Food packaging films and methods of making food packaging films

Abstract

A packaging film including protein, a plasticizer, and reducing agent is provided. A coating for use with packaging films is also provided. The coating includes wax particles, ethyl cellulose, and an emulsifier. The film is prepared by a method comprising mixing protein with water to form a first mixture, obtaining a supernatant from the first mixture, adding a plasticizer and reducing agent to the supernatant to form a second mixture, and drying the second mixture to form the film. The coated film is prepared by a method comprising melting wax to form melted wax, adding an emulsifier and a solvent to the melted wax to form a third mixture, homogenizing the third mixture to form an emulsion, adding ethyl cellulose to the emulsion to form a coating solution, and applying the coating solution to a film to form the coated film.

Description

FOOD PACKAGING FILMS AND METHODS OF MAKING FOOD PACKAGING FILMSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 464,446, filed on May 5, 2023, which is incorporated herein by reference in its entirety.FIELD

[0002] This application relates generally to packaging films for food products.BACKGROUND

[0003] Packaging materials are used to contain and protect a variety of items during storage and transport. A variety of materials such as cardboard, plastics, metal, and glass have been used for packaging, and most packaging materials are deposited in a landfill after use. Nonrenewable resources such as petroleum have been used to produce conventional non- biodegradable plastics. Though plastic-based packaging may be desirable due to its low cost, packaging materials containing such plastics can persist for a considerable period of time in the environment after disposal.

[0004] There has been increasing demand that renewable resources and / or materials that more readily degrade in the environment be used to produce packaging materials. For example, polyhydroxyalkanoate (PHA) films are made from renewable resources, including bacterial sources. Also, polyhydroxybutanoate (PHB) films are water-insoluble but easily degraded. Poly(2-hydroxypropanoic acid) (polylactic acid, PLA) films are also degradable. Polyvinyl alcohol (PVA) films are made from a synthetic polymer but are water soluble and can degrade when subjected to environmental conditions (e.g., sunlight, moisture, or microorganisms in soil). Further, materials based on bio-renewable and easily degradable cellulose have found recent use.

[0005] However, while each of these polymers may be advantageous in terms of degradability or being produced from renewable resources, films formed from these polymersmay not provide the mechanical properties, such as tensile strength, puncture strength, water vapor permeability, and oxygen transmission, that are required for specific applications. For example, while water solubility may be beneficial in terms of degradation properties after disposal, solubility may limit the usefulness of the material as packaging for liquid food products or food products with a high water activity. Also, the pH of a liquid or food product may be detrimental to the stability of the packaging material during the desired shelf life of the product.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a schematic diagram of a film according to some aspects;

[0007] FIG. 2 is a schematic diagram of a coated film according to some aspects;

[0008] FIG. 3 is a light microscopic image (lOOx magnification) of a beeswax emulsion from a method of making a coated film according to some aspects;

[0009] FIG. 4 is a graph of flow behavior of an example coating solution illustrating the viscosity (Pa • s, Y axis) as a function of the shear rate (1 / s, X axis);

[0010] FIG. 5 is a stress-strain plot of an example film illustrating the stress (kPa, Y axis) as a function of strain (%, X axis);

[0011] FIG. 6 is a stress-strain plot of an example film illustrating the stress (kPa, Y axis) as a function of strain (%, X axis);

[0012] FIG. 7 and FIG. 8 are moisture loss plots of example ketchup sachets illustrating weight-loss (%, Y axis) as a function of storage time (days, X axis);

[0013] FIG. 9 is a graph of the rheological variation of example ketchup sachets illustrating the viscosity (Pa • s, Y axis) as a function of the shear rate (1 / s, X axis);

[0014] FIGS. 10 and 11 are graphs showing the weight loss of ketchup-filled sachets made with coated and uncoated films over 2 days storage;

[0015] FIGS. 12 and 13 are graphs showing the weight loss rate of ketchup-filled sachets made with coated and uncoated films over 2 days storage; and

[0016] FIG. 14 is a graph showing the weight loss rates required to achieve 1, 2, 3, 4, 5, and 6-month shelf lives.

[0017] Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and / or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. Certain actions and / or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. The terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.DETAILED DESCRIPTION

[0018] Described herein are films, which, in some approaches, may be coated films, that may be used to package food products. Also described herein are bio-based films, which, in some approaches, may be coated films, that may be used to package food products. As used herein, the term "bio-based" means that the films are derived from plants and / or other renewable materials and are an alternative to petroleum-derived products. For example, the food product may be an aqueous food product such as condiments (e.g., ketchup) or other high water activity food product. The film may be disintegrable and / or dissolvable, in a basic solution, water, and / or under composting conditions. Additionally, the film may have mechanical and barrier properties that make it suitable as a food packaging material. The film described herein may be formed into any desirable package, and in some examples, the film may be formed into a sachet.

[0019] Also described herein are coatings, including wax-based coatings, for films. The coatings may be applied to the protein-based films described herein or films made from other materials.

[0020] Examples of the film are shown in FIG. 1 and FIG. 2. As shown in FIG. 1, in some approaches, the film may include a protein base film 10, which may or may not include a coating 12 applied thereon. As shown in FIG. 2, in some approaches, the film is a coated film 14, which may include the protein base film 10 or another base film 10', and which includes the coating 12. As used herein, the term "film" may refer to a coated film or an uncoated film (i.e., a "base film").

[0021] Protein Film

[0022] In one approach, the film comprises a protein base film 10. The protein base film 10 may prevent the external environment from damaging a food product packaged within the film and may act as a support for the coating (if a coating is included).

[0023] To provide a film able to dissolve in water, the protein used in the film should be substantially water soluble. In one aspect, the protein may be a defatted protein product. In some approaches, the protein is not alcohol soluble because the resulting base film might then be redissolved by a subsequently applied coating solution when an alcohol (such as ethanol) is used as a solvent. Exemplary proteins that are alcohol soluble include prolamins (e.g., zein and wheat gluten).

[0024] The protein may include one or more of soybean protein, pea, other legume, and gelatin. In one particular approach, the protein is soybean protein. In some examples, the soybean protein may be obtained from defatted soybean dreg or defatted soybean meal. In these examples, the defatted soybean dreg or defatted soybean meal may be mixed with water and then centrifuged to obtain soybean protein in the supernatant.

[0025] For applications where compostability is more desirable than dissolvability in water, additional proteins may be used. For example, cottonseed protein and sesame seed protein may be used.

[0026] The amount of crude protein in a protein ingredient may depend on the form of the protein-containing ingredient (e.g., whether the ingredient is in the form of an isolate, aconcentrate, or a flour). Thus, for purposes herein, the amount of crude protein is the amount of protein contributed by any protein-containing ingredient. The amount of crude protein in a soybean ingredient or in the film may be measured by the Association of Official Analytical Chemists (AOAC) Official Method 992.15 (which is incorporated herein by reference in its entirety). Additionally, or alternatively, the amount of crude protein in a soybean ingredient or in the film may be measured by the Dumas Method.

