Plant-based protein coating

Abstract

The present invention relates to a method for coating a substrate, to the coated substrate thus obtained, to a kit for coating a substrate and to the use of the coated substrate for manufacturing an article.

Description

[0001] The present invention relates to a method for coating a substrate, a coated substrate obtained therefrom, a kit for coating a substrate, and the use of the coated substrate for manufacturing articles.

[0002] The demand for replacing polluting plastic packaging with biodegradable alternatives is growing. Paper-based packaging is increasingly popular with consumers because paper or cardboard is highly biodegradable and derived from natural plant sources. Uncoated paper or cardboard packaging is highly biodegradable in many cases (e.g., home compost, freshwater, or soil, if not properly disposed of in the environment). It can also be easily recycled through well-established commercial recycling systems.

[0003] However, paper-based packaging has very poor moisture and oil barrier properties, thus limiting its use as a packaging material to dry and non-greasy items. If the product is oily, it will migrate through the paper, seep into the outer surface of the packaging, leaving unsightly marks or damaging the surface it is on. Furthermore, the packaged items offer little protection from environmental influences; for example, if a dry product is sensitive to moisture, it will be damaged by the ingress of moisture.

[0004] Paper-based packaging can be coated with synthetic polymers (such as, for example, polyvinyl alcohol polymers). While these synthetic polymers can provide good moisture and oil barrier properties, they are themselves non-biodegradable. If discarded into the environment, the coating degrades into microplastics, polluting soil and waterways. If such coated paper, especially when using a thick coating to achieve good barrier properties, enters the waste paper recycling stream, it can cause problems such as clogging filters in repulping tanks or reduced quality of recycled paper due to polymer incorporation.

[0005] Paper-based packaging can also be coated with animal-derived polymers such as casein and chitosan.

[0006] Fibers such as cellulose fibers or inorganic fibers also benefit from protective coatings to reduce their susceptibility to the environment and wear. The biodegradability of such coatings is again highly desirable.

[0007] Furthermore, coatings are needed as a barrier to protect other substrates from the ingress or loss of moisture, oil, and gases (especially during transportation and storage) to extend shelf life. For example, seeds need protection, and a biodegradable coating to prevent microplastic residues from entering the soil is highly desirable. Protecting fruits and vegetables is also desirable, and the coating should be edible, digestible, and plant-derived.

[0008] Therefore, there remains a need for highly biodegradable, preferably naturally plant-derived, and edible coatings with good water and oil barrier properties. For such materials to have a significant impact on the amount of non-biodegradable waste generated, these coatings must be inexpensive, easy to handle, and applied to the material using existing industrial-scale coating processes. It is also highly desirable that such coatings be very thin to reduce costs and minimize resource consumption and impact on the material's recycling capacity.

[0009] Plant polysaccharides (such as starch) are inherently hydrophilic, and their sensitivity to moisture means they cannot provide good water barrier properties, especially at high humidity levels. Furthermore, natural starch is highly prone to retrogradation in aqueous solutions and when dried into coatings, necessitating extensive chemical modification. Chemically modified starches are generally more soluble in water than natural starches, making them unsuitable as water and moisture barriers. Extensive chemical modification often results in poor biodegradability (e.g., cationic starch used as a sizing agent in paper processing). Moreover, aqueous solutions of natural starches are typically unstable over time, making their use in industrial-scale coating processes even more challenging.

[0010] Proteins are considered an attractive natural polymer because they are readily available, renewable, and biodegradable. Plant-based proteins are particularly attractive because they can be obtained from biomass feedstocks to produce bio-based coatings. However, their commercial application has to date been limited by significant processing challenges related to their poor solubility in water.

[0011] Albumins are the most water-soluble plant-based proteins; however, their abundance in seed storage materials is low, and they are lost during extraction due to their solubility, making them difficult to obtain for industrial processing. Globulins are the most abundant plant-based proteins, and their solubility can be tuned by selecting solvent systems to make them suitable for industrial-scale processing. However, coatings formed with globulins have poor water barrier properties, greatly limiting their use.

[0012] Glutelin has been studied as a coating material, but its extremely low solubility makes it particularly difficult to incorporate into aqueous coating processes. Therefore, solvents with higher levels of toxicity (such as high levels of ethanol and glacial acetic acid) are required, which could lead to environmental problems (if released into the atmosphere) or human hazards (such as explosion risks). Glutelin is essentially insoluble in water and can only be processed in toxic solvents.

[0013] Experiments have been conducted to produce plant-based protein coatings from solvent systems where harmful solvents are diluted in water, such as WO2013 / 010119 which uses a water, alcohol, and acid solvent system with zein. However, large quantities of harmful solvents still need to be handled on an industrial scale.

[0014] Plant-based proteins like gluten are desirable coatings because they are naturally waterproof. However, their hydrophobicity means it's difficult to form a thin, consistent, homogeneous, and flat layer on hydrophilic substrates such as paper, resulting in poor coating performance. Multiple coatings can be applied to improve coating integrity, but such thick coatings increase processing and material costs.

[0015] Furthermore, the most commonly used plant-based gliadin, zein, has a bright yellow color that can impart to any coated material. This negatively impacts the product's appearance and the ability to print clearly on such a coating, making the final product unacceptable to consumers.

[0016] Surprisingly, it has been discovered that thin, water- and oil-resistant coatings can be produced using plant-based proteins such as glutenin, applied to a substrate using a two-step coating process with two different mixtures. The first mixture comprises one or more liquids and one or more biodegradable polymers. The second mixture comprises one or more liquids, one or more plant-based glutenins, and one or more fatty acids. Preferably, the biodegradable polymer in the first mixture is dispersed in a predominantly aqueous solvent. Most preferably, the protein in the first mixture is dispersed in a predominantly aqueous solvent containing water and low levels of organic acids, which has low viscosity and spreads very easily on the substrate, enabling the formation of a thin, homogeneous, defect-free oil barrier coating.

[0017] The first coating transforms the irregular and rough substrate surface into a more regular and smoother surface. The first coating then promotes the spreading of a second mixture containing one or more plant-based gliadin and one or more fatty acids, thereby enabling the formation of a uniform, thin second coating, and thus an overall thin coating. This minimizes the use of biodegradable polymers (especially the least water-soluble biodegradable polymers such as proteins) and harmful solvents, thereby reducing material and processing costs and hazards during manufacturing.

[0018] Therefore, in a first aspect, the present invention relates to a method of coating a substrate, the method comprising the following steps: Prepare a first mixture comprising one or more liquids and one or more biodegradable polymers; Prepare a second mixture comprising one or more liquids, one or more plant-based glutenin and one or more fatty acids; The first mixture is applied to at least a portion of at least a first surface of a substrate to produce a first coating; Optionally, dry the first coating; The second mixture is applied over at least a portion of the first coating on the substrate to produce a second coating; Dry the first coating and / or the second coating.

[0019] "Above" implies that the first and second coatings can be in direct contact with each other. In contrast, there may be an intermediate layer between the first and second coatings. Therefore, "above" only specifies the order of the first and second coatings relative to the substrate, not the relationship between them.

[0020] The first mixture comprises one or more biodegradable polymers. According to the invention, the biodegradable polymers are selected from polysaccharides, proteins, other naturally derived polymers, and biodegradable synthetic polymers.

[0021] According to the present invention, polysaccharides include polysaccharides of plant origin, polysaccharides of algae origin, polysaccharides of fungi origin, and polysaccharides of microorganism origin.

[0022] Plant-derived polysaccharides are the most abundant polysaccharides and include starch and cellulose.

