Plant Protein Polysaccharide Film

Abstract

The present invention relates to a film comprising a combination of vegetable protein and polysaccharide at 50 wt% or more based on the total mass of the film at 55% relative humidity and 22°C, wherein the mass ratio of polysaccharide to vegetable protein is in the range of 0.1:1 to 2:1, and the vegetable protein is pretreated with an organic acid.

Description

[Technical field]

[0001] The present invention relates to films comprising plant proteins and polysaccharides, and methods for preparing the films. The present invention also relates to uses of the films and methods related to the films, including coating or encapsulating products. The present invention also relates to film-forming compositions and films obtained therefrom. [Background technology]

[0002] There is an increasingly urgent need to reduce the environmental impact of many everyday activities and the amount of non-renewable resources involved in these activities. One example of this is the increased use of biodegradable packaging to replace traditional plastics, such as polyethylene and polypropylene (e.g., edible films used in food packaging). Biopolymers, including polysaccharides and proteins, are particularly useful materials because they are renewable resources and often have very good biodegradable properties. There is an increasing trend to use plant-derived biopolymers rather than animal-derived biopolymers. Plant-derived biopolymers typically require fewer total resources to produce than animal-derived biopolymers and do not have the same ethical issues as animal-derived materials. However, plant-based biopolymers often have significantly different processing challenges, more pronounced than many animal-derived biopolymers, and require unique solutions. In addition, certain plant materials, such as gluten, can cause health problems and allergic reactions in people.

[0003] In this regard, the development of packaging materials made from plant-derived biopolymers, including water-soluble and water-dispersible films, has been of particular interest. Traditionally, polysaccharides such as starch have been used for this purpose, often due to their low cost and ready availability. However, the mechanical properties of polysaccharide films, especially starch films, are typically highly dependent on ambient humidity and temperature conditions. This makes scale-up of production more complicated and narrows the window of use when used to package consumer products. Furthermore, starch films typically tend to have low tensile strength and / or insufficient elongation, meaning that they are brittle or can easily break or tear, thereby limiting their usefulness as packaging films. Films used in typical packaging equipment, such as Vertical-Form-Fill-Seal sachet-making machines, need to be robust enough to withstand the pulling of the equipment. Films that have excessive elongation when pulled are difficult to handle in typical packaging equipment, as the stretching makes centering and indexing very difficult. Typically, starch can be chemically modified, for example by cross-linking, to improve mechanical properties such as tensile strength, but this often has undesirable consequences, such as reduced solubility and / or dispersibility in water, reduced biodegradability, the use of non-recyclable synthetic chemicals, and increased complexity and cost.

[0004] A particular problem with starch-based films is that starch is sensitive to low temperatures due to retrogradation. Food packaging can often be subjected to low temperatures and high humidity when the packaged food is stored in a refrigerator. This means that it has not been possible to develop a commercially available film containing large amounts of starch that is robust enough to withstand all conditions that may be required for food packaging. However, the low cost and ready availability of starch means that it is still a desirable material to incorporate into such films. The term "starch-based" or "polysaccharide-based" refers to a material that contains significant levels of starch or polysaccharide, such as >5 wt%. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] CN114034595A Summary of the Invention [Problem to be solved by the invention]

[0006] Thus, there is a need to develop polysaccharide-based, especially starch-based, water-soluble / water-dispersible films that are sufficiently robust and have suitable mechanical properties to be used as packaging films. They should be able to be handled in the manufacturing process, formed into packages, for example by heat sealing, and be able to withstand transportation and storage over a range of temperatures, including low temperatures. Such films should not require synthetic chemically processed materials, be mostly or entirely based on biopolymers of plant origin, be highly biodegradable, and be safe and economical to produce. A preferred feature of food packaging is that it is edible, thus further minimizing waste and increasing consumer convenience.

[0007] There is also a need for such films to be suitable for storage in humid environments, especially for use in packaging home and personal care products, which are likely to be stored in bathrooms and kitchens. Current synthetic polymers such as PVOH can become sticky in humid conditions, causing individually packaged tablets or sachets to stick to each other and render them unusable. Polysaccharide-based films, especially starch-based films, are also highly sensitive to environmental humidity and can also become sticky and eventually disintegrate, rendering them unusable for such product applications. [Means for solving the problem]

[0008] In view of the first aspect, the present invention provides a film comprising a combination of polysaccharide and plant protein at 55% relative humidity and 22° C., 50 wt % or more relative to the total mass of the film, the mass ratio of polysaccharide to plant protein being in the range of 0.1:1 to 2:1, and the plant protein being pretreated with an organic acid. The incorporation of plant protein into the film may mitigate drawbacks such as limited tensile strength of polysaccharide materials, while maintaining advantages such as high biodegradability, more efficient use of renewable raw materials and avoidance of ethical issues. Plant proteins are typically more difficult to process than animal proteins due to higher levels of non-polar amino acids and consequently lower solubility. Simple attempts to form films from "intact" plant proteins will not be successful. Appropriate pretreatment of the plant protein to unfold the protein is necessary to allow successful incorporation of the protein into the polysaccharide. Processing of proteins of animal origin is typically not relevant or applicable to processing of plant proteins, and different plant proteins may have different physical or chemical properties. For example, corn zein is known to produce brittle films.

[0009] Films incorporating alkali-treated plant proteins are known in the art. Typically, plant protein slurries are treated at high pH and temperature to solubilize the plant proteins. The solubilized protein solution is then typically blended with other materials, such as plasticizers, cast onto a flat surface, and dried to form a film. However, due to the nature of the alkali-induced changes to the protein, the treated proteins are more sensitive to moisture and are less robust. Plant protein films made by this approach typically have lower tensile strength and higher elongation, especially at higher humidity. This makes them less suitable for use in packaging equipment. In addition, alkali treatment typically results in plant protein films with poorer storage stability at higher humidity. This makes alkali-treated proteins less suitable as materials to mitigate the shortcomings associated with polysaccharide-based films.

[0010] Plant proteins can also be solubilized by salt solutions at low protein concentrations, however, forming films incorporating plant proteins by using low protein content solutions is simply not economically feasible due to the large amounts of water required to evaporate to form such films.

[0011] Treatment of plant proteins with organic acids in combination with heating and shearing may result in treated plant proteins suitable for incorporation into polysaccharide-based films, thus mitigating the drawbacks associated with polysaccharides. Without wishing to be bound by theory, it is believed that when plant proteins are added to an organic acid-based solvent system and subjected to physical stimuli such as heating and / or sonication, the plant proteins are partially unfolded, exposing hydrophobic amino acids that were initially buried within the untreated structure of the protein. Once partially unfolded, co-solvents can interact with the unfolded protein molecules. For example, organic acids have a stronger route to protonate amino acid residues, allowing the formation of anionic salt bridges that stabilize hydrophobic interactions. Also, when heated at high temperatures, non-covalent intermolecular contacts between proteins are disrupted.

[0012] Furthermore, it is believed that when the protein solution is cooled below the sol-gel temperature, non-covalent intermolecular contact between proteins is possible, thus promoting the self-organization of plant protein molecules into a network of interconnected protein aggregates. This means that organic acid-treated plant proteins are typically less sensitive to moisture than alkali-treated plant proteins, but still capable of forming films. An additional benefit of organic acid treatment is that typically higher protein concentrations can be used, compared to, for example, the use of salt solutions. This simplifies production and reduces production costs by reducing the amount of solvent that needs to be evaporated when plant proteins are incorporated into polysaccharide-based films.

[0013] Therefore, the drawbacks associated with polysaccharide films can be better mitigated by the incorporation of organic acid treated plant proteins.

[0014] It is highly preferred that the solvent system containing the organic acid does not contain highly concentrated organic acids, such as glacial acetic acid, due to safety issues associated with handling such materials; lower concentrations are suitable.

[0015] Preferably, the film of the first aspect of the invention comprises: a first layer comprising a polysaccharide; a second layer comprising a vegetable protein, the vegetable protein being pretreated with an organic acid; and Including, The second layer is in contact with the first surface of the first layer.

[0016] Viewed from a further aspect, the present invention relates to a method for preparing a film as described hereinabove, comprising the steps of: (i) mixing polysaccharides in water, optionally with sonication, to form a polysaccharide mixture; (ii) dissolving the plant protein in water and an organic acid, optionally using sonication, to form a protein solution; (iii) mixing the polysaccharide mixture and the protein solution to form a film-forming composition; (iv) forming the film-forming composition into a film at 55% relative humidity and 22° C. comprising 50 wt % or more of a combination of plant protein and polysaccharide, based on the total weight of the film, wherein the weight ratio of polysaccharide to plant protein is in the range of 0.1:1 to 2:1; The present invention provides a method comprising:

[0017] Viewed from a further aspect, the present invention relates to a method for preparing a film as described hereinabove, comprising the steps of: (i) mixing polysaccharides in water, optionally with sonication, to form a polysaccharide mixture; (ii) forming the polysaccharide mixture into a first layer on a surface; (iii) dissolving the plant protein in water and an organic acid, optionally using sonication, to form a protein solution; (iv) forming a protein solution into a second layer on the first surface of the first layer, such that the resulting film comprises at least 50 wt % of a combination of polysaccharide and plant protein based on the total weight of the film at 55% relative humidity and 22° C., and the weight ratio of polysaccharide to plant protein is in the range of 0.1:1 to 2:1; The present invention provides a method comprising:

[0018] Viewed from a further aspect, the present invention provides a product, preferably a home or personal care product, most preferably a dishwasher tablet, coated or encapsulated with a film as described herein above.

[0019] Viewed from a further aspect, the present invention relates to a method for coating or encapsulating a product, preferably a food product, comprising the steps of: (i) packaging the product in a film as described herein above; (ii) sealing a film around the product; The present invention provides a method comprising:

[0020] Viewed from a further aspect, the present invention provides the use of a film as described hereinabove for coating or encapsulating a product, preferably a food product.

[0021] The method for releasing a product coated or encapsulated with a film as described herein above comprises the steps of: (i) placing the coated or encapsulated product in water, preferably with agitation; (ii) dispersing the film, preferably in the presence of a surfactant, thereby releasing the product; Includes.

[0022] In view of a further aspect, the present invention provides a film-forming composition comprising a vegetable protein and a polysaccharide, wherein the mass ratio of vegetable protein to polysaccharide is in the range of 0.1:1 to 2:1, and the vegetable protein has been pretreated with an organic acid.

[0023] Viewed from a further aspect, the present invention provides a film obtained from a film-forming composition as described herein above. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The present invention describes a film that is robust and water dispersible. Thus, the film of the present invention is strong enough to withstand the manufacturing process and subsequent transportation and storage, but can then disperse upon contact with water, for example releasing the packaged product, making it useful as a packaging material. Thus, the present invention provides a film comprising a combination of plant protein and polysaccharide at 50 wt% or more relative to the total mass of the film at 55% relative humidity and 22°C, the mass ratio of polysaccharide to plant protein being in the range of 0.1:1 to 2:1, and the plant protein being pretreated with an organic acid.