[0027] The film may further include a plasticizer. The plasticizer may improve elasticity and toughness of the film (as compared to a similar film including the same ingredients but without a plasticizer therein). Any suitable plasticizer may be used. In some examples, the plasticizer comprises glycerol, propylene glycol, and 1,3-propanediol.

[0028] The film may further comprise a reducing agent, such as sodium sulfite. In some approaches, the reducing agent is water soluble. The reducing agent may be included to inhibit the formation of disulfide bonds in the protein. The reducing agent may increase the ability of the film to disintegrate and / or dissolve in basic solutions (e.g., a NaOH solution, a NaHCCh solution, etc.) (as compared to a film without sodium sulfite therein). The reducing agent may increase the film's flexibility and resistance to breaking (as compared to a film without reducing agent therein).

[0029] The protein base film described herein can be made by a variety of methods. In some examples, a method of making a film comprises: mixing protein with water to form a first mixture (the mixing may take place at room temperature or below about 60°C; generally, heating while mixing is not required); obtaining a protein-containing supernatant from the first mixture; heating the protein-containing supernatant to at an elevated temperature (e.g., about 95°C to about 100°C, in another aspect about 95°C to about 98°C, for about 5 to about 15 minutes) to denature the protein; adding a plasticizer and sodium sulfite to the heated supernatant and mixing to form a second mixture; and drying the second mixture to form the film. In particular, the protein may be mixed with water to solubilize at least a portion of the protein in a first mixture and then separating the soluble protein from the remainder of the protein source in a protein-containing supernatant. The mixing step may involve vigorously mixing, such as blending or homogenizing, and then centrifuging the mixture to form a pellet and supernatant. The separation step precipitates insoluble fibers present in the protein mixture(e.g., defatted soybean dreg). However, if a protein concentrate or isolate is used, separation may be unnecessary. Moreover, if an extrusion process (and not a casting process) is used to make the base film, centrifugation might be unnecessary as well.

[0030] For example, the mixture may be blended for about 1 to about 5 minutes, in another aspect about 1 to about 3 minutes, and centrifuged at about 2000 to about 10,000 rpm, in another aspect about 2000 to about 6000 rpm, in another aspect about 4000 rpm, for about 5 to about 15 minutes, in another aspect about 7 to about 12 minutes, and in another aspect about 10 minutes.

[0031] The protein-containing supernatant may then be separated from the pellet and the pellet discarded. The protein-containing supernatant may be placed in a boiling water bath and heated to about 85°C to about 130°C, in another aspect about 90°C to about 110°C, and in another aspect about 95°C, for about 5 to about 15 minutes, in another aspect about 8 to about 12 minutes, and in another aspect about 10 minutes.

[0032] In some examples, the method may further comprise grinding the mixture prior to centrifugation. In these examples, the grinding may promote the release of the protein into the supernatant. For purposes herein, the term "grinding" is used to encompass both grinding and other treatments that are effective to reduce the particle size of the protein source. Once the protein is obtained as part of the supernatant, the plasticizer and reducing agent may be added to form a second mixture. The second mixture may then be dried to form a film.

[0033] After the addition of the plasticizer and sodium sulfite to the heated supernatant, the second mixture may be centrifuged or otherwise treated to degas the second mixture. For example, any bubbles present may be removed by centrifugation or vacuum. For example, the second mixture may be centrifuged at about 800 rpm for 10 minutes.

[0034] In one approach, the protein is present in an amount within the range of about 20 wt% to about 50 wt%, about 30 wt% to about 45 wt%, or about 35 wt% to about 40 wt%, crude protein, based on a total weight of the base film mixture (prior to drying of the film). Soluble carbohydrates and minerals from protein-based ingredients may also be included in the base film, such as about 30 wt% to about 45 wt% carbohydrates and minerals in soybean meal. In another approach, the protein is mixed with water at a ratio of about 0.1:15, about 0.5:15, about 1:15, or about 1:9 to form a base film mixture.

[0035] In one approach, the plasticizer is present in an amount within the range of about 15 wt% to about 40 wt%, about 20 wt% to about 30 wt%, about 21 wt% to about 27 wt%, in another aspect about 21 wt% to about 23 wt%, in another aspect about 25 wt% to about 27 wt%, based on a total weight of the base film mixture (prior to drying of the film).

[0036] In one approach, the reducing agent is present in an amount within the range of about 0.01 wt% to about 2 wt%, about 0.1 wt% to about 1 wt%, about 0.1 to about 0.6 wt%, in another aspect about 0.1 wt% to about 0.2 wt%, in another aspect about 0.4 wt% to about 0.6 wt%, based on a total weight of the base film mixture (prior to drying of the film).

[0037] In another approach, water is present in an amount of about 20 wt% to about 60 wt%, about 25 wt% to about 55 wt%, or about 25 wt% to about 50 wt%, based on a total weight of the base film mixture (prior to drying of the film).

[0038] The base film mixture may then be spread onto a surface by any suitable technique, such as by wet casting or extrusion, and dried to form a film. For example, a two-stage drying step may be used: in stage 1, bottom heating at 60°C, at 1 atm, for about 4 hours; in stage 2, vacuum heating at 60° C.

[0039] After drying, the composition of the film on a dry weight basis is about 15% to about 40% crude protein (in another aspect about 20% to about 35%, in another aspect about 25% to about 30%), about 10 to about 40 percent plasticizer (in another aspect about 15% to about 30%, in another aspect about 20% to about 30%), about 0.1 to about 2.0 percent reducing agent (in another aspect about 0.1% to about 1.0%, in another aspect about 0.25% to about 0.8%). The remaining dry matter may include, for example, any other dry matter, such as carbohydrates and / or minerals that may be part of the protein ingredient.

[0040] In some approaches, the film may be combined with one or more additional layers of film, including a further layer of protein-based film or a film formed of other ingredients. In these approaches, the base film may be, for example, a polyvinyl alcohol-based film, such as HYDROPOL™ 30164P (Aquapak) film or a HYDROPOL™ 33104P (Aquapak) film.

[0041] In some aspects, the method of making a coated film further comprises making the protein base film as described above.

[0042] The films made by the methods described herein may be used to package food products. In some aspects, the films may be used to form sachets. In some examples, the sachet may be formed by heat-sealing the film to another portion of the film or to another piece of film. In some approaches, the sachet may be filled with a food product, such as a condiment, before the sachet is completely sealed. In one aspect, condiments such as ketchup, mayonnaise, mustard, relish, ponzu sauce, oil, vinegar, tartar sauce, fry sauce, and soy sauce may be provided in the sachet. In one aspect, the food product is aqueous and has a moisture content of about 67 wt% to about 70 wt% (e.g., ketchup) or in another aspect about 10 wt% to about 20 wt% (e.g., mayonnaise).