[0023] Starch is a carbohydrate polymer and the primary energy storage substance in plants. Starch consists of amylose and / or amylopectin. Amylose is a linear polysaccharide chain composed of glucose monomers linked by α(1,4) glycosidic bonds, and it constitutes approximately 20-30% of starch. Amylopectin is a highly branched polymer composed of glucose subunits. It consists of linear chains of glucose units linked by α(1,4) glycosidic bonds and numerous side chains that branch the structure through α(1,6) glycosidic bonds, and constitutes 70-80% of starch. In its natural form, starch is typically in the form of semi-crystalline granules. Sources of starch include, but are not limited to, fruits, seeds, and the roots or tubers of plants.

[0024] Starch can be natural or chemically, enzymatically, or physically modified. In a preferred aspect of the invention, the starch is selected from wheat starch, potato starch, pea starch, waxy potato starch, corn starch, waxy corn starch, high amylose corn starch, tapioca starch, cassava starch, rye starch, sorghum starch, chickpea starch, soybean starch, or mixtures thereof, preferably potato starch. In an optional preferred aspect of the invention, the starch is modified starch, selected from acid-treated starch, dextrin, alkali-modified starch, bleached starch, oxidized starch, enzyme-treated starch, maltodextrin, cyclodextrin monosaccharide phosphate, disaccharide phosphate, acetylated starch, hydroxypropylated starch, hydroxyethyl starch, sodium octenyl succinate starch, aluminum octenyl succinate starch, or cationic starch, or mixtures thereof, preferably acid-treated starch.

[0025] Some starches are classified as waxy starches. Waxy starches are mainly composed of amylopectin and lack a significant amount of amylose. Typical waxy starches include waxy corn starch, waxy rice starch, waxy potato starch, and waxy wheat starch.

[0026] Optionally, some starches are classified as high amylose.

[0027] Modified starch is prepared by altering the properties of natural starch through physical, enzymatic, or chemical treatments. Starch can be modified, for example, by enzymes, heat treatment, oxidation, or reactions with various chemicals.

[0028] In a preferred aspect of the invention, the starch is selected from wheat starch, potato starch, pea starch, waxy potato starch, corn starch, waxy corn starch, high amylose corn starch, cassava starch, cassava flour, rye starch, sorghum starch, chickpea starch, soybean starch, or mixtures thereof, preferably potato starch.

[0029] In a preferred aspect of the invention, the starch is a modified starch selected from acid-treated starch, dextrin, alkali-modified starch, bleached starch, oxidized starch, enzyme-treated starch, maltodextrin, cyclodextrin monosaccharide phosphate, disaccharide phosphate, acetylated starch, hydroxypropylated starch, hydroxyethyl starch, sodium octenyl succinate starch, aluminum octenyl succinate starch, or cationic starch or mixtures thereof, preferably acid-treated starch.

[0030] Cellulose is a complex polysaccharide composed of 3,000 or more glucose units. It is a fundamental structural component of plant cell walls and is the most abundant of all naturally occurring organic compounds. Cellulose can be extracted from plant or algal sources. Preferably, the cellulose used in the first mixture of the present invention is in the form of microfibrillated cellulose (MFC), nanofibrillated cellulose (NFC), microbial nanocellulose, or cellulose nanocrystals (CNC).

[0031] Nanofibrillated cellulose (NFC), also known as cellulose nanofibers (CNF) or cellulose nanofibers (CNF), is a material containing nanoscale cellulose fibrils, typically with a high aspect ratio. NFC is usually obtained from another natural source of wood pulp or cellulose fibers, usually through processes involving subjecting the pulp / fibers to mechanical shear forces.

[0032] Cellulose can be modified, and among those modifications, cellulose esters with a degree of substitution between 0.2 and 2.5 may be mentioned.

[0033] Cellulose fibers are commonly used in the paper industry and are the base material in this invention.

[0034] Algal polysaccharides include those derived from red algae, brown algae, and green algae, with alginate (whether or not cross-linked), carrageenan, red alginic acid, agar, ulvan, and gums being preferred.

[0035] As used in this article, the phrase “polysaccharide of red algae” refers to polysaccharides obtained from red macroalgae (or red seaweed) or red microalgae, either through an extraction process from naturally grown or cultured red macroalgae or red microalgae, or through a synthetic process that produces substances identical to those present in naturally grown or cultured red macroalgae or red microalgae.

[0036] As used in this article, the phrase "polysaccharide of brown algae" refers to a polysaccharide obtained from brown macroalgae (or brown seaweed) or brown microalgae, either through an extraction process from naturally grown or cultured brown macroalgae or brown microalgae, or through a synthetic process to produce a substance that is identical to the substance present in naturally grown or cultured brown macroalgae or brown microalgae.

[0037] In a preferred aspect of the invention, the first mixture comprises at least one polysaccharide derived from red algae or brown algae. Algae are broadly classified into three groups based on the pigments in their biomass: Rhodophyta (red algae), Phaeophyta (brown algae), and Chlorophyta (green algae). These three groups of algae differ in their chemical composition, as well as the types of carbohydrates, proteins, and lipids, resulting in different biopolymers that can be extracted for industrial applications.

[0038] Macroalgae (also known as seaweed) contain varying proportions of cellulose as structural support for their cell walls, with the gaps within these walls filled with different levels of polysaccharides. Red seaweed contains large amounts of agar, carrageenan, and alginate. Brown seaweed contains large amounts of alginate.

[0039] In a preferred aspect of the invention, the polysaccharides derived from red algae or brown algae are extracted from macroalgae.

[0040] Examples of large red algae (or red seaweed) include species of the genera *Eucheuma*, *Furcellaria*, *Gelidiella*, *Gracilaria*, *Gigartina*, *Gelidium*, *Gymnogongrus*, *Hypnea*, *Kappaphycus*, *Lemanea*, *Mastocarpus*, *Palmaria*, *Porphyra*, *Schmitzia*, *Chondrus*, *Mastocarpus*, *Acrochaetium*, and *Audouinella*. Species of the genera *Polysiphonia*, *Solieria*, *Vertebrata*, *Pterocladia*, *Acanthopeltis*, and *Asparagopsis* are preferred; species of the genera *Euchema*, *Glechoma*, *Geotrichum*, or *Gracilaria* are also preferred; *Euchema cottonii* is even more preferred.

[0041] Examples of brown macroalgae (or brown seaweeds) include species of the genera *Sargassum*, *Ascophyllum*, *Kelp*, *Saccharina*, *Laminaria*, *Rugelopteryx*, *Ecklonia*, *Durvillea*, *Macrocystis*, and *Lessonia*.

[0042] In a preferred aspect of the invention, the polysaccharides derived from red algae or brown algae are extracted from microalgae. Microalgae are tiny algae invisible to the naked eye. They are single-celled organisms but can exist in aggregates.

[0043] Microalgae and macroalgae used to obtain polysaccharides from red or brown algae can be obtained from the natural environment (e.g., when washed ashore by coastal waters), produced through aquaculture in ponds, tanks, or pipes, or engineered to produce algal-derived polysaccharides under controlled conditions or in similar industrial environments.

[0044] To reduce greenhouse gases in the atmosphere, microalgae and macroalgae are sometimes cultivated to capture carbon from carbon dioxide or methane. The algae then become a source for extracting polysaccharides derived from them. Alternatively, polymers with identical properties can be chemically synthesized extracellularly from the algae, producing the same materials as those extracted from naturally grown or cultured algae.

[0045] Carrageenan, agar, and red alginic acid are part of the polysaccharide family, typically obtained from the cell walls of red algae. Alginate is also part of the polysaccharide family, typically obtained from brown algae. This contrasts with polysaccharides derived from green algae, such as ulvan.

[0046] Carrageenan, agar, and red algin are all polysaccharides with a galactose backbone, but they differ in the proportion and position of sulfate groups and the proportion of 3,6-anhydrogalactose.