[0025] In the film of the present invention, the mass ratio of polysaccharide to plant protein is in the range of 0.1:1 to 2:1.

[0026] In preferred films of the present invention, the weight ratio of polysaccharide to vegetable protein ranges from 0.15:1 to 1.5:1, more preferably from 0.2:1 to 1.3:1, and even more preferably from 0.5:1 to 1.2:1. The combination of low levels of vegetable protein and polysaccharide in these weight ratio ranges has been found to increase the strength of the film without negatively affecting the ability of the film to disperse in water.

[0027] To determine the total protein content in a given sample of film, the contained soluble nitrogen fraction can be quantitatively measured according to the Kjeldahl method, and then the total protein content can be obtained by multiplying the nitrogen content, expressed as a percentage by mass of the dry product, by a factor of 6.25, a method well known to those skilled in the art.

[0028] The total starch content in a given sample of film can be determined by standard methods AOAC Method 996.11 or AOAC Method 2014.10, which use the combined action of α-amylase and amyloglucosidase to hydrolyze starch to glucose, followed by glucose determination with a glucose oxidase / peroxidase reagent.

[0029] The method for determining the content of pullulan in a given sample of film follows the basic method described in CN114034595A with modifications and includes the following steps:

[0030] Step 1: Dispersion of pullulan-containing film sample A 3 g sample of the film is dispersed in 100 ml of DI water at 40° C. by stirring with an overhead stirrer at high speed for 20 minutes to separate the film sample into small fractions and to dissolve the pullulan.

[0031] Step 2: Centrifugation and separation of the insoluble fraction Solid-liquid separation of the dispersed film samples is carried out by centrifugation at >1000 g for 10 minutes and the supernatant liquid is collected.

[0032] Step 3: Alcohol precipitation Add 3 volumes of >95% pure ethanol to the supernatant to precipitate pullulan. Mix thoroughly and let sit for 30 minutes. Collect the solid precipitate by centrifugation at 1000 g for 5 minutes.

[0033] Step 4: Drying the precipitate The precipitate from step 3 is collected and dried at 80° C. until the sample reaches constant weight. The final constant weight is the amount of pullulan present in the original 3 g sample.

[0034] A preferred film of the present invention is a monolayer film, an example of which is graphically depicted in Figure 1a.

[0035] Another preferred film of the present invention is a multilayer film. Thus, a preferred film of the present invention is a first layer comprising a polysaccharide; a second layer comprising a vegetable protein, the vegetable protein being pretreated with an organic acid; and Including, a second layer in contact with the first surface of the first layer, the film comprising at least 50 wt % of a combination of plant proteins and polysaccharides based on the total weight of the film at 55% relative humidity and 22° C.; The mass ratio of polysaccharide to plant protein ranges from 0.1:1 to 2:1.

[0036] An example of such a multilayer film is graphically depicted in FIG. 1b, where layer (1) is the first layer and layer (2) is the second layer.

[0037] In a preferred film of the present invention, the first layer further comprises a vegetable protein, which is pretreated with an organic acid.

[0038] In preferred films of the present invention, the second layer further comprises a polysaccharide.

[0039] In a preferred film of the present invention, the first layer further comprises a plant protein, the plant protein being pretreated with an organic acid, and the second layer further comprises a polysaccharide. As will be understood by those skilled in the art, the weight ratio of polysaccharide to plant protein in each of the first and second layers can be the same or different. Preferably, the weight ratio of polysaccharide to plant protein in each of the first and second layers is different. More preferably, the weight ratio of polysaccharide to plant protein in the first layer is greater than the weight ratio of polysaccharide to plant protein in the second layer.

[0040] In preferred films of the present invention, the first layer has an onset melting temperature in the range of 55°C to 85°C, determined as described on page 22 hereof.

[0041] As will be appreciated by those skilled in the art, additional layers may be added to the films of the present invention.

[0042] The film of the present invention comprises a vegetable protein. In a preferred film of the present invention, the vegetable protein is selected from soy protein, pea protein, rice protein, potato protein, wheat protein, rapeseed protein, sunflower protein and / or sorghum protein, preferably selected from pea protein, potato protein, rapeseed protein, sunflower protein and / or rice protein, more preferably pea protein.

[0043] In a preferred film of the present invention, the vegetable protein is a protein from the Fabaceae family, preferably pea protein.

[0044] Preferred films of the present invention are free of soy protein, and / or wheat protein, and / or sorghum protein.

[0045] In a preferred film of the present invention, the vegetable protein source is a vegetable protein isolate, preferably a pea protein isolate.

[0046] In preferred films of the present invention, the vegetable protein source is a vegetable protein concentrate.

[0047] In a preferred film of the present invention, the vegetable protein source is vegetable flour, preferably pea flour.

[0048] In preferred films of the present invention, the vegetable protein source is obtained from waste streams, for example waste streams from the agriculture or food industries.

[0049] A preferred film of the present invention comprises 2.0 to 40 wt %, preferably 2.5 to 35 wt %, more preferably 3.0 to 30 wt % of vegetable protein based on the total weight of the film at 55% relative humidity and 22°C.

[0050] The organic acid is an organic compound having acidic properties, preferably a carboxylic acid. In the preferred film of the present invention, the organic acid used for pretreatment of the vegetable protein is selected from acetic acid, alpha-hydroxy acid, or beta-hydroxy acid. More preferably, the organic acid is selected from acetic acid, lactic acid, citric acid, malic acid, maleic acid, glycolic acid, gluconic acid, tartaric acid, beta-hydroxypropionic acid, beta-hydroxybutyric acid, beta-hydroxybeta-methylbutyric acid, 2-hydroxybenzoic acid, and carnitine, or a mixture thereof, preferably acetic acid.

[0051] In preferred films of the present invention, the organic acid used to pre-treat the vegetable protein is a volatile organic acid (i.e., one that has a boiling point below 120° C.), preferably acetic acid, because volatile organic acids can be easily removed from the film-forming composition during the casting or drying process such that the final film contains little, if any, residual organic acid.

[0052] The films of the present invention exhibit a useful combination of properties, which means that they are robust, yet dispersible in water. Without wishing to be bound by theory, it is believed that the increased strength of the films of the present invention can be attributed to the pretreatment of the plant protein with organic acid. This is believed to be because the plant protein unfolds in the presence of organic acid at high temperature, making it more accessible to interact with the polysaccharides present, for example, via hydrogen bonds. These increased protein-polysaccharide interactions reduce the level of polysaccharide retrogradation, which is responsible for the brittleness of conventional polysaccharide-based films.

[0053] Pretreatment of the plant protein with an organic acid results in a plant protein having a protein secondary structure having at least 40% intermolecular β-sheets, at least 50% intermolecular β-sheets, at least 60% intermolecular β-sheets, at least 70% intermolecular β-sheets, at least 80% intermolecular β-sheets, or at least 90% intermolecular β-sheets.

[0054] For the avoidance of doubt, pre-treatment of the plant protein with an organic acid is carried out prior to combining the plant protein with the polysaccharide.

[0055] Preferably, the pretreatment of the plant protein with organic acids comprises the use of an aqueous solution of organic acids. More preferably, the aqueous solution of organic acids has a concentration of at least 5% (v / v), preferably at least 10% (v / v), more preferably at least 15% (v / v), more preferably at least 20% (v / v), more preferably at least 25% (v / v), more preferably at least 30% (v / v), more preferably at least 40% (v / v), even more preferably at least 50% (v / v). Alternatively, the aqueous solution of organic acids has a concentration of 90% (v / v) or less, preferably 80% (v / v) or less, more preferably 70% (v / v) or less. Concentrated acid solutions are dangerous to handle on a large scale.

[0056] Polysaccharides are carbohydrate polymers. Polysaccharides or polycarbohydrates are the carbohydrates most abundantly found in foods. They are long chain polymeric carbohydrates made up of monosaccharide units linked together by glycosidic bonds. The carbohydrates can be reacted (hydrolyzed) with water using amylase enzymes as catalysts, which produces the constituent sugars (monosaccharides or oligosaccharides). Their structures range from linear to highly branched. An example of a linear polysaccharide is pullulan. Starch consists essentially of amylose, which is linear, and / or amylopectin, which is branched, and in its native form is typically in the form of semi-crystalline granules. Starch sources include, but are not limited to, fruits, seeds, and roots or tubers of plants.

[0057] Some starches are classified as waxy starches, which consist essentially of amylopectin and do not contain any appreciable amount of amylose. Exemplary waxy starches include waxy maize starch, waxy rice starch, waxy potato starch, and waxy wheat starch.

[0058] Alternatively, some starches are classified as high amylose starches.

[0059] Modified starches are prepared by treating native starch physically, enzymatically, or chemically to change its properties. Starch can be modified, for example, enzymatically, by heat treatment, oxidation, or by reaction with various chemicals.

[0060] In the films of the present invention, the starch can be a native starch or a modified starch, or a mixture thereof.

[0061] In preferred films of the invention, the starch is selected from wheat starch, potato starch, pea starch, waxy potato starch, maize starch, waxy maize starch, high amylose maize starch, tapioca starch, cassava starch, rye starch, sorghum starch, chickpea starch, soybean starch, or mixtures thereof, preferably potato starch.

[0062] In another preferred film of the present invention, the starch is selected from acid treated starch, dextrin, alkali modified starch, bleached starch, oxidized starch, enzyme treated starch, maltodextrin, cyclodextrin monostarch phosphate, distarch phosphate, acetylated starch, hydroxypropylated starch, hydroxyethyl starch, sodium starch octenyl succinate, aluminum starch octenyl succinate or cationic starch, or mixtures thereof, preferably acid treated starch.

[0063] A preferred film of the present invention comprises 30-70 wt %, preferably 40-65 wt %, more preferably 45-60 wt % of polysaccharide based on the total weight of the film at 55% relative humidity and 22°C.

[0064] Preferred films of the present invention comprise at least 55 wt. % of a combination of vegetable proteins and polysaccharides, based on the total weight of the film, at 55% relative humidity and 22°C, and preferably at least 60 wt.

[0065] Preferred films of the present invention comprise no more than 75 wt.%, preferably no more than 72 wt.%, more preferably no more than 70 wt.% of a combination of vegetable proteins and polysaccharides based on the total weight of the film at 55% relative humidity and 22°C.

[0066] A preferred film of the present invention comprises 50-75 wt %, preferably 55%-72 wt %, more preferably 60-70 wt % of the combination of plant protein and polysaccharide based on the total weight of the film at 55% relative humidity and 22°C.

