but also for the development of scaffolds for regenerative medicine and plastic surgery (Betz et al., 2012; Liu et al., 2019; Mehling, Smirnova, Guenther, & Neubert, 2009; Munoz-Ruiz et al., 2019; Zeynep & Erkey, 2014). By contrast, literature evidence about protein aerogels for food application is basically focus on dairy and egg white proteins (Chen, Wang, & Schiraldi, 2013; Kleemann, Selmer, Smirnova, & Kulozik, 2018; Selmer, Kleemann, Kulozik, Heinrich, & Smirnova, 2015). Proteins are also used in combination with other biopolymers to drive the internal morphology of composite aerogels. For instance, soy proteins have been demonstrated to be suitable for controlling the transition from fibrillar- to network-like architecture in composite protein-cellulose aerogels (Arboleda et al., 2013), while zein has been suggested as sacrificial porogen to obtain macropores within continuous starch aerogels (Santos-Rosales et al., 2019). 2.1.3. Hydrogels from other biopolymers Recently, it has also been demonstrated that not only biopolymers with building blocks of saccharides or aminoacids can beget gels, but also those made of polyphenolic compounds, such as lignin, which might gel upon cross-linking (Li, Ge, & Wan, 2015). In addition, polynucleotides seem to be excellent components for the construction of hydrogels with tunable mechanical properties (Gačanin, Synatschke, & Weil, 2019). This is due to the fact that the gel network is stabilized by covalent bonding and not by low energy and non-specific interactions, as occurs in polysaccharides. 2.2. Organogels Despite the high number of literature results on aerogel preparation from hydrogels, information about the possibility of obtaining aerogels from organogels is almost absent. An organogel can be defined as tridimensional networks entrapping an organic liquid (Co & Marangoni, 2012; Patel & Dewettinck, 2016; Térech & Weiss, 1997). In the food sector, this organic fluid is often represented by oil, which accounts for the use of the organogel synonym “oleogel”. Most oleogelators are low molecular weight compounds that self-assemble to form thermo-reversible organogels. The latter are likely to be unsuitable for aerogel production. However, more recently, it has been demonstrated that even large biopolymers could be used for organogelation. Examples of biopolymers able to network in oil are cellulose derivative ethylcellulose, hydrophobic chitin “whiskers” and protein emulsions/foams (Davidovich-Pinhas, Barbut, & Marangoni, 2015; Huang et al., 2015; Laredo, Barbut, & Marangoni, 2011; Nikiforidis & Scholten, 2015; Patel, 2018; Romoscanu & Mezzenga, 2006). Removal of the solvent from these oleogels could be applied to turn them into highly lipophilic aerogels, with unique oil absorption features. The feasibility of producing hydrophobic aerogels from oleogels was recently investigated, allowing scaffolds entrapping 0.6 g oil/g (Manzocco, Basso, Plazzotta, & Calligaris, 2021). 2.3. Tissues It has been inferred that even tissues could represent optimal candidates for the preparation of bioaerogel-like materials (Plazzotta et al., 2018b). For instance, vegetable matrices can be regarded as complex networks of cellulose, embedding water within intra- and inter-cellular spaces. Adequate drying of fresh-cut salad waste actually allowed obtaining aerogel-like materials with high internal surface (>100 m2/g) and low density (<0.5 g/cm3) (Plazzotta et al., 2018a, 2018b). The use of tissues for aerogel preparation could present the advantage of simplifying the production process, since the gelling phase is not required. In addition, development of aerogel from vegetable or animal wastes could allow valorization of industrial discards, which typically represent an environmental and economic burden. 3. Applications of aerogels in food Aerogels are porous materials, mainly occupied by air, which could find applications as low-calorie ingredients, able to tune nutrient release and modulate satiety. In addition, because of the large surface area and open pore structure, aerogels can accommodate several components, begetting a full range of functionalized derivatives. Fig. 2 shows a schematization of the possible strategies for aerogels functionalization. From one side, aerogels can be used to protect and deliver target molecules, potentially triggered by adverse environmental conditions or undesired tastes and odors. On the other hand, based on their capacity to entrap large amount of unsaturated lipids, aerogels could also be regarded as promising sources for the preparation of fat substitutes with health protecting capacity. 3.1. Functional ingredients Aerogel production steps (e.g. gel formation, solvent exchange, drying) are expected to modify the physical structure and the chemical interactions among the biopolymers used for their preparation. It is thus likely that diffusion, erosion, swelling and fragmentation during digestion of polymer chains within an aerogel structure would occur according to rates other than those typically associated to the unstructured polymer. Similarly, environmental conditions affecting digestion would be significantly altered. This opens up brand new possibilities for using aerogels as promising functional ingredients. In fact, in the simplest case, a functional food is requested to tune the release of nutritional compounds in the gastrointestinal tract, according to the specific consumer needs. For instance, there is a growing interest in technological strategies to increase the amount of resistant starch in the diet. Resistant starch has actually the potential of improving human health by protecting against diseases such as colon cancer, type 2 diabetes and obesity. In this context, Ubeyitogullari, Brahma, Rose, and Ciftci (2018) have demonstrated that wheat starch aerogels obtained from starch gelatinised at 120 °C provided a 4.5-fold increase in resistant starch content, even after cooking. On the other hand, highly porous aerogel particles could also be regarded as empty fillers, being inert or active depending on the occurrence of interactions with the other food components. In addition, the proportion of air inclusion in a gel matrix is known to improve the food sensory properties by enhancing taste and flavour perception. This is attributed to a higher diffusion rate of tastants when air is included, and contributes to an increased delivery and perception of saltiness, sweetness and flavor (Chiu, Hewson, Yang, Linforth, & Fisk, 2015; Goh, Leroux, Groeneschild, & Busch, 2010). In this sense, the introduction of aerogels in foods would represent an additional strategy to reduce energy and salt intake through the diet (Osterholt, Liane, Roe, & Rolls, 2007). Nevertheless, studies on the compatibility of aerogels with other food components during food processing and storage are almost negligible, and no information is available on the effect of aerogels on food sensory properties and consumer acceptability. 3.2. Delivery systems The possibility of using aerogels as novel carriers has shown great promise and is certainly the most studied application in the food sector. Basically, the loading of the target compound in the aerogel can be performed at any step of its preparation (Fig. 2). Depending on this choice, two main strategies of aerogel functionalisation can be identified: wet and post drying impregnation. Table 2 compares the efficacy of these techniques when applied to impregnate differently prepared aerogels. Table 2. Main functionalisation strategies and amount of loaded compound in aerogels of different nature and shape, and prepared according to different drying techniques. Literature references are also reported. Functionalisation strategy Aerogel nature Drying technique Aerogel shape Loaded compound Loading (g/g aerogel) Literature reference Wet impregnation in water Glucomannan FD M Sunflower oil <0.8 Lehtonen et al. (2020) β-glucan SCD M Flax oil <0.1 Comin et al. (2012) β-glucan SCD M Flax lignan <0.1 Comin, Temelli, and Saldaña (2015) in ethanol Bacterial cellulose SCD M Vitamin C 0.3 Haimer et al. (2010) Alginate SCD P Resveratrol 0.6 Dos Santos et al. (2020) Alginate SCD P Passion fruit extract 0.6 Viganó et al. (2020) in SC CO2 β-glucan SCD M Flax oil 1.4 Comin et al. (2012) Post drying impregnation without assisting solvent Starch FD M Trans-2- hexanal n.r. Abhari, Madadlou, and Dini (2017) hexane-assisted Whey protein FD M Fish oil 2.6 Ahmadi et al. (2016) SC CO2-assisted Whey protein SCD P Fish oil 0.7 Kleemann et al. (2020) and Selmer et al. (2019) Egg white protein SCD P Fish oil 0.7 Kleemann et al. (2020) and Selmer et al. (2019) Sodium caseinate SCD P Fish oil 0.2 Kleemann et al. (2020) and Selmer et al. (2019) Starch SCD M α-tocopherol 0.2 De Marco & Reverchon, 2017 Starch SCD M Vitamin K3 <0.1 De Marco and Reverchon (2017) Alginate SCD S Vitamin D3 <0.1 Pantić, Knez, and Novak (2016) and Pantić, Kotnik, Knez, and Novak (2016) Alginate SCD P Benzoic acid 0.2 García-González et al. (2015) Pectin SCD P Benzoic acid 0.1 García-González et al. (2015) Starch SCD P Benzoic acid 0.2 García-González et al. (2015) Starch SCD M Phytosterols 0.1 Ubeyitogullari and Ciftci (2019) Chitosan SCD M Lactulose <0.1 Díez-Municio et al. (2011) Chitosan SCD P Lactulose <0.1 Díez-Municio et al. (2011) Post drying oil absorption without assisting solvent Iceberg salad FD M Sunflower oil 3.2 Plazzotta et al. (2018b) Whey protein FD P Sunflower oil 2.3 Plazzotta et al. (2020) k-carrageenan SCD M Sunflower oil 4.3 Manzocco et al. (2017) Whey protein SCD P Sunflower oil 5.6 Plazzotta et al. (2020) n.r. Not reported. M: Monoliths; P: Particles; S: Spheres; FD: freeze-drying; SCD: supercritical drying. 3.2.1. Wet impregnation If target molecule incorporation is performed before drying, the process is generally referred to as wet impregnation (Fig. 2). In this case, the target compound is dissolved in one of the solvents that come into contact with the biopolymer during aerogel preparation (water or ethanol). Alternatively, the target molecule can be vehiculated by the SC-CO2 flow during supercritical drying of the alcogel following a drying impregnation approach (Comin et al., 2012). For instance, the target molecule could be simply inserted in the aqueous or ethanol solution used for hydrogel and alcogel preparation, respectively. This approach requires the molecule to exert a certain affinity to the selected solvent as well as to be resistant to environmental conditions of polymer gelation (e.g., high temperature, extreme pH and ionic force) and/or subsequent steps (solvent exchange and drying). Wet impregnation can be also performed into the alcogel. In this case, the alcogel is soaked in an ethanol solution containing the target molecule for a specific time. Following, drying is carried out using supercritical CO2, which extracts ethanol and causes precipitation of the target molecule within the aerogel pores by an antisolvent mechanism (Miguel, Martín, Gamse, & Cocero, 2006). The efficacy of aerogel wet impregnation is strongly dependent on the target molecule-solvent affinity (Table 2). In fact, aerogel impregnation with phenol compounds, which are characterized by a high solubility in ethanol, seems quite effective. By contrast, oil impregnation by mixing with the aqueous phase of the hydrogel is efficacious only if water removal is performed by freeze drying, and thus avoiding possible oil transfer to supercritical CO2 (Comin et al., 2012; Lehtonen et al., 2020). A higher oil loading can be achieved by performing alcogel drying with a mixture of supercritical CO2 and oil (Comin et al., 2012). It has been postulated that the presence of oil in the supercritical CO2 may also assist in the removal of ethanol from the gel pores, although the mechanisms is not clear (Comin et al., 2012). 3.2.2. Post-drying impregnation In the post-drying impregnation, the active substance is loaded in the dried aerogel. This can be performed by simply immersing the aerogel in the liquid target molecule (Table 2). Such procedure was used for loading aerogels with an anti-fungal volatile (trans-2-hexanal) and can only be applied when the target molecule is a liquid that does not solubilize the aerogel polymer. In most cases, the target molecule to be loaded in the aerogel is generally solubilised in an assisting solvent, which is then allowed to diffuse into the aerogel pores. The subsequent removal of the solvent from the aerogel causes solute precipitation/absorption into the matrix pores. Depending on the characteristic of the target molecule, adequate solvents are selected. For instance, Ahmadi, Madadlou, and Saboury (2016) performed post drying oil impregnation by soaking a starch aerogel in a solution of hexane-oil. Following, hexane was evaporated under hood. Nevertheless, the most efficient and common methodology for post-drying impregnation is currently based on the use of supercritical CO2 as assisting solvent (Table 2). In this case, a supercritical CO2 solution saturated with the target molecule is allowed to diffuse into the aerogel pores. Molecule impregnation would result from chemical adsorption onto the aerogel pores as well as by capillary condensation and local precipitation upon depressurization (Gurikov & Smirnova, 2018). The depressurization of supercritical CO2 is a critical step for impregnation: although fast depressurization is generally associated to higher loadings, slow depressurization allows avoiding the precipitation of the delivered compound onto the surface of the material (Selmer et al., 2019). The latter is certainly undesired when particle agglomeration should be avoided to maintain the typical free-flowing property of dried materials. Post drying loading assisted by supercritical CO2 has been applied with reference to pharmaceutical compounds (Betz et al., 2012; García-Gonzalez & Smirnova, 2013) as well as food ingredients (Table 2). The solubility of the target compounds in the solvent (i.e. supercritical CO2) is a critical factor controlling the impregnation efficacy (Table 2) (Viganó et al., 2020). Post drying impregnation of aerogels with non-polar compounds, such as oil, is generally reported to be quite effective, providing loading ratios in the range of 0.2−0.7 g oil/g aerogel (Kleemann et al., 2020; Selmer et al., 2019). By contrast, impregnation of molecules with lower polarity (vitamins or lactulose) seems more critical (Díez-Municio, Montilla, Herrero, Olano, & Ibáñez, 2011; García-González et al., 2015; Ubeyitogullari & Ciftci, 2019). Accordingly, when impregnation involves complex mixtures of molecules with different affinity for SC-CO2, such as oils, the relative abundance of their components in the entrapped oil can be significantly different from that of the original oil. For instance, fish oil entrapped in protein aerogels presented much higher content in triglycerides and cholesterol, and lower content in free fatty acids than fish oil used for loading (Selmer et al., 2019). Comparing data reported in Table 2, it is interesting to note that high loading efficacy of lipids was observed for impregnation into both protein- and polysaccharide-based aerogels. This suggests that the contribution of physical entrapment into the aerogel pores is probably the most critical factor controlling lipid impregnation. In other words, oil absorption into the pores would be driven by number, dimension, interconnectivity and size distribution of pores rather than by the chemical interaction of oil components with the functional groups available on the aerogel surface. 3.2.3. Stability and functionality of aerogel delivery systems Despite the abundance of papers dealing with impregnated aerogels, limited information is available about their capacity of modifying stability and functionality of the entrapped components. Available data suggest that aerogels would be able to protect sensitive compounds. For instance, entrapping plant extracts into cellulose aerogels was shown to highly maintain their antioxidant activity (De Oliveira et al., 2020). Aerogel coating seems to be critical to decrease oxygen susceptibility of loaded oil. To this regard, Ahmadi et al. (2016) showed that fish oil entrapped in whey protein aerogels coated with zein presented about 60 % lower peroxide value than oil impregnated without coating. The peculiar physical properties of aerogels are also expected to modify the bioavailability of loaded molecules. To this regard, in vitro bioavailability of phytosterols loaded into starch aerogels resulted significantly higher (35 %) than that of the crude phytosterols (3 %) (Ubeyitogullari, Moreau, Rose, & Ciftci, 2019). The authors also inserted these phytosterol-loaded aerogels into “real” food products, namely granola bars and puddings (Ubeyitogullari & Ciftci, 2019). Introduction of phytosterols in food in the form of aerogel-protected particles made in vitro bioavailability three times higher than when they were added as free ingredients. This effect was attributed to the lower crystallinity level of phytosterols entrapped into the aerogels. Unlike polysaccharide aerogels which easily dissolve in water, those made of proteins are generally more resistant during swelling and digestion. This is due to the fact that proteins undergo substantial denaturation during hydrogel formation. In addition, hydrogel drying further promotes contraction of the protein backbone, leading to the maximization of the interactions among proteins (Tang, Wei, & Guo, 2014). Due to this water insolubility, the release of loaded molecules is generally delayed (Betz et al., 2012). As an example, fish oil loaded in protein aerogels was mainly released during intestinal digestion, whereas only a small amount was released during oral and gastric digestion (Kleemann et al., 2020). 3.3. Fat replacers According to their open pore structure and large surface area, aerogels quickly uptake large amounts of oil. This capacity is particularly interesting for the preparation of oleogels, which are mainly proposed as fat substitutes to obtain healthier foods with reduced content of saturated/trans fatty acids (Patel & Dewettinck, 2016; Stortz, Zetzl, Barbut, Cattaruzza, & Marangoni, 2012). According to this application, the oil fraction is driven into the pores of aerogel particles by capillary forces and held at the aerogel surface by surface-oil interactions. For this reason, large amounts of oil closely stick onto the aerogel surface both inside the pores and outside the aerogel particle, which loses the typical dry appearance. The presence of oil at the surface of the hydrophilic particles favors particle-particle interactions, due to intense hydrogen bonding in a nonpolar environment (De Vries, Lopez Gomez, Jansen, van der Linden, & Scholten, 2017). This mechanism allows the formation of a strong particle network, where protein particles behave like building blocks able to embed oil within pores as well as to hold it tightly in the interparticle space (Plazzotta et al., 2020). Absorbed oil is generally higher than 2 g per g of aerogel, regardless of the chemical nature of the aerogel (Table 2). In the case of oleogels obtained from aggregation of whey protein aerogels, the oil content exceeded 5 times the weight of the aerogel particles. The obtained material did not lose any oil upon centrifugation and presented the typical plastic behavior of commercial solid fats (Plazzotta et al., 2020). 