[0047] Carrageenan is a linear anionic sulfated polygalactan formed from disaccharide repeating units, consisting of alternating 3-linked β-d-galactopyranose, 4-linked α-d-galactopyranose, or 4-linked 3,6-dehydro-α-d-galactopyranose. Based on the degree of free sulfate, six different types exist, but only three are commercially available: ι-type, κ-type, and λ-type. Carrageenan is used as an additive in the cosmetics, pharmaceuticals, and food industries, primarily for controlling product viscosity and as an emulsifier. κ-type carrageenan is specifically classified as food additive E407. Processed *Euphorbia* algae are classified as food additive E407a.

[0048] Agar is a linear sulfated polygalactan. It is a heteropolysaccharide comprising agarose (typically 70%) and agar gum (typically 30%) polymers. Agar is widely known for its gelling properties and is largely produced for food applications (e.g., it is classified as food additive E406) and for use in microbiological assays and techniques. In food applications, agar can replace animal-derived gelatin. Agarose is a linear polysaccharide with repeating units of β-1,3-linked d-galactose and α-1,4-linked 3,6-anhydro-L-galactose. Agar gum has the same backbone as agarose but is slightly branched and contains numerous anionic groups such as pyruvate, sulfate, and uronic acid groups.

[0049] Red alginate is an anionic sulfated polysaccharide. Under EU law, it is classified as a food additive along with κ-carrageenan (E407). Red alginate is a salt of a linear polymer primarily composed of (1→3)-linked β-D-galactopyranose, (1→4)-linked 3,6-dehydro-α-D-galactopyranose, and (1→3)-linked β-D-galactopyranose 4-sulfate structural units. The weight-average molar mass values ​​reported in the literature vary between approximately 290 and 500 kDa.

[0050] Alginate is a polysaccharide commonly obtained from the cell walls of brown algae. Alginate is a biopolymer of β-D-mannuronic acid and α-L-guluronic acid, and its molecular weight range and monomer ratio vary depending on the source. This results in alginate solutions having a certain range of viscosity. Alginate is widely used in many applications, including the manufacture of films and coatings.

[0051] Therefore, in a preferred aspect of the invention, at least one polysaccharide derived from red or brown algae is selected from alginate (where the counter ion of the salt is a monovalent ion), carrageenan (e.g., l-type carrageenan, κ-type carrageenan, or λ-type carrageenan), and red alginate. Most preferably, the first mixture comprises at least one alkali metal salt of alginic acid, preferably lithium alginate, sodium alginate, potassium alginate, or a mixture thereof, more preferably sodium alginate. Optionally, the first mixture comprises ammonium alginate.

[0052] In an optional aspect of the invention, the first mixture comprises at least one fungal-derived polysaccharide, preferably pullulan. Pullulan is a linear polysaccharide comprising three maltotriose units linked by α(1–4) glycosidic bonds, wherein consecutive maltotriose units are interconnected by α(1–6) glycosidic bonds. It is derived from the fungus *Brucea budscens* (…). Aureobasidium pullulansPullulan is produced through starch fermentation. It is primarily used by cells to resist dehydration and predation. The presence of this polysaccharide also facilitates the diffusion of molecules into and out of cells. In pharmaceutical capsules and other medical applications (such as tissue engineering), it is used as a vegetarian alternative to gelatin. It is also used as a food additive, E-number E1204.

[0053] Microbial polysaccharides, also known as microbial fermentation polysaccharides, are edible gums synthesized by bacteria and fungi (including molds and yeasts). Examples of microbial polysaccharides include dextran, gellan gum, rhamsan gum, veslan gum, and xanthan gum. Other examples of microbial polysaccharides include microbial cellulose. Microbial cellulose refers to cellulose produced by microorganisms. Examples of microbial cellulose include bacterial cellulose formed by carbon atoms linked by β-1,4 glycosidic bonds, which can be produced by bacteria of the genera *Acetobacterium* (e.g., *Acetobacter xylinum* and *Gluconacetobacter xylinum*), *Rhizobium*, *Alcaligenes*, *Agrobacterium*, and *Pseudomonas*.

[0054] Other plant-derived polysaccharides include polyglucans, such as those commonly known as "polydextrose," fructose polymers or polyfructans such as inulin and levan, or xylan, pectin, dextran, natural gums such as xanthan gum, gum arabic, guar gum, ark sylvestris gum, tragacanth gum, ghatti gum, carob gum, locust bean gum, etc.

[0055] Dextran is a polysaccharide derived from D-glucose linked by glycosidic bonds. Dextran is mentioned in two forms: α-glucan and β-glucan. Examples of polysaccharides include α-glucans having 1,3-, 1,4-, and / or 1,6-links. Elsinan, reuteran, and other α-glucans are also suitable, but the proportion of 1,6-links is preferably less than 70%, more preferably less than 60%. Other suitable polysaccharides include β-1,3-glucan, glucomannan, galactan, and galactomannan; other gums include heterogels.

[0056] In a preferred aspect of the invention, the first mixture comprises at least one polymer of a natural source selected from lignin and its derivatives, rosin acid and its derivatives, polyhydroxyalkanoates (PHAs), chitin, chitosan, collagen, and natural rubber latex.

[0057] Lignin is the second most abundant biopolymer on Earth (after cellulose), and it is separated from cellulose for industrial processing. Lignin is an amorphous, three-dimensional polymer that "glues" cellulose fibers together, giving plants structural integrity. Lignin accounts for about one-third of the mass of a tree. Lignin is a branched, cross-linked network of C9 phenylpropenyl units, formed by the enzymatic dehydrogenation polymerization of coumarin (common in grasses), coniferyl alcohol (common in softwoods), and sinapyl alcohol (common in hardwoods). The relative proportions of these units depend on the source of the lignin (i.e., the plant). The sulfite process, developed in 1867, is typically an acidic process that uses sulfite and bisulfite ions to remove lignin under elevated temperatures and pressures. Sulfite combines with lignin to form lignin sulfonates, which are soluble in aqueous cooking liquor. Lignosulfonates in waste cooking liquor can be used as dispersants, binders, adhesives, and cement additives.

[0058] According to the present invention, rosin acid is understood to be a mixture comprising a variety of rosin acid molecules. Such mixtures are readily available and naturally occurring, including but not limited to tall oil rosin, gum rosin, or wood rosin. These natural mixtures may contain varying amounts of abietic type and / or pimarian type rosin acids, such as abietic acid, longleaf abietic acid, neoabietic acid, L-piperidine, pimarian acid, isopimarian acid, or dehydroabietic acid. In addition to rosin acids having one carboxylic acid functional group, rosin acids having two or more carboxylic acid functional groups are also considered rosin acids in the sense of this invention.

[0059] According to the present invention, a rosin acid derivative is any molecule having a rosin acid molecular skeleton but modified in at least one of the following ways: In one embodiment, at least one double bond is hydrogenated (hydrogenation). In another embodiment, at least one ring on the rosin acid skeleton is dehydrogenated to obtain an aromatic ring (dehydrogenation). In yet another embodiment, adducts with conjugated double bonds of the rosin acid skeleton are included (particularly the addition of maleic anhydride in a Diels-Alder type reaction). The resulting adduct is considered to be a type of rosin acid derivative according to the present invention.

[0060] Natural polyesters (especially polyhydroxyalkanoates (PHAs)) are produced naturally by bacteria. PHAs can be produced on an industrial scale by growing specific bacteria and providing them with very specific combinations of carbon and nitrogen sources.

[0061] Chitin is a naturally occurring nitrogenous polysaccharide widely found in the shells of crustaceans, and the cell walls of insects and fungi. Its structure is formed by the polymerization of N-acetylglucosamine units via β-1,4 glycosidic bonds.