[0067] Preferred films of the invention contain 10-20 wt %, preferably 10-15 wt %, of water based on the total weight of the film at 55% relative humidity and 22°C.

[0068] The preferred film of the present invention further comprises a plasticizer. The plasticizer is useful for improving film flexibility. Preferably, the plasticizer is selected from glycerol, polyethylene glycol, propylene glycol, sorbitol, mannitol, xylitol, triethyl citrate, fatty acids, glucose, mannose, fructose, sucrose, urea, lecithin, wax, amino acids and organic acids (e.g. lactic acid, citric acid, glycolic acid, malic acid, gluconic acid or tartaric acid), or mixtures thereof, preferably glycerol.

[0069] As one skilled in the art will appreciate, organic acids may be used to pre-treat the vegetable protein and then remain to subsequently function as plasticizers in the resulting film.

[0070] If the film is intended for packaging food, the plasticizer must be suitable for human consumption. The preferred plasticizers mentioned above are all suitable for human consumption (i.e., they are food grade materials).

[0071] Preferred films of the invention contain 5-25 wt %, preferably 10-20 wt %, more preferably 13-19 wt % plasticizer based on the total weight of the film at 55% relative humidity and 22°C.

[0072] Preferred films of the present invention further comprise a pigment or dye, preferably selected from azo, quinophthalone, triphenylmethane, xanthene or indigoid dyes, iron oxides or hydroxides, titanium dioxide, or natural dyes, and mixtures thereof. Examples include Patent Blue V, Acid Brilliant Green BS, Red 2G, Azorubine, Ponceau 4R, Amaranth, D+C Red 33, D+C Red 22, D+C Red 26, D+C Red 28, D+C Yellow 10, Yellow 2G, FD+C Yellow 5, FD+C Yellow 6, FD+C Red 3, FD+C Red 40, FD+C Blue 1, FD+C Blue 2, FD+C Green 3, Brilliant Black BN, Carbon Black, Iron Oxide Black, Iron Oxide Red, Iron Oxide Yellow, Titanium Dioxide, Riboflavin, Carotene, Anthocyanin, Turmeric, Cochineal Extract, Chlorophyllin, Canthaxanthin, Caramel, Betaine and Candurin® Pearlescent Pigments. More preferably, the pigment or dye is a food colorant, preferably a food colorant derived from a vegetable source, more preferably a food colorant selected from carotenoids, chlorophyllin, anthocyanin and betanin.

[0073] The preferred film of the present invention further comprises a structural agent. The use of the structural agent can help improve the strength of the film. Preferably, the structural agent is selected from microcrystalline cellulose, microfibrillated cellulose containing cellulose fibers extracted from citrus fruit pulp, cellulosic materials containing fine fibrous cellulose from fermentation, starch microcrystals, clays, or mixtures thereof, preferably microfibrillated cellulose from citrus pulp.

[0074] A preferred film of the present invention contains 0.5 to 5 wt %, preferably 0.6 to 2.5 wt %, of said structure enhancing agent based on the total weight of the film at 55% relative humidity and 22°C.

[0075] The preferred film of the present invention further comprises a hydrophobic agent.Preferably, the hydrophobic agent is a plant-based oil, preferably a non-volatile plant-based oil, preferably a vegetable oil, preferably selected from vegetable oil, rapeseed oil, canola oil, soybean oil, sunflower oil, safflower oil, corn oil, and flavored oil, or a mixture thereof.Examples of flavored oils include thyme oil, basil oil, olive oil, chili oil, rosemary oil, garlic oil, citrus oil, or lavender oil.

[0076] Alternatively, the hydrophobic agent is a plant-based fatty acid, which is a saturated or unsaturated fatty acid, or a mixture thereof.Preferably, the plant-based fatty acid is non-volatile.Preferred saturated fatty acids include caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid.Preferred unsaturated fatty acids include myristoleic acid, palmitoleic acid, oleic acid, and linoleic acid.

[0077] Without wishing to be bound by theory, it is believed that the presence of a hydrophobic agent, such as a vegetable-based oil or vegetable-based fatty acid, in the film of the present invention improves the surface integrity of the film. This is believed to be because, during the preparation of the film, the hydrophobic agent migrates to the top surface of the cast composition, thereby inhibiting the premature formation of a skin thereon, which means that steam can escape more easily and, once dry, fewer air bubbles are formed and entrapped within the film.

[0078] The use of flavored oils as the hydrophobic agent in the films of the present invention provides the added advantage that the film itself can act as a flavor delivery vehicle, for example when the film is used to package food products.

[0079] Preferred films of the present invention contain 0.3-2.5 wt %, preferably 0.6-2.0 wt %, more preferably 0.7-1.5 wt % of hydrophobic agent based on the total weight of the film at 55% relative humidity and 22°C.

[0080] Preferred films of the present invention are suitable for human or animal consumption, i.e., the films are edible films. More preferably, the films of the present invention do not contain ingredients derived from animal sources, making them suitable for consumption by vegetarians / vegans.

[0081] Preferred films of the present invention are digestible.

[0082] Edible, as used herein, refers to a film that is digestible and provides some nutritional benefit on its own. This is in contrast to a film that is safe to eat but does not provide nutrition on its own. An example of these latter films is a film made from HPMC, hydroxypropyl methylcellulose, or other cellulose-based films, which are widely used in the pharmaceutical industry. A characteristic of edible films is that they are inherently very rapidly biodegradable. Starch is often chemically modified to improve its cross-linking ability. Although such techniques can be very effective in improving the physical properties of starch, this very often reduces its digestibility and use as an edible material. Therefore, it is preferred that the starch used in these films has not been subjected to prior chemical processing other than hydrolysis.

[0083] Preferred films of the present invention do not contain chitosan.

[0084] The film of the present invention has high dispersibility in water. This means that the film of the present invention can be used as a packaging material for products that do not generate waste during the final use of the product. For example, the film of the present invention can be used to package detergent, and the film can disperse in water to release the detergent during the washing process. Alternatively, the film of the present invention can be used to package food, and the film can disperse in water to release the food during the cooking process. Thus, in the preferred film of the present invention, when 0.2g of the film is boiled in water for 3 minutes while stirring, and then poured through a 2mm mesh sieve, no more than 0.15g, preferably no more than 0.1g, more preferably no more than 0.05g of residue is collected on the sieve. Advantageously, the residue is completely biodegradable, and this means that the film has no negative impact on the environment.

[0085] In preferred films of the invention, the pH of a dispersion of the film at a concentration of 1 g film in 10 g deionized water at 25° C. is greater than 5, preferably greater than 5.5, more preferably greater than 6. This has the advantage that when the film is used to package food products, the film, once dispersed, does not impart a sour or other negative flavor to the food product.

[0086] In the preferred films of the present invention, the viscosity of a dispersion of the film at a concentration of 1 g of film in 50 g of deionized water is -1 less than 100cps at 25℃ and 10s -1 less than 90cps at 25°C and 10s, -1 This has the advantage that the film, once dispersed, does not negatively affect the viscosity of the product, e.g., if the packaged product is a beverage, the dispersed film will not unduly thicken the beverage and cause a negative consumer experience.

[0087] In preferred films of the invention, the film has a tensile strength, measured by ASTM D882-18 at 76% relative humidity and 5°C, of ​​0.15 to 5 MPa, preferably 0.17 to 3.5 MPa.

[0088] In preferred films of the present invention, the film has a breaking strain, measured by ASTM D882-18 at 76% relative humidity and 5°C, of ​​10 to 150%, preferably 15 to 120%.

[0089] In preferred films of the invention, the plant protein in the second layer has a secondary structure with at least 40% intermolecular β-sheet content, at least 50% intermolecular β-sheet content, at least 60% intermolecular β-sheet content, at least 70% intermolecular β-sheet content, at least 80% intermolecular β-sheet content, or at least 90% intermolecular β-sheet content as measured by FTIR when the second layer is prepared on an inert surface, such as a glass surface.

[0090] To investigate the secondary structure of the plant protein in the second layer, Fourier transform infrared (FTIR) analysis was performed. FTIR spectroscopic data were collected using an FTIR VERTEX 70 spectrometer (Bruker) with a diamond attenuated total reflectance (ATR) element.

[0091] The second layer containing the plant protein should be in direct contact with the diamond ATR cell. Data were collected using 128 scans at 4 cm-1 resolution with background subtraction. For protein structural analysis, the spectra were smoothed and normalized with a second-order and seven-point window Savitzky-Golay filter. The second derivative of the amide I band (1600-1700 cm-1) was calculated from the smoothed data and deconvoluted to quantify the secondary and quaternary structural contributions. In preferred films of the present invention, the biodegradation percentage of the film after 28 days with respect to O2 consumption, measured according to ISO-14851, is 70-100%, more preferably 80-100%, even more preferably 85-100%.

[0092] In preferred films of the present invention, the percentage biodegradation of the film with respect to CO2 production after 28 days, as measured according to ASTM D6691, is 85-100%, more preferably 90-100%, and even more preferably 95-100%.

[0093] In preferred films of the present invention, after the film is conditioned at 55% relative humidity and 20°C for at least 1 hour and then sealed by applying a pressure of between 3 and 5 bar for a period of 1 second at a temperature of 120°C, the film has a heat seal strength of at least 40 N / m, preferably at least 60 N / m, more preferably at least 80 N / m, even more preferably at least 100 N / m and most preferably at least 120 N / m, measured according to ASTM F88 / F88M-15 at 55% relative humidity and 20°C.

[0094] The present invention also relates to a film comprising a combination of vegetable protein and polysaccharide at 50 wt% or more, based on the total weight of the film, at 55% relative humidity and 22°C, wherein the vegetable protein is pretreated with an organic acid, and the weight ratio of polysaccharide to vegetable protein is in the range of 0.1:1 to 2:1, and the film has a tensile strength of 0.15 to 5 MPa as measured by ASTM D882-18 at 76% relative humidity and 5°C and / or a breaking strain of 10 to 150%, as measured by ASTM D882-18 at 76% relative humidity and 5°C.

[0095] Preferred characteristics of the film are as described above.

[0096] The present invention also relates to a method for preparing a film as described herein above, comprising the steps of: (i) mixing polysaccharides in water, optionally with sonication, to form a polysaccharide mixture; (ii) dissolving or dispersing the plant protein in water and an organic acid, optionally using sonication, to form a protein solution; (iii) mixing the polysaccharide mixture and the protein solution to form a film-forming composition; (iv) forming the film-forming composition into a film comprising a combination of polysaccharide and vegetable protein at 50 wt. % or more based on the total weight of the film at 55% relative humidity and 22° C., wherein the weight ratio of polysaccharide to vegetable protein is in the range of 0.1:1 to 2:1; The present invention provides a method comprising:

[0097] In step (i), sonication inherently heats the solution due to the applied sonic energy.