4. Applications of aerogels in food packaging Packaging materials have multiple purposes, being the most important to protect the packed product against mechanical stress, gases and vapors, moisture, light, temperature, microbes, and dirt (Robertson, 2010). Packaging materials are selected based on their capacity to provide this protection, taking into account the other functions that a packaging material may perform, including containing, transporting, serving, presenting the product, and providing information to consumers. Packaging materials can be used as primary packaging, i.e. consumer packaging, or secondary packaging which contains a defined number of primary packages. Secondary packaging units can also be gathered in a tertiary packaging for better transport and storage. The concept of packaging materials also includes a variety of components that can be inserted in the primary packaging to provide further information of the product quality and shelf-life (intelligent packaging), or to extend the shelf-life by adsorbing or releasing functional components (active packaging) (Dobrucka & Przekop, 2019). Other important criteria for packaging materials are their price and environmental impacts, including origin of raw materials, sustainability of processing, and recycling routes. Importantly, consumer experience and user friendliness determine the market potential of packaging materials. The most important and unique property of aerogels for food packaging is their porous structure, leading to low weight and high specific surface area. This provides interesting opportunities for mechanical protection, thermal insulation, or active packaging materials capable of adsorbing or releasing specific compounds. Aerogel structures also offer an inspiring basis for designers to develop and construct material shapes (Michaloudis & Dann, 2017), which is essential in packaging design. The mechanical properties of aerogels are determined by their porous morphology (Ghafar et al., 2017). Reinforcing components, such as nanoparticles or fibers can be added to increase the aerogel strength. A practical illustration of the aerogel strength is the weight an aerogel can withstand on it. For example, a chitin-based aerogel square weighing 60 mg and having ∼5.6 cm3 apparent volume withstood an object of 100 g without any shape distortion (Yan et al., 2020). Such strong materials could provide efficient protection to packed food against mechanical stress that could occur during transport or handling. Moisture can alter material properties, especially of materials derived from bio-based polymers. Repeated (minimum five cycles) mechanical milling followed by freezing in liquid nitrogen and thawing partially separated micro- and nanosized fibrils from cellulose fibers, and enabled preparation of dimensionally stable aerogels that retained their shapes and geometric sizes in solutions (Khlebnikov, Postnova, Chen, & Shchipunov, 2020). This is a highly useful property with materials in contact with moist substances, like many foods. A bio-based thermal insulator, such as aerogel, could be a sustainable replacement for expanded polystyrene used widely to pack products that need either cold storage, such as fish, or maintaining the temperature of hot contents, such as ready-made meals or hot beverages (Mikkonen et al., 2013). Pectin-TiO2 nanocomposite aerogels were proposed for the storage of temperature-sensitive food and prepared via a sol-gel process (Nešić et al., 2018). The thermal conductivity of these aerogels was 0.022–0.025 W/m K, being lower than the thermal conductivity of air (0.024−0.032 W/m K). The thermal conductivity of pectin aerogels followed the aerogel density within a U-shaped curve, where the density depended on preparation conditions, such as cross-linking degree and pH of the solvent (Groult & Budtova, 2018). Pectin aerogels with thermal conductivity as low as 0.0147 ± 0.0002 W/m K were obtained with the optimized preparation method. The conjunction of the thermal insulation and the lightweight is especially attractive for specialized food service conditions like aircraft meal services or crewed spacecraft food, where solutions with reduced fuel consumption is a must. An active aerogel component was developed to be used to extend the shelf-life of fresh fruit and vegetables (Lehtonen et al., 2020). This innovation was based on in situ production and release of a volatile compound (hexanal), which affects plant metabolism by decreasing ethylene production, and prevents growth of spoilage microbes. The concept was tested with blueberries, where less mold growth was observed, and cherry tomatoes, which maintained their firmness longer when packed with the hexanal-releasing active component in comparison with control samples. 5. Aerogels within EU food regulation The use of aerogels in foods is not mentioned in current regulation. To this regard, not only the criticisms of production but also the safety issues of the final aerogels require some considerations. Among the advantages of aerogels, literature indicate the absence of hazardous chemicals in the material preparation. Nevertheless, attention should be paid to the use of ethanol in water substitution step. The operation must be performed using ethanol without any denaturant, and considering that volatile residues could remain selectively adsorbed on the high surface area of the aerogel. This might lead to consumption limitations for specific consumers, such as children or people with religious dietary restrictions. As regards aerogel safety under EU regulation, the question is whether these novel materials can be examined under the current Novel Foods Regulation (EU Regulation 2015/2283, 2015). Based on this regulation, ‘novel food’ means any food that was not used for human consumption within the European Union before 1997, and that falls under a defined list of categories. Among the latter, specific mention is made to food with a new or intentionally modified molecular structure as well as food resulting from technological interventions not previously used. Although not yet used for human consumption, most biopolymer aerogels seem not to fall under this category since they are made with polymers with a long history of safe food use and obtained by drying technologies which have long been used in the food sector. Nevertheless, in aerogel production, unit operations are combined according to a novel process, in order to intentionally modify the physical structure. The large specific surface area and the pore sizes than come thereof is regarded as a property characteristic of the nanoscale (EU Regulation 2015/2283, 2015). In other words, even if aerogel monoliths or particles have sizes well above the order of 100 nm, their large surface area would account for specific physico-chemical properties that are different from those of the non-nanostructured form of the same polymer. In this sense, aerogels could be considered as engineered nanomaterials. The debate on aerogels within food regulation is also open to other considerations, including the fact that the surface area of commercial foods obtained by freeze drying and supercritical extraction can fall in the same magnitude range of aerogels. However, in this case, there is a conceptual difference since the large surface area of aerogels is intentionally exploited to functionalise the material and improve its performance. Research on food aerogels is still in its embryonic phase and hence has not yet risen the attention of legislators. More information is certainly needed to distinguish aerogels that can be inserted in the diet from those that will require a specific authorisation. As regards the use of aerogel as packaging materials, mention should be made to the general principles of safety and inertness for all Food Contact Materials, defined in the Commission Regulation (EC) No 1935/2004. This regulation states that the materials shall not release their constituents into food at levels harmful to human health or that change food composition, taste and odour in an unacceptable way. This should be ensured when aerogels are developed as packaging materials. Active and intelligent materials are considered under specified rules in Commission Regulation (EC) No 450/2009, as by their design they are not inert. Such materials may for example absorb substances from food packaging interior such as liquid and oxygen, release substances into the food such as preservatives, or indicate expiry of food through labelling that changes colour when maximum shelf life or storage temperature is exceeded. Substances permitted for the manufacture of active and intelligent materials are listed in the regulation. New packaging materials, including aerogel delivery systems, must go through safety evaluation as defined in the European Food Safety Authority guidelines (https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/j.efsa.2008.21r). One possible solution is to coat the aerogel packaging surface with a barrier layer. 6. Future trends and research needs An obvious concern with use of aerogels relates to their costs. Bio-based aerogels are typically obtained using highly purified molecules which are costly and produced with considerable waste generation. On the contrary, to allow valorization of industrial discards, which typically represent an environmental and economic burden, aerogels can be prepared according to virtues cycles of circular economy (Budtova et al., 2020). The production of cellulose-based aerogels has been explored using aqueous suspensions of cellulosic fractions of waste biomass, including cane bagasse, lupin hull, corn bracts, rice and oat husks, and spent coffee grounds (Ciftci et al., 2017; De Oliveira et al., 2019, 2020; Fontes-Candia, Erboz, Martinez-Abad, Lopez-Rubio, & Martinez-Sanz, 2019; Jing et al., 2019; Liu, Li, Zhang, Zhu, & Qiu, 2020; Zhang, Kwek, Li, Tan, & Duong, 2019). A further option is based on directly turning cellulose-rich vegetable waste into aerogels with the advantage of simplifying production process (Plazzotta et al., 2018b). Similarly, an increasing number of recent publications explore the possibility to upgrade low-value side streams to obtain aerogels for packaging applications from renewable resources (Alakalhunmaa et al., 2016). Thus the cost contribution of raw materials for aerogel preparation may be low but, on the other hand, a multiple step production process that requires the use of high amounts of solvents, such as supercritical CO2, is costly. Minimization of fresh solvent and continuous CO2 drying process could facilitate aerogel production and reduce costs in industrial scale compared to batch production (Mißfeldt et al., 2020). Research about aerogel structure in the context of its relationship with molecular composition, processing techniques and potential functionality in food is currently being studied at laboratory level. By contrast, the fate of aerogel ingredients within food materials is almost unknown. Aerogel particles were inserted into two food products, namely, granola bars and puddings, without any specific processing issue, and provided circumstantial evidence that aerogels can be successfully implemented in food formulations (Ubeyitogullari & Ciftci, 2019). Nevertheless, the specific physical properties of aerogels suggest the need for proper adjustments of formulation, processing and storage conditions of aerogel-containing foods. The latter should be then submitted to in vitro studies to clearly highlight their fate in human gut as well as to studies evaluating consumer attitude towards aerogels and market acceptance potentiality. When considering aerogels for food packaging, two main challenges should be addressed by the aerogel community. Firstly, transparency of bio-based aerogels should be improved. The visual appearance of packaging materials is significant for consumer experience, with transparent materials being often preferred to allow visibility of the packed food. Highly transparent aerogels from oxidized cellulose were recently developed (Plappert et al., 2017) and lead the way to broadening the properties and application range of aerogels. Secondly, after use, packaging materials can be recycled back to material production, burnt for energy, composted, or discarded to landfill. The aerogel composition and its eventual assembling into multicomponent materials will strictly condition the potential recycling options. Finally, the main issue to be tackled in aerogel technology to become a mainstream solution for food applications is a clear definition of the conditions for their safe use for human consumption and food contact. Testing aerogels with nanostructured properties is not a trivial task, especially when they are inserted in foods, and will require the availability of methods designed to clearly define nature and kinetics of their interaction with biological tissues. 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Water-Based Flexographic Printing Steps Up to the Sustainability Challenge
By Takumi Saito, Printing Solutions Project, Asahi Kasei Corporation The recent Leaders Summit on Climate, hosted by U.S. President Biden, demonstrates the growing commitment leaders of many countries have to addressing the climate crisis by reducing greenhouse gas (GHG) among other initiatives. This will likely translate into increased regulatory pressure on a variety of industries, including printing, to moderate their emissions of CO2 and other global warming gases such as CH4 and N2O. As a leading supplier to the flexographic printing industry, Asahi Photoproducts is dedicated to delivering flexographic solutions that are in harmony with the environment. In doing so, the company enables its customers to be proactive in contributing to the overall reduction of GHG emissions Over the last half century, Asahi Photoproducts has worked hard to bring innovative solutions to flexography, and most recently with the Asahi AWP™ CleanPrint water-washable plates. This solvent-free process delivers more sustainable printing while at the same time improving Overall Equipment Effectiveness (OEE) in the press room to the tune of 30% or more, which results in a significant increase in quality due to the precise register these plates deliver. What that means for the printing industry is that flexography is now competitive with gravure for all except the longest print runs. To validate this assertion, Flexo Technical Association Japan (FTAJ) and Water-based Flexographic Printing Advancement Council partnered with the Sustainable Management Promotion Organization (SuMPO), a well-known Japanese association, to calculate GHG emissions during the entire printing process for each of these two technologies, using the Life Cycle Assessment method (Fig.1). The results were enlightening. We found that when printing a job of 5,000 linear meters with water-based flexographic printing and comparing the result with the simulation of the same job with gravure printing, GHG emissions from water-based flexographic printing can be reduced by about 65% compared to gravure. We measured GHG emissions from the gravure life cycle at 668 kg, whereas emissions from water-based flexography were 231 kg. The gravure printing simulation results from using electronic engraving of the cylinders and solvent-based inks, while water-based flexographic printing uses water-washable plates and water-based inks. The results are shown in the image below, broken down into 3 steps: platemaking/engraving, ink manufacturing, and printing. Calculation result by SuMPO about GHG Emissions (kg-CO2e) at 5,000m printing.(This result is calculated by the conditions of Ref.1 and not typical value of water-based flexo printing and solvent gravure printing) The sustainability of the print can be further enhanced by using solvent-free laminating where lamination is required or desired, instead of dry lamination where the bonding agent is dissolved in solvent, applied, and then evaporated in a drying oven. With solvent-free lamination, a low viscosity adhesive is applied, requiring only a heated nip to mate it to the substrate. This creates an additional advantage of solvent-free lamination beyond the reduced GHG and VOC emissions since it does not require a drying component, further reducing energy consumption and increasing its sustainability as compared to the conventional dry lamination process. Thus, we recommend water-based flexographic printing technology combined with solvent-free lamination and water-washable flexographic printing plates as the most sustainable approach to producing packaging. All of this demonstrates the significant progress that has been made towards reduction of the carbon footprint for flexographic printing as compared to gravure, and the fact that this approach to packaging printing has the potential to change the global packaging market. But we are not stopping here. The talented and innovative engineers at Asahi Photoproducts continue to seek new ways to reduce the environmental impact of flexographic printing processes even further, and we have full confidence that they will find even more ways to make flexographic printing more sustainable. Ref.1: Calculation Assumptions by Sustainable Management Promotion Organization (SuMPO). Film substrate and packaging process are not included in this calculation since there is no difference in-between water-based flexo printing and solvent gravure printing at them. This calculation is done by 5 colors printing. Plate making processes are: water washable plate technology for flexo printing, electronic engraving technology for gravure printing. Utility data at printing machine is based on typical and theoretical data on product catalogue since actual utility can be fluctuated as per actual printing condition and environment. Printing speeds are: water-based flexo 200m/min., solvent gravure 150m/min. Disposal method of printing wastages are: water disposal at water-based flexo, incineration at solvent gravure. Plate sleeve at flexo printing and steel cylinder at gravure printing are part of printing machine and not included in this calculation. Proofing process is not included in this calculation. GHG emissions of ink manufacturing are based on published data of Japan Printing Ink Makers Association*. Transportation of intermediates and wastage are, 500km for intermediates, 100km for wastage respectively. LCI Database IDEAv2.3 is used *. For more information about flexographic solutions from Asahi Photoproducts that are in harmony with the environment, visit www.asahi-photoproducts.com.  Note 1: “CFP value of each ink type” released by Japan Printing Ink Makers Association. (http://www.ink-jpima.org/pdf/20110712-3.pdf)  Note 2: LCI database IDEA version 2.3, released by National Institute of Advanced Industrial Science and Technology, LCA study group, Sustainable Management Promotion Organization
Nestlé unveils Perrier® water bottles created by ground-breaking recycling technology
Nestlé has unveiled prototypes for its Perrier® water bottles based on a novel recycling technology. The bottles were produced as part of the Carbios global consortium to support the industrialization of an innovative technology that allows plastic to be endlessly recycled while maintaining properties that are virtually equivalent to virgin plastics. The consortium members include L'Oréal, Suntory Beverage & Food Europe and PepsiCo. Using this novel technology, experts at Nestlé's research and development center for Waters in Vittel, France produced the first Perrier® 50cl prototype bottles made from colored recycled PET materials. The prototypes were thoroughly tested in terms of safety, quality, and performance. They were also specially adapted to withstand the pressure of carbonated water, while also incorporating the iconic design and green color of the Perrier® bottle. While recycled PET bottles already exist in the marketplace, this new technology when developed at industrial scale, will help increase the amount of PET plastic that can be recycled. Jean-Francois Briois, Head of Packaging Material Science and Environmental Sustainability for Nestlé Waters global R&D says, "It is very exciting to see that the quality of the prototype bottles made from 100% colored recycled PET materials is virtually identical to clear virgin PET. Thanks to this partnership with Carbios, we are able to achieve the great challenge of combining quality, iconic design and sustainability. When we reach industrial scale, this enzymatic recycling technology will enable us to produce high-quality rPET bottles and help Nestlé in its journey to reduce the use of virgin plastics." The Carbios technology uses enzymes from naturally occurring microorganisms to break down PET plastic into its constituent parts, which can then be converted back into new, virgin-grade like plastic. The ground-breaking process is also unique because it enables the production of recycled PET from any type of PET plastic, regardless of color or complexity. This allows the recycling of more types of PET plastic that would otherwise go to waste or be incinerated, thus creating an endless, fully closed loop for plastic recycling. Nestlé's R&D expertise and infrastructure was also leveraged to create bottle preforms using the technology for other Carbios consortium members. Each member then further blew up the preforms into specific bottle shapes according to their needs. The Carbios partnership and resulting innovations are part of Nestlé's continuous efforts to lead the shift from virgin plastics to food-grade recycled plastics and to accelerate the development of innovative sustainable packaging solutions. Nestlé also recently unveiled two new packaging innovations for its Vittel® natural mineral water bottles which are made with as little recycled plastic as possible.