[0043] In one aspect, the package (or sachet) is able to contain an aqueous food product for a desired shelf life while also being biodegradable (or compostable) and / or water soluble upon disposal. For example, the packaging material may be capable of providing a shelf life of at least 1 week, at least 2 weeks, at least 3 weeks, or at least 4 weeks, when the packaging material contains an aqueous food product. To have an acceptable shelf life, an aqueous food product should not lose more than 3% moisture / total weight over the shelf-life period when stored at 20-25°C and 40-60% relative humidity, in another aspect at 20°C and 40% relative humidity.

[0044] In some aspects, the films disclosed herein may have mechanical properties that make them suitable to package food. In one example, it is desired that the films (with or without coating) have a tensile strength of at least 50 N. In another example, it is desired that the films (with or without coating) are resistant to a puncture force of at least 20 N. The mechanical properties may be determined according to the methods described in the Examples below.

[0045] In some aspects, the films disclosed herein may be partially or completely disintegrable and / or dissolvable, in a basic solution, water, and / or under composting conditions. The ability of a film to disintegrate and / or dissolve may be determined according to the methods described in the Examples below.

[0046] Coating

[0047] The protein films described herein and / or films prepared from other materials (e.g., polyvinyl alcohol or modified polyvinyl alcohol films), may be combined with a coating to modulate physical properties of the film. The coating may act as food-contact layer that mayprevent film-and-food mass transfer. The coating may also serve as a moisture barrier by reducing water vapor transmission and / or oxygen transmission through the film(s).

[0048] The coating generally includes wax particles, a high melting fat, or a combination thereof. As used herein, the term "high melting fat" refers to a fat that melts above 50°C. A high melting fat has a high concentration of saturated fatty acids and longer hydrocarbon chains. Suitable high melting fats include hydrogenated palm oil and hydrogenated soybean oil. Suitable waxes include, for example, beeswax.

[0049] In one approach, the coating includes wax particles. In one approach, the wax particles are present in an amount within the range of about 60 wt% to about 70 wt%, in another aspect about 60 wt% to about 66 wt%, in another aspect about 60 wt% to about 62 wt%, in another aspect about 64 wt% to about 66 wt%, based on a total weight of the coating.

[0050] The wax particles are dispersed in a solvent to form the coating. Suitable solvents are able to solubilize the high melting fat or wax. The solvent should also not wet the base film. The solvent may include, for example, ethanol, methanol, benzyl alcohol, and ethyl acetate. The solvent is included in an amount of about 650 to about 800 wt%, in another aspect about 650 to about 700 wt%, in another aspect about 750 to about 800 wt%, based on a total weight of the coating solids (i.e., the total solids content of the coating). Because the solvent is later evaporated from the coating mixture when applied to a film, theoretically leading to no residual solvent in the final coating layer, the amount of solvent is calculated on the basis of total coating solids.

[0051] In one aspect, the coating may further comprise ethyl cellulose. Ethyl cellulose generally has good solubility in alcohol solvents. The ethyl cellulose forms a dense matrix that holds the dispersed fat or wax particles and improves the attachment of the coating layer to the base film. Other ingredients with similar functionality, and which are soluble in alcohol, may also be used. In one approach, the ethyl cellulose is present in an amount within the range of about 30 wt% to about 40 wt%, in another aspect about 31 wt% to about 36 wt%, in another aspect about 31 wt% to about 33 wt%, in another aspect about 34 wt% to about 36 wt%, based on a total weight of the coating (prior to drying).

[0052] In some examples, the wax particles have a mean particle size within the range of about 5 pm to about 30 pm, in another aspect about 5 pm to about 10 pm, and in another aspect about 40 pm to about 50 pm. In general, having too large of particles is more likely to lead to deficiencies in the barrier properties. The particle size distribution may be mono modal or bimodaL However, at least in one aspect, it is believed that a bimodal particle size distribution may be more advantageous for blocking moisture migration through the film. Particle size may be measured by microscopy or by a dynamic light scattering particle size analyzer.

[0053] Further reduction of the mean particle size of the wax may be beneficial. By reducing the mean particle sizes, the thickness of the coating may also be reduced and the wax within the coating may be more evenly distributed. The mean particle size may be reduced by adding other fat solids to the wax. Further, one or more ingredients acting as a surfactant and / or emulsifier may be included. The emulsifier may be used to stabilize wax particles in the coating. Suitable emulsifiers may include an emulsifier or blend of emulsifiers comprising a hydrophilic emulsifier, such as those having an HLB value of at least 10. For example, polysorbate emulsifiers such as TWEEN® 20, TWEEN® 80, and combinations thereof may be used. In one approach, the one or more emulsifier is present in an amount within the range of about 2 wt% to about 3.5 wt%, about 2 wt% to about 3 wt%, about 2.4 wt% to about 3 wt%, about 2.4 wt% to about 2.6 wt%, based on a total weight of the coating (prior to drying). It was found that including TWEEN®80 at less than 1 wt% can destabilize the wax solution. Therefore, if TWEEN®80 is used, it should be included at higher amounts.

[0054] The coating described herein can be made by a variety of methods. In some examples, a method of making a coated film comprises: melting the wax to form melted wax; adding an emulsifier and a solvent to the wax before or after the melting step to form a mixture; homogenizing the mixture to form an emulsion; adding ethyl cellulose to the emulsion to form a coating solution; and applying the coating solution to a film to form the coated film.

[0055] The wax may be melted and emulsified so that the wax particles may be well dispersed, and the coating has a substantially even, homogenous distribution of wax. For purposes herein, the term "homogenize" is used to encompass both homogenization and high shear treatments capable of providing a homogenous mixture of wax particles.

[0056] The coating may be applied by any suitable method, such as one or more of dip coating, roll coating, spraying, spin coating, electrospraying, spray atomization, and flow coating.

[0057] In some approaches, the coating may be applied to a film or packaging material at a thickness of about 70 pm to about 150 pm, in another aspect about 70 pm to about 120 pm, in another aspect about 78 pm to about 82 pm, and in another aspect about 118 pm to about 120 pm.

[0058] To further illustrate the present disclosure, examples are given herein. It is to be understood that these examples are provided for illustrative purposes and are not to be construed as limiting the scope of the present disclosure.EXAMPLES

[0059] Example 1 - Preparation of Soybean Protein Films (Sample "A")

[0060] Each of the following Sample "A" films was prepared according to the following method. Each Sample "A" film included soybean protein, glycerol as the plasticizer, and sodium sulfite.