[0098] In a preferred process of the present invention, the mixing step (i) is carried out at a temperature in the range of 70-100°C, preferably 85-95°C.

[0099] In a preferred method of the present invention, the dissolving step (ii) is carried out at a temperature in the range of 70-100°C, preferably 85-95°C.

[0100] In a preferred process of the invention, the organic acid is removed between steps (ii) and (iii).

[0101] In a preferred process of the present invention, the mixing step (iii) is carried out at a temperature in the range of 70 to 100°C, preferably 85 to 95°C.

[0102] In a preferred process of the present invention, the mixing step (iii) is carried out at a temperature in the range of 70 to 100°C, preferably 85 to 95°C.

[0103] In a preferred method of the present invention, steps (i), (ii) or (iii) further comprise sonication and / or ultrasound treatment.

[0104] In a preferred method of the invention, step (iv) comprises casting the film-forming composition onto a surface. Preferably, the surface is a preformed layer comprising a polysaccharide or a preformed layer comprising a plant protein. Alternatively, the surface is a glass plate or other backing material, such as a PET carrier film. Alternatively, the surface is a moving belt, preferably a moving steel belt.

[0105] In a preferred process of the invention, in step (iv) the film-forming composition is at a temperature in the range of from 50 to 95°C, more preferably from 50 to 85°C.

[0106] In a preferred method of the invention the surface is heated. Preferably the surface is heated to a temperature in the range of 50 to 130°C, more preferably 55 to 100°C.

[0107] In a preferred process of the invention, step (iv) further comprises heating the film in an oven, preferably at a temperature in the range of from 70 to 150°C.

[0108] In another preferred method of the present invention, step (iv) comprises extruding the film-forming composition through an orifice to form a film.

[0109] A preferred method of the present invention further comprises an ageing step. Preferably, said ageing step comprises subjecting the film to a temperature between 10 and 35° C. for a period of one week.

[0110] In a preferred method of the invention, steps (i)-(iv) are repeated to produce a multilayer film. Thus, steps (i)-(iv) can be performed to produce a first layer, and then steps (i)-(iv) can be repeated to produce a second layer on a first surface of the first layer.

[0111] The present invention also relates to a method for preparing a film as described herein above, comprising the steps of: (i) mixing polysaccharides in water, optionally with sonication, to form a polysaccharide mixture; (ii) forming the polysaccharide mixture into a first layer on a surface; (iii) dissolving the plant protein in water and an organic acid, optionally using sonication, to form a protein solution; (iv) forming a protein solution into a second layer on the first surface of the first layer, such that the resulting film comprises at least 50 wt % of a combination of plant protein and polysaccharide based on the total weight of the film at 55% relative humidity and 22° C., and a weight ratio of polysaccharide to plant protein is in the range of 0.1:1 to 2:1; The present invention provides a method comprising:

[0112] In step (i), sonication inherently heats the solution due to the applied sonic energy.

[0113] In a preferred process of the present invention, the mixing step (i) is carried out at a temperature in the range of 70-100°C, preferably 85-95°C.

[0114] In a preferred method of the present invention, step (i) further comprises sonication and / or ultrasound treatment.

[0115] In a preferred method of the invention, step (ii) comprises casting the polysaccharide mixture onto a surface. Preferably, the surface is a preformed layer comprising polysaccharides or a preformed layer comprising plant proteins. Alternatively, the surface is a glass plate or other backing material, such as a PET carrier film. Alternatively, the surface is a moving belt, preferably a moving steel belt.

[0116] In a preferred process of the invention, in step (ii) the polysaccharide mixture is at a temperature in the range of 50 to 95°C, preferably 50 to 85°C.

[0117] In a preferred method of the invention the surface is heated. Preferably the surface is heated to a temperature in the range of 50 to 130°C, more preferably 55 to 100°C.

[0118] In a preferred method of the present invention, the dissolving step (ii) is carried out at a temperature in the range of 70-100°C, preferably 85-95°C.

[0119] In a preferred method of the present invention, step (iii) further comprises sonication and / or ultrasound treatment.

[0120] In a preferred process of the invention, the organic acid is removed between steps (iii) and (iv).

[0121] In a preferred method of the invention, step (iv) comprises casting the protein solution onto the first surface of the first layer. Preferably, the first surface of the first layer is heated to a temperature in the range of 50 to 95°C, more preferably 55 to 85°C.

[0122] In a preferred method of the invention, in step (iv) the protein solution is at a temperature in the range of 50 to 100°C, preferably 55 to 90°C.

[0123] The present invention also provides a product, preferably a food product, coated or encapsulated with a film as described herein above.

[0124] Preferably, the product is a food product, a pharmaceutical product, a cleaning product, an agricultural product (eg, animal feed) or a pharmaceutical product, a chemical product, or a cosmetic product.

[0125] Preferably, the product is a solid product, a powder product, or a liquid product with a water activity of less than 50%.

[0126] The water activity of a material is the % equilibrium relative humidity of the material divided by 100. The % equilibrium relative humidity of a sample is measured by use of a humidity probe. Suitable equipment includes a Rotronics HC2-AW unit manufactured by Process Sensing Technologies, operated in accordance with instructions dated 03 / 31 / 2016 or later. The unit should have been calibrated within one year of use according to the procedure using salt solutions as specified in the operating instructions. The test sample is placed in a sample cup and placed in the test unit. A humidity cell is then placed in the sample cup to seal the sample in the sample cup. The free water in the test sample is then allowed to equilibrate with the air in the headspace above the sample, and the final humidity level in the headspace is measured by the HC2 unit and reported as % equilibrium relative humidity (eRH) at the test temperature. The %eRH is then divided by 100 to obtain the water activity of the sample. To avoid temperature dependent variations, measurements should be performed at temperatures between 20°C and 25°C.

[0127] Preferably, the product is a solid product selected from a soup or flavour preparation (e.g. a soup base solid), a personal detergent (e.g. a soap bar, a body wash, a body scrub or a shampoo), a laundry detergent tablet or a dishwasher detergent tablet. More preferably, the product is a soup base solid. Alternatively, the product is a laundry detergent tablet or a dishwasher detergent tablet.

[0128] Preferably, the product is a powder product selected from powdered food, powdered drink, milk powder, powdered soup, powdered hot chocolate, powdered coffee, soup flakes, and powdered shampoo. More preferably, the product is a powdered drink.

[0129] Preferably, the product is a non-aqueous liquid product that is an oil or a hair care product. More preferably, the product is a cooking oil.

[0130] The present invention also provides a method for coating or encapsulating a product, preferably a food product, comprising the steps of: (i) packaging the product in a film as described herein above; (ii) sealing a film around the product; The present invention provides a method comprising:

[0131] Preferred products are as described above.

[0132] Preferably, step (ii) comprises heat sealing.

[0133] As will be understood by those skilled in the art, the sealing process requires contact between sections of the film containing polysaccharide. For example, a composite film containing polysaccharide and vegetable protein can be sealed to another composite film containing polysaccharide and vegetable protein, or to itself. However, if the film is a multi-layer film, for example, containing a polysaccharide layer and a vegetable protein layer, the polysaccharide layer needs to be sealed to another film containing polysaccharide, or to itself. This is because polysaccharides can melt (or gelatinize) at a much lower temperature compared to vegetable protein. Residual water present in the polysaccharide layer also helps to lower the melting (or gelatinization) temperature of the polysaccharide.

[0134] In a preferred method of the invention, the duration of step (ii) is less than 2 seconds, more preferably less than 1 second, most preferably less than 0.5 seconds.

[0135] In another preferred process of the present invention, step (ii) is carried out at a temperature below 160°C, more preferably below 140°C, most preferably below 120°C.

[0136] The present invention also provides the use of a film as described herein above for coating or encapsulating a product, preferably a food product.

[0137] Preferred products are as described above.

[0138] The present invention also provides a sachet prepared by the method as described herein above.

[0139] Preferred sachets of the present invention do not stick to other sachets when maintained in a humid environment.

[0140] The present invention also relates to a method for releasing a product coated or encapsulated with a film as described herein above, comprising the steps of: (i) placing the coated or encapsulated product in water; (ii) dispersing the film, thereby releasing the product; The present invention provides a method comprising:

[0141] Preferred products are as described above.

[0142] Alternatively, the product is released during the cooking process.

[0143] Preferably, the product is released during the cleaning process.

[0144] In a preferred process of the invention, step (ii) further comprises mechanical agitation, e.g. stirring or shaking.

[0145] The present invention also provides a film-forming composition comprising a vegetable protein and a polysaccharide, wherein the mass ratio of the polysaccharide to the vegetable protein is in the range of 0.1:1 to 2:1, and the vegetable protein is pretreated with an organic acid.

[0146] Preferred features are as described above in connection with the films of the invention.

[0147] The present invention also provides a film obtained from the film-forming composition as described hereinabove.

[0148] Preferred features are as described above. [Brief description of the drawings]

[0149] [Figure 1a] 1 is a graphical representation of a monolayer film of the present invention. [Figure 1b] 1 is a graphical representation of a multilayer film of the present invention. [Figure 2a] FIG. 1 shows an intact packaged tablet of film E7 before starting the dishwasher. [Figure 2b] This corresponds to 5 minutes into the cycle. [Figure 2c] This corresponds to 10 minutes into the cycle. [Figure 2d]This corresponds to 15 minutes into the cycle. [Figure 2e] FIG. 11 corresponds to the end of the cycle. [Diagram 3] FIG. 1 shows dishwasher tablets packaged in film E7; A: stack of tablets at t=0; B: fusion test at t=0; C: stack of tablets after 48 hours at 70% RH; D: fusion test after 48 hours at 70% RH. [Figure 4] FIG. 1 shows dishwasher tablets packaged with PVOH; A: stack of tablets at t=0; B: coalescence test at t=0; C: stack of tablets after 48 hours at 70% RH; D: coalescence test after 48 hours at 70% RH. EXAMPLES

[0150] material Pea protein isolate (PPI) (80 wt% protein, 4 wt% carbohydrate) (ProEarth P16109) was purchased from Cambridge Commodities Ltd. Tapioca starch (Alpha Instant), potato starch (pregelatinized), corn starch, and rice starch were purchased from BakeRite. Corn amylopectin (starch derived from corn) and maltodextrin were purchased from Sigma-Aldrich Co. Waxy maize starch (Ultratex) was purchased from Special Ingredients Ltd. Food grade glycerol (APC Pure) and potato starch (heat soluble) were purchased from APC Corporation. Vegetable (rapeseed) oil was purchased from Tesco Ltd, UK. Lactic acid (food grade, ≧80%) was purchased from Cambridge Commodities Ltd. Acetic acid (glacial, food grade) was purchased from Fisher Scientific. Pullulan was purchased from Rongsheng Biotechnology Co. Ltd.