[0062] Chitosan is a naturally occurring linear biopolymer, a derivative of chitin, obtained by partial (approximately 50%) or substantial basic N-deacetylation of chitin (also known as poly(N-acetyl-D-glucosamine)). Chitosan contains free amine (-NH2) groups and can be characterized by the ratio of N-acetyl-D-glucosamine units to D-glucosamine units, expressed as the degree of deacetylation (DD) of the fully acetylated polymeric chitin.

[0063] The term natural rubber latex refers to polyisoprene polymer, a type of elastic material. Polyisoprene typically has a molecular weight between 100,000 and 1,000,000 Daltons. It is usually derived from the latex sap of certain trees, such as those in the genera *Hevea* and *Ficus*. This milky-white latex is present directly beneath the bark and is harvested using the careful tapping method.

[0064] In a preferred aspect of the invention, the biodegradable synthetic polymer is selected from polyvinyl alcohol (PVOH) and polyvinyl alcohol copolymers, such as butene glycol-vinyl alcohol copolymer (BVOH), which is produced by copolymerizing butene glycol with vinyl acetate and then hydrolyzing vinyl acetate. Suitable butene glycol monomers are selected from 3,4-diol-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-ol-1-butene, 4-acyloxy-3-ol-1-butene, etc.; polyalkylene oxides, such as polyethylene oxide or polyethylene glycol (PEG); poly(methacrylic acid), polyacrylic acid, polyacrylate, acrylate copolymers, maleic acid / acrylic acid copolymers; polyacrylamide; poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (polyAMPS); polyamide, polyN-vinylacetamide (PNVA); polycarboxylic acids and salts.

[0065] Polylactic acid (PLA) is a biodegradable polymer. It is a linear aliphatic polyester chemically synthesized from lactic acid, which can also be produced by fermenting simple sugars such as glucose and maltose from corn or potatoes, sucrose from sugarcane or beet sugar, and lactose from cheese.

[0066] The first and second mixtures of the present invention can be prepared by mixing a biodegradable polymer or one or more plant-based glutenins with one or more fatty acids separately into a liquid, or vice versa. "Liquid" means that the respective components are in a liquid state at ambient temperature and pressure.

[0067] In a preferred aspect of the invention, the solid powder protein is completely dispersed in one or more liquids to produce a first liquid mixture. In an alternative preferred aspect of the invention, the one or more liquids are completely absorbed by the solid powder protein to produce a first solid powder mixture. Mixing can be carried out at a temperature ranging from 15°C to 95°C, more preferably from 20°C to 90°C. In an exemplary method, the first mixture is maintained at a temperature above 70°C for at least 5 minutes, more preferably at 80°C for at least 5 minutes. Mixing can be achieved through a mild low-shear process (e.g., stirring, mixing by a paddle mixer), a process involving medium shear (e.g., a rotor-stator mixer, such as a Silverson mixer), or a process involving high shear (e.g., a high-pressure homogenizer or a sonicator), wherein mixing is achieved at the microstructural level. Mixing can be achieved using a combination of low-shear, medium-shear, and / or high-shear processes. In a preferred method, the first mixture is subjected to high shear using a high-pressure homogenizer, a sonicator, or similar equipment.

[0068] In a preferred aspect of the invention, the solid powder protein is completely dispersed in one or more liquids to produce a second liquid mixture. In an alternative preferred aspect of the invention, the one or more liquids are completely absorbed by the solid powder protein to produce a second solid powder mixture. Mixing can be carried out at a temperature ranging from 15°C to 60°C, more preferably from 20°C to 55°C. In a preferred method, the second mixture is maintained at a temperature above 40°C for at least 5 minutes, more preferably at 50°C for at least 5 minutes. Mixing can be achieved through a mild low-shear process (e.g., stirring, mixing by a paddle mixer), a process involving medium shear (e.g., a rotor-stator mixer (e.g., a Silverson mixer)), or a process involving high shear (e.g., a high-pressure homogenizer or acoustic treatment), wherein mixing is achieved at the microstructural level. Mixing can be achieved using a combination of low-shear, medium-shear, and / or high-shear processes. In a preferred method, the second mixture is subjected to medium shear using a rotor-stator mixer or similar equipment.

[0069] In processes with moderate shear (e.g., rotor-stator mixers, such as the Silverson mixer), liquid is drawn into a work head by a high-speed rotor, where it is intensely mixed in the gap between the rotor and stator. Hydraulic shearing then occurs as the liquid is forced through a stator screen and circulated back into the liquid mixture. This produces a homogeneous material, but with limited particle size reduction.

[0070] High-pressure homogenization is a process that pumps a liquid flow through a constriction (e.g., a valve, impingement surface, narrow tube, or slit), inducing varying degrees of shear, turbulence, and / or cavitation, thereby homogenizing the sample, i.e., mixing and / or reducing the particle size of any component of the liquid. High shear forces lead to friction between fluid elements and can increase the temperature of the mixture. Optionally, high-pressure steam can be used, resulting in additional heating of the liquid. High-pressure homogenization can also pasteurize the liquid, extending the shelf life of the resulting mixture. The liquid can be passed through a homogenizer once or multiple times at different pressures and / or kinetic energy levels to achieve desired mixture properties. The inlet temperature can vary, but is preferably ambient temperature. The coolant temperature can vary, but is preferably about 5°C. The selection of pressure, inlet, and coolant temperature results in a range of liquid temperatures at the nozzle. Preferably, the liquid temperature at the nozzle is 20°C to 35°C at 50 MPa, or 35°C to 50°C at 100 MPa, or 70°C to 95°C at 250 MPa.

[0071] Acoustic or ultrasonic processors disrupt particle size by rapidly vibrating tips or probes, causing bubbles in the mixture to collapse quickly—a process known as cavitation. This simultaneously generates a significant amount of energy, leading to an increase in liquid temperature.

[0072] The energy input through medium or high shear treatment, more preferably high shear treatment (such as high-pressure homogenization or acoustic treatment), breaks down larger aggregates of plant-based proteins in the liquid, producing a mixture of soluble protein molecules and insoluble dispersed plant-based protein particles with a smaller particle size than those produced by low-shear treatment. The smaller particle size is advantageous because the plant-based protein particles spread more evenly and uniformly when the liquid dries on the substrate to form a coating. This results in fewer defects (often called pinholes) where the substrate or undercoat is exposed and allows moisture or oil to enter, thus reducing the effectiveness of the coating. The smaller particle size is also advantageous because it helps form a stable dispersion or solution of plant-based protein particles in the liquid. Such a stable liquid can then be stored for a longer period and only requires mild mixing before coating the substrate. This is advantageous because the production of the first and second mixtures for the coating kit may take place at a different manufacturing location than the coating process, and there may be a considerable time interval between them.

[0073] Preferably, the plant-based protein dispersed in the first mixture has an average diameter d50 of 0.5 micrometers to 100 micrometers, more preferably 1 micrometer to 50 micrometers, even more preferably 1 micrometer to 35 micrometers, and most preferably 2 micrometers to 25 micrometers.

[0074] Preferably, the plant-based protein dispersed in the second mixture has a particle size with an average diameter d50 of 0.01 micrometers to 30 micrometers, more preferably 0.1 micrometers to 25 micrometers, and most preferably 1 micrometer to 20 micrometers.

[0075] The proteins of this invention include animal-based proteins, single-cell-based proteins, and plant-based proteins.

[0076] Animal-based proteins include, for example, casein, caseinate, and gelatin.

[0077] Casein is the main protein in cow's milk and is composed of four major phosphoproteins. Micellar casein is obtained from skim milk via a cold process, through microfiltration. This very simple process allows casein to retain its natural structure, just like its natural micellar superstructure in milk. Sodium caseinate is obtained from the curd formed by lactation. The curd is then further processed by chemical redissolving through alkalization with sodium hydroxide.