[0061] Defatted soybean dreg was blended with water at a weight ratio of 1 : 9 (1 part (1 kg) defatted soybean dreg to 9 parts (9 kg) water) using a soymilk grinder. The grinding process involved three cycles, in which the grinder was operated at high speed for 30 seconds and stopped for 10 seconds. Then the mixture was centrifuged at 4000 rpm for 10 minutes. Glycerol and sodium sulfite were added to the supernatant from the centrifugation and then heated to 95°C. The mixture was held at 95°C for 10 minutes to form a solution. The solution included 96.3 wt% supernatant of defatted soybean dreg, 3.6 wt% glycerol, and 0.1 wt% sodium sulfite.

[0062] An open square aluminum pan (10 cm x 10 cm x 5 cm) was heated in a water bath (85 °C ± 1 °C) for 10 to 12 minutes. The solution (about 100 g) was preheated and transferred to the aluminum pan and then incubated in the water bath without agitation. The film gradually developed on the liquid surface after several minutes. The developed film was carefully isolated using a glass rod and dried at room temperature.

[0063] Example 2 - Preparation of Soybean Protein Films Without Reducing Agent (Sample "B")

[0064] Sample "B" films were prepared according to a comparable method to that described above for the Sample " A" film, except that the Sample "B" films were prepared without sodium sulfite and, instead, additional heated soybean meal solution was used: 96.4% aqueous supernatant of defatted soybean dreg; 3.6% glycerol, and 0% sodium sulfite.

[0065] Example 3 - Preparation of Soybean Protein Films (Sample "C")

[0066] Each of the Sample "C" films was prepared according to the following method. Each Sample "C" film included soybean protein, glycerol as the plasticizer, and sodium sulfite.

[0067] Defatted soybean meal was mixed with distilled water at a weight ratio of 1:9. The mixture was homogenized using a kitchen blender for 2 minutes and then centrifuged at 4000 rpm for 10 minutes. The supernatant from the centrifugation was collected and placed in a boiling water bath, heated to 95°C, and kept at 95°C for 10 minutes to form a heated soybean meal solution. Then, 2.5 wt% glycerol and 0.05 wt% anhydrous sodium sulfite (by weight of the heated soybean meal solution) were added into the heated soybean meal solution, and the combination was well-mixed to form a protein liquid. The protein liquid was centrifuged at 800 rpm for 10 minutes for degassing. No sediment (pellet) was produced in the centrifugation. After degassing, the protein liquid was transferred into a tray that was coated with a layer of solid beeswax. The protein liquid was dried at 60°C for 4 hours, and then dried in a vacuum drying oven (at a pressure of -0.06 to -0.07 MPa) for 4 hours to form the film. Then, the film was removed from the beeswax surface by peeling by hand.

[0068] Example 4: Preparation of Beeswax Coating Solutions (Sample "D")

[0069] Each of the Sample "D" beeswax coating solutions was prepared according to the following method. Each Sample "D" coating solution included beeswax particles, ethyl cellulose, and a polysorbate surfactant (TWEEN® 80) as the emulsifier.

[0070] Sample D was prepared as follows. 1.120g beeswax was melted at 80°C for 15 min. Then 3g octenyl succinic anhydride-modified starch (OSA starch) was added to 480 grams 90°C deionized water, stirred at 200 rpm for 3 minutes at 90°C. The mixed OSA starch solution wasadded to the melted beeswax and stirred at 300 rpm for 10 minutes to prepare emulsion "A". Emulsion A was subjected to highspeed shearing at 11000 rpm for 3 minutes at 90°C. The homogenized emulsion A was then mixed with oxidized acetate starch at a weight ratio 5:1 to obtain emulsion "B".

[0071] Then a 5%(w / w) acetate starch dispersion was prepared using deionized water and heated to 100°C in a boiling water bath until complete pasting.

[0072] A coating solution was prepared by mixing the acetate starch paste and emulsion B at a weight ratio of 1:1.

[0073] Example 5: Preparation of Beeswax Coating Solutions (Sample "E")

[0074] In the following Examples, each of the Sample "E" beeswax coating suspensions was prepared according to the following method. Each Sample "E" coating solution included beeswax particles, ethylcellulose, and a polysorbate surfactant (TWEEN® 80) as the emulsifier.

[0075] Beeswax was melted at 80°C. Then, 1.25 wt% polysorbate surfactant (by weight of the beeswax) was added with continuous stirring for 10 minutes. The melted beeswax and polysorbate surfactant mixture was cooled to 65°C and mixed with ethanol at a ratio of 1:4 (w / w). The mixture was stirred at 65°C and 300 rpm for 10 minutes. The mixture was then further homogenized using an IKA high-speed homogenizer at 65°C for 3 minutes until a stable emulsion was obtained. The hot emulsion was then transferred to an ice water bath and cooled to room temperature (25°C).

[0076] Each batch (10 g) of beeswax emulsion was diluted with 15 g of an ethanol solution pre-dissolved with 7 wt% ethylcellulose, mixed well, and then stored in a capped bottle before use.

[0077] FIG. 3 shows a microscopy image using a light microscope (100X magnification) of the beeswax emulsion. As shown in FIG. 3, the beeswax particles were substantially uniform in size. The beeswax particles in the beeswax emulsion and coating solution had a mean particle size of about 40 pm to about 50 pm. Particle size was measured using Image-J software.

[0078] The flow behavior of the coating solution is shown is FIG. 4. The viscosity of the coating solution exhibited significant shear-thinning behavior. At low shear rates (<10 / s),viscosity quickly changed from about 0.2 Pa • s to about 1.8 Pa • s at 25°C. The viscosity was measured using a TA Discovery HR-2 rheometer equipped with a parallel plate geometry (PLATE H / A-AL ST 40MM SMART_SWAP). The flow behavior of the coating solution indicates that the coating can be easily and evenly applied onto a film surface to form a continuous thin coating layer on the film.

[0079] Example 6: Preparation of Coated Films

[0080] In the following Examples, each of the example coated films was prepared according to the following method. Some example coated films included the Sample "A" film as the base film (prepared according to Example 1 above), some example coated films included the Sample "C" film as the base film (prepared according to Example 3 above), some example coated films included HYDROPOL™ 30164P (Aquapak) film as the base film, and some example coated films included HYDROPOL™ 33104P (Aquapak) film as the base film. Some example coated films included the Sample "D" coating (formed from the Sample "D" coating solution prepared according to Example 4 above), and some example coated films included the Sample "E" coating (formed from the Sample "E" coating solution prepared according to Example 5 above).

[0081] A sheet (17.5 cm x 17.5 cm) of the base film was fixed onto a hot surface (at 60°C). A pipette was used to transfer 1.5 mL of the example coating solution to the edge of the base film. The example coating solution was applied evenly to the base film with a glass rod. A hair dryer was used to accelerate the ethanol evaporation from the example coating solution (drying of the example coating solution). The application and drying of the example coating solution was repeated 10 times to form the example coating on the base layer. The finished coated film was stored at room temperature (25°C) before use.