[0151] In the examples which follow, all references to "room temperature" refer to a temperature of approximately 20°C.

[0152] Measurement method Water dispersion test A 0.2 g piece of film was placed in 600 ml of boiling water for 3 minutes with an overhead stirrer at 750 rpm positioned off-center so as not to touch the film. The water was observed for the presence or absence of debris. After this time, the mixture was passed through a 2 mm mesh sieve. The appearance of the residue collected on the sieve, if any, was observed and recorded. The film piece was carefully removed from the mesh using tweezers and the mass was measured.

[0153] Film Tensile Strength and / or % Elongation Test The films were tested according to ASTM D882-18 Tensile Properties of Thin Plastic Sheets using a Tinius Olsen 5ST tensile tester equipped with a 100N load cell.

[0154] The test films were cut into strips measuring 8.0 cm by 1.0 cm. The film thickness was measured at six points (three on each side of the strip being tested) with a micrometer (DML 3701P6 from RDM Test Equipment) and the results were averaged to determine the average cross-sectional thickness. The strips were then conditioned to 76% relative humidity (RH) at 5°C by exposing the film in a humidity chamber at 76% RH / 5°C for at least 24 hours to ensure that the strips were equilibrated before testing. Conditions were measured using commonly available devices, such as a Fisherbrand™ Traceable™ thermometer / clock / humidity monitor. Such conditions are typically those found in a domestic refrigerator. Alternatively, the strips were conditioned to 55% relative humidity at 22°C using the same method. Such conditions are typically those encountered in room temperature packaging and storage facilities.

[0155] To test the films, the strips were removed from the humidity chamber and clamped by parallel clamps on a 5ST test head with a 5 cm gap between the clamps. The upper clamp attached to the load cell was then moved upward at a constant rate of 50 mm / min to stretch the film until breakage and the force applied to the load cell was recorded. To minimize film state changes, this procedure was performed within 1 minute of removing the film sample from the humidity chamber. Tensile strength is the force at break divided by the average cross-sectional area of ​​the film before conditioning and testing. The % break strain is calculated as (film length at break-initial film length) / initial film length) x 100.

[0156] Example 1 Preparation of films A monolayer film (E5) and multilayer films (E6-E14) were prepared according to the procedures described below. Five comparative films (C1-C5) were also prepared according to the procedures described below.

[0157] Preparation of protein monolayer film C1 (i) Preparation of protein mixtures 150 ml of deionized water was mixed with 37.5 g of pea protein isolate in a 600 ml beaker at room temperature using an overhead stirrer to form a homogenous paste. 350 ml of acetic acid was then added with stirring along with 10.89 g of glycerol. The suspension was then sonicated (high intensity ultrasound) for 37 minutes and 30 seconds using a Bandelin Sonopuls HD4200 equipped with a TS113 probe. The sonicator was set at 50% amplitude with a cycle of 1 second on and 0.2 seconds off. Stirring was intermittent throughout the sonication to ensure the suspension was homogenous.

[0158] (ii) Film formation 25 ml of the mixture was poured into a 50 ml Falcon tube through a tea strainer to remove any remaining large clumps. The mixture was then further degassed by removing large bubbles with a pipette and placing the Falcon tube in an ultrasonic bath at 80°C for 5 minutes. The mixture was removed, cooled to 55°C, and poured onto a flat glass plate with a Mylar surface. The liquid was spread evenly on the plate using a knife blade to obtain a 500 micron wet film of the protein mixture. The glass plate was then dried in an oven at 80°C for 1 hour.

[0159] Preparation of potato starch monolayer film C2 (i) Preparation of the starch mixture 50.0 g of potato starch was dispersed in 500 ml of deionized water at room temperature in a 600 ml beaker by overhead stirring. 21.43 g of glycerol was then added and the suspension was stirred. The suspension was then sonicated (high intensity ultrasound) for 50 minutes at 95% amplitude with a cycle of 1 second on, 0.2 seconds off using a Bandelin Sonopuls HD4200 with a TS113 probe. Stirring was performed throughout the sonication to ensure homogenous suspension. The solution was then placed in an ultrasonic bath at 80°C for 30 minutes to remove bubbles.

[0160] (ii) Film formation 25 ml of the solution was poured into a 50 ml Falcon tube through a tea strainer to remove any remaining large clumps. The solution was then further degassed by removing large bubbles with a pipette and placing the Falcon tube in an ultrasonic bath at 80° C. for 5 minutes. The mixture was removed, cooled to 55° C., and poured onto a flat glass plate with a Mylar surface. The liquid was spread evenly using a knife blade to obtain a 500 micron thick wet film of the protein mixture. The plate was then placed in an oven at 80° C. for 1 hour to form a dry film.

[0161] Preparation of tapioca starch monolayer film C3 (i) Preparation of Tapioca Starch Mixture 50.0 g of tapioca starch (STT) was dispersed in 500 ml of deionized water at room temperature in a 600 ml beaker by overhead stirring. 21.43 g of glycerol was then added and the suspension was stirred. The suspension was then sonicated for 50 minutes using a Bandelin sonicator at 95% amplitude with a cycle of 1 second on and 0.2 seconds off. The solution was then placed in an ultrasonic bath at 80°C for 30 minutes to remove bubbles.

[0162] (ii) Film formation 25 ml of the solution was poured into a 50 ml Falcon tube. The solution was then further degassed by removing large bubbles with a pipette before being cooled to 55° C. and poured onto a flat glass plate with a Mylar surface. The liquid was spread evenly using a knife blade to obtain a 500 micron thick wet film of the protein mixture. The plate was then placed in an oven at 80° C. for 1 hour to form a dry film.

[0163] Preparation of potato starch and pullulan monolayer film C4 (i) Preparation of Potato Starch and Pullulan Mixture 37.5 g potato starch and 37.5 g pullulan were dispersed in 500 ml freshly boiled deionized water in a 600 ml beaker by overhead stirring. A hot plate was used to keep the solution above 80° C. 18.75 g glycerol was then added and the mixture was stirred for an additional 2 minutes.

[0164] (ii) Film formation The mixture was then degassed under vacuum using a FlackTek Speedmixer. The mixture was removed, cooled to 55°C, and poured in 25 ml onto a flat glass plate with a Mylar surface. The liquid was spread evenly using a knife blade to obtain a 300 micron thick wet film of the protein mixture. The plate was then placed in an oven at 80°C for 1 hour to form a dry film.

[0165] Preparation of protein-starch monolayer film C5 (without organic acid treatment step) (i) Preparation of the starch mixture 11.25 g of soluble potato starch was dispersed in 75 g of room temperature deionized water by stirring in a 250 ml flask. 5.625 g of glycerol and 0.23 g of vegetable oil were then added and the suspension was stirred. The suspension was then sonicated (high intensity ultrasound) for 7 minutes and 30 seconds using a Bandelin Sonopuls HD4200 with a TS113 probe. The sonicator was set at an amplitude of 95% amplitude with a cycle of 1 second on and 0.2 seconds off. Stirring was performed throughout the sonication to ensure homogenous suspension. There was no further heating, but the energy of the sonication raised the temperature of the mixture to above 80° C. by the end of the sonication period. The mixture was then placed in a heated ultrasonic water bath at 80° C. for 30 minutes to allow trapped air bubbles to escape.

[0166] (ii) Preparation of PPI mixtures Pea protein isolate (PPI), 7.5 g, was added to 100 g water in a 250 ml tall beaker using an overhead stirrer to form a homogenous paste. The PPI mixture was then sonicated (high intensity ultrasound) for 7 minutes and 30 seconds using a Bandelin Sonopuls HD4200 equipped with a TS113 probe. The sonicator was set at 50% amplitude with a cycle of 1 second on and 0.2 seconds off. Stirring was intermittent throughout the sonication to ensure a homogenous suspension.

[0167] (iii) Preparation of Protein-Starch Mixtures 150 ml of the PPI mixture from step (ii) and 0.54 g of lactic acid were added to the starch mixture from step (i). The combined mixture was sonicated for 3 minutes at 50% amplitude with a cycle of 1 second on and 0.2 seconds off using a Bandelin Sonopuls HD4200. The combined mixture was then placed in an ultrasonic bath at 80° C. for 5 minutes to aid in the removal of air bubbles.

[0168] (iv) Film formation 25 mL of the combined mixture from step (iii) was poured into a 50 ml Falcon tube through a tea strainer to remove any remaining large clumps. The mixture was then further degassed by removing large bubbles with a pipette and placing the Falcon tube in an ultrasonic bath at 80° C. for 5 minutes. The mixture was removed, cooled to 55° C., and poured onto a flat glass plate having a Mylar surface. The liquid was spread evenly on the plate using a RK K Control Coater Model 101 equipped with a knife edge to obtain a film of uniform thickness of 1000 microns. The glass plate was then placed in an oven at 80° C. for 1 hour. After this time, the film could be peeled off from the test-prepared Mylar surface.

[0169] Preparation of protein-starch monolayer film E5 (i) Preparation of the starch mixture 22.50 g of soluble potato starch was dispersed in 150 g of room temperature deionized water by stirring in a 250 ml flask. 5.625 g of glycerol and 0.23 g of vegetable oil were then added and the suspension was stirred. The suspension was then sonicated (high intensity ultrasound) for 14 minutes and 15 seconds using a Bandelin Sonopuls HD4200 equipped with a TS113 probe. The sonicator was set at 95% amplitude with a cycle of 1 second on and 0.2 seconds off. Stirring was performed throughout the sonication to ensure homogenous suspension. After sonication, 0.54 g of lactic acid was added with stirring. There was no further heating, but the energy of the sonication raised the temperature of the mixture to above 80° C. by the end of the sonication period. The mixture was then placed in a heated ultrasonic water bath at 80° C. for 30 minutes to allow trapped air bubbles to escape.

[0170] (ii) Preparation of PPI mixtures 30 g water was mixed with 7.5 g pea protein isolate in a 250 ml tall beaker using an overhead stirrer to form a homogenous paste. 70 ml acetic acid was then added with stirring along with 1.876 g glycerol. The suspension was then sonicated (high intensity ultrasound) for 7 minutes and 30 seconds using a Bandelin Sonopuls HD4200 equipped with a TS113 probe. The sonicator was set at 50% amplitude with a cycle of 1 second on and 0.2 seconds off. Stirring was intermittent throughout the sonication to ensure the suspension was homogenous.

[0171] (iii) Preparation of Protein-Starch Mixtures 150 ml of the PPI mixture from step (ii) and 0.54 g of lactic acid were added to the total starch mixture from step (i) to form a combined mixture. The combined mixture was sonicated for 3 minutes at 50% amplitude with a cycle of 1 second on and 0.2 seconds off using a Bandelin Sonopuls HD4200. The combined mixture was then placed in an ultrasonic bath at 80° C. for 5 minutes to aid in the removal of air bubbles.