A juicy orange makes for a tastier juice: The neglected role of visual material perception in packaging design
Francesca Di Cicco *, Yuguang Zhao , Maarten W.A. Wijntjes , Sylvia C. Pont , Hendrik N.J. Schifferstein Delft University of Technology, Department of Human-Centered Design, Landbergstraat 15, 2628CE Delft, the Netherlands * Corresponding author.E-mail address: email@example.com (F. Di Cicco).Contents lists available at ScienceDirectFood Quality and Preferencejournal homepage: www.elsevier.com/locate/foodqualhttps://doi.org/10.1016/j.foodqual.2020.104086Received 1 July 2020; Received in revised form 16 September 2020; Accepted 16 September 2020 Available online 18 September 20200950-3293/© 2020 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Abstract Food appearance sets intentions and expectations. When designing packaged food much attention is devoted to packaging elements like color and shape, but less to the characteristics of the images used. To our awareness, no study has yet investigated how the appearance of the food shown on the package affects consumers’ preferences. Often, orange juice packages depict an orange. Juiciness being one of the most important parameters to assess oranges’ quality, we hypothesized that an orange with a juicier appearance on the package would improve the overall evaluation of the juice. Using image cues found to trigger juiciness perception of oranges depicted in 17th century paintings, we designed four orange juice packages by manipulating the highlights on the pulp (present vs. absent) and the state of the orange (unpeeled vs. peeled). In an online experiment, 400 participants, each assigned to one condition, rated expected naturalness, healthiness, quality, sweetness and tastiness of the juice, package attractiveness and willingness to buy. Finally, they rated juiciness of the orange for all four images. A one-way ANOVA showed a significant effect of the highlights on juiciness. A MANOVA showed that the presence of highlights, both in isolation and in interaction with the peeled side, also significantly increased expected quality and tastiness of the juice. The present study shows the importance of material perception and food texture appearance in the imagery of food packaging. We suggest that knowledge from vision science on image features and material perception should be integrated into the process of packaging design. Keywords Packaging design；Imagery；Material perception；Juiciness 1. Introduction Product packaging plays an influential role in guiding the in-store purchase decisions of consumers. For instance, the packaging shape and color contribute significantly in guiding consumers’ first impression of a product seen from a distance and at an angle on retail shelves (Garber, Hyatt, & Boya, 2008). The processing of visual packaging cues tends to dominate the purchase decision process (Schifferstein et al., 2013). On the basis of the packaging characteristics people see, they try to predict how the product will taste (Schifferstein et al., 2013). Hence, the design of food product packages can have a major effect on how its content is experienced during consumption. Studies have demonstrated that packaging shape (Velasco et al., 2016) and color (Garber et al., 2008) affect the expectations consumers have when they open a package and consume its content. Besides shape and color, imagery is another extrinsic cue contributing to build expectations and sensory experiences (Piqueras-Fiszman & Spence, 2015). A congruent and pleasant image on orange juice packaging has been shown to affect its taste, by improving palatability, freshness and aroma perception (Mizutani et al., 2010). In a recent review, Gil-Pérez, Rebollar and Lidón (2020) summarized the last decade of research on the effect of various elements of packaging imagery on consumers’ perception and expectations, offering a framework to use these findings to promote healthy eating behaviors. In the current paper, we are particularly interested in the role of images on orange juice packages. Orange juice is consumed worldwide, and a glass of 100% fruit juice can account for one of the five daily recommended portions of fruits and vegetables, representing a healthier alternative to carbonated beverages. Images on orange juice packages usually depict a glass of juice or an orange shown either entire or cut in half. A topic that has been largely neglected thus far is the role of the visualization of the material properties of the objects depicted in the package image. Material perception can be easily overlooked, since it is something that people evaluate effortlessly on a daily basis when, for example, they judge the ripeness of an apple or the slipperiness of a floor. Studies on material perception in food packaging have considered only the material properties of the packaging itself, showing that glossy packaging materials are associated with high fat levels (De Kerpel, Kobuszewski Volles, & Van Kerckhove, 2020) and tastiness (Ye, Morrin & Kampfer 2019). No study, to the best of our knowledge, has looked into the perceived material properties of the product presented in the packaging imagery. Studies have shown that the visual features of food can affect the perception of properties responsible for food quality, like freshness. Changes in freshness perception of fish (Murakoshi, Masuda, Utsumi, Tsubota, Wada, 2013), fruits and vegetables (Arce-Lopera, Masuda, Kimura, Wada, & Okajima, 2015) were shown to be related to the luminance distribution of the food image. Despite this critical role that food appearance plays on consumers’ perception and acceptability of products, a thorough understanding of its effect in packaging imagery is still missing. In this paper we aim to address this gap by investigating how the visual perception of juiciness of an orange shown on the package of orange juice affects the inferred properties of the product. Juiciness is a key textural property of food, mainly dependent on the amount of juice and its rate of release during chewing (Szczesniak, 2002). It is usually studied in relation with in-mouth perception using trained sensory panels (Harker, Amos, Echeverría, & Gunson, 2006), or via physical measurements to determine food quality (Guthrie et al., 2005). To understand how juiciness can be visually communicated and how it is estimated, it is necessary to know the image cues that trigger its perception. One research approach consists in unraveling the implicit knowledge of painters by using images of paintings as experimental stimuli. Paintings are considered a corpus of perceptual experiments by vision scientists (Cavanagh, 2005), since painters have been studying the key image cues exploited by the human visual system to perceive material properties for centuries. In a psychophysical study on visual perception of the juiciness of citrus fruits depicted in 17th century paintings (Di Cicco, Wijntjes, & Pont, 2020), the authors identified the ‘highlights on the pulp’ and the ‘peeled side’ of the fruits as the image features that most contributed to perceived juiciness. Therefore, the hypotheses of the present study are: H1: The presence (absence) of the features ‘highlights’ and ‘peeled side’ in the image would result in a significantly higher (lower) perception of juiciness of the orange shown in the packaging imagery. H2: The image of an orange with a juicier (less juicy) appearance on the packaging would enhance (decrease) the expected quality, naturalness, healthiness, and tastiness of the juice, and therefore the willingness to buy. 2. Method 2.1. Stimuli To systematically vary the visual perception of juiciness, we adopted the image features found to be associated with it, ‘highlights on the pulp’ and the ‘peeled side’ of the fruits (Di Cicco et al., 2020). In agreement with these findings, we designed four stimuli following a 2 × 2 design via digital manipulation of the highlights on the pulp (present vs. absent) and physical manipulation of the state of the orange (unpeeled vs. peeled). The digital manipulation and the design of the packages were done using Adobe Photoshop (CC 2017.0.1). The stimuli are shown in Fig. 1. Fig. 1. Stimulus set with zoomed-in version on the orange images and the features manipulated. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) 2.2. Participants Four groups of 100 participants were recruited online through the Amazon Mechanical Turk (AMT) platform. Each participant was randomly assigned to one of the four conditions and rated a set of attributes. Participants with a rating time below 1 s were removed, as we assumed they were just rushing through the experiment to increase their financial gain. Such participants’ sampling resulted in a total of 359 participants, circa 90 per condition. All participants were naïve to the purpose of the experiment. They agreed to the informed consent prior to the experiment. The experiment was conducted in agreement with the Declaration of Helsinki and approved by the Human Research Ethics Committee of Delft University of Technology. 2.3. Procedure The experiment was coded in Python, using the Boto3 package to communicate to Amazon Mechanical Turk. The experiment consisted of two parts. In the first part, participants were presented with one of the packages from the four conditions following a between-subject design. In this part of the experiment they were asked to rate naturalness, healthiness, quality, and the expected sweetness and tastiness of the juice, the attractiveness of the package, and the willingness to buy. The ratings were done using a slider on a continuum, ranging from 0 to 100, with the anchoring points being ‘low’ and ‘high’, respectively. In the second part of the experiment, all participants rated the perceived juiciness of the orange in the image for all four conditions following a within-subject design. Before starting the actual rating in the second part, participants did four practice trials that were meant to give them an overview of the stimuli to set an internal scale for the ratings. After the practice trials, they rated the juiciness of the orange shown in the image, using the same slider as in the first part, ranging on a continuum from 0 (low) to 100 (high). The four trials in the second part were randomized across participants. 3. Results We will first report the outcomes of the second part of the study about juiciness perception of the four stimuli, before reporting the outcomes of the first part of the study about the overall evaluation of the juice in each of the four conditions. 3.1. Effect of visual cues on juiciness perception In the second part of the experiment, all participants rated juiciness for all four conditions. To test whether the manipulation of the visual cues affected the visual perception of the juiciness of the oranges shown on the packages, we performed a two-way repeated measures ANOVA, with ‘highlights on the pulp’ and ‘peeled side’ as independent variables and perceived juiciness as dependent variable. Juiciness perception of the orange increased significantly with the presence of the highlights (F(1, 358) = 34.05, p < .001, η2partial = 0.087), whereas the peeled side caused no significant increase (F(1, 358) = 0.305, p > .05, η2partial = 0.001). The mean values and the standard errors of the four conditions are reported in Table 1. Table 1. Mean and standard errors of the juiciness ratings in the four conditions. Condition Mean Standard error Highlights – peeled side 0.65 0.014 No highlights – peeled side 0.58 0.016 Highlights – unpeeled side 0.64 0.014 No highlights – unpeeled side 0.56 0.016 The interaction effect between highlights and peeled side was also not significant (F(1, 358) = 0.5, p > .05, η2partial = 0.001). This indicates that highlights on the pulp of the orange triggered a significantly higher perception of juiciness than if they were not present, regardless of the state of the orange being peeled or not. 3.2. Effect of visual cues on product’s assessment We conducted a MANOVA to examine the effect of the presence of the visual cues ‘highlights on the pulp’ and ‘peeled side’ as independent variables, on the expected naturalness, healthiness, quality, sweetness and tastiness of the juice, attractiveness of the package, and the willingness to buy, as dependent variables. We found a main effect of the presence of the highlights on expected quality (F(1, 355) = 4.1, p < .05, η2partial = 0.011) and tastiness of the juice (F(1, 355) = 4.7, p < .05, η2partial = 0.013). The main effect of peeling the side of the orange was not significant for any of the attributes (F ranged from 2.1 to 0.1, p > .05). However, there was a significant interaction effect of the presence of the highlights with the peeling of the orange for the quality and taste of the juice (F(1, 355) = 5.1, η2partial = 0.014 for quality and F(1, 355) = 3.7, η2partial = 0.01 for tastiness, p < .05). Peeling the orange resulted in a larger effect on the quality and tastiness of the juice for oranges with highlights (M = 0.58, SE = 0.29 for quality; M = 0.73, SE = 0.26 for tastiness), than for oranges without highlights (M = 0.45, SE = 0.30 for quality; M = 0.61, SE = 0.27 for tastiness). 3.3. Mediation analysis We found that the presence of highlights on the pulp of the orange shown in the package’s imagery was related to a significant increase in juiciness perception of the orange in the image, as well as an increase in expected quality and tastiness of the juice. Therefore, we were interested to know whether consumers expected the juice to be of higher quality and taste better for images of oranges with highlights, because they perceived the orange to be juicier. Or, in other words, we wanted to test whether juiciness perception of the orange acted as a mediator on expected quality and tastiness of the juice. To test the significance of the indirect effect we performed a biased-corrected bootstrapping procedure with 10.000 samples (PROCESS, model 4, Hayes, 2013). The 95% confidence interval (CI) of the indirect effect included zero both for quality (−0.02 to 0.06) and for tastiness (−0.02 to 0.08), indicating that the indirect effect of the highlights on expected quality and tastiness of the juice through juiciness perception of the orange, was not significant. However, a linear regression with juiciness predicting quality and taste, showed that the juiciness of the orange on the package was related to the tastiness (b = 0.29, p = .000) and quality (b = 0.22, p = .002) of the juice. 4. Discussion Building on the research on material perception and on food packaging imagery, in this study we investigated the role that juiciness perception of an orange displayed on the package of orange juice plays in product evaluation. We first tested how the perceived juiciness of the orange changed when manipulating the presence of the image features found to trigger juiciness perception, i.e. the presence of highlights and the peeled side (Di Cicco et al., 2020). The visual perception of juiciness may not be an often discussed topic in the scientific perception literature, but it is well-known to professionals who convincingly render material properties, like painters, graphic designers or food photographers. For example, to make a burger look juicy in a photo, the trick is to spray it with oil to increase the amount of specularly reflected light. In agreement with this “implicit” knowledge, our results showed a significant effect of highlights on juiciness perception. The presence of highlights on the pulp of the orange reveals the three-dimensional shape of the cells (Ho, Landy, & Maloney, 2008), i.e. whether they are round and swollen with juice or flat and dry. This gives a straightforward indication of the amount of juice present, that people can adopt to estimate how juicy the orange would be. The peeled side on the contrary, had no significant effect on juiciness perception of the orange in the image. Peeling an orange on the side adds a cue for translucency perception by increasing the visibility of the light gradient. Juiciness is related to translucency, since the juice contained in the cells acts as medium that allows the light to scatter within the orange pulp. However, the present study suggests that translucency alone is not strong enough as a cue to increase juiciness perception. A peeled side can also reveal the bumpiness of the cells swollen with juice, and thus contribute to juiciness perception, but the bumpiness may be perceived to be more articulated in combination with the highlights (Ho, Landy, & Maloney, 2008). The MANOVA results indicated that the presence of highlights on the orange pulp significantly increased expected quality and tastiness of the juice. The peeled side showed no significant effect in isolation, but it showed a significant interaction effect where peeling in the presence of highlights increased the expected quality and taste of the juice. The MANOVA also showed that the image manipulations did not affect the other attributes. Naturalness and healthiness were likely not influenced because an image of an orange was shown in all four testing conditions, and showing the ingredient in its unprocessed form is often associated with the perception of a natural and healthy product (Machiels & Karnal, 2016). The non-significant effect on purchase intentions was unexpected, considering the increase in expected quality and taste evaluation. Possibly, our stimulus set did not offer sufficient variations to induce a significant difference in willingness to buy, since the image of the orange was always congruent with the product category. Mediation analysis did not confirm that the presence of highlights increased expected quality and taste evaluations, because the orange in the image was perceived to be juicier. However, the regression coefficients of juiciness on taste and quality evaluations were both positive and significant, suggesting that as juiciness perception of the orange image increased, the expected quality and tastiness of the juice also tended to increase. Even though no studies so far have looked into the effect of the material properties of the food shown in packaging imagery, several researchers have investigated the role of food textural properties on consumers’ liking and acceptance. Our results on the effect of the highlights are in good agreement with studies that identified glossiness as a critical surface property for consumers’ liking and sensory evaluation of diverse food products, like chocolate (Krasnow & Migoya, 2015), fruits and vegetables (Arce-Lopera et al., 2015), and fish (Murakoshi et al., 2013). One limitation of our approach, which should be addressed in a future study, was that our stimulus set relied solely on attributes inference based on implicit cues, i.e. the image features. This could have required an enhanced cognitive effort, which not all participants may have been able or willing to make (Machiels & Karnal, 2016). It would be interesting to see if including explicit textual information could increase the effect on product quality and tastiness expectations. The main aim of the present study was to draw the attention of packaging designers and food industries to the importance of the visual appearance and material perception of food presented in the packaging imagery. It is a popular saying that “we eat we our eyes first”, as the visual experience of food appearance is usually the first way how we interact with a product, setting intentions and expectations (Schifferstein et al., 2013). As surface textural properties of food can deeply affect consumers’ perception of the product (Chen, 2007), we propose to integrate multidisciplinary insights from vision science and material perception into making better informed decisions in the process of packaging design. The first step should be finding which image cues trigger the perception of an intended material property, and then integrate these cues in the imagery shown on the package. This study, for example, demonstrated that adding highlights on the pulp of the depicted orange contributes to communicate the juiciness of the oranges squeezed to make the juice. This is necessary because only by knowing which image cues trigger the perception of the desired material property, it is possible to visually communicate the intended message to consumers effectively. 5. Conclusion In this study, we showed that material perception of the food shown on the package influences consumers’ evaluation of the packaging content. More specifically, we manipulated the image features that contribute to the visual perception of juiciness of oranges, i.e. the highlights on the pulp and the peeled side. We hypothesized that the image of a juicy orange on the package, would elicit a better overall impression of the orange juice. This hypothesis was confirmed, at least for certain attributes, as we found that juiciness perception was positively correlated with expected quality and tastiness of the juice. The presence of the highlights on the orange pulp significantly increased juiciness perception of the orange, and the interaction of highlights with the peeled side, showed a significant effect on expected quality, and tastiness of the juice. In terms of practical applications of this study, we recommend to include insights from vision science to improve design decision making for packaging design. CRediT authorship contribution statement Francesca Di Cicco: Conceptualization, Methodology, Formal analysis, Writing - original draft. Yuguang Zhao: Software, Investigation. Maarten W.A. Wijntjes: Supervision, Funding acquisition, Writing - review & editing. Sylvia C. Pont: Supervision, Funding acquisition, Writing - review & editing. Hendrik N.J. Schifferstein: Conceptualization, Formal analysis, Writing - review & editing. Acknowledgements Funding: This work was supported by the Netherlands Organization for Scientific Research (NWO) [NICAS “Recipes and Realities” project number 628.007.005 awarded to Jeroen Stumpel and Sylvia C. Pont; VIDI “Visual communication of material properties” project number 276.54.001 awarded to Maarten W.A. Wijntjes]; and by Delft University of Technology. References Arce-Lopera 等，2015 C. Arce-Lopera, T. Masuda, A. Kimura, Y. Wada, K. Okajima Model of vegetable freshness perception using luminance cues Food Quality and Preference, 40 (2015), pp. 279-286 Cavanagh, 2005 P. Cavanagh The artist as neuroscientist Nature, 434 (7031) (2005), pp. 301-307 Chen, 2007 J. Chen Surface texture of foods: Perception and characterization Critical Reviews in Food Science and Nutrition, 47 (6) (2007), pp. 583-598 De Kerpel et al., 2020 L. De Kerpel, B. Kobuszewski Volles, A. Van Kerckhove Fats are glossy but does glossiness imply fatness? The influence of packaging glossiness on food perceptions Foods, 9 (90) (2020), pp. 1-13 Di Cicco et al., 2020 Di Cicco, F., Wijntjes, M. W. A., & Pont, S. C. (2020). If painters give you lemons, squeeze the knowledge out of them. A study on the visual perception of the translucent and juicy appearance of citrus fruits in paintings. Manuscript under review. Garber et al., 2008 L.L. Garber Jr., E.M. Hyatt, Ü.Ö. Boya The mediating effects of the appearance of nondurable consumer goods and their packaging on consumer behavior H.N.J. Schifferstein, P. Hekkert (Eds.), Product experience, Elsevier, London, UK (2008), pp. 581-602 Gil-Pérez et al., 2020 I. Gil-Pérez, R. Rebollar, I. Lidón Without words: The effects of packaging imagery on consumer perception and response Current Opinion in Food Science, 33 (2020), pp. 69-77 Guthrie et al., 2005 J.A. Guthrie, K.B. Walsh, D.J. Reid, C.J. Liebenberg Assessment of internal quality attributes of mandarin fruit. 1. NIR calibration model development Australian Journal of Agricultural Research, 56 (4) (2005), p. 405, 10.1071/AR04257 Harker et al., 2006 F.R. Harker, R.L. Amos, G. Echeverría, F.A. Gunson Influence of texture on taste: insights gained during studies of hardness, juiciness, and sweetness of apple fruit Journal of Food Science, 71 (2) (2006), pp. S77-S82 Hayes, 2013 A.F. Hayes Introduction to mediation, moderation, and conditional process analysis: A regression-based approach The Guilford Press, New York (2013) Ho et al., 2008 Y.-X. Ho, M.S. Landy, L.T. Maloney Conjoint measurement of gloss and surface texture Psychological Science, 19 (2) (2008), pp. 196-204 Krasnow and Migoya, 2015 M.N. Krasnow, F. Migoya The effect of hardening surfaces on gloss, surface appearance, and consumer acceptance of chocolates Journal of Culinary Science & Technology, 13 (2) (2015), pp. 175-183 Machiels and Karnal, 2016 C.J.A. Machiels, N. Karnal See how tasty it is? Effects of symbolic cues on product evaluation and taste Food Quality and Preference, 52 (2016), pp. 195-202 Mizutani et al., 2010 N. Mizutani, M. Okamoto, Y. Yamaguchi, Y. Kusakabe, I. Dan, T. Yamanaka Package images modulate flavor perception for orange juice Food Quality and Preference, 21 (7) (2010), pp. 867-872 Murakoshi et al., 2013 T. Murakoshi, T. Masuda, K. Utsumi, K. Tsubota, Y. Wada Glossiness and perishable food quality: Visual freshness judgment of fish eyes based on luminance distribution PLoS One, 8 (3) (2013), p. e58994 Piqueras-Fiszman and Spence, 2015 B. Piqueras-Fiszman, C. Spence Sensory expectations based on product-extrinsic food cues: An interdisciplinary review of the empirical evidence and theoretical accounts Food Quality and Preference, 40 (2015), pp. 165-179 Schifferstein et al., 2013 H.N.J. Schifferstein, A. Fenko, P.M.A. Desmet, D. Labbe, N. Martin Influence of package design on the dynamics of multisensory and emotional food experience Food Quality and Preference, 27 (1) (2013), pp. 18-25 Szczesniak, 2002 A.S. Szczesniak Texture is a sensory property Food Quality and Preference, 13 (4) (2002), pp. 215-225 Velasco et al., 2016 C. Velasco, A.T. Woods, O. Petit, A.D. Cheok, C. Spence Crossmodal correspondences between taste and shape, and their implications for product packaging: A review Food Quality and Preference, 52 (2016), pp. 17-26 Ye et al., 2020 N. Ye, M. Morrin, K. Kampfer From glossy to greasy: The impact of learned associations on perceptions of food healthfulness Journal of Consumer Psychology, 30 (1) (2020), pp. 96-124