[0078] Collagen is a major structural protein found in connective tissues such as cartilage, bone, tendons, ligaments, and skin, and it is also a major protein in the extracellular matrix of human cells. Collagen is typically extracted from equine, bovine, porcine, ovine, and fish sources. Collagen contains a triple helix, which is usually composed of two identical chains (α1) and an additional chain (α2) with a slightly different chemical composition.

[0079] Gelatin is a protein derived from collagen through controlled hydrolysis. Depending on the method used to process gelatin from natural collagen (using acidic or alkaline pretreatment), two types of gelatin can be formed: Type A and Type B. Type A is cationic gelatin produced by partial acid hydrolysis of collagen. Type B gelatin is derived from anionic gelatin produced by alkaline treatment of collagen.

[0080] As used in this article, “single-cell protein” (SCP), also known as microbial protein, refers to microbial biomass that can be used in protein-rich human foods and animal feeds. SCP can replace traditional sources of protein supplementation, such as soybean meal or fishmeal.

[0081] Biomass includes microbial biomass, single-cell protein, or microbial protein. Preferably, biomass includes single-cell protein or microbial protein. Single-cell protein or microbial protein refers to protein extracted from microorganisms or microbial cultures. Biomass includes biomass derived from aerobic fermentation, or biomass derived from both aerobic and anaerobic fermentation.

[0082] The microorganisms used in anaerobic and / or aerobic fermentation can be selected from algae, yeasts, filamentous fungi, and bacteria. Microorganisms can be yeasts such as *Saccharomyces cerevisiae*, *Pichiapastoris*, *Komagataella pastoris*, *Komagataella phaffi*, *Komagataella pseudopastoris*, *Kluyveromyces lactis*, *Yarrowia lipolytica*, *Hansenula polymorpha*, *Geotrichum candidum*, or *Candidautilis*. Microorganisms can also be selected from the following filamentous fungi: *Acremonium*, *Agaricus*, *Aspergillus*, *Aureobasidium*, *Chrysosporium*, *Coprinus*, *Filibasidium*, *Fusarium*, *Humicola*, *Magnaporthe*, *Mucor*, *Myceliophthora*, and *Neocallimus*. The genera are astix, Neurospora, Paecilomyces, Penicillium, Piromyces, Panerochaete, Pleurotus, Schizophyllum, Talaromyces, Rasamsonia, Thermoascus, Thievaria, Tolypocladium, and Trichoderma.Preferably, the filamentous fungi are Penicillium chrysogenum, Aspergillus niger, Acremonium alabamense, Aspergillus awamori, Aspergillus foetidus, Aspergillus sojae, Aspergillus fumigatus, Talaromyces emersonii, Rasamsonia emersonii, Aspergillus oryzae, Chrysosporium lucknowense, Fusarium oxysporum, Myceliophthora thermophila, Trichoderma reesei, and Thievaria terrestris.

[0083] The algae used in this application are preferably selected from the group consisting of: glaucophyte, rhodoplast, and chloroplast. More preferably, the algae are selected from the group consisting of: glaucophyte, rhodoplast, and chloroplast. More preferably, the algae used in this application are heterotrophic algae, and even more preferably, heterotrophic algae such as *Chlorella*, *Nannochloropsys*, *Nitzschia*, *Thraustochytrium*, or *Schizochyttrium*.

[0084] The term "bacteria" includes both Gram-negative and Gram-positive microorganisms. Suitable bacteria can be selected from, for example, genera such as *Escherichia*, *Anabaena*, *Caulobacter*, *Gluconobacter*, *Rhodobacter*, *Pseudomonas*, *Paracoccus*, *Bacillus*, *Brevibacterium*, *Corynebacterium*, and *Rhizobium* (*Sinorhizium*). The genera are: Flavobacterium, Klebsiella, Enterobacter, Lactobacillus, Lactococcus, Methylobacterium, Staphylococcus, Streptomyces, Actinomycetes, Xanthomonas, or Sphingomonas.Preferably, the bacterial cells are selected from the group consisting of: Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus puntis, Bacillus megaterium, Bacillus halodurans, Bacillus pumilus, G. oxydans, Caulobacter crescentus CB 15, Methylobacterium extorquens, Rhodobacter sphaeroides, Rhodobacter capsulatus, Pseudomonas zeaxanthinifaciens, Paraacoccus denitrificans, Escherichia coli, Corynebacterium glutamicum, and Staphylococcus aureus. The fungi include *Streptomyces carnosus*, *Sinorhizobium melioti*, and *Rhizobium radiobacter*.

[0085] Plant-based proteins mainly consist of globular proteins, which are storage proteins and can be divided into albumin (soluble in water), globulin (soluble in dilute salt solution), gliadin (soluble in ethanol aqueous solution), and glutenin (soluble in dilute acid / alkali solution or insoluble in water).

[0086] Albumin and globulin are primarily found in all legumes (greater than 50%) and some false cereals (such as quinoa and amaranth). Globulin accounts for approximately 70 wt% to 78 wt% of the protein in legume seeds, while albumin constitutes approximately 10 wt% to 20 wt%. Globulin is the storage protein in most legume seeds. Globulin has a higher molecular weight than albumin and is insoluble in pure water but soluble in dilute salt solutions. Globulin is generally more soluble in water than glutathione.

[0087] Storage proteins from different plants can be classified according to their sedimentation coefficients in Svedberg units (S). This coefficient indicates the sedimentation rate of macromolecules in a centrifugal field. However, it should be noted that expected sedimentation can vary slightly depending on the plant type and / or the extraction protocol used. Therefore, the sedimentation coefficient is not intended to be limiting, but rather a useful guide for the classification of storage proteins.

[0088] The main globulins found in legumes are pea globulin (7S) and lentinan (11S). Pea globulin (7S) has a trimer structure with a molecular weight (MM) of approximately 175-180 kDa and lacks disulfide bonds. Mutually In contrast, 11S globulin has a hexamer (MM of approximately 340-360 kDa) quaternary structure, containing six subunits (MM of approximately 60 kDa) linked by non-covalent interactions. Each subunit pair contains an acidic chain (MM - 40 kDa) and a basic chain (MM - 20 kDa) linked by disulfide bonds. The ratio (L / V) of 11S globulin to pea globulin is not fixed and may vary depending on the legume variety and species. A third type of globulin in legumes is convicilin, which has 3 or 4 subunits, each with an MM of approximately 70 kDa and a sedimentation coefficient of approximately 8S. Convicilin is present in lower amounts compared to other globulins. Other globulins include, for example, 2S globulin, blue bean globulin, SFA, hemp seed globulin, amygdalin, concanavalina globulin, cruciferin, and helianthinin.

[0089] Albumin, found in legume proteins, is a soluble protein with a variable molecular weight (approximately 12-28 kDa). Albumins include, for example, 2S albumin, napin, barley trypsin inhibitors, and wheat α-amylase inhibitors. In typical commercial protein isolates, only residual amounts of albumin are usually present, as it is typically removed during protein extraction.

[0090] Globulins are typically obtained from soybeans, peas, rice, potatoes, rapeseed, sunflowers, lentils, chickpeas, beans, broad beans, mung beans, sunflower seeds, pumpkin seeds, flax, chia, canola, lupins, alfalfa, moringa, borage, hemp seeds, and cottonseed; preferably from pea protein, potato protein, rapeseed protein, and / or sunflower protein.

[0091] Glutelin and gluten make up 85% of the protein in cereals and pseudocereals. Glutelin is commonly found in wheat, corn, barley, and rye, while gluten is typically found only in wheat and rice.