[0172] (iv) Film formation 25 mL of the combined mixture from step (iii) was poured into a 50 ml Falcon tube through a tea strainer to remove any remaining large clumps. The mixture was then further degassed by removing large bubbles with a pipette and placing the Falcon tube in an ultrasonic bath at 80° C. for 5 minutes. The mixture was removed, cooled to 55° C., and poured onto a flat glass plate having a Mylar surface. The liquid was spread evenly on the plate using a RK K Control Coater Model 101 equipped with a knife edge to obtain a film of uniform thickness of 1000 microns. The glass plate was then placed in an oven at 80° C. for 1 hour. After this time, the film could be peeled off from the test-prepared Mylar surface.

[0173] Preparation of potato starch-protein monolayer film E6 (i) Preparation of the starch mixture 500 ml of deionized water was mixed with 50 g of potato starch in a 600 ml beaker at room temperature using an overhead stirrer. 21.43 g of glycerol was then added and the suspension was stirred. The suspension was then sonicated (high intensity ultrasound) and processed according to the procedure described in step (i) of the preparation of starch monolayer film C2.

[0174] (ii) Film formation – starch layer 5 ml of the mixture produced in step (i) was poured into a 50 ml Falcon tube. The mixture was then further degassed by removing large bubbles with a pipette and placing the Falcon tube in an ultrasonic bath at 80° C. for 5 minutes before being removed and cooled to 55° C. The liquid was poured onto a flat glass plate with a Mylar surface and spread evenly on the plate using a knife blade to obtain a 100 micron wet film of the protein mixture. The glass plate was then placed in an oven at 80° C. for 30 minutes to form a dry film layer.

[0175] (iii) Preparation of protein mixtures 150 g water was mixed with 37.5 g pea protein isolate (PPI) in a 600 ml beaker at room temperature using an overhead stirrer to form a homogenous paste. Then 350 ml acetic acid and 10.89 g glycerol were added with stirring. The mixture was then sonicated (high intensity ultrasound) and processed according to the procedure described in step (i) of the preparation of protein monolayer film C1.

[0176] (iv) Film formation – protein layer 25 ml of the mixture produced in step (iii) was poured into a 50 ml Falcon tube. The mixture was then further degassed by removing large bubbles with a pipette and placing the Falcon tube in an ultrasonic bath at 80° C. for 1 minute, followed by cooling to 55° C., and then spread using a knife blade onto the exposed surface of the dry film prepared in step (ii) (i.e., the surface not in contact with the glass plate) to obtain an approximately 500 micron thick wet film of the PPI mixture. The plate was then placed in an oven at 80° C. for 30 minutes to form a multilayer film.

[0177] Preparation of potato starch-protein multilayer film E7 (i) Preparation of the starch mixture The starch mixture was prepared according to the procedure in step (i) of the preparation of film E6.

[0178] (ii) Film formation – starch layer 15 mL of the mixture from step (i) was cast into a film according to step (ii) of the preparation of film E6, except that a wet film thickness of 300 microns was applied to the Mylar surface of the glass plate. The film was allowed to dry at 80° C. for 30 minutes.

[0179] (iii) Preparation of protein mixtures The PPI mixture was prepared according to the procedure in step (iii) of the preparation of film E6.

[0180] (iv) Film formation – protein layer 25 ml of the mixture from step (iii) was spread on the exposed surface of the dry film prepared in step (ii) according to step (iv) of the preparation of film E6.

[0181] Preparation of potato starch-protein multilayer film E8 (i) Preparation of the starch mixture The starch mixture was prepared according to the procedure in step (i) of the preparation of film E6.

[0182] (ii) Film formation – starch layer 5 mL of the mixture from step (i) was cast into a film according to step (ii) of the preparation of film E6.

[0183] (iii) Preparation of protein mixtures The PPI mixture was prepared according to the procedure in step (iii) of the preparation of film E6.

[0184] (iv) Film formation – protein layer 45 ml of the mixture from step (iii) was spread onto the exposed surface of the dried film prepared in step (ii) according to step (iv) of the preparation of film E6, except that a wet film thickness of 900 microns was applied. The film was left to dry at 80° C. for 60 minutes.

[0185] Preparation of potato starch-protein multilayer film E9 (i) Preparation of the starch mixture The starch mixture was prepared according to the procedure in step (i) of the preparation of film E6.

[0186] (ii) Film formation – starch layer 25 mL of the mixture from step (i) was cast into a film according to step (ii) of the preparation of film E6, except that a wet film thickness of 500 microns was applied to the Mylar surface of the glass plate. The film was allowed to dry at 80° C. for 60 minutes.

[0187] (iii) Preparation of protein mixtures The PPI mixture was prepared according to the procedure in step (iii) of the preparation of film E6.

[0188] (iv) Film formation – protein layer 25 ml of the mixture from step (iii) was spread on the exposed surface of the dry film prepared in step (ii) according to step (iv) of the preparation of film E6.

[0189] Preparation of potato starch / pullulan-protein multilayer film E10 (i) Preparation of starch / pullulan mixture 37.5 g potato starch and 37.5 g pullulan were dispersed in 500 ml freshly boiled deionized water in a 600 ml beaker by overhead stirring. A hot plate was used to keep the solution above 80° C. 18.75 g glycerol was then added and the mixture was stirred for an additional 2 minutes.

[0190] (ii) Film formation – starch / pullulan layer 25 mL of the mixture from step (i) was degassed under vacuum using a FlackTek Speedmixer, cooled to 55°C and poured onto a flat glass plate with a Mylar surface. The liquid was spread evenly onto the plate using a knife blade to obtain a 300 micron wet film of the starch / pullulan mixture. The film was left to dry at 80°C for 30 minutes.

[0191] (iii) Preparation of protein mixtures The PPI mixture was prepared according to the procedure in step (iii) of the preparation of film E6.

[0192] (iv) Film formation – protein layer 25 ml of the mixture from step (iii) was spread on the exposed surface of the dry film prepared in step (ii) according to step (iv) of the preparation of film E6.

[0193] Preparation of tapioca starch-protein multilayer film E11 (i) Preparation of the starch mixture 25.0 g of tapioca starch was dispersed in 200 ml of deionized water at room temperature in a 400 ml beaker by overhead stirring. 6.25 g of glycerol was then added and the suspension was stirred. The suspension was then sonicated (high intensity ultrasound) for 25 minutes at 95% amplitude with a cycle of 1 second on, 0.2 seconds off using a Bandelin Sonopuls HD4200 with a TS113 probe. Stirring was performed throughout the sonication to ensure homogenous suspension. The solution was then placed in an ultrasonic bath at 80°C for 30 minutes to remove bubbles.

[0194] (ii) Film formation 12.5 ml of the solution was poured into a 50 ml Falcon tube. The solution was then further degassed by removing large bubbles with a pipette and placing the Falcon tube in an ultrasonic bath at 80° C. for 5 minutes. The mixture was removed, cooled to 55° C., and poured onto a flat glass plate with a Mylar surface. The liquid was spread evenly using a knife blade to obtain a 200 micron thick wet film of the protein mixture. The plate was then placed in an oven at 80° C. for 30 hours to form a dry film.

[0195] (iii) Preparation of protein mixtures 60 ml of water was mixed with 16 g of pea protein isolate (PPI) in a 400 ml beaker at room temperature using an overhead stirrer to form a homogenous paste. 140 ml of acetic acid and 6.86 g of glycerol were then added with stirring. The suspension was then sonicated (high intensity ultrasound) for 15 minutes using a Bandelin Sonopuls HD4200 equipped with a TS113 probe. The sonicator was set at 50% amplitude with a cycle of 1 second on and 0.2 seconds off. Stirring was intermittent throughout the sonication to ensure the suspension was homogenous.

[0196] (iv) Film formation – protein layer 20 ml of the mixture produced in step (iii) was poured into a 50 ml Falcon tube. The mixture was then further degassed by removing large bubbles with a pipette and placing the Falcon tube in an ultrasonic bath at 80° C. for 1 minute, followed by cooling to 55° C., and then spread using a knife blade onto the exposed surface of the dry film prepared in step (ii) (i.e., the surface not in contact with the glass plate) to obtain a wet film of the PPI mixture approximately 400 microns thick. The plate was then placed in an oven at 80° C. for 30 minutes to form a multilayer film.

[0197] Preparation of tapioca starch / protein monolayer film E12 50 ml of the mixture produced in E11 step (i) was added to 100 ml of the mixture produced in E11 step (iii) in a 250 ml beaker using an overhead stirrer at room temperature to form a homogenous mixture. The mixture was placed in an ultrasonic bath at 80° C. for 5 minutes to remove bubbles. 30 ml of the mixture was poured into a 50 ml Falcon tube. The mixture was removed and poured onto a flat glass plate with a Mylar surface and spread evenly on the plate using a knife blade to obtain a 600 micron wet film of the protein-starch blend. The glass plate was then placed in an oven at 80° C. for 1 hour to form a dry film.

[0198] Preparation of starch-protein multilayer film E13 (i) Preparation of the starch mixture 2000 ml of room temperature deionized water was mixed with 85.7 g of glycerol in a Klarstein food processor (Grand Prix Chef Edition). 200 g of potato starch was then added and the program: temperature 85°C, speed 4, 45 minutes was started. The batch was then transferred to a VEVOR vacuum chamber connected to a 1 / 4 hp 3 cfm single stage vacuum pump for degassing. The material was poured into a container which was then sealed and the vacuum pump was operated for 5-10 minutes until the slurry was free of air bubbles.

[0199] (ii) Film formation – starch layer The casting of the starch layer was carried out using a standard roll-to-roll machine with a pressure vessel, a fluid pump, a slot die unit, a feed roller, a web across a series of rollers and load cells allowing tension control, a drying oven approximately 2 meters long, and a take-up roller. The backing material used for this casting was a standard 72 μm PET roll. The starch mixture prepared in (i) was poured into the pressure vessel and then tightly closed to ensure no leakage. The vessel was then pressurized to 1-2 bar and the starch mixture was pumped by a progressive cavity pump to feed the slot die. The equipment was set to the following parameters: Oven temperature: 100~140℃ Line speed: 0.4~1m / min Slot die width: 300mm Fluid pump flow rate: 50~120ml / min Slot die distance from backing material: 0.2~0.4mm Shim distance between slot lips: 150~200μm

[0200] The wet thickness varied between 300-550 μm and was adjusted to approximately 350 μm by adjusting the parameters. The film emerging from the oven drying and the resulting roll was then removed from the collection winder and positioned as a feed roll so that a second film could be cast on top of it.