Nestlé develops two new packaging innovations for Vittel® natural mineral water bottles
JUN 08, 2021 Nestlé has developed two new packaging innovations for its Vittel® natural mineral water bottles. The novel water bottles are designed to function just like traditional plastic bottles but with much less plastic. The first innovation is the Vittel® GO system which consists of a reusable hard protective case designed to hold 50cl refills of Vittel® natural mineral water that are made with 40% less plastic than a traditional 50cl Vittel® bottle. Because the bottles are made with as little recycled plastic as possible, they are very flexible and light, which means they must be used with the reusable protective case to make it easy to drink the water. The second packaging innovation is a 100% recyclable 1-liter Vittel® Hybrid bottle that is made from two types of materials. It opens up new possibilities for the development of the next generation of water bottles. The first material is an ultra-thin plastic bottle made entirely from recycled content. It uses two times less plastic than a classic 1L bottle. The plastic layer is surrounded by a fiber-based material made from 100% recycled cardboard and old newspapers. Proprietary technologies enable the plastic and fiber-based layers to be locked together to create a functional, sturdy water bottle that can be easily used without any damage. Nestlé packaging experts are currently developing a tearing system which allows consumers to easily separate the paper and plastic components for recycling when the hybrid bottle is empty. The new packaging innovations were developed by experts at Nestlé's research and development center for Waters in Vittel, France who received special funding from Nestlé's internal R&D 'Shark-Tank' initiative. To develop the hybrid bottle, the experts worked in collaboration with Ecologic Powered by Jabil, a Californian start-up that specializes in eco-design of packaging. Both the Vittel® GO and Vittel® Hybrid water bottles will be available for consumer testing in France in July. These two innovations are part of the company's continuous efforts to introduce novel packaging materials to help Nestlé reduce its use of virgin plastics by one third by 2025. Read the full press release (in French): Nestlé Waters France
Collaborations for circular food packaging: The set-up and partner selection process
Joana Kleine Jäger, Laura Piscicelli ∗Copernicus Institute of Sustainable Development, Utrecht University, Princetonlaan 8A, Utrecht, 3584 CB, The Nether Author Info *Corresponding author.E-mail address: firstname.lastname@example.org (L. Piscicelli). Received 22 August 2020, Revised 13 December 2020, Accepted 15 December 2020, Available online 17 December 2020. Editor: Prof. Ioannis Nikolaou https://doi.org/10.1016/j.spc.2020.12.025 ©2020 The Author(s). Published by Elsevier B.V. on behalf of Institution of Chemical Engineers. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ ) Abstract More than 40% of petroleum-based plastic materials produced are converted into packaging and half of those to food packaging. Around 95% of plastic packaging, however, is lost to the economy after a short first-use cycle and is often discarded in landfills or ends up in the natural environment. The circular economy is widely promoted as a solution to the current inefficient production, use, and disposal of plastic food packaging, most frequently via recycling or reuse. While the concept of circular food packaging has lately been taken up by policy and industry initiatives in Europe, its implementation remains limited due to the high degree of cross-chain collaboration required. Nevertheless, literature on collaboration in the circular economy is still scarce and provides little guidance on how to build up effective circular partnerships. This research aims to fill this knowledge gap by answering the research question: “How do focal firms set up and choose collaborations for circular food packaging?” A qualitative Delphi method was used to develop a theoretical framework based on collaboration literature and refine it by means of semi-structured qualitative interviews with 17 food companies operating in Europe and circular packaging experts. Results show that the process of identifying and establishing collaborations for circular food packaging typically follows nine steps, spread over five phases. The study also found fourteen possible partner roles and nine partner characteristics that are important in the selection and evaluation of potential partners for circular collaborations. Keywords Circular economy；Reusable food packaging；Recyclable food packaging；Cross-chain collaboration；Collaboration set-up；Partner selection 1. Introduction More than 40% of petroleum-based plastic materials produced are converted into packaging and half of those to food packaging (Rhim et al., 2013). Around 95% of plastic packaging (worth about US$80–120 billion), though, is lost to the economy after a short first-use cycle and is often discarded in landfills or ends up in the natural environment (Ellen MacArthur Foundation [EMF], 2017; Geyer et al., 2017). Such uncaptured waste represents an increasing concern due to its persistence and the negative effects of plastic marine debris on oceans, wildlife, and humans (Jambeck et al., 2015). In addition, plastic's after-use externalities generate significant economic costs; energy intensive plastic incineration and production processes contribute to climate change; and around 6% of the global oil production is consumed by plastic production (EMF, 2017; European Commission [EC], 2018; Geyer et al., 2017). A circular economy – defined as “an economic system that is based on business models which replace the ‘end-of-life’ concept with reducing, alternatively reusing, [and] recycling […] materials in production/distribution and consumption processes” (Kirchherr et al., 2018, p.264) – is often promoted as a solution to the current inefficient production, use, and disposal of food packaging. As a regenerative system, a circular economy aims at slowing, closing, and narrowing material and energy loops (Bocken et al., 2016). Circular packaging solutions include redesigning packaging formats and delivery models, introducing reusable packaging, and improving the economics and quality of recycled plastic materials (EMF, 2017). Based on existing literature, reusable and recyclable food packaging are identified as common, feasible, and least controversial circular food packaging strategies (Schmidt Rivera et al., 2019; Pauer et al., 2019). While the concept of circular food packaging has lately been taken up by policy and industry initiatives in Europe (see EC, 2018), the reuse and recycling rates of food packaging still remain low. Contaminated, mixed materials and food-safety concerns often hamper the initial separation and sorting, as well as later recycling and reuse of primary packaging in direct contact with food (Davis and Song, 2006). Recyclable food packaging requires effective post-consumer collection, sorting, and recycling processes implemented in practice and at scale, as well as financially attractive secondary material markets (EMF 2017; American Institute for Packaging and the Environment Ameripen, 2018). Due to the fragmentation and complexity of recycling value chains, improving the alignment between stakeholders and their interests is key for the development of recyclable food packaging (Hahladakis and Iacovidou, 2018). From all (potentially) recyclable materials, plastics represent a priority area since they are currently causing challenges throughout the value chain and their entire life cycle (EC, 2018; Hahladakis and Iacovidou, 2018). Plastic packaging, currently the most commonly used packaging material, shows low recycling rates due to a range of technical, economic, environmental, social, and legal issues (Kazulytė and Kruopienė, 2018; World Economic Forum (WEF), Ellen MacArthur Foundation (EMF), McKinsey & Company 2016). For instance, while mechanical recycling changes the structure of plastic polymers potentially causing downcycling and hindering repeated recycling, chemical recycling is not (yet) economically viable. Furthermore, hazardous chemicals in packaging, legal requirements for food-grade recycling, waste separation by consumers, collection and sorting represent common challenges. Addressing these challenges do not only ask for improved recycling technologies, but also for collaboration among all stakeholders of the supply chain. For instance, to design for recyclability, manufacturers need to ensure that packaging has an after-use value, which requires local working waste management systems (Kazulytė and Kruopienė, 2018; Geueke et al., 2018; Hahladakis and Iacovidou, 2018; Hopewell et al., 2009). Similarly, major barriers towards the implementation of reusable food packaging systems lie in the reorganization of complex, global supply chains and relationships within those (Coelho et al., 2020). Reusable packaging “has been conceived and designed to accomplish within its lifecycle a certain number of trips, rotations or uses for the same purpose for which it was conceived” (International Organization for Standardization [ISO], 2016). Such a lifetime extension requires a systemic change in the way producers, retailers, and consumers operate. Within reusable food packaging, Coelho et al. (2020) distinguish between refillable packaging by bulk dispenser/parent packaging, returnable, and transit packaging. Formats of reusable food packaging are variable, including cleanable glass or stainless-steel containers (Geueke et al., 2018). Building on concerns that a truly circular economy cannot be achieved by recycling alone (cf. Haas et al., 2015), reusable food packaging contributes to a circular economy by decreasing materials or process impacts, while presenting untapped business potentials, for example by adapting to individual needs, improving the user experience, increasing brand loyalty, optimizing operations, integrating digital technologies, or cutting costs (Rigamonti et al., 2019; Ameripen, 2018; Ellen MacArthur Foundation EMF, 2019). At the same time, however, reusable food packaging is facing regulatory and security (e.g. tamperproofing) restrictions, high infrastructural and logistical requirements, and may collide with branding/marketing standards (Ameripen, 2018; Hopewell et al., 2009). To overcome implementation barriers of both recyclable and reusable food packaging, joint forces via collaborations outside of and along the value chain are needed (Clark et al., 2019; EMF, 2017). In this way, information insufficiencies, poorly coordinated and fragmented local initiatives, and the lack of communication between packaging producers/designers and waste management – which often slows down the development of innovative solutions – can be overcome (Ordoñez and Rahe, 2013). Within the collaborative process, the initial task of selecting partners and establishing collaborations is considered a major collaboration-specific challenge determining later success and potential issues (Solesvik and Westhead, 2010; Kelly et al., 2002; Brown et al., 2018). During this initial phase, however, firms may act on unfamiliar territory, lack clear reference frames, or encounter cultural differences and tensions (Kelly et al., 2002). Moreover, the collaboration choice criteria (e.g. partner type and characteristics) and set-up process have not been specifically analyzed in the circular economy context (Lahti et al., 2018; Brown et al., 2018), thus providing companies with little to no guidance for establishing effective cross-chain partnerships. This research aims to fill this knowledge gap by answering the research question: “How do focal firms set up and choose collaborations for circular food packaging?” As collaboration helps overcome obstacles towards implementing circular food packaging, food companies can benefit from such insights and resulting practical advice. Furthermore, this study extends existing research on circular food packaging by providing valuable empirical knowledge on (supply chain) management practices. Finally, this research contributes to circular economy literature, where collaborative approaches and particularly the collaboration choice and set-up process are barely covered. In the next section, existing literature on the collaboration set-up process and partner selection is reviewed to build the initial theoretical framework that will be refined by means of the empirical study. Section 3 describes the methodology adopted in this study. Results are presented and discussed in Section 4. Section 5 concludes the paper by providing an account of its key findings and managerial implications, and acknowledging the study's main limitations as well as avenues for future research. 2. Literature review The creation of collaborative networks is acknowledged in the literature as a key driver towards a circular economy (Brown et al., 2018; De Angelis et al., 2018; Dora, 2019; Farooque et al., 2019; Leising et al., 2018; Mishra et al., 2019; Ruggieri et al., 2016; Witjes and Lozano, 2016). Businesses pursuing collaborative endeavors can overcome common circular economy inhibitors such as less accessible and expensive technology, lack of clear guidance and consensus, high upfront investment, or regulatory uncertainty (Mishra et al., 2019; Brown et al., 2018). Compared to linear operations, the need for collaboration is even increased in a circular economy since, for instance, industrial symbiosis collaborative partnerships allow waste from a supply/process chain to become a resource for another one (De Angelis et al., 2018; Fraccascia et al., 2019). Collaboration is considered here as an umbrella term, broadly understood as “joint planning, joint implementation and joint evaluation between individuals or organizations” (Shirley 1981, p.6). In the context of a circular economy, collaborations encompass different forms of cooperation along (vertical) and outside (horizontal) the value chain, as well as firm-internal collaboration. To realize circular food packaging, for example, focal firms need to set up internal cross-functional teams and collaborate with external partners in terms of industrial symbiosis, pursuing common goals, and exchanging knowledge (Clark et al., 2019). For circular food packaging, collaboration allows packaging design/prototypes to reach viability, legal compliance, and consumer trust. Likewise, sharing platforms for reusable food packaging or new recycling technologies can be developed by means of cross-chain collaborations with a variety of stakeholders (Guillard et al., 2018; Meherishi et al., 2019; Brown et al., 2019). Nonetheless, not only studies on collaborative circular economy supply chain relationships are lacking (Dora, 2019), but in particular approaches enabling collaborative circular food packaging call for further research (Meherishi et al., 2019). Additionally, when reviewing literature on the collaboration choice and set-up, circular economy-specific insights are limited. Thus, traditional and sustainability collaboration literature is additionally reviewed in this section to develop a preliminary theoretical framework. 2.1. Collaboration set-up process In the course of the collaboration set-up, firms choose attractive partners in terms of “the degree to which the initiating firm in a particular alliance project sees a partner as desirable, favorable, appealing, and valuable” (Shah and Swaminathan, 2008, p. 473). This set-up process commonly represents a root of (later) collaborative obstacles and is characterized by difficulties (Kelly et al., 2002). To circumvent those, the precondition stage of the collaboration success measurement model by Czajkowski (2007) outlines a series of steps to be taken. Other collaboration literature proposes similar frameworks (e.g. Kelly et al., 2002; George and Farris, 1999; Bryson et al., 2015; Duysters et al., 1999). Moreover, Brown et al. (2019) introduce key steps of collaborative circular oriented innovation. Overall, it is possible to identify in the existing literature six main consecutive collaboration set-up steps: (1) recognition of the need and potential benefits of collaborating, e.g. a problem insoluble alone, risk spreading, additional resources/capabilities (George and Farris, 1999; Czajkowski, 2007; Bryson et al., 2015); (2) development of the vision, goal, and criteria for partner selection (Duysters et al., 1999; Czajkowski, 2007; Brown et al., 2019); (3) internal development of required skills and commitment to human resources, including a collaborative mind-set, orientation towards learning, ability to share and absorb knowledge/skills (Duysters et al., 1999; Bryson et al., 2015); (4) analysis of the external business environment and potential partners, i.e. “roadmapping” breaks down scenarios to milestones and can indicate needed competencies and necessary steps to reach those (Rohrbeck et al., 2013; George and Farris, 1999; (Duysters et al., 1999); Czajkowski, 2007); (5) partner assessment and selection (see Section 2.2); and (6) informal and formal agreements with partners (Kelly et al., 2002; Czajkowski, 2007; Duysters et al., 1999; Bryson et al., 2015; George and Farris, 1999). 2.2. Partner selection In the fifth step of the ideal collaboration set-up process described above, Geringer (1991) distinguishes task-related roles (i.e. knowledge, skills, resources, competences, network links, influence) and partner-related characteristics (i.e. cultural, procedural, systemic fit) as selection criteria to choose attractive partners. Regarding the latter, Kelly et al. (2002) argue that relational criteria often tend to be forgotten but are key to mutually successful alliances. Since circular economy or sustainability specific partner characteristics are not discussed in extant literature, partner selection criteria of traditional collaboration literature are taken into consideration, resulting in eight main characteristics: (1) strategic fit, e.g. between the market, strategy, management, or geography (Solesvik and Westhead, 2010; Dietrich et al., 2010); (2) goals alignment to enable information exchange, incentives alignment, mutual benefits, and shared risks (Barrat, 2004; Dietrich et al., 2010); (3) (financial) advantageousness (Shah and Swaminathan, 2008; Solesvik and Westhead, 2010); (4) good reputation within an industry (Solesvik and Westhead, 2010); (5) enthusiasm (Solesvik and Westhead, 2010); (6) (collaborative) commitment as willingness to supply tangible resources (Dietrich et al., 2010; Shah and Swaminathan, 2008); (7) trustworthiness, in particular among the top management teams (Shah and Swaminathan, 2008; Dietrich et al., 2010; Barrat, 2004; Solesvik and Westhead, 2010); and (8) open communication, i.e. the ability and willingness to drive transparent and honest information flows (Barrat, 2004). Complementarity could be considered an additional partner characteristic. In this study, however, it is equated to task-related selection criteria, i.e. partner roles. Eleven roles of relevance for circular food packaging can be distinguished as second set of partner selection criteria, which build on the roles identified by Goodman et al. (2017) in sustainable innovation processes, case study evidence on partner selection for strategic alliances by Solesvik and Westhead (2010), and the classification of circular players proposed by Brown et al. (2019). Those roles address either, or both, research and business purposes, since food firms striving towards circular food packaging commonly need to combine those purposes. The roles can be assigned to three different collaboration stages: starting, developing, or realizing the project. In the first stage, the initiator inspires and generates ideas for an innovation (Goodman et al., 2017); whereas the financier provides direct or indirect funding (Solesvik and Westhead, 2010; Brown et al., 2018; Goodman et al., 2017). In the developing stage, the piloter/refiner develops, tests, and enhances products/services (Solesvik and Westhead, 2010; Goodman et al., 2017; Brown et al., 2018), while the closed loop material expert supports the “development of closed network functions for materials” (Brown et al., 2018, p. 193). In the last stage – realizing the project – the use-phase supporter facilitates the product-life-extension (Brown et al., 2018), and the impact extender promotes the increased usage of products/services (Goodman et al., 2017). The remaining roles are either related to the collaboration process or address stakeholders outside the value chain. In the first case, the mediator integrates stakeholders and creates networks (Goodman et al., 2017), whereas the knowledge broker engages in collaborations for joint learning (Brown et al., 2018). In the second case, the enabler has regulatory, market, and political knowledge and influence (Solesvik and Westhead, 2010; Goodman et al., 2017); the educator changes the perception and behavior of the public (Goodman et al., 2017); and the legitimator creates credibility via assurance and promotion (Goodman et al., 2017). 