[0092] Glioproteins are rich in proline and glutamine amino acids. They have a relatively high proportion of nonpolar functional groups. They are less abundant than globulins and are found in fewer plant species. These include wheat glioprotein from wheat, barley glioprotein from barley, secalin from rye, zeatin (α, β, γ) from corn, sorghum glioprotein from sorghum, and avenin from oats. Glioproteins are generally much less water-soluble than globulins.

[0093] Preferably, the first mixture comprises one or more plant-based proteins selected from the group consisting of: soybean protein, pea protein, rice protein, potato protein, rapeseed protein, sunflower protein, lentil protein, chickpea protein, kidney bean protein, broad bean protein, mung bean protein, sunflower seed protein, pumpkin seed protein, flaxseed protein, chia protein, canola protein, lupin protein, alfalfa protein, moringa protein, borage protein, hemp seed protein, and cottonseed protein, preferably selected from pea protein, potato protein, rapeseed protein, and / or sunflower protein. Most preferably, the first mixture comprises pea protein.

[0094] Preferably, the second mixture comprises one or more proteins selected from the group consisting of: wheat gliadin, barley gliadin, rye gliadin, zein, sorghum gliadin, and oat protein. Most preferably, the second mixture comprises zein.

[0095] In a preferred aspect of the invention, the first mixture comprises 5% or more by weight of one or more biodegradable polymers.

[0096] In another preferred aspect of the invention, the second mixture contains 5% or more by weight of one or more plant-based glutenin.

[0097] The second mixture contains fatty acids, more preferably oleic acid.

[0098] The weight ratio of fatty acids to gluten in the second mixture is preferably 1:10 to 10:1, more preferably 1:5 to 5:1, even more preferably 1:2 to 2:1, and most preferably 1:1.2 to 1.2:1. In a preferred embodiment, the weight ratio of fatty acids to gluten in the second mixture is preferably 1:1.

[0099] Fatty acids include, but are not limited to, fatty acids having a carbon chain length of 6 to 22 carbon atoms, preferably 10 to 22 carbon atoms, and more preferably 18 to about 20 carbon atoms. Both saturated and unsaturated carbon chains apply. Oleic acid is a monounsaturated 18-carbon chain.

[0100] Fatty acids can be extracted from animal or plant fats and oils. They can be used in the mixtures of the present invention as pure compounds or as part of natural oils, such as rapeseed oil, which has a high content of oleic acid. Preferably, oleic acid is extracted from plant sources.

[0101] To avoid being bound by theory, it is believed that oleic acid increases the hydrophobicity of the second coating, resulting in a coating with better performance. Furthermore, it improves the solubility of gluten, a plant-based protein, in the second mixture, making processing easier and faster. At higher oleic acid levels, less alcohol is needed to prepare homogeneous mixtures of gluten-based proteins. At high oleic acid levels, hazy dispersions of gluten in the mixture are observed to become clear. This is advantageous because it reduces the industrial hazards associated with handling large quantities of highly flammable materials such as low molecular weight alcohols (e.g., ethanol).

[0102] Plasticizers can be added to the first or second mixture to aid processing and increase the flexibility of the coating. When the substrate being coated is flexible, it is important to prevent it from cracking during handling (e.g., when cards are folded into boxes), thus exposing the original uncoated substrate underneath. Plasticizers can be hydrophobic or hydrophilic. Hydrophilic plasticizers can negatively affect the coating's moisture resistance, while hydrophobic plasticizers can negatively affect the coating's oil resistance; therefore, the content needs to be controlled to balance these characteristics.

[0103] Preferably, one or more hydrophilic plasticizers in the first mixture or the second mixture are independently selected from the group consisting of: a) Polyols formed from 1 to 20 repeating hydroxylation units, each unit containing 2 to 6 carbon atoms, provided that when the polyol is formed from only one repeating unit, it has at least 4 carbon atoms, excluding sorbitol. b) Ethers, thioethers, inorganic and organic esters, acetals, and amino derivatives of polyols formed from 1 to 20 repeating hydroxylation units, each unit containing 2-6 carbon atoms, excluding acetates, triethyl citrate, and tributyl citrate of glycerol. c) The reaction product of a polyol and a chain extender, having 1 to 20 repeating hydroxylation units, each unit containing 2 to 6 carbon atoms. d) Polyol oxidation products having 1 to 20 repeating hydroxylation units, each unit containing 2 to 6 carbon atoms, including at least one aldehyde or carboxyl functional group or a mixture thereof.

[0104] Hydrophobic plasticizers can be water-insoluble vegetable oils or waxes.

[0105] More preferably, one or more plasticizers in the first or second mixture are independently selected from glycerol, polyethylene glycol, propylene glycol, sorbitol, mannitol, xylitol, triethyl citrate, monoglycerides, diglycerides, triglycerides, glucose, mannose, fructose, sucrose, urea, lecithin, waxes, amino acids, or mixtures thereof, with glycerol and / or oleic acid being most preferred. Preferably, the plasticizer is bio-based, and even more preferably plant-derived. The plasticizer may also be added in the form of a mixture with other components (preferably bio-based, and even more preferably plant-derived mixtures).

[0106] The plasticizer content in the first mixture is preferably from 0.5 wt% to 50 wt%, more preferably from 1 wt% to 30 wt%, even more preferably from 1 wt% to 15 wt%, and most preferably from 1 wt% to 5 wt%.

[0107] The plasticizer content in the second mixture is preferably 0.5 wt% to 70 wt%, more preferably 1 wt% to 50 wt%, even more preferably 1 wt% to 30 wt%, even more preferably 1 wt% to 20 wt%, even more preferably 1 wt% to 15 wt%, and most preferably 1 wt% to 10 wt%.

[0108] The ratio of plant-based protein to plasticizer in the first mixture is preferably 5:1 to 1:5, more preferably 3:1 to 1:3, or even more preferably 3:1 to 1:1.

[0109] The ratio of plant-based protein to plasticizer in the second mixture is preferably 6:1 to 1:6, more preferably 5:1 to 1:3, or even more preferably 5:1 to 1:1.

[0110] In an optional preferred aspect of the invention, the first mixture further comprises one or more acids selected from the group consisting of organic and inorganic acids. An acid is a compound that dissociates in water to create an acidic environment. Inorganic acids are generally considered strong acids that dissociate completely in water, while organic acids are generally considered weak acids that dissociate partially in water. Organic acids are preferred for food-grade coatings.

[0111] In a preferred aspect of the invention, the first mixture further comprises one or more inorganic acids selected from the group consisting of hydrochloric acid, sulfuric acid, sulfurous acid, nitric acid, and phosphoric acid. Most preferably, the first mixture comprises hydrochloric acid. It is not desirable to be bound by theory, but it is believed that adjusting the pH of the dispersion with inorganic acids makes the proteins more soluble and easier to disperse into a uniform slurry because they are further away from their isoelectric point. This allows for the formation of a more uniform layer when the first mixture is applied to a substrate.

[0112] In a preferred aspect of the invention, the first mixture further comprises one or more organic acids selected from the group consisting of acetic acid, α-hydroxy acids, or β-hydroxy acids. More preferably, the organic acid is selected from acetic acid, lactic acid, citric acid, malic acid, maleic acid, glycolic acid, gluconic acid, tartaric acid, β-hydroxypropionic acid, β-hydroxybutyric acid, β-hydroxyβ-methylbutyric acid, 2-hydroxybenzoic acid, and carnitine. Even more preferably, the first mixture comprises acetic acid and / or lactic acid, with lactic acid being the most preferred.

[0113] In the preferred coating of the present invention, the organic acid is a volatile organic acid (i.e., an organic acid with a boiling point below 120°C at atmospheric pressure), preferably acetic acid. This is because volatile organic acids can be readily removed from the coating mixture during the drying step, resulting in a final coating containing very little (if any) residual organic acid.