[0201] (iii) Preparation of protein mixtures 740g water was mixed with 94.4g pea protein isolate (PPI) in a 1000ml tall beaker using an overhead stirrer to form a homogenous slurry. 60g acetic acid and 23.6g glycerol were then added with stirring. The mixture was placed in a 90°C water bath for 20-30 minutes with shaking every 10 minutes. After this step, the slurry was transferred to a Hielscher 1kW sonicator (with booster) and a total of 200kJ of energy was applied with shaking approximately every 30 minutes. The sonication took approximately 30 minutes to reach the target energy. The process was repeated three times to produce a total of 2400ml of product, which was then degassed using a Synergy Flacktek Speedmixer for 3-5 minutes at settings of 2000rpm; 50mBar.

[0202] (iv) Film formation – protein layer The coating equipment as described in step (ii) was used for this layer, except that the backing had already been coated with a first layer of starch. The protein mixture prepared in step (iii) was poured into a pressure vessel and the coater was set to the following parameters: Oven temperature: 100~130℃ Line speed: 0.7~1m / min Slot die width: 300mm Fluid pump flow rate: 40~120ml / min Slot die distance from backing material: 0.2~0.25mm Shim distance between slot lips: 150~200μm

[0203] The multilayer film emerged from the oven drying exhibiting minimal bubbles and / or defects. The two layers each had a thickness of approximately 30 μm.

[0204] Preparation of starch-protein multilayer film E14 (i) Preparation of the starch mixture The starch mixture was prepared according to the procedure described in step (i) of the preparation of film E13.

[0205] (ii) Film formation – starch layer 2000 ml of the batch described in step (i) was cast into a roll of film following the procedure described in step (ii) of the preparation of film E13.

[0206] (iii) Preparation of protein mixtures 1200 g of deionized water was measured and poured into a large 3 L stainless steel vessel. The vessel was placed in a water bath set at 95° C. and the water was mixed at 900 rpm using an overhead stirrer equipped with an impeller blade. 320 g of pea protein isolate was added to the mixture and left to stir for 3 minutes until a homogenous mixture was formed. 800 g of acetic acid was measured and poured into the mixture which was stirred at 700 rpm for 40 minutes. The temperature of the mixture was measured to ensure it had reached 85° C. and, if necessary, stirring was continued for at least 10 minutes to ensure the mixture had reached 85° C. The mixture was then sheared using a Silverson high shear homogenizer at 7000 rpm for 3 minutes.

[0207] The freshly shear mixed slurry was then poured into a plastic flat container or large Petri dish to a height of approximately 10 mm. The container was then sealed and stored in a refrigerator for 16-28 hours.

[0208] After storage, the formed gel was cut into 1 cm x 1 cm squares and the gel cubes were transferred to a 75 μm filter bag using a spatula. The bag with the gel cubes was then suspended in a bucket containing 6 liters of reverse osmosis water. After 1 hour and 30 minutes, 3 liters of water were removed and replaced with 3 liters of fresh reverse osmosis water. The bag and gel cubes were left in the water and swirled every 20 minutes for 90-150 minutes. The pH was measured and if it was below 2.9, then the previous two steps were repeated until the pH reached a value above 2.9.

[0209] The filter bag was then removed from the water and squeezed vigorously to remove as much excess water as possible. The slurry was then transferred to a 1 liter container and the gel mash was sheared using an Ultra-Turrax mixer at 15000 rpm for 15 minutes with shaking every 5 minutes. 21.71 g of glycerol was then added to the mixture followed by an additional 5 minutes of Ultra-Turrax mixing at 15000 rpm. The container was then placed in an ice bath and the mixture was sonicated with a Hielschler sonicator until it reached 0.25 kJ / ml. The slurry was filtered through a 212 μm mesh and stored in a plastic bucket.

[0210] (iv) Film formation – protein layer 2000 ml of the mixture prepared in step (iii) was poured into the pressurized vessel of the coater described in step (iv) of film E13. The following parameters were used in the equipment settings: Oven temperature: 100~115℃ Line speed: 0.5~0.9m / min Slot die width: 300mm Fluid pump flow rate: 50~90ml / min Slot die distance from backing material: 0.15~0.2mm Shim distance between slot lips: 150~200μm

[0211] The multilayer film emerged from the oven drying exhibiting minimal bubbles and / or defects. The two layers each had a thickness of approximately 30 μm.

[0212] The composition of each of the films prepared is shown in Table 1.

[0213] [Table 1A]

[0214] [Table 1B]

[0215] [Table 1C]

[0216] Example 2 Determination of the onset melting temperature and sealing strength of polysaccharide monolayers (i) Preparation of polysaccharide monolayers 10.0 g of polysaccharide was dispersed in 100 ml of deionized water at room temperature in a 250 ml flask by overhead stirring. 4.29 g of glycerol was then added and the suspension was stirred. The suspension was then sonicated for 10 minutes at 95% amplitude using a Bandelin sonicator with cycles of 1 second on and 0.2 seconds off. The solution was then placed in an ultrasonic bath at 80°C for 1 minute to remove bubbles.

[0217] 20 ml of the solution was poured into a 50 ml Falcon tube. The solution was then further degassed by removing large bubbles with a pipette before being cooled to 55° C. and poured onto a flat glass plate with a Mylar surface. The liquid was spread evenly using a knife blade to obtain a wet film approximately 400 microns thick. The plate was then placed in an oven at 80° C. for 50 minutes to dry the layer of film.

[0218] (ii) Measurement of melting temperature using a differential scanning calorimeter (DSC) The films produced in step (i) were conditioned overnight at 55% relative humidity and 20°C. The onset of melting temperature is a function of the total film composition, including moisture level. Small test samples (10-20mg) were cut from each film and accurately weighed. Each sample was placed in a 40μL aluminum pan (#51119870, purchased from Mettler Toledo) and heated from 25°C to 160°C at a heating rate of 10°C / min in a nitrogen atmosphere using a Mettler Toledo DSC822e. A hole was pierced in the lid of the pan using a 50μm diameter needle prior to sealing. An empty pan was used as a reference. The normalized heat flow was recorded and plotted as a function of temperature.

[0219] The onset temperature of melting of a sample is defined as the first inflection point on the DSC curve that indicates an increase in the rate of heat flow into the sample with increasing temperature. As the sample begins to melt, the heat flow into the sample increases, thus causing a change in slope and an inflection point on the graph.

[0220] The inflection points of the graph can be determined by an operator's visual evaluation of the normalized heat flow plot. However, this analysis is now typically performed using software analysis tools. Such analysis tools are typically included as part of the equipment operating system. Suitable software includes the STARe evaluation software supplied by Mettler-Toledo.

[0221] The data from the normalized DSC plots obtained above were analyzed using STARe evaluation software version 16.30 to determine the onset melting temperatures. The results are shown in Table 1 below. The thermal properties of a starch mixture are a complex combination of the relative ratios of amylose to amylopectin in the starch prior to heat treatment, as well as the properties of the other components.

[0222] [Table 2]

[0223] (iii) Determination of sealing strength Test specimens of several layers produced in step (i) were prepared and subjected to seal strength measurements. Test specimens of 25 mm width were cut to the dimensions indicated in ASTM F88 / F88M-15 and conditioned overnight at 55% RH and 20°C. The test strip specimens were then sealed using an RDM heat sealer to obtain a fin seal. The sealed specimens were tested in a Tinnius Olsen tensile tester using technique A (unsupported). A sealing temperature of 100°C and a dwell time of 1 second were used. The results are shown in Table 2 below.

[0224] [Table 3]

[0225] As demonstrated above, the melting onset temperature of a material is inversely related to its ability to form a strong seal. For example, an STT-based layer has a low onset temperature and forms a strong seal. A BPS-based layer has a slightly higher onset temperature and also forms a strong seal. However, a CSS-based layer has a much higher onset temperature and, as a result, forms a seal with a much lower seal strength.

[0226] The lower initiation temperature of the polysaccharide-containing layers of the multilayer films of the present invention is advantageous for a number of reasons. Not only have it been demonstrated that stronger seal strengths can be achieved, but the lower initiation temperature also means that lower temperatures need to be applied to the outer alginate-containing layers of the multilayer films of the present invention to effect an effective seal of the inner polysaccharide-containing layers. This means that film degradation (e.g., as a result of burning) is avoided, and also that shorter residence times are required to form the seal, making the sealing process more industrially viable.

[0227] Example 3 Measurement of film tensile strength and elongation Rectangular test specimens 80 mm long and 10 mm wide were cut (which is within the specifications set forth in ASTM D882) and conditioned overnight at 55% RH and 22 °C. Test specimens were tested using a Tinnius Olsen tensile tester with flat grip inserts, an initial grip spacing of 50 mm, and a test speed of 50 mm / min (strain rate of 1 mm / mm min).

[0228] Great care was taken when cutting the specimens to avoid nicks and tears that would cause premature failure and to ensure consistent sample quality.

[0229] The results are shown below in Table 3. Tensile strength is reported in MPa and elongation at break in %.

[0230] [Table 4]

[0231] The protein monolayer film (C1) had a higher tensile strength than the polysaccharide monolayer films (C2, C3, C4), as expected.

[0232] The potato starch monolayer film (C2) had very low tensile strength and was not suitable for industrial application as a film. However, the monolayer film made from a mixture of potato starch and organic acid treated protein (E5) had good tensile strength and % breaking strain, resulting in a robust and easily handled film.

[0233] A comparable monolayer film (C5) in which the protein was not treated with acid cracked upon drying and did not produce a viable film that could not be tested for tensile strength or elongation.

[0234] The tapioca starch monolayer film (C3) had very low tensile strength and was not suitable for industrial application as a film. However, blending low levels of tapioca starch with protein as a monolayer film (E12) reduced the protein tensile strength and elongation, which was still acceptable for handling and fabrication into sachets. The equivalent multilayer film (E11) showed less loss in tensile strength or elongation than the monolayer film.

[0235] Multilayers with different polysaccharides (potato starch, tapioca starch, pullulan) in different ratios all had good tensile strength and elongation (E6, E7, E8, E9, E10, E11).

[0236] Multilayer films with lower levels of organic acids (E13 and E14) resulted in films with very good tensile strength.

[0237] Example 4 Sealing strength measurement Test specimens 25 mm wide were cut to the dimensions indicated in ASTM F88 / F88M-15 and conditioned overnight at 55% relative humidity and 20°C. The test strip specimens were then sealed using an RDM heat sealer to obtain a fin seal. The sealed specimens were tested using technique A (unsupported) in a Tinnius Olsen tensile tester. A sealing temperature of 120°C and a dwell time of 1 second and a pressure between 3-5 bar were used. It is well known that sealing pressure has a negligible effect on seal strength. The results are shown in Table 4 below. The maximum force encountered when stressing each specimen to failure is reported as Newtons per meter (N / m).