3. Methods This exploratory study aims at identifying the typical collaboration set-up process of focal food firms for circular food packaging alongside the partner selection criteria applied in terms of roles and partner characteristics. To do so, a qualitative Delphi method is adopted since the approach: a) makes it possible to leverage the knowledge of a group of experts on a topic to understand a phenomenon in greater depth; b) can be used for concept/framework development; and c) is suitable for studies whose research questions and aims are intended to inform practice (Brady, 2015; Fletcher and Childon, 2014; Okoli and Pawlowski, 2004). More specifically, a theoretical framework on the collaboration set-up process, partner roles, and partner characteristics is first developed based on traditional and, when available, circular economy and sustainability collaboration literature. Second, the framework is probed with circular food packaging experts. Finally, a refined framework is elaborated. The scope of the research was limited to reusable and recyclable primary retail food packaging in North-Western Europe: empirical evidence stems from the Netherlands, Germany, the UK, France, and Switzerland. This geographical scope makes it possible to gather descriptive empirical evidence (Bryman, 2012) with relatively advanced circular food packaging initiatives. Moreover, social, political, and economic factors are relatively comparable. Primary packaging in direct contact with food is of interest in this study since reuse and recycling pose a larger challenge for primary packaging compared to secondary or tertiary packaging. Hence, improvements in these areas are key (Davis and Song, 2006). Since packaging avoidance is generally more desirable than reusable or recyclable food packaging, food items not necessarily requiring packaging are excluded from the investigation. Qualitative interviews (Eisenhardt, 1989) were preferred over a quantitative inquiry in order to uncover practices and experiences in the circular food packaging field and support the theory refinement in a descriptive manner. By means of a three-step general purposive sampling strategy, 17 interviewees were chosen based on their: (1) work on reusable and/or recyclable food packaging; (2) insights on focal food firms’ processes; and (3) knowledge on the collaboration choice and set-up process for circular food packaging. The sample included three food-products multinational corporations (MNCs; M1-M3), two food-products small and medium-sized enterprises (SMEs; S1-S2), four food retailers (R1-R4), and two reuse service providers (U1-U2) (see Table 1). The variety of interviewees included in the sample made it possible to examine contrasting elements, namely: reusable vs. recyclable food packaging; retailers vs. food producers; and SMEs vs. MNCs. Subsequently, six circular food packaging experts (E1-E6) were interviewed with the aim to test, extend, and better understand the insights gathered in the first round of interviews. The semi-structured interviews had an average length of 60 minutes and were conducted in the last quarter of 2019. To enhance their comparability and reliability, two interview guides based on the theoretical framework originally developed were used (see Supplementary material). As guidance, visualizations of the theoretical framework (set-up process, partner roles, partner characteristics) were shared with the interviewees during the interview. Open-ended questions were used to gain specific details of the experiences, beliefs, and learnings of the interviewees. Table 1. Interviewee profiles. Interviewee Organization type Function in the organization E1 Recyclability initiative Sustainable packaging consultant E2 Consulting and assurance firm Sustainability senior manager E3 Circular Economy consultancy Founder, circular economy consultant E4 Circular Economy consultancy Sustainable packaging consultant E5 Sustainable packaging organization Sustainable packaging expert E6 Sustainable packaging organization Sustainable packaging expert M1 Food-products MNC Circular economy packaging director M2 Food-products MNC Sustainable packaging senior manager M3 Food-products MNC Sustainability and circular economy manager S1 Sustainable SME food producer Founder S2 Sustainable SME food producer Manager R1 Multinational retailer Sustainable packaging specialist R2 Multinational retailer Sustainability specialist R3 Retailer Innovation and sustainability specialist R4 Organic SME retailer and wholesaler Communication & PR specialist U1 Reusable packaging service provider Founder, manager U2 Reusable packaging service provider Co-founder, advisor All but one interview were recorded and fully transcribed. With the help of NVivo, the data were coded and analyzed using thematic analysis techniques (Brady, 2015). The analysis started with open coding rounds, gradually focusing, ending with axial coding (Corbin and Strauss, 1990). Theoretical saturation was reached after three coding rounds. To explore connections, for instance between partner types and roles, single pieces of data were coded to several concepts, i.e. coding a mentioned player not only under the respective partner type but also performed role. Categories and sub-categories were developed in an iterative, progressive manner, and were used for testing and eventually refining the original theoretical framework. Strict coding rules were applied by constantly comparing the interview data to emerging theoretical categories (Bryman, 2012). The modified framework (see Fig. 1) brings together the collaboration set-up process, partner roles, partner characteristics and includes the collaboration types as well as the influencing factors additionally identified by means of the interviews. Fig. 1. Revised framework: Collaboration set-up process and partner selection for circular food packaging. 4. Results and discussion Results suggest that food companies necessarily require collaborations for circular food packaging, since they cannot fulfill all tasks (i.e. roles) internally. The type of partners sought for, however, differs between companies. In addition, the data provide insights into partner characteristics of importance, the typical collaboration set-up process followed, and factors influencing this process. This section introduces the refined theoretical framework and substantiates it with quotes from the interviews. Results provide empirical evidence for all six set-up steps originally identified, seven of the eight partner characteristics, and all eleven roles included in the preliminary framework. Yet, the findings go beyond existing collaboration and circular economy literature by identifying three novel set-up steps, two partner characteristics, and three partner roles; and revising two set-up steps, one partner characteristic, and three partner roles. As a result, this section proposes a collaboration choice and set-up framework (Fig. 1) to facilitate the realization of collaborations for circular food packaging. Since “there is no ideal process” (S1) these set-up steps represent a typical rather than a fixed process. 4.1. Prerequisites phase Results provide evidence for an initial ‘prerequisites phase’ in the collaboration set-up process, of which the first step, the motivation to work towards a circular economy, appears to be influenced by the size of the food firm. In particular, MNCs seem to be generally more motivated due to resources available, unless a SME's whole strategy is oriented towards sustainability: “For this [working with the government and educational institutions towards recyclability], the company is not big enough, we do not even have an R&D department for that. A [large food brand] can afford such things, they obviously all have that now” (R4). Moreover, within firms, an internal lead, who drives circular economy initiatives, can represent an important motivator (cf. Lueneburger and Coleman, 2010). As a second step, in line with collaboration literature, firms have to recognize the need and potential benefits to collaborate for circular food packaging. Interviewees confirmed that this awareness would usually be present: “[Collaboration] is by default part of all of our roadmaps for sustainability topics” (M3). The data indicate that this need is higher for recyclable food packaging, where competitors jointly establish and use waste management systems. For reusable food packaging, collaboration can enhance its economic viability, but service providers often act as orchestrators, bypassing collaboration between competitors. 4.2. Understanding phase In the ‘understanding phase’, this research identified the step of understanding the market and material flows. While interviewees agreed that this analysis would usually not follow a pre-defined approach, still, it provides the basis for well-informed partner choices and enables negotiations. This third step informs all subsequent ones and is thus important earlier in the process than assumed in the existing literature. For circular food packaging, firms need to understand the possible product-packaging combinations suitable for the specific food. This, as well as the location of operation, influences the collaborations required. Findings also suggest that different collaboration types are necessary depending on the development stage of the local reuse/recycling system. Four types are identified: a) vertical networks aiming to develop the packaging reuse/recycling system when this is not yet in place or well-functioning, b) horizontal networks to develop new materials for/utilize existing systems, and c) one-to-one alliances to improve packaging or technologies. Irrespective of the system's development stage, food companies also employ d) informal collaborations for knowledge exchange. In line with collaboration literature, as a fourth step, most firms were found to develop a circular food packaging vision and strategy to “adapt your resources where you want to be” (M2). Comparing circular economy strategies, firms may take the hierarchical ladder of resource value retention options (“R-hierarchies” or “R-framework”; see also Reike et al., 2018) into account. Generally, interviewees favored reusable over recyclable food packaging in terms of system impact. The analysis shows that to realize a circular food packaging vision, top management support as well as alignment of the circular food packaging vision and strategy across the firm is required. Since changes towards circular business logics might be radical and cause organizational inertia (Lahti et al., 2018), firms require flexibility, early transparent communication, and the exertion of influence: “In every revolution it takes two generations, why? Because the mindsets need to change” (R2). 4.3. Preparation phase In the ‘preparation phase’, food companies were found to assess internal capabilities and gaps in order to identify potential partners with complementary resources and capabilities (cf. Dyer and Singh, 1998). This study introduces 14 roles (see Fig. 1), which food companies or their partners may fulfill to realize circular food packaging, of which three (‘internal-educator’, ‘market-expert’, ‘end-of-life supporter’) were added and three (‘impact extender’, ‘enabler’, ‘promoter’) slightly amended compared to previous literature. The three roles associated to the project's realization phase are found to be the most important and, thus, require the fulfillment of all nine identified partner characteristics introduced later (Section 4.4). While brands can fulfill all roles except the ‘end-of-life supporter’, retailers never take up seven of the fourteen possible roles. One interviewee explained: “If someone kicks [retailers] with the broom then they move. […] They truly see the urge for them to move, but they will not move any faster than it's needed. Whereas [there are] some of the major brands that are really out there, stating ambitions and doing the extra mile. That's totally different” (E3). Besides the position in the value chain, the type of partners sought after appears to differ based on the project type. For recyclable food packaging, roles of importance mirror the identified challenges being of technical, legal/safety, or economic nature. The ‘financier’ can provide/enable (in)direct financing. Governments should create “completely different financial structures for collection, sorting, recycling” (E4). Building on Brown et al. (2018), the ‘circularity expert’, identified by the interviewees as too little represented in practice, advises and supports the development of recycling networks, potentially in the form of working groups/consortia: “The main benefit [of the consortium] is education, understanding where we will be going, but we also run webinars for the stakeholders and we provide advice, documentation. There's knowledge coming out of each of the work streams” (E1). Third, the newly identified ‘end-of-life supporter’ is relevant for recyclable food packaging with shorter lifetimes. To improve packaging's end-of-life treatment, brands but also retailers frequently endorsed extended producer responsibility (EPR) schemes: “That's why we are pushing for EPR, because it will allow us to have a level playing field, and then it's not just a few or couple of companies contributing, but it's everybody” (M3). Reusable food packaging requiring new service-oriented business models calls for three other major roles. In line with Goodman et al. (2017), consumers promoting circular food packaging can act as ‘impact extender’: “I think that the reusable business will mainly be driven by the what I will call the dark-green or light-green consumers” (M2). In addition, most interviewees advocated for a pre-competitive circular economy approach between competing companies to address shared problems (cf. De Angelis et al., 2018). Second, the ‘promoter’ can communicate and promote circular food packaging products to establish credibility and publicity: “People [should] get used to it, so they only go to the supermarket when they bring their glass jar” (S1). Finally, in line with Brown et al. (2018), the ‘use-phase supporter’ establishes, operates, and utilizes value chain networks to extend packaging's life. This role is frequently performed by reuse system providers with innovative, service-oriented reuse models. The findings back up literature (cf. Ameripen, 2018) pointing towards a shortage of this actor. Besides differences between project types, the findings highlight three circular economy-enabling roles. First, the ‘mediator’ connects different actors to build one-to-one collaborations or networks. Second, the ‘knowledge broker’ manages collaborative processes and research outcomes: “We really need players that can see other trends and developments within different sectors, linking it, and actually driving that project forward, because it's a very different thinking then within a company or within a value chain. If you're talking about cross-value-chain coalitions, I've only seen it work if there was an external project leader” (E3). In keeping with Brown et al. (2018), this actor benefits from good networks and circular economy knowledge, i.e. actors combining the ‘knowledge broker’ and ‘circularity expert’ are powerful. Both the ‘knowledge broker’ and ‘mediator’ are identified as actors currently lacking. Third, the ‘enabler’ (co-)creates, steers, and pushes legislation, norms, and the market towards circular food packaging. Interviewees stated that cooperation between politics and businesses can enable joint regulatory circular economy changes, while reducing regulatory uncertainties (cf. Clark et al., 2019). To ease the uptake of circular food packaging, some interviewees called for European-wide legislation. Moreover, this research identified two circular economy-educating roles of importance as a circular economy requires a novel economic system: the ‘external educator’, who instructs individuals holding powerful positions and consumers as indispensable actors in a circular economy (Goodman et al., 2017; Kirchherr et al., 2018): “Yes, education everywhere. But you need kind of an education, maybe some basic one for people to understand that circular economy is different than just doing less bad and reducing impacts” (M2). Furthermore, the newly introduced actor ‘internal educator’ disseminates and transfers knowledge within firms. Some interviewees argued that food companies would devote too little effort to this task. Finally, three roles are found to be generally important, rather than circular economy-specific: the either idea-spreading, pressure-creating, or action-oriented ‘initiator’; the ‘piloter’ developing, piloting, and improving technologies or circular food packaging systems; and the newly identified ‘market expert’ with market-related and consumer knowledge: "We need to understand what drives the behavior and how we can change it, what we do to ensure that we bring customers on the journey with us” (R1). As a sixth step, companies were found to typically form a team internally. In contrast to existing collaboration literature, food companies do not appear to require internal alliance building skills, but employees need collaborative skills, expertise on circular food packaging, and the ability to deal with uncertainties and complexities. Despite MNCs could hire circular food packaging specialists (which is often not possible for SMEs), particularly retailers would rarely do so. Furthermore, in accordance with Lahti et al. (2018), this study identifies setting up steering committees to handle difficulties in collaborative circular food packaging projects as a helpful tool. 4.4. Partner involvement phase As part of the ‘partner involvement phase’, the external outreach (step seven in Fig. 1) frequently came up in the interviews, while rarely being addressed in collaboration literature. Although firms prefer prolonging existing relationships due to relation-specific investments and knowledge sharing routines (cf. Dyers and Singh, 1998), this research found that for circular food packaging some new partners are needed compared to linear food packaging (cf. Lahti et al., 2018). During this step, the earlier introduced ‘mediator’, who connects different players, may play a role. The data show that, subsequently, companies generally evaluate potential partners in regard to their desirability, favorability, appeal, and value (cf. Czajkowski, 2007; Shah and Swaminathan, 2008) to choose compatible ones. In response to the absence of an understanding of circular economy partner types (Brown et al., 2019), alongside the introduced roles, this study introduces partner characteristics assisting in the evaluation. One characteristic included in the preliminary framework (Section 2.2), ‘enthusiasm’, was discarded from the refined framework (Fig. 1) since it proved to be less relevant than assumed by extant literature: some interviewees classified it as a potentially temporary, person-related, not action-oriented state. Beyond excluding this characteristic, this research not only defines nine important partner characteristics, but goes further to show which are generic and which circular economy-specific. Three characteristics are paramount in a circular economy. First, for circular food packaging, a ‘strategic fit’ is important, including the circular food packaging vision, company culture, context, or geographical proximity for material exchange collaborations: “They [our partner] really work for everything that we embody, on our set of requirements, our own needs” (S2). Second, it was found that ‘creativeness/open mindedness’ is key since circular food packaging usually entails collaboration in multiplayer networks, complexities, and uncertainties. This characteristic has not been highlighted by existing collaboration literature. Similarly, however, Rohrbeck et al. (2013), Lahti et al. (2018), and Pieroni et al. (2019) call for creativity and open-mindedness when conceptualizing circular business models. Third, ‘open communication’ to enable collaborative learning as continuous, reciprocal achievement was named as a desired norm in some interviews (cf. Clark et al., 2019). In this way, progression, company advantages, and the reduction of uncertainties could be enabled. Moreover, this study identified two other characteristics as baseline for circular economy collaborations. Since in a circular economy value is generated in synergetic interrelationships, and uncertainties and difficulties ask for flexibility, “that flexibility will arise if they [your partners] are aligned with your mission” (U2), i.e. ‘goals alignment’ is important. Second, due to mutual dependence and reciprocity in a circular economy (cf. Lahti et al., 2018), ‘commitment’ in terms of wanting the change and investing resources was frequently mentioned. The findings indicate that progressive organizations tend to be more committed since realizing circular food packaging requires additional time and monetary investments, while pay-offs are rather long-term. Finally, results highlight four characteristics found in the collaboration literature as generic partner characteristics: ‘complementarity’ (which is covered under partner roles in this study), e.g. to “be able to perform what is needed” (E3); financial ‘advantageousness’, representing one of the three circular economy priorities (i.e. financial advantages for companies, lower resource consumption, and less pollution for the environment; see also Geissdoefer et al., 2017); ‘no negative reputation’ rather than a necessarily good reputation; and ‘trustworthiness’ in terms of (individuals within an organization) adhering to promises due to common mutual dependences and relation-specific investments in a circular economy. 4.5. Formalisation phase In the final ‘formalisation phase’, this study confirms literature calling for informal (e.g. collaborative goals, division of roles) and formal (e.g. financial and confidentiality related) agreements to establish collaborations with partners chosen based on their roles and characteristics. The findings highlight that reaching full consensus in multiplayer collaborations for circular food packaging may neither always be possible nor needed when objectives, impacts, or costs between partners differ. The management, contract/transaction design, and administration of novel circular economy collaborations, however, call for further exploration (cf. Korhonen et al., 2018; Meherishi et al., 2019; Fischer and Pascucci, 2017; De Angelis et al., 2018; Lahti et al., 2018). 