[0082] Example 7: Preparation of Example Ketchup Sachets

[0083] In the following Examples, each of the example ketchup sachets was prepared according to the following method.

[0084] Each example ketchup sachet included Coated Film 4 (described in Table 2 below) formed of HYDROFOL™ 33104P film and coated with the Sample "E" coating of Example 5.

[0085] The coated film was cut into a small square (8 x 8 cm) and then folded in half. A kitchen heat sealer was used for 10 seconds on each side to seal three sides of the sachet. A pipette was used to transfer 5~6 g of ketchup (Heinz) into the sachet at 40°C. Then, the fourth side of the sachet was heat-sealed with the kitchen heat sealer for 10 seconds to form the example ketchup sachet.

[0086] Example 8 - Testing of Films

[0087] The Sample "A" film of Example 1 and the Sample "B" film of Example 2 were both transparent films without breaks or holes, and each was tested for disintegration / dissolution ability and mechanical properties.

[0088] Disintegration / Dissolution

[0089] Each film was cut into small strips (1 cmx 4 cm) and immersed into a disintegration / dissolution solution. Either a 1% NaOH solution (with a pH of about 12.7) or a1 % NaHCCh solution (with a pH of about 8.5) was used as the disintegration / dissolution solution, and the disintegration / dissolution solution was either preheated to 70°C or used at room temperature (25°C). The disintegration processes of the films were observed and images thereof were recorded.

[0090] Both the Sample "A" film and the Sample "B" film completely dissolved in the preheated (70°C) NaOH solution within 3 to 5 minutes. Both the Sample "A" film and the Sample "B" film also dissolved in the room temperature (25°C) NaOH solution but after several hours.

[0091] These results indicate that the films can be fast-dissolved in hot strong alkaline solutions, and the dissolved soy protein could subsequently be recycled by acid precipitation and purification.

[0092] The Sample "B" film did not dissolve in the preheated (70°C) NaHCOs solution. The Sample "B" film kept intact (retained its shape) even after the 5-minute dissolution test. The Sample "A" film was partially dissolved in the preheated (70°C) Na HCO3 solution and disintegrated into small factures without agitation. The undissolved residues were soft and weak in texture and could be easily transformed into suspended fine particles by mild swirling.

[0093] These results indicate that self-disintegration coinciding with partial dissolution of the Sample “ A" film may be achieved in household or kitchen conditions by applying a hot soda powder solution with limited shaking.

[0094] Mechanical Properties

[0095] Dumbbell-shaped strips were cut from each film using a razor blade. Each testing strip was fixed to a Brookfield CT3 Texture Profile Analyzer (Brookfield, Middleboro, MA, USA) equipped with the TA-DGA Dual Grip Fixture (Brookfield, Middleboro, MA, USA).

[0096] Tensile tests were carried out at room temperature (25°C). The initial distance between the grips was 30 mm, the tensile speed was 1.2cm / min, and the trigger point load was O mN.

[0097] Stress versus strain data was gathered using TexturePro CT software (Brookfield, Middleboro, MA, USA) and exported to an Excel spreadsheet. Stress was plotted versus strain, and the breaking point was defined on the plot beyond which the testing strip was stretched to break. Tensile strength and rate of elongation at break were equal to the stress and strain at the breaking point, respectively. The Young's modulus was also calculated from the stress-strain data.

[0098] The mechanical properties of the Sample "A" film and the Sample "B" film are shown in Table 1.

[0099] TABLE 1

[0100] Thickness was measured using a digital microcalliper.

[0101] The stress-strain plot for the Sample "B" film is shown in FIG. 5, and the stress-strain plot for the Sample "A" film is shown in FIG. 6.

[0102] Both the Sample " A" film and the Sample "B" film were about 500 pm thick.However, compared to the Sample "B" film, the Sample “ A" film exhibited a higher rate of elongation at break. Further, within the range of elastic deformation (about 10% -25% stain), the Young's modulus of the Sample "B" film was about 50% less than the Young's modulus of the Sample "A" film. These results indicate that the Sample "A" film is more flexible and harder to break than the Sample "B" film.

[0103] Example 9

[0104] Four examples of the coated film were prepared as described above. The base film and coating solution used to form each example coated film is shown in Table 2.

[0105] TABLE 2

[0106] The thickness of the coated films was measured using a digital microcaliper. Coated film 1 had a thickness of 450 pm, Coated Film 2 had a thickness of 270 pm, Coated Film 3 had a thickness of 110 pm, and Coated Film 4 had a thickness of 104 pm.

[0107] Mechanical Properties

[0108] The mechanical properties of each of the example coated films were measured (as described in Example 8), and the test results are shown in Table 3. Tensile strength and elongation were tested according to ISO 527-3 using type 2 specimens using a 2.5kN universal test machine from Testometric (UK). The tensile strength test was conducted at 500 mm / min. The test specimens had a width of 25mm and a length of 150mm. Puncture strength was testedusing the same 2.5kN universal test machine according to ASTM F1306 A, using a 3.2 mm (0.125 in.) diameter hemispherical (biaxial stress) probe.

[0109] TABLE 3

[0110] As shown in Table 3, each of Coated Film 2, Coated Film 3, and Coated Film 4 had a tensile strength greater than 50 N. As also shown in Table 3, each of Coated Film 3 and Coated Film 4 had a puncture force greater than 20 N. Coated Film 2 had a puncture force just under the target value, it had an acceptable tensile strength and Coated Films 3 and 4 had acceptable values for both tensile strength and puncture force. These results indicate that the example coated films may have tensile strength and puncture resistance suitable for use as a ketchup sachet.

[0111] Barrier Properties

[0112] Oxygen transmission rates (OTR) and water vapor transmission rates (WVTR) were tested for Coated Films 1-4. Oxygen transmission rate was measured at 23°C and 0% relative humidity according to a test based on ASTM D3985 & ASTM F1927. Conditions for OTR measurement were as follows: rate of flow of oxygen on test gas side (20 cc / min); rate of flow of the nitrogen carrier gas (10 cc / min); size of area exposed to permeation (5 cm2); condition procedure (30 minutes bypass); temperature of test environment (23°C, 0% RH); and apparatus used (Systech 8001 oxygen permeation analyzer). The target OTR was less than 10 cc / m2 / day at 23°C at 0% relative humidity.

[0001] Water vapor transmission rate was measured at 38°C and 90% relative humidity using a test based on ASTM F1249. The target WVTR was less than 10 cc / m2 / day. Only Coated Films 3 and 4 were close to the target WVTR. Conditions for WVTR measurement were asfollows: rate of flow of wet nitrogen on test gas side (20 cc / min); rate of flow of the nitrogen carrier gas (10 cc / min); size of area exposed to permeation (5 cm2); condition procedure (60 minutes bypass); temperature of test environment (38°C, 90% RH); and apparatus used (Permatran W 3-34).