[0114] In the preferred coating of this invention, the organic acid is a low-volatility organic acid (i.e., an organic acid with a boiling point greater than 120°C at atmospheric pressure), preferably lactic acid. This is because low-volatility organic acids are less easily removed from the coating mixture during the drying step, thus giving them a dual function as plasticizers.

[0115] The first coatings of this invention exhibit a useful combination of properties, meaning they are robust and provide oil barrier properties. The increased robustness of the coatings of this invention can be attributed to the mixing of plant-based proteins with organic acids in the first mixture and the formation of a dense protein first coating after drying.

[0116] To avoid being bound by theory, it is proposed that when the plant-based protein of the first mixture is added to an aqueous solution of organic acid, the plant-based protein partially unfolds, leading to the exposure of hydrophobic amino acids initially embedded in the protein's native structure. After partial unfolding, the organic acid can interact with the unfolded protein molecules. For example, the organic acid more readily protonates amino acid residues and can form anionic salt bridges with stable hydrophobic interactions. Furthermore, heating the first mixture containing organic acid at elevated temperatures disrupts non-covalent protein-protein contacts. It is also proposed that applying mechanical stirring (e.g., ultrasonic treatment or high-pressure homogenization) to the first mixture containing organic acid breaks down large colloidal protein aggregates into smaller aggregates and disrupts intermolecular interactions. Furthermore, it is proposed that cooling the first protein mixture containing organic acid enables non-covalent protein-protein contacts, thereby promoting the self-assembly of plant-based protein molecules into interconnected protein aggregates. Drying the colloidal suspension of the plant-based protein aggregates on a substrate to form a first coating results in the formation of a dense protein layer with improved stability and oil barrier properties.

[0117] Mixing plant-based proteins with organic acids in a first mixture and drying them to form a dry coating can result in the plant-based proteins having a protein secondary structure with at least 30% intermolecular β-sheet, 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.

[0118] The mixing of plant-based proteins with organic acids can be carried out using pure acids (e.g., glacial acetic acid). However, large-scale processing of concentrated acid solutions is dangerous. Preferably, the mixing of plant-based proteins with organic acids involves the use of an aqueous solution of the organic acid. More preferably, the aqueous solution of the organic acid has a concentration of at least 2% (v / v), preferably at least 3% (v / v), and more preferably at least 4% (v / v). Optionally, the aqueous solution of the organic acid has a concentration of no more than 50% (v / v), preferably no more than 40% (v / v), and more preferably no more than 30% (v / v).

[0119] Adding organic acids to the first mixture of plant-based proteins can also produce a mixture that is physically more stable over time, which means that industrial-scale production is simpler if larger batches of the first mixture can be manufactured and stored separately until needed.

[0120] The content of inorganic acid and / or organic acid in the first mixture is preferably 1 wt% to 20 wt%, more preferably 1.5 wt% to 15 wt%, and most preferably 2 wt% to 10 wt%.

[0121] In a preferred aspect of the invention, the second mixture further comprises one or more organic acids selected from the group consisting of acetic acid, α-hydroxy acids, or β-hydroxy acids. More preferably, the organic acid is selected from acetic acid, lactic acid, citric acid, malic acid, maleic acid, glycolic acid, gluconic acid, tartaric acid, β-hydroxypropionic acid, β-hydroxybutyric acid, β-hydroxyβ-methylbutyric acid, 2-hydroxybenzoic acid, and carnitine.

[0122] Adding organic acids to the second mixture of plant-based proteins can also produce a mixture that is physically more stable over time, which means that industrial-scale production is simpler if larger batches of the second mixture can be manufactured separately and stored until needed.

[0123] The organic acid content in the second mixture is preferably 0.5 wt% to 50 wt%, more preferably 1 wt% to 40 wt%, and most preferably 1 wt% to 30 wt%.

[0124] In an optional preferred aspect of the invention, the first mixture comprises a plant-based protein, said plant-based protein being an alkali-treated plant-based protein, wherein the plant-based protein has been mixed with a base or alkali such that when the resulting plant-based protein is mixed into water, the pH of the dispersion is greater than 7.5, preferably greater than 8, more preferably greater than 9, and even more preferably greater than 10. This process typically produces plant-based proteins that are more easily dispersed in water.

[0125] In an optional preferred aspect of the invention, the first mixture comprises a plant-based protein at a neutral pH, wherein the plant-based protein has been mixed with water, and the dispersion has a pH of 6.5 to 7.5. This process typically produces plant-based proteins that are less easily dispersed in water.

[0126] Water is the preferred liquid in the first and second mixtures due to its low cost and safety properties.

[0127] One or more liquids in the second mixture are preferably selected from water and alcohol.

[0128] One or more liquids in the first mixture preferably do not contain alcohol, especially ethanol.

[0129] In a preferred aspect of the invention, the alcohol improves the solubility and stability of the plant-based protein, glutenin, in the second mixture prior to coating. In an alternative preferred aspect of the invention, the second mixture further comprises one or more alcohols selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, and pentanol. In a preferred second mixture of the invention, the alcohol is volatile (i.e., an alcohol with a boiling point below 120°C at atmospheric pressure), preferably ethanol. This is because volatile alcohols can be readily removed from the coating mixture during the drying step, resulting in a final coating containing very little (if any) residual alcohol.

[0130] The first and / or second mixtures may additionally contain waxes. Preferred waxes are made from natural waxes that have passed the OECD 301B biodegradability screening test, such as beeswax, rapeseed wax, castor wax, candelilla wax, soybean wax, palm oil wax, or another natural wax, provided that the exposure temperature does not exceed the wax's melting point. In some cases, some paraffin oil-based waxes may also pass OECD 301B.

[0131] The first and / or second mixtures may additionally contain titanium dioxide. This can provide a whitening effect to the paper substrate and also act as a processing aid by reducing the viscosity of the protein mixture.

[0132] The first mixture and / or the second mixture may additionally contain phyllosilicates. Preferably, the phyllosilicates are serpentine minerals, clay minerals, chlorite minerals, or mica minerals, or mixtures thereof. Preferably, the clay minerals are selected from bentonite, kaolinite, pyrophyllite, vermiculite, and montmorillonite (e.g., montmorillonite, cloisite, laponite, hectorite, etc.) or mixtures thereof.

[0133] Furthermore, foliated silicates can be used as an intermediate layer between the first and second coatings. Not wanting to be bound by theory, it is thought that they act as a mechanical adhesive between the two coatings, aiding their bonding through mechanical interlocking.

[0134] Furthermore, metals or metalloids can be used as an intermediate layer between the first and second coatings, a so-called "metallization" layer. The purpose is typically to improve the oxygen barrier properties of the packaging. Metal atoms, such as aluminum, or metalloids, such as aluminum oxide (AIOx) and silicon oxide (SiOx), or alloys thereof, are deposited on the surface. This can also be achieved through transfer metallization, in which an ultrathin layer of metal or metalloid material is deposited onto a support film, which is then positioned in contact with the target substrate, such that the metal or metalloid layer is transferred onto the substrate.

[0135] The first mixture and / or the second mixture may additionally contain a biodegradable polymer. Preferably, the additional biodegradable polymer is selected from starch, algae-derived polysaccharides, fungal-derived polysaccharides, microbial-derived polysaccharides (e.g., gellan gum and bacterial cellulose), microbial-derived polyesters (e.g., polyhydroxyalkanoates, PHAs), chitosan, lignin, cellulose, micron-fibrillated cellulose (MFC), nanofibrillated cellulose (NFC), microbial nanocellulose, or cellulose nanocrystals (CNC). Preferably, the additional biodegradable polymer is of natural origin. Preferably, the additional biodegradable polymer is not of animal origin.