5. Conclusions As a response to the current inefficient production, use, and disposal of food packaging, focal food firms are important actors for the realization of circular food packaging. As central players, they can wield power over the supply chain and, by collaborating, overcome existing implementation challenges. Through the comprehensive analysis of the collaboration choice and set-up process of food companies, a theoretical framework was developed and refined (Fig. 1), providing insights into the collaboration set-up steps, partner roles, partner characteristics, collaboration types, and influencing factors. Findings show that food firms typically follow nine steps when establishing collaborations for circular food packaging. Since they cannot fulfill all tasks internally, they require collaborative support. The importance of the 14 specified circular economy roles, of which 11 are by far more important or additionally needed in the context of circular food packaging compared to traditional collaborations, is found to be influenced by the firm's position in the supply chain, the project type (here reusable vs. recyclable food packaging), the firm's size, and the product (here properties of the food). Moreover, based on the development stage of the local reuse or recycling system, four different collaboration types (i.e. vertical networks, horizontal networks, one-to-one alliances, informal alliances) appear to be required. The framework also encompasses nine characteristics to choose compatible partners, five of which are shown to be of particular relevance in a circular economy. The findings of this research have some important (supply chain) managerial implications, which increasingly need to complement technical circular food packaging explorations. Firms that want to move towards circular product offers, such as circular food packaging, are facing complexities and uncertainties on how and with whom to establish collaborations. This research may be of interest to these firms, but also other circular economy stakeholders, by providing them with guidance on how to find and set-up collaborations for circular food packaging. By understanding roles of importance in a circular economy, specifically for reusable and recyclable food packaging, firms can identify and enhance their own capacities while being informed about required (additional) partners to realize circular food packaging. Based on these insights, they can establish new suitable collaborations, while maintaining already existing ones, in order to reach identified circular food packaging targets. Despite the promising contributions offered to the circular economy collaboration and circular food packaging field, this study has some limitations that need to be acknowledged. First, within the geographical scope, but even more in other geographies than North-West Europe, differences can be expected. While North-West Europe has, for instance, relatively advanced recycling systems, at the same time, compared to other geographies, disposable, convenient packaging became a norm. Therefore, reusable packaging may be more common and accepted by consumers in other areas such as Central or Eastern Europe. Similarly, the collaboration choice and set-up process may differ in the four collaboration types identified, as well as between different models and packaging formats of reusable and recyclable food packaging. The external validity of the results is also limited due to the sample size of 17 interviewees. However, expert-interviews were included to enhance the generalizability of the findings. Future research could validate the framework for other geographical contexts and other circular economy fields than circular food packaging. Many identified elements of the proposed framework likely hold true for any collaborative circular economy project; still, this is to be confirmed and possible differences need to be empirically determined. Furthermore, specific elements such as the influencing factors, the collaboration types, or the role of SMEs in circular food packaging collaborations, often falling short in MNC-driven initiatives, could be investigated. For instance, the role of and influence on collaboration of the ‘enabler’ will become apparent in the coming year 2021, when the plastic tax on nonrecycled packaging waste will be introduced in Europe. This tax most likely will influence the dynamics on the recycled material market and, hence, also the type of collaborations needed. For instance, food companies may need to increasingly collaborate with ‘end-of-life supporters’ to improve recycling technologies, which may require a pre-competitive approach in terms of collaborating with ‘impact extenders.’ Moreover, the relation between partner roles and characteristics, as well as typical combinations of roles were only broached in this study. An in depth-analysis of those could be conducted. In addition, future research could focus on the collaboration realization phase, including the underlying governance mechanisms. Similarly, possible learning and transformation processes of organizations aiming to perform the identified characteristics is worth of further investigation. Finally, based on the proposed framework, practical tools to guide practitioners could be developed, for example in the form of a guided collaboration set-up workflow process, a gap analysis to identify partner roles of importance, or an evaluation checklist to assess potential partners’ characteristics. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Supplementary materials Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.spc.2020.12.025 . References Barratt, M. , 2004. Understanding the meaning of collaboration in the supply chain. Supply Chain Manage.: Int. J. 9 (1), 30–42 . Bocken, N.M.P. , de Pauw, I. , Bakker, C. , van der Grinten, B , 2016. Product design and business model strategies for a circular economy. J. Ind. Prod. Eng. 33, 308–320 . Brady, S.R. , 2015. 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Essential oils as additives in active food packaging
ShubhamSharmaabcSandraBarkauskaiteaAmit K.Jaiswalab*SwarnaJaiswalab a School of Food Science and Environmental Health, College of Sciences and Health, Technological University Dublin – City Campus, Grangegorman, Dublin 7, Ireland b Environmental Sustainability and Health Institute, Technological University Dublin – City Campus, Grangegorman, Dublin 7, Ireland c Centre for Research in Engineering and Surface Technology (CREST), FOCAS Institute, Technological University Dublin – City Campus, Kevin Street, Dublin 8, Ireland. *Corresponding author at: School of Food Science and Environmental Health, College of Sciences and Health, Technological University Dublin – City Campus,Grangegorman, Dublin 7, Ireland.E-mail addresses: amit.jaiswal@TUDublin.ie, email@example.com (A.K. Jaiswal), swarna.jaiswal@TUDublin.ie, firstname.lastname@example.org (S. Jaiswal). https://doi.org/10.1016/j.foodchem.2020.128403 Received 1 July 2020; Received in revised form 30 August 2020; Accepted 12 October 2020 Available online 15 October 20200308-8146/© 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/) Abstract Food packaging can be considered as a passive barrier that protects food from environmental factors such as ultraviolet light, oxygen, water vapour, pressure and heat. It also prolongs the shelf-life of food by protecting from chemical and microbiological contaminants and enables foods to be transported and stored safely. Active packaging (AP) provides the opportunity for interaction between the external environment and food, resulting in extended shelf-life of food. Chemoactive packaging has an impact on the chemical composition of the food product. The application of natural additive such as essential oils in active packaging can be used in the forms of films and coatings. It has been observed that, AP helps to maintain temperature, moisture level and microbial and quality control of the food. This review article provides an overview of the active packaging incorporated with essential oils, concerns and challenges in industry, and the effect of essential oil on the packaging microstructure, antioxidant and antimicrobial properties. Keywords Essential oils；Food packaging；Active food packaging；Shelf life；Antimicrobial activity；Antioxidant property；Food safety 1. Introduction Food packaging plays its primary role in the protection of the food product from the influence of the external environment. The major goal of the food packaging is to hold food in best economical way, satisfying both industrial and consumer requirement, ensuring food safety and minimising environmental effects. Advances in food packaging researches led to the development of active packaging, and intelligent packaging. Active packaging is a novel method used to prolong the shelf-life of perishable foods, maintain or improve the quality and safety of prepared foods due to its interaction with the product. Besides, active packaging has potential to replace the addition of active compounds into foods, reduce the movement of particles from packaging materials to food, and get rid of industrial processes that can cause the introduction of pathogenic microorganism into the product (Schaefer & Cheung, 2018). This packaging system also has an advantage in the reduction of foodborne illness outbreaks and food recalls (Vilela et al., 2018). Intelligent packaging consists of “materials and articles that monitor the condition of packaged food or the environment surrounding the food”. It detects changes in the condition of the food or it’s environment, such as pH and temperature changes, thereby extending the function of traditionally used packaging materials by indicating the state of the product through visual changes (Realini & Marcos, 2014). Unlike intelligent packaging, active packaging does not require any changes in the food in order to operate efficiently (Brockgreitens & Abbas, 2016). Depending on the types of additives incorporated into the food packaging material, active packaging can be categorized into chemoactive and bioactive. In chemoactive packaging chemicals used as an active agent in the packaging material. It has an impact on the chemical composition of the food product and gaseous atmosphere inside a pack (Brockgreitens & Abbas, 2016). Gas scavenging packaging tends to remove gases, which dehydrates the food products and led to the formation of an unfavourable environment for the growth of microbes. Oxygen in the packaging facilitates the growth of aerobic bacteria and causes undesirable changes in food like fat rancidity and meat browning (Busolo & Lagaron, 2012). Various oxygen-reactive materials such as iron, titanium, zinc, etc are used in packaging material as oxygen scavenger (Busolo and Lagaron, 2012, Di Maio et al., 2015). Ethylene gas act as a ripening agent. Ethylene scavengers are used to extend the shelf life of fruits and raw vegetables (Brockgreitens and Abbas, 2016, Terry, Ilkenhans, Poulston, Rowsell, & Smith, 2007). In addition, bioactive packaging contains antimicrobial agents that interact with biological molecules and may inhibit the growth of various microorganisms (Brockgreitens & Abbas, 2016). For example, Azadbakht, Maghsoudlou, Khomiri, and Kashiri (2018) studied the incorporation of Eucalyptus globulus essential oil in chitosan and examined the antimicrobial activity of packaged sliced sausages. The results showed that the log reduction value could be improved by increasing essential oil concentration. However, there is a growing concern towards chemoactive packaging due to the use of synthetic additives and materials that can cause adverse health effects or make packaging unsustainable for recycling leading to high waste volume. For example, incorporation of synthetic antioxidants such as butylated hydroxyanisole into active packaging results in improved quality of food products because this antioxidant has a potential to protect against lipid oxidation (Domínguez et al., 2018). Despite the fact that butylated hydroxyanisole is a beneficial towards food quality and is widely used in active packaging, it might have a disruptive effect on the endocrine system in humans (Pop, Kiss, & Loghin, 2013). Moreover, the incorporation of particular materials into active packaging can also affect product safety. As defined by Martillanes, Rocha-Pimienta, Cabrera-Bañegil, Martín-Vertedor, and Delgado-Adámez (2017), the use of absorbent pads in food packaging is a very successful approach in controlling moisture released by the food product. However, this packaging method has some limitations because after a while, unsanitary juices become trapped in pads causing undesirable odours, spoilage and potential growth of foodborne pathogens. In this case, natural antioxidants such as polyphenols, essential oils etc. can be added into the absorbent pads that would promote the quality and safety of food products. Issues with chemoactive packaging led to discover new alternatives such as the incorporation of bioactive compounds from natural sources (Ribeiro-Santos et al., 2017, Ribeiro-Santos et al., 2017). Due to growing consumer demand for natural products, synthetic additives are replaced by natural substances such as essential oils, polyphenols and other natural extracts (Poojary et al., 2017, Vinceković et al., 2017). For example, the addition of natural antioxidants in active packaging material can protect packaged meat from lipid oxidation. Antioxidants can interact with the food product and package headspace resulting in the prevention of active chemical compounds to be used in food products. Antioxidant active packaging can either release antioxidants into the food and the package or absorb oxygen and other compounds from the food or its surroundings. Also, active packaging containing natural antioxidants (polyphenols, essential oils etc) is a cost-saving alternative that also has the potential to eliminate food safety risks (Domínguez et al., 2018). Therefore, the natural substances play a significant role in the antioxidant activity of the active packaging. For example, the effectiveness of active packaging containing thyme essential oil/β-cyclodextrin ε-polylysine nanoparticles (TCPNs) was tested by Lin, Zhu, and Cui (2018). The results showed that TCPNs incorporated into gelatin nanofibers significantly improved the antimicrobial properties against bacteria such as Campylobacter jejuni. This review article is focused on application of essential oil as additives in active food packaging. Numerous aspects such as current application of essential oils into active food packaging, migration of active compounds from a package to food, effect of essential oil incorporation on the antioxidant and antibacterial properties together with impact of essential oil on the packaging microstructure has been discussed. Furthermore, legal aspects of the use of essential oils in food and future trend are provided. 2. Essential oils Essential oils are volatile liquids extracted from various parts of the aromatic plants like barks, seeds, flowers, peel, fruit, roots, leaves, wood, fruits, whole plants and named depending from which plant they are obtained (El Sawi et al., 2019, Khorshidian et al., 2018, Ríos, 2016). According to International Organization for Standardization (ISO), essential oil is a ‘product obtained from a natural raw material of plant origin, by steam distillation, by mechanical processes from the epicarp of citrus fruits, or by dry distillation, after separation of the aqueous phase if any by physical processes’ and it can also be treated physically without changing its composition (Mati & Nat, 2013). Essential oils could be extracted by different methods, such as hydro-distillation, steam distillation, hydro-diffusion and solvent extraction (Aziz et al., 2018). Hydro-distillation is a process in which plant materials are immersed in water in the vessel and the mixture is boiled. The main advantage of hydro-distillation is the extraction from the hydrophobic plants with a high boiling point and the technique is capable of extracting the plant material under 100 °C (El Asbahani et al., 2009). Another extraction method is steam distillation, which is mostly applied. According to Masango (2005), 93% of the extraction could be obtained from this steam distillation. The plant material is heated using steam provided by steam generator. The steam is allowed only to pass through the plant while the boiling water does not mix with the plant material. Heat provided by steam determines the effectiveness of the structural breakdown of the plant material and releases the essential oil. It reduces the amount of waste water produced during the extraction process. In hydro-diffusion extraction, required dried plant materials and the steam is provided with a container. In this process the steam temperature is reduced under 100 °C at low temperature and vacuum is provided by the top of the generator (Vian, Fernandez, Visinoni, & Chemat, 2008). Another process is the solvent extraction method, where solvent like acetone, hexane, ether or ethanol is mixed with the plant material and mildly heated, filtrated and the solvent is evaporated. The filtrated mixture is mixed with alcohol in order to dissolve essential oil and then distillation takes place at low temperature (Tongnuanchan & Benjakul, 2014). Physical characteristics of essential oils include their high solubility in ether, alcohol, and fixed oils, but low solubility in water which is denser than oils (Dhifi et al., 2016, Filly et al., 2016). Essential oils are usually colourless and liquid at room temperature and are distinguished by their distinctive odour. These volatile liquids can be characterized by refractive index measurement and their high optical activity (Dhifi et al., 2016). These extracts of aromatic plants are composed of organic compounds such as carbon, hydrogen, and oxygen, and in some cases, nitrogen and sulfur derivatives. Carbon and hydrogen atoms tend to attract functional groups resulting in a relatively inactive framework of atoms in the essential oils (Moghaddam & Mehdizadeh, 2017). These aromatic liquids are diverse due to the presence of different functional groups, and they exist in various forms, including aldehydes, alcohols, ethers, ketones, acids, amines, sulphides, epoxides, and others (Başer, 2007). 2.1. Chemical components Based on their chemical composition, essential oils can be divided into terpenes and hydrocarbons (Moghaddam & Mehdizadeh, 2017). 2.1.1. Terpenes Terpenes are composed of a different number of isoprene units (Blowman, Magalhães, Lemos, Cabral, & Pires, 2018). Depending on the number of isoprene units, terpenes can be categorized into hemiterpenes (C5H8), monoterpenes (C5H8)2, sesquiterpenes (C5H8)2, diterpenes (C5H8)4, etc. (Rubulotta, 2019). Almost 90% of all essential oils are composed of monoterpenes. Some examples monoterpenes structured essential oils are Lavandula luisieri, Cymbopogon citratus, white and green tea (Dias et al., 2017, Santana-Rios et al., 2001). Terpenes can also be divided into groups such as acyclic, monocyclic and bicyclic (Blowman et al., 2018). Terpenoid is a type of terpene that has oxygen attached to its backbone. The chemical structure of the most common terpenes is shown in Fig. 1. Fig. 1. Chemical structures of essential oil constituents (Blowman et al., 2018). 2.1.2. Hydrocarbons Other constituents of essential oils are hydrocarbons that are made of carbon and hydrogen atoms. Depending on their structure, hydrocarbons are categorized into aliphatic, alkanes, and aromatic hydrocarbons. It is well-known that citrus oil has a specific acid odour caused by aliphatic hydrocarbons that are composed of 8–10 carbon atoms connected linearly. Also, an aliphatic molecule with six carbon atoms provides a leafy-green scent in floral oils, while octanal aldehydes are responsible for the smell in orange oil. Essential oils contain just a trace amount of aliphatic compounds that have oxygenated functional groups attached to them and responsible for odour. On the other hand, alkanes are composed of carbon atoms liked together by single bonds while alkynes comprise of carbon-carbon triple covalent bonds. Aromatic hydrocarbons are responsible for pleasant odour due to the presence of benzene ring in their structure (Bhavaniramya, Vishnupriya, Al-Aboody, Vijayakumar, & Baskaran, 2019). 2.2. Types of essential oils Essential oils contain a wide variety of mixtures that can be identified based on their aroma compounds. Different types of essential oils include Azadirachta indica (neem), Lavandula angustifolia (lavender), Thymus vulgaris (thyme), Eucalyptus globulus (eucalyptus), Cinnamomum zeylanicum (cinnamon), Syzygium aromaticum (clove), Citrus limonum (lemon), Melaleuca alternifolia (tea tree), Brassica nigra (mustard), and others (Bhavaniramya et al., 2019). These volatile compounds are responsible for controlling microbial growth and preserving food. For instance, neem essential oil is a volatile mixture extracted from seed kernels of the neem tree. It has unpleasant sulphur and garlic aroma (Bodiba & Szuman, 2018). The study carried out by Ali, Sultana, Joshi, and Rajendran (2016), showed that neem essential oil significantly improved the antibacterial activity in poly (ethylene terephthalate) polyester fabric. Lavender essential oil is produced by steam distillation from the plant known as Lavandula angustifolia. This type of oil contains several chemical compounds that include linalyl acetate, linalool, lavandulol, lavandulyl acetate, B-ocimene, l-fenchone, viridiflorol, camphor, etc. (Bhavaniramya et al., 2019). A study by Jamróz, Juszczak, and Kucharek (2018), used lavender essential oil in starch furcellaran-gelatin (S/F/G) films to test their antioxidant, antimicrobial and physical properties. The results showed that the different concentrations (2%, 4% and 6%) of lavender essential oil in S/F/G film had positive and negative effects on its physical properties. At the same time, antioxidant and antimicrobial ability was significantly improved leading to the prolonged shelf-life of packed foods. 3. Current application of essential oils into active food packaging Essential oils are widely used in the food industry due to their natural antimicrobial, antioxidant or biopreservative effect, which helps to prolong the shelf-life in foods. Fruits and vegetables are the most common types of foods where essential oils are applied, including other groups such as fish products, meat products, milk and dairy products, and bread and baked foods. However, when essential oils are added directly to the food matrix, they start to degrade quickly due to interaction between their unstable, volatile composition and external factors such as light, oxidation, and heating. That is why the recent technologies created new methods to improve the stability of essential oils by encapsulating them in liposomes, polymeric particles, and solid lipid nanoparticles (Fernández-López & Viuda-Martos, 2018). Additionally, the Regulation EU No 450/2009 (Commission Regulation EU No 450/2009, 2009) states that “active materials and articles means that are intended to extend the shelf-life or to maintain or improve the condition of packaged food; they are designed to deliberately incorporate components that would release or absorb substances into or from the packaged food or the environment surrounding the food”. When active agents are encapsulated into packaging material, they release active compounds that improve the quality and safety of food products (Commission Regulation EU No 450/2009, 2009). The application of essential oils in active packaging can be used in the forms of films and coatings. Films are usually thin sheets that are made beforehand and can be used as covers, wrappers, layer separation or packaging for various foods. On the other hand, coatings are defined as films that can be applied onto the surface of an edible product (Ribeiro-Santos et al., 2017, Ribeiro-Santos et al., 2017). There are several examples of essential oils and their constituents incorporated into active films. For example, chitosan films containing Eucalyptus globulus essential oil were developed for the packaging of sliced sausages that have a high potential to reduce the antimicrobial activity and control food-borne contamination in food systems (Azadbakht et al., 2018). Another study carried out by Perdones, Escriche, Chiralt, and Vargas (2016) showed chitosan-based coatings containing lemon essential oil were very effective in delaying the ripening process in strawberries due to their reduced respiratory rate. It was also determined that after seven days of storage, the aroma of lemon essential oil did not have any impact on the organoleptic properties of strawberries. 