[0238] [Table 5]

[0239] As expected, the protein monolayer film C1 did not heat seal.

[0240] The polysaccharide monolayer films C2, C3 and C4 had very high heat seal strength.

[0241] The blend of tapioca starch and protein monolayer film (E12) has a lower seal strength compared to the tapioca starch monolayer film (C3), but this is still acceptable for forming sachets in industrial processes. The same composition prepared as a multilayer (E11) is preferred because it maintains the high seal strength of the tapioca starch monolayer (C3).

[0242] The starch-pullulan:protein multilayer (E10) maintains the superior high seal strength of the starch-pullulan monolayer (C4).

[0243] The potato starch:protein multilayers have acceptable sealing even at very low levels of starch (E6, E7, E8, E9).

[0244] Protein / starch multilayer E6 (having a film thickness of 67 μm and conditioned and stored at 55% relative humidity and 20° C. temperature) was subjected to further seal strength testing at different sealing temperatures, 1 second dwell time and 5 bar pressure. The average and maximum seal strength results are shown in Table 5 below.

[0245] [Table 6]

[0246] For this film composition, the ideal heat seal temperature was 130°C, where the average and maximum seal strengths reached their maximum. At lower temperatures, there was insufficient heat to gelatinize the starch and form a good seal. At higher temperatures, the material began to decompose and seal strength decreased.

[0247] Example 5 Dispersing tablet sachets for dishwashers Multilayer film E7 was used to produce sachets by heat sealing the edges along the length of the film using an RS PRO heat sealer at power 2. The sealed sachet contained Reckitt Benckiser's commercially available dishwasher Finish® tablets pre-packaged with PVOH. The sachet could be easily handled and maintained its integrity.

[0248] The dispersion of the film and the dissolution of the product were tested in real life conditions using a Bosch "Series 2" dishwasher and compared to commercially available PVOH packaged tablets. The cycle chosen was Eco 45, washing for 45 minutes at 45°C, with the dishwasher cycle paused every 5 minutes to evaluate the condition of the sachet and to evaluate the dissolution of the tablet. Table 6 shows how the film of the invention dispersed in the first 10 minutes of the cycle, which was completely dispersed after 15 minutes and there was no trace of the film at the end of the cycle. This compares favorably with the control PVOH film, which initially dissolved somewhat faster. Figure 2 shows the dissolution of a tablet packaged with the film of the invention during the dishwasher cycle. Figure 2a shows the intact packaging and tablet before the dishwasher was started. Figure 2b corresponds to 5 minutes into the cycle, Figure 2c corresponds to 10 minutes into the cycle, Figure 2d corresponds to 15 minutes into the cycle and Figure 2d corresponds to the end of the cycle, when neither the tablet nor the film remain.

[0249] [Table 7]

[0250] This test demonstrates that the films of the present invention can be made into sachets that are safe for consumers to handle and capable of releasing detergent upon contact with water in a dishwasher.

[0251] Example 6 Fusion resistance of protein multilayers in high humidity conditions Sachets were produced using the E7 multilayer film by heat sealing the edges along the length of the film using an RS PRO heat sealer at power 2. The sealed sachets contained Reckitt Benckiser's commercially available dishwasher Finish® tablets pre-packaged with PVOH. The sachets were easy to handle and could maintain their integrity.

[0252] One of the most common types of feedback from customers on existing PVOH-packaged dishwasher tablet products is that the packaged tablets stick together and fuse together, making them difficult to separate and often rendering them unusable. This is due to the fact that PVOH has a fast dissolution rate in water, meaning that high humidity in the environment can cause the film to become sticky. To test the resistance of sachets made with the multilayer of the present invention encapsulating dishwasher tablets to fusing, samples were stored at 70% relative humidity and 20°C, high humidity conditions commonly found in areas such as the bathroom or kitchen of a home where dishwasher detergent products are typically stored. Five stacks of tablets packaged in the film of the present invention were stored alongside a similar stack of commercially available tablets packaged in PVOH. After 48 hours of exposure to high humidity, the samples were evaluated for ease of separation from each other. This was done by taking the top tablet of the stack and observing whether a single tablet could be removed. As can be seen in Figure 3, the sample packaged in the film of the present invention showed no problem or resistance to individually removing the top tablet from its stack, while in Figure 4, the PVOH packaged sample fused and stuck to each other, causing the top three tablets to be unintentionally removed together. [Explanation of symbols]

[0253] 1. First Layer 2. Second Layer

Claims

1. A film comprising a combination of plant protein and polysaccharide in an amount of 50 wt% or more based on the total mass of the film at 55% relative humidity and 22°C, wherein the mass ratio of polysaccharide to plant protein is in the range of 0.1:1 to 2:1, and the plant protein has been pretreated with an organic acid.

2. a first layer comprising a polysaccharide; a second layer comprising a vegetable protein, the vegetable protein being pretreated with an organic acid; and Including, The film of claim 1 , wherein the second layer is in contact with the first surface of the first layer.

3. 3. The film of claim 2, wherein the first layer further comprises a vegetable protein, the vegetable protein being pretreated with an organic acid.

4. 4. The film of claim 2 or claim 3, wherein the second layer further comprises a polysaccharide.

5. 3. The film according to claim 1 or 2, wherein the weight ratio of polysaccharide to plant protein is in the range of 0.15:1 to 1.5:1, more preferably 0.2:1 to 1.3:1, even more preferably 0.5:1 to 1.2:

1.

6. 3. The film of claim 1, wherein the film has a thickness between 20 μm and 120 μm.

7. 3. The film according to claim 1 or 2, wherein the vegetable protein is selected from soy protein, pea protein, rice protein, potato protein, rapeseed protein and / or sunflower protein, preferably selected from pea protein, potato protein, rapeseed protein, sunflower protein and / or rice protein, preferably the vegetable protein is pea protein.

8. 3. The film according to claim 1, comprising 2.0 to 40 wt. % of vegetable protein, based on the total weight of the film, at 55% relative humidity and 22°C.

9. 3. The film according to claim 1 or 2, wherein the polysaccharide is selected from pullulan, wheat starch, potato starch, pea starch, waxy potato starch, maize starch, waxy maize starch, high amylose maize starch, tapioca starch, cassava starch, rye starch, sorghum starch, chickpea starch, soybean starch, modified starch, or mixtures thereof, preferably the starch is potato starch.

10. 3. The film according to claim 1, comprising 30 to 70 wt. % of polysaccharide, based on the total mass of the film, at 55% relative humidity and 22°C.

11. 3. The film according to claim 1, which contains 8 to 20 wt. % water, based on the total weight of the film, at 55% relative humidity and 22°C.

12. 3. The film according to claim 1 or 2, further comprising a plasticizer, preferably the plasticizer is selected from glycerol, polyethylene glycol, propylene glycol, sorbitol, mannitol, xylitol, triethyl citrate, fatty acids, glucose, mannose, fructose, sucrose, urea, lecithin, waxes, amino acids and organic acids, or mixtures thereof, more preferably the plasticizer is glycerol.

13. 13. The film of claim 12, comprising 5 to 30 wt. % of plasticizer, based on the total weight of the film, at 55% relative humidity and 22°C.

14. 3. The film according to claim 1 or 2, further comprising a pigment or dye, preferably the pigment or dye is selected from food colourings, preferably food colourings derived from plant sources, more preferably food colourings selected from carotenoids, chlorophyllins, anthocyanins and betanins.

15. 3. The film of claim 1 or 2, further comprising a structural enhancing agent, preferably selected from microcrystalline cellulose, microfibrillated cellulose comprising cellulose fibers extracted from citrus fruit pulp, cellulosic materials comprising fine fibrous cellulose from fermentation, starch microcrystals, clay, or mixtures thereof, preferably microfibrillated cellulose from citrus pulp.

16. 16. The film of claim 15, comprising 0.5 to 5 wt % of the structural enhancing agent, based on the total weight of the film, at 55% relative humidity and 22°C.

17. 3. The film of claim 1 or 2, further comprising a hydrophobic agent, preferably the hydrophobic agent being a plant-based oil or a plant-based fatty acid.

18. 18. The film of claim 17, comprising up to 5.0 wt% of a hydrophobic agent, based on the total weight of the film, at 55% relative humidity and 22°C.

19. 3. The film according to claim 1, wherein the organic acid used for the pretreatment is selected from acetic acid, alpha-hydroxy acids, and beta-hydroxy acids.

20. 4. The film of claim 2 or 3, wherein the plant protein in the second layer has a protein secondary structure having at least 40% intermolecular β-sheet, at least 50% intermolecular β-sheet, at least 60% intermolecular β-sheet, at least 70% intermolecular β-sheet, at least 80% intermolecular β-sheet, or at least 90% intermolecular β-sheet.

21. 10. A method for preparing the film of claim 1, comprising: (i) mixing polysaccharides in water, optionally with sonication, to form a polysaccharide mixture; (ii) dissolving the plant protein in water and an organic acid, optionally using sonication, to form a protein solution; (iii) mixing the polysaccharide mixture and the protein solution to form a film-forming composition; (iv) forming the film-forming composition into a film; A method comprising:

22. 10. A method for preparing the film of claim 2, comprising: (i) mixing polysaccharides in water, optionally with sonication, to form a polysaccharide mixture; (ii) forming the polysaccharide mixture into a first layer on a surface; (iii) dissolving the plant protein in water and an organic acid, optionally using sonication, to form a protein solution; (iv) forming the protein solution into a second layer on the first surface of the first layer; A method comprising:

23. A product, preferably a food product, coated or encapsulated with a film according to claim 1 or 2.

24. 24. The product of claim 23, which is a dishwasher tablet.

25. 1. A method of coating or encapsulating a product, preferably a home care or personal care product, comprising: (i) packaging a product in the film of claim 1 or 2; (ii) sealing a film around the product; A method comprising:

26. 26. The method of claim 25, wherein the duration of step (ii) is less than 2 seconds, more preferably less than 1 second, more preferably less than 0.5 seconds, and step (ii) is carried out at a temperature of from 60°C to 160°C, preferably from 80°C to 140°C, more preferably from 100°C to 120°C.

27. 3. Use of a film according to claim 1 or 2 for coating or encapsulating a product, preferably a home or personal care product.

28. 10. A method for releasing a product coated or encapsulated with the film of claim 1 or 2, comprising: (i) placing the coated or encapsulated product in water, preferably with agitation; (ii) dispersing the film, preferably in the presence of a surfactant, thereby releasing the product; A method comprising:

29. 29. The method of claim 28, wherein the product is released during a cooking process or a cleaning process.

30. A film-forming composition, wherein the mass ratio of polysaccharide to plant protein is in the range of 0.1:1 to 2:1, and the plant protein is pretreated with an organic acid.

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