[0113] The barrier properties of the example coated films were measured, and the results are shown in Table 4.

[0114] TABLE 4

[0115] Dispersibility / Solubility

[0116] A cold water dispersibility test was performed by mixing at least 1 g (dry basis) of the films (having dimensions of at least 25 mm x 25 mm) with 1 L of tap water under stirring conditions (magnetic stir rod) at 150 rpm in a 2 L beaker. The films were stirred for 16 hours at 25°C ± 2°C in the dark. A magnetic stir rod kept the samples in suspension throughout the test. After this period, the films were subjected to the determination of the water dispersible fraction (D) by sieving over a 10 mm screen. Solubility is determined by filtration through a 0.45 jim filter.

[0117] The tests were performed according to EN 14987 Plastics - Evaluation of disposability in waste-water treatment plants - Test scheme for final acceptance and specifications (2006). Tests were performed in triplicate.

[0118] A yellowish solution was obtained for Coated Film 1 after 16 hours of stirring. Big test item pieces were retained on the 10 mm sieve that appeared to be intact. As insufficient dispersibility was obtained, the reactor contents were not filtered.

[0119] For Coated Film 2, a yellowish turbid solution was obtained. The test item piecesappeared largely intact, but for some the yellow and white layer had detached. A large amount of test material was retained on the 10 mm sieve.

[0120] Table 5 below shows the amount of test material, after drying at 50°C, added to IL of tap water at the start of the experiment and the amount of material that remained on the 10 mm sieve after the 16-hour test. According to EN 14987 (2006), a material is considered to be cold water dispersible if it produces a dispersible fraction of > 90% after dissolution in cold water. The test results in Table 5 show that 32.1% of the original weight was retained on the 10 mm sieve. This corresponds to a dispersibility of 67.9% ± 1.5% for Coated Film 1.

[0121] TABLE S*SD = standard deviation

[0122] In order to be cold water soluble, a soluble fraction of > 90% must be obtained after filtration through a 0.45 pm filter. The solubility of Coated Films 1 and 2 were not evaluated, as insufficient dispersibility was obtained. Coated Film 2 and coated film 3 were found to be not dispersible and not soluble.

[0123] Table 5 also shows the pH at the start and end of the 16-hour test. According to EN 14987 (2006), the initial pH should be neutral. The pH slightly increased for the Coated Film 1 samples. There was a slight decrease in pH for Coated Film 2.

[0124] After the dispersibility / solubility test, Coated Film 4 had left disintegrating white residues, so the dissolution solution was dried to evaluate the solubility of coated film 4. The results indicated that 49.84% ± 4.69% of Coated Film 4 dissolved in water at 25°C (and 41.16% ± 2.80% of Coated Film 4 dissolved in water at 60°C). These results indicate that Coated Film 4 may be considered as partially cold-water dissolvable.

[0125] Hot Water Dispersibility and Solubility

[0126] A hot water dispersibility test was performed by mixing at least 1 g (dry basis) of the films (having dimensions of at least 25 mm x 25 mm) with 1 L of tap water under stirring conditions at 150 rpm in a 2 L beaker. The films were stirred for 16 hours at 60°C ± 2°C in the dark. After this period, the suspension was subjected to the determination of the water dispersible fraction (D) by sieving over a 10 mm sieve. The total test was 16 hours and the test was performed in triplicate. Solubility was determined by filtration through a 0.45 pm filter. The test was performed according to EN 14987 (2006).

[0127] According to EN 14987 (2006), a material is considered to be hot water dispersible if it produces a dispersible fraction of > 90% after dissolution in hot water. Further, according to EN 14987 (2006), the initial pH should be neutral.

[0128] A very turbid solution was obtained for Coated Film 1 at the end of the 16-hour test. Big test item pieces were retained on the 10 mm sieve and they looked intact. As insufficient dispersibility was obtained, the reactor contents were not filtered.

[0129] For Coated Film 2, a turbid solution was obtained at the end of the 16-hour test. A lot of test item pieces remained on the 10 mm sieve. The pieces appeared largely intact but for some, the yellow and white layer had detached. The reactor contents were not filtered, as insufficient dispersibility was observed.

[0130] Table 6 shows results of the hot water dispersibility tests. Table 6 shows the amounts of test material, after drying at 50°C, added to IL of tap water at the start of the experiment and the amount of material that remained on the 10 mm sieve after the 16-hour test. According to EN 14987 (2006), a material is considered to be hot water dispersible if it produces a dispersible fraction of > 90% after dissolution in hot water. The results show that 29.3% of the original weight was retained on the 10 mm sieve, corresponding to a dispersibility of 70.7% ± 3.7% .

[0131] TABLE 6*SD = standard deviation

[0132] In order to be hot water soluble, a soluble fraction of > 90% must be obtained after filtration through a 0.45 pm filter. The solubility of test item Coated Film 1, Coated Film 2, and Coated Film 3 was not evaluated, as insufficient dispersibility was obtained. The samples were not hot water dispersible or hot water soluble.

[0133] Table 6 also shows the pH at the start and end of the 16-hour test. According to EN 14987 (2006), the initial pH should be neutral. The pH slightly decreased significantly for the Coated Film 1 samples. The pH drop was more significant for Coated Film 2 (dropping nearly 2 pH points). The pH drop was less significant for Coated Film 3.

[0134] Disintegration under Simulated Composting Conditions

[0135] Further samples of Coated Films 1 and 2 were prepared as described above. The purpose of this test is to evaluate the disintegration of a material at ambient temperature in compost to evaluate suitability for home composting. The test set-up was based, with some modifications, on the international standard ISO 20200 Plastics - Determination of the degree of disintegration of plastic materials under simulated composting conditions in a laboratory-scale test (2015), incorporated herein by reference.

[0136] Coated Film 1 had a thickness of about 0.38 mm, Coated Film 2 had a thickness of about 0.28 mm, and Coated Film 3 had a thickness of about 0.12 mm as measured with a digital micrometer. The test materials were placed in slide frames, mixed with compost, and incubated at 28°C ± 2°C in the dark. The test was performed in duplicate per test item. The compostconsisted of an 80 / 20 mixture of < 10 mm mature compost and fresh milled vegetable, garden and fruit waste (VGF), respectively. The mature compost was a mixture of mature VGF and green compost. The VGF compost was derived from the organic fraction of municipal solid waste (MSW) and was further stabilized and aerated in a pilot-scale composting bin under controlled conditions in order to obtain completely mature compost. The age of the VGF compost was 14 weeks. The green compost was derived from garden waste, prunings, tree roots and stumps and was stabilized in a full-scale composting plant. The composts were mixed in a ratio of 50% VGF compost and 50% green compost.

[0137] The compost was regularly stirred and moistened if needed to provide a moisture content of about 50%. The visual appearance of the slide frames with test material was evaluated.