4. Effect of essential oil incorporation on the food packaging material microstructure The observation of the food packaging material microstructure incorporated with active compounds such as essential oils can be carried out using Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM). SEM uses an electron beam to scan the structure of edible films with essential oils and compare to the construction of the film that does not contain lipid. In comparison to the traditional food packaging materials that are mostly non-polar plastics, biodegradable packaging and edible films are usually composed of polysaccharides and proteins. Packaging material qualifies to be biodegradable if it completely decomposes or break down into natural elements after its disposal. The edible films or coatings are made from the edible material such as lipids, polysaccharides or protein. These edible films or coatings are formed by pouring an aqueous solution on the flat surface followed by drying at constant temperature. Essential oils can be incorporated within the edible film matrix by using different methods such as emulsification or homogenization. In the aqueous phase, essential oils containing polymer tend to appear in fine emulsions while in dried films, lipid droplets become incorporated into the polymer structure. The structural arrangement of components has an impact on the final microstructure of the packaging material, which can be changed due to coalescence, creaming and droplet flocculation during the drying period. Also, the polymer forming film has an impact on the loss of essential oils. That is why the interaction between the polymer and essential oils enhances emulsion stability leading to the significantly improved microstructure of the film (Atarés & Chiralt, 2016). According to the study carried out by Atarés, Pérez-Masiá, and Chiralt (2011), HPMC films incorporated with ginger essential oil which contributed to a more open structure and thicker films compared to the film with no essential oils. Another study by Acevedo-Fani, Salvia-Trujillo, Rojas-Graü, and Martín-Belloso (2015), identified that the addition of essential oils such as thyme, lemongrass and sage into alginate films causes the roughness in the film surface. Its composition can also determine the final microstructure of the food packaging material. For example, Atarés, Bonilla, and Chiralt (2010) created sodium caseinate films with a small amount of cinnamon and ginger essential oils. The study showed that ginger oil droplets were observed in the protein matrix containing homogeneously distributed cinnamon oil. The conclusion was drawn that different behaviour of both essential oils causes structural differences in the film during drying and result from the complex interactions taking place between the lipid, the protein and the solvent. 4.1. Physical properties The physical properties of biodegradable food packaging materials containing essential oils are highly depended on their structure. For example, the study carried out by Ojagh, Rezaei, Razavi, and Hosseini (2010), showed that the incorporation of cinnamon essential oil into chitosan films improves its structure and physical properties such as tensile strength, surface hydrophobicity and lower flexibility. 4.1.1. Tensile properties Tensile properties of the food packaging materials usually depend on the interaction between polymer matrix and essential oil components. Ojagh et al. (2010) conducted a study that proved that the addition of cinnamon oil into films increases their tensile strength due to reorganization in polymer matrix caused by the essential oil. Moreover, it is well known that essential oils are complex liquids that contain numerous volatile chemicals responsible for different functions. The most common compound in the essential oil is phenol which causes protein cross-linking by interacting with different protein sites resulting in improved tensile strength of the film (Atarés & Chiralt, 2016). 4.1.2. Barrier properties Barrier properties of the food packaging materials plays a significant role in improving product quality and safety due to its ability to prevent moisture. The water vapour permeability (WVP) and the surface hydrophobicity are evaluated by measuring the water contact angle (WCA) that allows determining hydrophobicity/hydrophilicity of the packaging material. The hydrophobicity/hydrophilicity ratio has an effect on the packaging materials ability to control water vapour processes. Since essential oils have a non-polar molecular structure meaning that they are hydrophobic, the incorporation of these volatile liquids into hydrophilic polymer matrices causes the improvement of barrier properties (Atarés & Chiralt, 2016). Pires et al. (2013) also conducted a study proving that incorporation of citronella, coriander, tarragon and thyme oils into hake proteins significantly reduces the water vapour permeability. 4.1.3. Optical properties: colour, transparency, gloss Properties such as colour, transparency and gloss of the packaging materials influence the appearance of the food product and consumer acceptability. The surface colour of the packaging material is highly depended on the type and concentration of the essential oil added within the packaging material. Yahyaoui, Gordobil, Herrera Díaz, Abderrabba, and Labidi (2016) formulated films with PLA, rosemary, myrtle and thyme essential oils. The incorporation of these essential oils showed a slight colour change which increased when the concentration of essential oils increased. In contrast, the study carried out by Mohsenabadi, Rajaei, Tabatabaei, and Mohsenifar (2018) proved that the incorporation of free rosemary essential oil into the starch-carboxy methyl cellulose did not have a significant effect on the optical properties of the films. Arezoo, Mohammadreza, Maryam, and Abdorreza (2019) tested the incorporation of cinnamon essential oil and nano TiO2 into sago starch films and found an increase in yellowness which is associated with cinnamon essential oil colour. In a study carried out by Sharma, Barkauskaite, Duffy, Jaiswal, and Jaiswal (2020a) on a poly (lactide)-poly (butylene adipate-co-terephthalate) (PLA-PBAT) film incorporated with the thyme oil and clove oil showed that incorporation of clove oil and thyme oil had significant impact on packaging film optical property. The results showed that the clove oil composite films depicted pale yellow colour with less transparency and high UV-light barrier property as compared to thyme oil composite films (Sharma et al., 2020a). In a different study, the authors observed that biodegradable films incorporated with essential oils have a higher UV-light barrier compared to the control PLA/PBAT film (Sharma, Barkauskaite, Duffy, Jaiswal, & Jaiswal, 2020b). PLA/PBAT-eucalyptus films (10 wt%) have exhibited 40% increase of UV-blocking property than control film while PLA/PBAT-cinnamon films (10 wt%) exhibited 80% increase of UV-blocking property. The best UV-blocking properties were observed in PLA/PBAT-cinnamon films due to a high concentration of phenolic compound eugenol, which can absorb UV light (Sharma et al., 2020b). The transparency of the food packaging material can be measured by obtaining the light transmittance at a specific wavelength or applying Kubelka-Munk theory (Yang, Xu, Li, Zhou, & Lu, 2019). This method was used by Valencia-Sullca, Vargas, Atarés, and Chiralt (2018) examined the effect of cinnamon and oregano essential oils on the transparency of thermoplastic cassava starch-chitosan bilayer films. It was determined that the incorporation of the essential oil shows a higher opacity but reduces film transparency depending on the essential oil. Packaging materials with oregano essential oil had lower transparency than films with cinnamon oil due to the presence of different constituents in their structure that causes light scattering. The incorporation of the essential oils into polymer matrix may reduce film gloss, causing an increase in surface roughness. This effect could be due to the dispersion of oil droplets within the film surface which reduces the specular reflectance and increases roughness. Hover, the study carried out by Valencia-Sullca et al. (2018) determined that the incorporation of oregano and cinnamon essential oils into cassava starch-chitosan films did not affect the gloss of the monolayer. 4.2. Chemical properties The chemical properties of the food packaging materials containing essential oils can be determined by using Fourier-transform infrared spectroscopy (FTIR). This type of analysis allows examining solid materials and identifying functional groups present in their structure. Hedayati Rad, Sharifan, and Asadi (2018) studied the physicochemical and antimicrobial of kefiran /waterborne polyurethane films containing Zataria multiflora and Rosmarinus officinalis essential oils and determined that the increase in the concentration of essential oils causes different shifts of bands. This effect is due to altered intermolecular interaction between essential oils and film matrix caused by the increase in concentration. 5. Migration of active compounds from package to food Creating a suitable packaging for specific foods can be a challenging task because some of the compounds present in packaging materials can migrate into food and cause toxicity (Sendón et al., 2012). However, the interaction between packaging and food is preferred in active packaging systems where active agents such as oxygen and ethylene scavengers, carbon dioxide emitters and antimicrobial and antioxidant components provide functions to packaging materials (Vilela et al., 2018). As shown in Fig. 2., food packaging material incorporated with active compounds provide the protection against gases, vapours, biological, chemical and physical deterioration. Fig. 2. Functions of edible films and coatings (Salgado, Ortiz, Musso, Di Giorgio, & Mauri, 2015). There are many factors that may cause the migration of active compounds from package to food. For example, food components such as fats and moisture can increase the release of phenolic compounds from active packaging to the food. Besides, high temperatures and chemical affinity/solubility and can also increase the movement of molecules of the active agents. The migration tests can be used to determine the movement of active compounds in the polymeric matrices where a specific time and temperature conditions are applied depending on the type of food being packaged and its characteristics of use and storage. Additionally, other characteristics, such as the type of polymer and concentration of migrant components must also be taken into account when performing migration tests (Ribeiro-Santos et al., 2017, Ribeiro-Santos et al., 2017). The migration of active components can be measured using a chromatographic methods that allows separating, identifying and quatifying the bioactive compounds in packaging. For example, Ribeiro-Santos, de Melo et al. (2017) produced a whey protein film incorporated with a blend of essential oils and studied the migration of active compounds to food and a food stimulant. During this study, it was observed that eucalyptol migrated the most when compared to other active compounds. In addition, it was determined that the higher the concentration of essential oil blend in the film, the higher the migration rate of active compounds to a food. They also reported that an increase in temperature causes active compounds to migrate faster from the film. 6. Effect of essential oil incorporation on the antioxidant properties Food deterioration is usually caused due to the process called oxidation. It may affect food products during their processing and storage and result in irreversible changes on their organoleptic and nutritional properties. Lipid oxidation is one of the main factors causing food perishability because foods containing a high amount of fatty acids are more susceptible to oxidation. Lipid oxidation is responsible for discolouration, changes in texture, rancid flavour and odour, nutrient loss, and production of toxic compounds (Wang et al., 2019). Therefore, it is essential to prevent oxidation in food products by using natural antioxidants instead of chemical additives in active packaging that will lead to an increase of consumer acceptance of safe products. Since essential oils are rich in antioxidants, they are commonly used in edible films and coatings (Atarés et al., 2010, Jamróz et al., 2018). The antioxidant activity of essential oils can be expressed by their ability to act as oxygen scavengers and allow the diffusion of active agents into coated food products. Besides, the recent study carried out by Zheng et al. (2019), used the acorn starch and eugenol in edible chitosan-based film and determined that the incorporation of eugenol into edible film significantly increased the antioxidant activity (around 86.77%). A variety of different methods can be used to examine the antioxidant activity of essential oils in films. The most common analytical methods include FRAP assay and DPPH assay. FRAP assay is also known as ferric – reducing antioxidant power assay. FRAP or ferric-reducing antioxidant power assay is a method that uses antioxidants to reduce Fe3+to Fe2+ in colorimetric reaction at low pH. The ferrous – probe complex becomes blue and the absorbance is measured at the wavelength of 593 nm in relation to the total reducing capacity of antioxidants (Atarés & Chiralt, 2016). DPPH or 2,2-diphenyl-1-picrylhydrazyl free radical method is used to determine the antioxidant properties of natural products by showing the scavenging capacity of antioxidants present in plants and food extracts (Sujarwo & Keim, 2019). Both of these methods were used by Wu et al. (2019), to examine the antioxidant properties of chitosan-based coating with liposomes that contain laurel essential oil and nanosilver. They found that coatings incorporated with laurel essential oil and nano silver has a higher free radical scavenging capacity. Table 1 shows the recent studies on the use of essential oil in food packaging. Table 1. Recent studies dealing with the effect of essential oil addition on the in vitro antioxidant properties of films. Essential oil Polymer Result- Reference Thyme oil, Lemongrass oil and sage oil Sodium Alginate • Thyme oil shown strongest antimicrobial activity • Nano-emulsions containing EOs and polysaccharides could be used to form edible films Acevedo-Fani et al. (2015) Eugenol Chitosan pectin starch • Improved functional properties of the film, antimicrobial and antioxidant property enhanced Zheng et al. (2019) SaturejaKhuzestanica Kefiran carboxymethyl cellulose • Exhibited antimicrobial activity against S. aureus and E. coli • Improved antioxidant property Hasheminya et al. (2019) Cinnamon oil Chitosan-gum arabic edible film • Enhanced the water barrier properties of films • Greatly enhanced antioxidant effectiveness Xu et al. (2019) Eugenol and/or ginger essential oil Gelatin chitosan • Enhanced UV–Vis light barrier and antioxidant properties • Increased roughness of the film surface Bonilla, Poloni, Lourenço, and Sobral (2018) Helichrysum italicum Along with cold nitrogen plasma • S. aureus viable count reduced in biofilm below 2 logs CFU per cm2 after 1‐day storage Cui, Li, Li, and Lin (2016) R. officinalis L, A. herba alba Asso, O. basilicum L, M. pulegium L. Sodium alginate • Decreased moisture, thickness and tensile strength • High antibacterial effect against foodborne pathogenic bacteria and a strong antioxidant ability Mahcene et al. (2020) Oregano oil Soy Protein • Strong antibacterial activity against E. coli and S. aureus • Better mechanical properties and water vapor barrier property due to encapsulation Dos Santos Paglione et al. (2019) Rosemary oil, mint oil Chitosan pectin and starch polymer • Reduced tensile strength and water barrier properties. • Improved flexibility • Zone of inhibitions against B. subtilis, E. coli and L. monocytogenes increased at least by 40% Akhter, Masoodi, Wani, and Rather (2019) Cinnamon oil, marjoram oil, and thyme oil polypropylene (PP) surfaces • Optimized disinfectants successfully eliminate 24, and 168-hour old immature and mature biofilms formed on PP surfaces Vidács et al. (2018) Clove oil Citrus pectin • Improved heat stability • Antimicrobial efficiency against S. aureus and L. monocytogenes Nisar et al. (2018) Ginger essential oil Gelatin based film • Improved antioxidant activity but no antibacterial activity observed Alexandre, Lourenço, Bittante, Moraes, and do Amaral Sobral (2016) Rosemary extracts cassava starch films • Significant antioxidant activity, enhanced UV-properties Piñeros-Hernandez, Medina-Jaramillo, López-Córdoba, and Goyanes (2017) Thyme essential oil β-cyclodextrin ε-polylysine nanoparticles, gelatin • Exhibited excellent antimicrobial activity against C. jejuni on chicken Lin et al. (2018) Clove essential oil Polylactic acid and poly(butylene adipate-co-terephthalate) • Clove oil exhibited 80% UV blocking property • Complete killing of S. aureus that is a reduction from 6.5 log CFU/mL to 0 log CFU/mL was observed Sharma et al. (2020a) Clove essential oil (CEO) ß-cyclodextrin (ß-CD) • Absorb water from the relative humidity of 60% • Decreased elasticity Maestrello, Tonon, Madrona, Scapim, and Bergamasco (2017) Rosemary essential oil starch-carboxy methyl cellulose • Inhibitory effects against S. aureus increased, higher water vapor permeability Mohsenabadi et al. (2018) Thyme essential oil Polylactic acid and poly(butylene adipate-co-terephthalate) • Thyme oil composite film exhibited 20% UV blocking property • Inhibited E. coli biofilm growth by 71.39% Sharma et al. (2020a) Citronella oil, coriander oil, tarragon oil and thyme oil Hake protein • Decrease in mechanical properties, inhibition against Shewanella putrefaciens • Increased antioxidant property Pires et al. (2013) Laurel essential oils Chitosan coated polyethylene (PE) films • Strong antimicrobial activity. • Extend storage period of pork from 9 days to 15 days at 4 °C Wu et al. (2019) Cinnamon essential oil Polylactic acid nano film • MIC against E. coli and S. aureus was approximately 1 mg/ml. • Effectively prolong the shelf life of pork Wen et al. (2016) Cinnamon essential oil Polylactic acid and poly(butylene adipate-co-terephthalate) • 10% (w/w) cinnamon oil PLA-PBAT film exhibited 80% increase of UV-blocking property • Inhibited E. coli biofilm by 89.82% • Reduced S. aureus growth by 4.26 log CFU/ml Sharma et al. (2020b) Rosemary oil, Myrtle oil and Thyme oil Polylactic acid (PLA) • 1.5% commercial thyme oil and 5% natural myrtle oil significantly increase the antifungal activity against Aspergillus niger sp. Yahyaoui et al. (2016) Lavender essential oil starch, furcellaran and gelatin (S/F/G) films • Showed antioxidant and antimicrobial ability Jamróz et al. (2018) Pine essential oil Polylactic acid and poly(butylene adipate-co-terephthalate) • Lower Young's modulus and greater elongation at break Hernández-López et al. (2019) Eucalyptus essential oil Polylactic acid and poly(butylene adipate-co-terephthalate) • UV blocking property enhanced by 40% • Reduced S. aureus growth by 3.04 log CFU/ml and E. coli by 3.58 log CFU/ml • Inhibits E. coli biofilm by 84.37% Sharma et al. (2020b) 7. Effect of essential oil incorporation on the antibacterial properties Food can quickly deteriorate due to the presence of pathogenic and spoilage microorganisms. The growth of spoilage microorganisms may result in lipid oxidation that causes degradation of materials in food and changes its appearance, texture, smell and taste. On the other hand, food-borne pathogens may directly or indirectly infect humans and cause certain diseases. Incorporation of bioactive compounds such as essential oils into active packaging may increase the shelf-life of food products resulting in a reduced amount of waste. Essential oils extracted from various parts of aromatic plants contain several bioactive compounds that can act as antimicrobial agents (Atarés & Chiralt, 2016). Fig. 3. shows various mechanisms of essential oils activity against microorganisms. Fig. 3. Mechanisms of antimicrobial activity of essential oils (Khorshidian et al., 2018). The antibacterial properties of essential oils can be assessed in vitro by applying different methods that include agar wells method, disk diffusion method, agar dilution method and broth dilution method. Thielmann, Muranyi, and Kazman (2019) used broth microdilution method to test the antibacterial activity of 179 commercial essential oil samples against food-borne pathogenic bacteria Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The results showed that thyme and oregano essential oils are the most effective as well as Azadirachta indica and Litsea cubeba essential oils that can be considered as new antibacterial candidates against E. coli and S. aureus. The use of some essential oils in biodegradable materials for active food packaging can be quite limited because of their potent odour. However, the addition of essential oils into the food packaging material matrix, can significantly improve its antimicrobial properties by creating the interaction with film polymer and reducing the movement of antimicrobial agents into foods. The migration of antimicrobial compounds into the food products is depended on various factors such as the electrostatic interactions between antimicrobial agent and the polymer matrix, osmosis, physical changes and environmental conditions (Atarés & Chiralt, 2016). As it was mentioned before, the antibacterial activity of food packaging materials can be tested using different methods. One of the most common screening methods is a disc diffusion assay where a film disc is placed on top of the previously inoculated agar plate. Sánchez Aldana, Andrade-Ochoa, Aguilar, Contreras-Esquivel, and Nevárez-Moorillón (2015) used this method to study the antibacterial activity of pectic-based edible films that contain Mexican lime essential oil. The results showed that bagasse pectic films exhibited better in vitro antibacterial activity against E. coli, S. typhimurium, S. aureus, B. cereus and L. monocytogenes while films with Mexican lime bagasse and pomace were more effective against Gram-negative bacteria. 8. Legal aspects of the use of essential oils in food In order of essential oils to be used as flavouring agents in and on food products, they must be registered by the European Commission (EC) (Commission, 2008). Regulation (EC) No 1334/2008 issued by European Commission contains various requirements that must be put in place to ensure the safe use of flavourings. It also provides with the list of definitions describing different types of flavourings. In addition to this regulation, Annex I was introduced on 1 October 2012 containing the Union list of approved flavourings which is reviewed and updated periodically. Regulation (EC) No 1334/2008 indicates that undesirable substances must not be added into foodstuffs unless they are included in the authorised Union list. In the United States, the Food and Drug Administration (FDA) also approved the list of essential oils that can be used as flavouring agents. Besides, these essential oils are classified as GRAS (Generally Recognised as Safe). However, FDA notes that essential oils are considered safe if they are used in recommended quantities (US FDA, 2018). Even though essential oils can be used as food additives, in some cases, they can cause allergic reactions. The use of the essential oils can cause adverse health effects such as eye, skin and mucous membrane irritations and sensitivity to oils which have aldehyde and phenol groups in their composition (Ali et al., 2015). Tisserand, Young, Tisserand, and Young (2014) also reported several essential oils that can cause allergic severe effects in case of acute oral ingestion. For example, ingestion of clove essential oil can result in acidosis, degradation in liver functions, reduced blood glucose levels, convulsion, ketonuria or even coma. Poisoning from citronella essential oil can be distinguished by the signs and symptoms that include fever, vomiting, convulsions, cyanosis and deep and rapid respiration. Hence, it is crucial to determine the balance between the effectiveness and toxicity of essential oils (Ribeiro-Santos, Andrade et al., 2017). 9. Limitations of using essential oil as food packaging Essential oils have numerous significances when incorporated in food packaging such as increase in antioxidant property, UV barrier property, antimicrobial property and many more. However, it has a few limitations as well. The major drawbacks of the use of essential oil as active agents is its low solubility, high volatility, its strong aroma and the possibility of negatively affecting organoleptic properties of food. Furthermore, essential oils possess poor solubility, heat and light sensitivity, and high volatility. Due to these, the chances of losing the essential oil from the packaging increases. To save EO from losing techniques like nano emulsification and encapsulation have been used. To overcome low solubility and heat and light denaturation Moghimi, Aliahmadi, and Rafati (2017) had incorporated nanoemulsions of Thymus daenensis EO in hydroxyl propyl methyl cellulose (HPMC) films (Moghimi et al., 2017). Moreover, Lee and Park (2015), had encapsulated thyme essential oil into halloysite nanotubes (HNTs) by a vacuum process to control the release rate and to solidify the thyme oil (Lee & Park, 2015). Another major drawback of essential oil in food packaging is its possibility of negatively affecting organoleptic properties of food. As food consist of various interconnected microenvironment having complex matrices. If the level of EO high in the product it may exceed the acceptable level of organoleptic, resulting in the change of the natural taste of the food product (Ribeiro-Santos et al., 2017). Nano fibres are been studied more as food packaging to overcome the negative impact. Aytac, Ipek, Durgun, Tekinay, and Uyar (2017) had fabricated thymol inclusion complex (IC) encapsulated electrospun zein nanofibrous webs (zein-THY/γ-CD-IC-NF) as a food packaging material (Aytac et al., 2017). Wen et al. (2016), had incorporated cinnamon essential oil/β-cyclodextrin inclusion complex into polylacticacid nanofibers via electrospinning technique (Wen et al., 2016). 10. Future trends There is a variety of foods that are very susceptible to spoilage microorganisms and lipid oxidation during their storage period that leads to high losses in the market. Also, the continually growing consumer demand for healthy and safe food products led the researchers to find more natural alternative approaches in order to enhance the quality and safety of foods together maintaining their nutritional values and sensory attributes. Since essential oils are approved as additives by EC and FDA, they are now most likely to be used in and on the food products instead of synthetic preservatives. That is why there is a growing interest in essential oils being used as additives in active packaging due to their bioactive properties. More and more researches develop patents proving the beneficial properties of essential oils in the food packaging (Ribeiro-Santos, Andrade et al., 2017). The patent number WO 2013084175A1 (Ortoloni, Sagratini, Sirocchi, & Vittori, 2013) states that the incorporation of Rosmarinus officinalis, Citrus limon and Vitis vinifer essential oils into packaging materials, have a potential to inhibit and control the development of biogenic amines in fresh produce. Moreover, in the patent US20160325911A1 (Domingo, García, Prieto, & Saldaña, 2016) had filed for the development of an antimicrobial compositions for food packaging consisting of salicylaldehyde and carvacrol, thymol or their mixture. Also, the subject of patent US20190008146A (Ramirez & Sanchez, 2019) is the degradable packaging for fruits and vegetables that are composed of polyolefin-based polymer matrix incorporated with a variety of essential oils such as eucalyptus, nutmeg, hinoki, cinnamon and oregano. Encapsulation of these essential oils into degradable packaging significantly increases its antifungal and antimicrobial properties. Zhang M, 2019 were granted a patent in method for conditioning and preserving beef by combining composite essential oil (clove essential oil, cinnamon essential oil and illicium verum essential oil) for 30 s and modified atmosphere packaging (Zhang, M., Feng, L., Xu, H. and Zhang, W., Nanjing Jianggao Drying Equipment Co Ltd and Jiangnan University, (2019), 2019). 11. Conclusion Food packaging plays a vital role in protecting food products from environmental factors such as UV light, oxygen, water vapour, pressure, heat. It also helps to improve food safety and prolong shelf-life by protecting from chemical and microbiological contaminants. There are several packaging technologies that help to maintain the quality of foods. The more innovative approaches like active packaging overtake the traditional packaging technologies due to their positive effects in solving ecological problems and increasing consumer acceptability. Though active packaging can contain synthetic additives, there is a growing interest in the use of bioactive compounds such as essential oils in biodegradable materials for active food packaging. Essential oils are volatile liquids extracted from various parts of the aromatic plants and can be identified based on their aroma compounds. These bioactive compounds are suitable for active packaging due to their ability to prevent the growth of food-borne pathogens and preserve food products. Current applications of essential oils into active food packaging include their use in the form of films and coatings that are applied onto different food groups such as fruits, vegetables, fish products, meat products, milk and dairy products, and bread and baked foods. The structural arrangement of essential oil components has an impact on the final packaging material microstructure. It can increase the tensile, barrier, and optical (colour, gloss and transparency) properties of the materials depending on the type and concentration of the essential oils. The migration of active compounds from biodegradable materials to food is highly depended on the food components such as moisture which can accelerate the emission of phenolic compounds from active food packaging materials. Essential oils increase the antioxidant activity of the packaging materials due to their ability to act as oxygen scavengers and allow the diffusion of active agents into coated food products. Since essential oils contain a high amount of bioactive compounds, they improve the antibacterial properties of the packaging material, which in turn protect foods from pathogenic bacteria. In order of essential oils to be used as additives in biodegradable material, they must be registered by the European Commission. Once the essential oils are approved as additives, they are now most likely to be used in and on the food products instead of synthetic preservatives. CRediT authorship contribution statement Shubham Sharma: Conceptualization, Investigation, Data curation, Writing - original draft. Sandra Barkauskaite: Conceptualization, Investigation, Data curation, Writing - original draft. Amit K. Jaiswal: Conceptualization, Writing - review & editing, Supervision, Project administration, Funding acquisition. Swarna Jaiswal: Conceptualization, Writing - review & editing, Supervision, Project administration. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. 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Expanded Alfa Laval Unique DV-ST UltraPure valve range boosts aseptic processing efficiency
To meet the rising demand for more efficient aseptic processing, Alfa Laval is extending its range of Unique DV-ST UltraPure diaphragm valves. The all-new range comes with slimmer actuators and optimized lightweight cast valve bodies with options for unbeatably economical operation. The enhanced DV-ST UltraPure range is fully customizable to meet virtually any aseptic process requirement across the food and pharmaceutical industries. Slimmer, space-saving actuators and lightweight cast valve bodies for optimized performance are the innovations behind the enhanced DV-ST UltraPure range. These smaller aseptic diaphragm valves deliver big – from lower total cost of ownership to tangible sustainability gains. “These enhancements make our Unique DV-ST UltraPure diaphragm valves second to none,” says Paw Kramer, Portfolio Manager, Valves and Automation, Alfa Laval. Smaller actuator footprint, big performance Size matters. The new stainless steel slim (SS/SL) DV-ST UltraPure actuator is 42% lighter, 25% more compact, and 17% shorter in height than most actuators. Another plus: it is more energy efficient due to reduced air consumption. Tested to perform a million strokes without service, these fully welded, maintenance-free actuators handle a wide range of pressures. Options include a stroke limiter, economical valve position indication, and comprehensive automated valve sensing and control. New Cast Optimized Performance (OP) valve bodies Joining the DV-ST UltraPure family of valve bodies is the new ASME BPE-compliant Cast OP. Engineered based on computational fluid dynamics analysis, it is 36% lighter in weight, on average, than the standard cast valve body and features a much smaller seat size. This translates into benefits including: reduced installation costs due to smaller footprint; faster, more energy-efficient cleaning cycles because there’s less steel to heat for sterilization in place; lower total cost of ownership due to smaller diaphragms, handles and/or actuators; and, safe, simple, low-cost maintenance. Engineered to exact customer specifications Fully customizable, the enhanced Unique DV-ST UltraPure range meets virtually any aseptic process requirement. It is backed by the Alfa Laval Q-doc documentation package for full parts traceability, smooth qualification and validation processes, and long-term peace of mind. To learn more about the enhanced Alfa Laval Unique DV-ST UltraPure range, visit www.alfalaval .com/unique-dv-st-ultrapure/ This is Alfa Laval Alfa Laval is active in the areas of Energy, Marine, and Food & Water, offering its expertise, products, and service to a wide range of industries in some 100 countries. The company is committed to optimizing processes, creating responsible growth, and driving progress – always going the extra mile to support customers in achieving their business goals and sustainability targets. Alfa Laval’s innovative technologies are dedicated to purifying, refining, and reusing materials, promoting more responsible use of natural resources. They contribute to improved energy efficiency and heat recovery, better water treatment, and reduced emissions. Thereby, Alfa Laval is not only accelerating success for its customers, but also for people and the planet. Making the world better, every day. It’s all about Advancing betterTM. Alfa Laval has 16,700 employees. Annual sales in 2020 were SEK 41.5 billion (approx. EUR 4 billion). The company is listed on Nasdaq OMX. www.alfalaval.com For further information, contact: Paw Kramer Portfolio Manager, Valves and Automation, Alfa Laval Phone: +45 28 95 57 05 E-mail: email@example.com Marianne Hojby Marketing Communication Manager, Alfa Laval Mobil : +45 28 95 44 71 E-mail: firstname.lastname@example.org
A Kind of Magic – Cosmetics Packaging Without Microplastic Pollution
/ins Sulapac has launched a ground-breaking innovation. Now, water-based products can be packaged with a new bio-based Sulapac barrier that biodegrades without leaving permanent microplastics behind The barrier is no longer an obstacle The beauty and personal care industry is worth over $500 billion a year and the market is expected to grow annually by 4.75%. Accordingly, the forerunners have eagerly been looking for sustainable packaging solutions. While around 90% of the cosmetics market consist of water-based emulsions, there has not been an alternative for water-based products that biodegrades without leaving permanent microplastics behind. Now, Sulapac has invented a patent-pending material for them. As well as being fully sustainable, the Sulapac barrier fits industry standard requirements. In fact, the test results have been fantastic.* “I’m excited that we managed to create a sustainable barrier that is suitable for water-based products! The development and extensive testing took longer than we anticipated, but now it’s finally official. We are pleased to offer a real game-changer to our customers together with the industry leaders like our Preferred Partner for Cosmetics, Quadpack,” says Dr. Suvi Haimi, CEO and co-founder of Sulapac. The complete package At present, Sulapac is also announcing a new flexible material designed for thin-walled jars with excellent impact strength. It has low carbon footprint based on eco-design, climate conscious raw materials and cost-efficient, high-volume manufacturing. Combined with the Sulapac barrier, the company’s trusted partners provide a compelling portfolio of different sized jars for both oil and water-based cosmetics. They also give support throughout the process, a turnkey solution. “The new barrier developed by Sulapac allows us to continue to offer sustainable innovations that meet and exceed market demands. From new capacities to cutting-edge technical solutions, Quadpack is happy to provide an ever-growing product range in Sulapac® material to all beauty brands,” says Pierre Antoine Henry, Head of Categories at Quadpack, Sulapac’s Preferred Partner for Cosmetics. Sulapac has made sure that the switch from conventional plastics is as easy as possible. The drop-in solution material can be mass produced with the existing plastic machinery. What’s more, its natural appearance and haptic feel make it stand out. Sulapac is beautiful, functional and sustainable, just like nature. Currently, the ideal way to recycle a product made of Sulapac material is via industrial composting. It biodegrades without leaving permanent microplastics behind. Mechanical and chemical recycling are also viable options, and Sulapac is developing a closed-loop system. The Take Back Sulapac pilot will be launched in the near future. Now, Sulapac is looking for forerunner cosmetic brands to join its mission to save the world from plastic waste. About Sulapac Sulapac® is an award-winning, patented bio-based material innovation for the circular economy. It accelerates the plastic waste-free future with sustainable materials that are beautiful and functional. Like nature. Sulapac was founded in 2016 by Dr. Suvi Haimi, Dr. Laura Tirkkonen-Rajasalo and Dr. Antti Pärssinen. The company has been ranked one of the 100 hottest startups in Europe by WIRED UK. Join the forerunners at sulapac.com. Together we can save the world from plastic waste. About Quadpack Quadpack is an international manufacturer and provider of enhanced packaging solutions for beauty brand owners and contract fillers. With offices and production facilities in Europe, the US and the Asia Pacific region, and a strategic network of manufacturing partners, Quadpack develops bespoke and customised packs for prestige, masstige and mass market customers. Listed on Euronext Growth in Paris since October 2019, Quadpack relies on a workforce of 600 people to build a more sustainable world. For more information, please visit www.quadpack.com Further information Suvi Haimi CEO and Co-Founder Sulapac email@example.com +358 44 029 1203 Antti Valtonen Head of Communications Sulapac firstname.lastname@example.org +358 40 729 4793 Mariam Khan Press officer Quadpack email@example.com +34 93 265 4463 Read more www.sulapac.com *Acceptable weight loss for cosmetic packaging is typically below 3%. The Sulapac Barrier measured a loss 1.3% in a Sulapac 4-part jar with emulsion in 40°C, over 12 weeks.
NEW BOPP FILM WITH IMPROVED THERMAL RESISTANCE
Innovia Films is launching a new film in its Propafilm™ range of transparent speciality packaging films. CHS offers improved thermal resistance and shrinkage properties compared to conventional polypropylene films. It has been designed to substitute traditional outer web films in laminates for applications such as pouches and lidding in various food markets. Paul Watters, Product Development Manager Packaging, Innovia Films explains “With CHS, we have developed a BOPP film with enhanced functionality which allows the film to be used in new application areas. We have been particularly successful with the film’s performance as the outer film of laminate structures used in retort pouch applications. In this application area there are a lot of mixed material laminates used and because of the drive towards simplified structures it is important to offer alternatives to the traditional films used and CHS is a part of this solution.” Watters continued “CHS will help our customer on the journey towards developing new structures based on mono-materials for better and more efficient recycling in the future.” CHS like many other Propafilm products has been classified as Made for Recycling by Interseroh. Paul Watters, explains “The Interseroh certification of CHS demonstrates that the film can be recycled in countries where the infrastructure exists to recycle polypropylene.” If you want more information or to trial this new film for your products then contact firstname.lastname@example.org
V-Shapes Introduces VS dflex for Convenient Nearline Sachet Printing
High-quality reel-to-reel nearline printing powered by Memjet and ColorGATE – ideal companions for V-Shapes unique single-dose packaging machine Bologna, Italy. 12 May 2021. V-Shapes, an innovative supplier of vertically integrated products and services for convenient, hygienic and sustainable single-dose packaging, today announced the launch of the V-Shapes VS dflex nearline reel-to-reel printer for printing the top layer of its unique single-dose sachets that are opened with a single gesture using one hand. This compact, professional-grade printing system, Powered by Memjet DuraFlex®, makes it easy to print flexible packaging on site, eliminating the need to outsource printing or to tie up other printing equipment in the plant, especially for shorter runs of customized sachets. VS dflex inks were designed for food packaging and specially formulated for quick drying after printing, allowing the substrate to be ready for use with the V-Shapes ALPHA fill and seal packaging/converting machine. The VS dflex touch screen interface makes it easy for operators to efficiently manage the printing process with minimal training required. “We have always had an objective of making high-quality printing available for our packaging/converting machines, to meet customer demand for faster time to market, personalization and more,” says Christian Burattini, CEO of V-Shapes. “We accomplished that earlier this year with the integration of the TrojanLabel T2 high volume digital label press into our V-Shapes PRIME single-lane packaging machine, and we have plans to integrate in-line printing into our six-lane ALPHA machine as well. But for those ALPHA machines already in the field or that will be acquired prior to availability of inline printing, we have developed VS dflex, a more productive reel-to-reel printing solution that makes it easier for packaging converters/fillers to accomplish the complete manufacturing process for our unique single-dose sachets under one roof with a compact footprint. In this configuration, the bottom layer of substrate is printed inline in black only.” The VS dflex reel-to-reel nearline printer takes advantage of the speed and image quality of Memjet’s DuraFlex® multicolor A3+ printhead and water-based pigment inks, along with the advanced features and color management capabilities of the ColorGATE Packaging Productionserver, a RIP and color management solution for industrial packaging printing to deliver high quality, color-accurate printing at 1600 dpi at a speed of up to 24.7 meters per minute (90 feet per minute). It uses certified recyclable substrates, either sourced from industry leader SIHL or with V-Shapes proprietary materials. “Our strategic partnership with SIHL is particularly valuable thanks to the ability to print very high quality with aqueous ink and no pre-treatment on SIHL Artysio laminates,” adds Burattini. “They also have our specific materials stocked in Germany and the U.S. to ensure fast and timely delivery.” “We are excited by the addition of VS dflex, the latest nearline printer from V-Shapes for their inline print, form, fill and seal packaging system,” says Russell Boa, Senior Vice President of Sales – North America and EMEA at Memjet. “The VS dflex enables professional printing with vivid colors, beautiful precision, simply and cost effectively at high production speeds. The combination of V-Shapes leadership in packaging innovation and technology integration makes them a first-class partner to work with.” “Founded in 1997, ColorGATE, unlike many other RIPs and color management vendors, has focused on industrial markets for the past decade, making this collaboration with V-Shapes and Memjet perfectly in line with our strategies and capabilities,” said Oliver Luedtke, Chief Marketing Officer at ColorGATE. “We have had a very productive relationship with the creative and innovative team at V-Shapes. We are absolutely aligned with them in the desire to bring top-notch color quality, digitization and Industry 4.0 compliance to the package printing process. We developed a bespoke Output Management Set specifically for this printing system that takes into account the Memjet DuraFlex architecture and brings all of the appropriate ColorGATE capabilities to the system for the utmost in printing productivity and quality. In addition, our REST API interface opens up for V-Shapes future opportunities for more workflow integration as their products continue to evolve.” To learn more about the VS dflex nearline printer, click here, and for other products and services from V-Shapes, visit www.V-Shapes.com.