[0138] The disintegration under simulated composting conditions of some of the example coated films was determined.

[0139] The disintegration of Coated Film 1 proceeded very swiftly during the test. After 1 week of composting, only a border of test material remained present in all slide frames.However, large pieces of test material could easily be retrieved from the composting reactors. It was noticed that the test material was very fragile. One week later (after 2 weeks of composing) the test material in all slide frames had completely disappeared, and no loosened pieces of test material could be retrieved from the composting reactors. Because complete disintegration was obtained for Coated Film 1, the test was stopped after 2 weeks of composting. These results indicate that Coated Film 1 is suitable for home composting.

[0140] Coated Film 2 also showed fast-composting behavior. After 1 week of composting, small tears and holes started to appear in the test material of approximately 50% of the slide frames, while the test material in the other slide frames remained intact. It was noticed that the test material had become white opaque. Three weeks later small tears and holes were observed in the test material of the major part of the slide frames. Moreover, some rather large holes were present in the test material of a few slide frames. During the following weeks, the size of the holes in the test material gradually increased. After 12 weeks of composting (end of the test for this test item), holes and tears of varying sizes were noticed inthe test material of the slide frames. However, loosened pieces of test material could be retrieved from the composting reactor. Based on the determination of the remaining surface of test material in slide frames, it was concluded that test material is characterized by an average disintegration percentage of < 81% (average disintegration percentage: 26.7%).

[0141] Coated Film 3 exhibited some visible edge breakage after 6 weeks of composting. For coated film 3, the test was conducted for 12 weeks of composting. The disintegration was insufficient. After 4 weeks, the test material had become white opaque. During the following weeks, no signs of disintegration were observed. After 12 weeks of composting (the end of the test), the test material remained intact in all slide frames. Coated Film 3 was characterized by a disintegration percentage of 0% after 12 weeks of composting at ambient temperature.

[0142] Example 10

[0143] Example ketchup sachets were prepared according to the method described above. Coated Film 4 from Example 9 was used to form the sachets.

[0144] Moisture Loss

[0145] Ten example ketchup sachets were stored in a desiccator at 25°C for 14 days. The relative humidity in the desiccator was unstable and sometimes was about 90%. The moisture loss was measured by weighing the sachets before and after storage and is shown in FIG. 7. Excluding the outliers, the moisture loss was below 3% within 7 days. The number of outliers is believed to be due to the manual coating process and the manual sealing of the samples. 40 replicates were used.

[0146] Additionally, an example ketchup sachet formed using Coated Film 4 was stored in a desiccator at 20%-40% relative humidity for 1 month at 25°C. This example ketchup sachet only had about 16% weight loss after 1 month.

[0147] Further, an additional example ketchup sachet formed using Coated Film 4 were stored in a desiccator for 7 days, during which the relative humidity ranged from 26% to 56% and the temperature ranged from 19.5°C to 26°C. The moisture loss was measured and is shown in FIG. 8.

[0148] The moisture loss for these example ketchup sachets was well controlled (within 2.74 ± 0.36% in 0 to 7 days). After fitting to the linear regression model (WL (%) = 0.44 * T - 0.39 (R2 = 0.9973)), the moisture loss of these example ketchup sachets after 14 days storage was predicted as about 5.77%, with the confidence interval of 5.59% to 6.09% (a=0.95).

[0149] These results indicate that the moisture loss for the example ketchup sachets is minimized by the coating.

[0150] The ketchup was easily squeezed out from the example sachet by hand after 7 days storage. The process was no different than the process of squeezing ketchup from a commercially available product. These results also indicated that the heat-sealing strength of Coated Film 4 is acceptable.

[0151] Moisture Variation

[0152] The moisture content of the ketchup within the sachets was determined using the direct drying method described in the Chinese standard GB 5009.3-2016 (which is incorporated herein by reference in its entirety). The water content of the filled ketchup (40 °C) was measured after the ketchup was sealed in the sachet and stored at 25°C and relativity humidity of 50% - 90% for 0, 7, and 14 days.

[0153] The moisture variation of the ketchup in the example sachets was measured and is shown in Table 7.

[0154] TABLE 7

[0155] As shown in Table 7, the moisture content for the ketchup reduced about 2% after 14 days of storage.

[0156] Rheological Variation

[0157] The flow behavior of the ketchup (after 0, 7 , and 14 days) was determined using a DHR-2 dynamic rheometer from TA Instruments, USA, with a stainless-steel vertebral plate of 40 mm diameter and a plate spacing of 1 mm at 25°C. The viscosity versus shear rate was plotted and the curves were fitted using the Power-law model. The flow behavior parameters n and k were determined from the flow equation, (T = k • £n. In the flow equation, n is flow index, and k is viscosity constant.

[0158] The rheological variation of the ketchup in the example sachets was measured and is shown in FIG. 9. The flow behavior parameters are shown in Table 8.

[0159] TABLE S

[0160] As shown in FIG. 9 and Table 8, the viscosity constant 'k' of the ketchup increased with storage time, while the flow index 'n' decreased with storage time. These results suggest some degree of dehydration may occur during the storage process. However, the ketchup samples had minimal thickening because of moisture loss and the dehydration of ketchup was limited during the 2-week storage.

[0161] The flow index n remained unchanged and the viscosity constant was only increased by less than 90% in the 14-day storage, showing a limited extent of dehydration. This would not affect the spreading, dipping and any reasonable application of the ketchup.

[0162] Example 11

[0163] A beeswax coating prepared according to Example 5 was applied in two ways to Hydropol 33104P (warm-water soluble "WWS") and Hydropol 30164P (hot-water soluble "HWS") polyvinyl alcohol films (films of 30 pm or 50 pm thick) from Aquapak Polymers Ltd. (Birmingham, UK). The beeswax coating was applied as either the inner layer or the outer layer on the films. The films were impulse-sealed to form sachets, filled with ketchup, and stored at 20-25°C at 40-60% relative humidity over two days. The sachets were weighed periodicallyover the two days storage to evaluate weight loss. The target was no more than 3% weight loss over the two-day experiment.

[0164] The following samples were evaluated using the "WWS" Hydropol film: (1) 30 pm WWS (no coating); (2) 50 pm WWS (no coating); (3) 50 pm WWS with beeswax coating as inner layer (total 87 pm thick); (4) 50 pm WWS with beeswax coating as inner layer (repeated sample) (total 87 pm thick); and (5) 50 pm WWS with beeswax coating as the outer layer (total 87 pm thick).

[0165] The following samples were evaluated using the "HWS" Hydropol film: (1) 30 pm HWS (no coating); (2) 50 pm HWS (no coating); (3) 50 pm HWS with beeswax coating as inner layer (total 76 pm thick); (4) 50 pm HWS with beeswax coating as inner layer (repeated sample) (total 76 pm thick); and (5) 50 pm HWS with beeswax coating as the outer layer (total 76 pm thick).

[0166] The results are shown in FIGS. 10 and 11. The films of 50 pm thickness performed better than the 30 pm films for both the Hydropol WWS and HWS films. Further, the Hydropol films with the beeswax coatings had significantly less weight loss than the uncoated Hydropol films for both the WWS and HWS types. The best results (below the 3% weight loss target) were obtained for the beeswax coating on the inner layer of both the WWS and HWS films.

[0167] The weight loss rates were determined for the WWS and HWS controls and the coated films, and the results are shown in FIGS. 12 and 13. The figures also show the target maximum weight loss rate of y=0.107 to achieve a 1-month shelf-life with no more than 3% weight loss. (The weight loss rate needed to achieve a 6-month shelf-life is 0.0179.) The best performing samples were those with the beeswax coating on the inner layer of both the WWS and HWS films, but both had weight loss rates higher than the target maximum rate. The coated WWS sample (inner surface) had a weight loss rate of 0.5322 and the coated HWS sample (inner surface) had a weight loss rate of 0.8651. The target maximum weight loss rates to achieve no more than 3% weight loss for different target shelf lives (1, 2, 3, 4, 5, and 6 months) are shown in FIG. 14.

[0168] It is to be understood that the ranges provided herein include the stated range and any value or sub-range within the stated range. For example, a range of about 5 wt% to about 15wt% should be interpreted to include not only the explicitly recited limits of range of about 5 wt% to about 15 wt%, but also to include individual values, such as 6.35 wt%, 7.5 wt%, 10 wt%, 12.75 wt%, 14 wt%, etc., and sub-ranges, such as about 7 wt% to about 10.5 wt%, about 8.5 wt% to about 12.7 wt%, about 9.75 wt% to about 14 wt%, etc. Furthermore, when "about" is utilized to describe a value, this is meant to encompass minor variations (up to + / - 10%) from the stated value.

[0169] All percentages and ratios are calculated by weight unless otherwise indicated. All percentages and ratios are calculated based on the total weight of the compound or composition unless otherwise indicated.

[0170] Reference throughout the specification to "an example," "one example," "another example," "some examples," "other examples," and so forth, means that a particular element (e.g., feature, structure, and / or characteristic) described in connection with the example is included in at least one example described herein, and may or may not be present in other examples. In addition, it is to be understood that the described elements for any example may be combined in any suitable manner in the various examples unless the context clearly dictates otherwise.

[0171] In describing and claiming the examples disclosed herein, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0172] While several examples have been described in detail, it is to be understood that the disclosed examples may be modified. Therefore, the foregoing description is to be considered non-limiting.

Claims

CLAIMSWhat is claimed is:

1. A food packaging film comprising: about 15 to about 40 wt. % crude protein; about 10 to about 40 wt. % plasticizer; and about 0.1 to about 2.0 wt. % reducing agent, all percentages based on a total dry weight of the film.

2. The food packaging film as defined in claim 1, wherein the protein is present in an amount within the range of about 20 wt% to about 35 wt% crude protein, based on a total dry weight of the film.

3. The food packaging film as defined in claim 1 or 2, wherein the plasticizer is present in an amount within the range of about 15 wt% to about 30 wt%, based on a total dry weight of the film.

4. The food packaging film as defined in any one of claims 1 to 3, wherein the reducing agent is present in an amount within the range of about 0.1 wt% to about 1.0 wt%, based on a total dry weight of the film.

5. The food packaging film as defined in any one of claims 1 to 4, wherein the plasticizer comprises glycerol.

6. The food packaging film as defined in any one of claims 1 to 5, wherein the crude protein is soybean protein.

7. A coated food packaging film comprising: a film; and a coating comprising: wax particles;ethyl cellulose; solvent; and an emulsifier having an HLB value of at least 10.

8. The coated food packaging film as defined in claim 6 or 7 , wherein the wax particles are present in an amount within the range of about 60 wt% to about 70 wt%, based on a total weight of the coating.

9. The coated food packaging film as defined in any one of claims 6 to 8, wherein the ethyl cellulose is present in an amount within the range of about 30 wt% to about 40 wt%, based on a total weight of the coating.

10. The coated food packaging film as defined in any one of claims 6 to 9, wherein the emulsifier comprises a polysorbate surfactant.

11. The coated food packaging film as defined in any one of claims 6 to 10, wherein the film comprising: about 15 to about 40 wt. % crude protein; about 10 to about 40 wt. % plasticizer; and about 0.1 to about 2.0 wt. % reducing agent, all percentages based on a total dry weight of the film.

12. The coated food packaging film as defined in claim 11, wherein the protein is present in an amount within the range of about 20 wt% to about 35 wt% crude protein, based on a total dry weight of the film.

13. The coated food packaging film as defined in claim 11 or 12, wherein the plasticizer is present in an amount within the range of about 15 wt% to about 30 wt%, based on a total dry weight of the film.

14. The coated food packaging film as defined in any one of claims 11 to 13, wherein the reducing agent is present in an amount within the range of about 0.1 wt% to about 1.0 wt%, based on a total dry weight of the film.

15. The coated food packaging film as defined in any one of claims 11 to 14, wherein the plasticizer comprises glycerol.

16. The coated food packaging film as defined in any one of claims 11 to 15, wherein the film is a polyvinyl alcohol film.

17. A method of making a food packaging film, comprising: mixing protein with water to form a first mixture; performing a separation step to form a pellet and supernatant from the first mixture, and obtaining the supernatant from the first mixture; adding a plasticizer and reducing agent to the supernatant to form a second mixture; and drying the second mixture to form the film, wherein the film comprises about 15 to about 40 wt. % crude protein; about 10 to about 40 wt. % plasticizer; and about 0.1 to about 2.0 wt. % reducing agent, all percentages based on a total dry weight of the film.

18. The method as defined in claim 17, further comprising grinding the first mixture.

19. The method as defined in claim 17 or 18, further comprising heating the second mixture.

20. The method as defined in any one of claims 17 to 19, wherein the separation step comprises centrifuging the first mixture.

21. A method of making a coated food packaging film, comprising: melting wax to form melted wax; adding an emulsifier and a solvent to the melted wax to form a third mixture;homogenizing the third mixture to form an emulsion; adding ethyl cellulose to the emulsion to form a coating solution; and applying the coating solution to a film to form the coated film.

22. The method as defined in 21, further comprising: mixing protein with water to form a first mixture; performing a separation step to form a pellet and supernatant from the first mixture, and obtaining the supernatant from the first mixture; adding a plasticizer and reducing agent to the supernatant to form a second mixture; and drying the second mixture to form the film, wherein the film comprises about 15 to about 40 wt. % crude protein; about 10 to about 40 wt. % plasticizer; and about 0.1 to about 2.0 wt. % reducing agent, all percentages based on a total dry weight of the film.

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