[0136] The first mixture and / or the second mixture may additionally contain other auxiliaries and processing agents, such as, but not limited to, anaphylactic agents, such as bittering agents (e.g., denatum salts, such as benzodenatum, denatum sugar, and denatum chloride; sucrose octaacetate; quinine; flavonoids such as quercetin and naringenin; and quassinoids such as quassin and brucine) and pungent agents (e.g., capsaicin, piperine, allyl isothiocyanate, and resinferatoxin), crosslinking agents, anti-blocking agents, defoamers, antioxidants, bleaching agents (e.g., sodium metabisulfite, sodium bisulfite, or other bleaching agents), and detackifying agents. Agents, extenders, fillers, lubricants, plasticizer compatibilizers, release agents, surfactants, gas barrier additives (e.g., nanoparticles such as layered silicate-type nanoclays, such as sodium montmorillonite), and other functional ingredients, wherein the amounts of the other additives and processing agents are suitable for their intended purpose.

[0137] The amount of such agents (alone or together) may be up to about 50 wt.%, 20 wt.%, 15 wt.%, 10 wt.%, 5 wt.%, 4 wt.% and / or at least 0.01 wt.%, 0.1 wt.%, 1 wt.% or 5 wt.% based on the weight of the dried coating.

[0138] Suitable surfactants may include, but are not limited to, nonionic, cationic, anionic, and amphoteric types. Suitable surfactants may include, but are not limited to: polyoxyethylene-modified polyoxypropylene glycol, alcohol ethoxylates, alkylphenol ethoxylates, tertiary acetylenols, and alkanolamides (nonionic); polyoxyethylene-modified amines, quaternary ammonium salts, and quaternized polyoxyethylene-modified amines (cationic); and amine oxides, N-alkyl betaine, and sulfobetaine (amphotericidal). Other suitable surfactants may include, but are not limited to, sodium dioctyl sulfosuccinate, lactated fatty acid esters of glycerol and propylene glycol, lactate esters of fatty acids, sodium alkyl sulfate, polysorbate 20, polysorbate 60, polysorbate 65, polysorbate 80, lecithin, acetylated fatty acid esters of glycerol and propylene glycol, and acetylated esters of fatty acids, and combinations thereof. The amount of surfactant in the dried coating may range from about 0.1 wt.% to about 2.5 wt.%, preferably from about 1.0 wt.% to 2.0 wt.%, based on the weight of the dried coating.

[0139] Suitable substrates for coating can be any substrate requiring protection. Substrate materials can be crystalline, amorphous, or fibrous. Materials can be natural or synthetic; optionally, they can be plant-based, animal-based, or inorganic. Typical crystalline materials include metals, typical amorphous materials include glass, optical fibers, and synthetic or bio-based polymers, and typical fibrous materials include paper, textiles, seeds, fruits, and vegetables.

[0140] On the one hand, plant-based protein coatings for fibers are preferred because the positively charged plant-based proteins and the negatively charged fibrous materials (e.g., cellulose) have opposite charges, resulting in a strongly bonded coating. These strong electrostatic interactions typically lead to enhanced properties, including mechanical properties such as strength, stiffness, abrasion resistance, water resistance, and elasticity. Polycations typically used for electrostatic bonding with negatively charged cellulose fibers are either animal-derived (e.g., chitosan) or non-biodegradable (i.e., polyethyleneamine).

[0141] Fiber-based materials can be derived from cellulose and can be selected from paper (bleached, unbleached, coated (with pores still present), uncoated, supercalendered), cardboard, wood, fabrics or textiles, seeds, fruits and vegetables.

[0142] Examples of paper materials can include typically thin, flexible paper, such as that used as packaging material or for making bags; and typically thicker, rigid paper or paperboard (e.g., corrugated cardboard, paperboard, molded fiberboard), such as that used as boxes, containers, plates, cups, or other storage or food service items. In this context, it is highly desirable that the coating is biodegradable and / or does not affect the recycling capacity of the paper or paperboard. Test methods commonly used to assess the impact of materials on recycling capacity include PTS-RH 021:2012, categories 1 and 2.

[0143] The coating can be heat-sealed to allow bags and boxes to be closed and sealed, which can also be advantageous.

[0144] Natural fibers include non-wood fibers such as cotton, Manila hemp, kenaf, sabai grass, flax, esparto grass, straw, jute, hemp, bagasse, milkweed fibers, and pineapple leaf fibers; and wood fibers such as wood or pulp fibers, such as those obtained from deciduous and coniferous trees, including softwood fibers such as northern and southern softwood sulfate (kraft) fibers, and hardwood fibers such as eucalyptus, maple, birch, and aspen. Pulp fibers can be prepared in high-yield or low-yield forms and can be pulped using any known method, including sulfate pulping, sulfite pulping, high-yield pulping, and other known pulping methods.

[0145] The natural fibers used in this invention can be recycled natural fibers, virgin natural fibers, or mixtures thereof. Furthermore, for good mechanical properties, it is desirable for the natural fibers to be relatively undamaged and mostly unrefined or only slightly refined.

[0146] Suitable wood materials can be any type of wood commonly used in home, office, and outdoor environments, and can include furniture and building materials. In such cases, it is desirable that the coating does not negatively alter the aesthetics and physical properties of the item.

[0147] In certain respects, the material includes porous cellulose materials. Cellulose materials typically include at least one of cellulose and hemicellulose, and may also include lignin (e.g., as a lignocellulose material).

[0148] Unless otherwise stated, cellulose-based fibers can include regenerated cellulose fibers, such as rayon or cuprammonium rayon, as well as high-yield pulping fibers. The term "cellulose-based fibers" also includes chemically treated natural fibers, such as mercerized pulp, chemically hardened or cross-linked fibers, or sulfonated fibers. It also includes mercerized natural fibers, regenerated natural cellulose fibers, cellulose produced by microorganisms, rayon processes, cellulose dissolving and coagulation spinning processes, and other cellulose materials or cellulose derivatives. Other cellulose-based fibers included are waste or recycled fibers and high-yield pulp fibers, including bleached chemithermomechanical pulp (BCTMP), chemithermomechanical pulp (CTMP), pressure / pressure thermomechanical pulp (PTMP), thermomechanical pulp (TMP), thermomechanical chemical pulp (TMCP), high-yield sulfite pulp, and high-yield sulfate pulp, all of which result in fibers with high levels of lignin but are still considered natural fibers. High-yield fibers are known, relative to typical chemically pulped fibers, for their stiffness in both dry and wet conditions.

[0149] Suitable fabric or textile substrates may include any cellulosic material commonly used in clothing or upholstery or other applications, such as cotton, jute, flax, sisal, hemp, etc.

[0150] Suitable seed substrates include those suitable for home, gardening, or agricultural environments. In this case, a biodegradable coating to avoid environmental pollution is highly desirable.

[0151] Fruits and vegetables can be fresh, dried, or frozen, and benefit from protective coatings during storage and transportation to increase their shelf life and reduce spoilage. Fruits and vegetables also benefit from coatings that provide a gas barrier to reduce the ripening effect of ethanol produced by other products stored in the vicinity. In this case, the coating must be edible, and ideally, it should be digestible.

[0152] Inorganic fibers are typically brittle and require protection from environmental impacts. Common examples of such fibers are silica-based fibers, such as optical fibers, which are very pure and have a very low refractive index; however, they are brittle. Alternatively, plastic fiber optic cables made of acrylates and polyimide can be used, but these eventually break down into harmful microplastics in the environment. Glass fibers also include those used in fiberglass products or mineral wool and rock wool.

[0153] In a preferred aspect of the invention, the substrate material is a fiber-based material. In another preferred aspect of the invention, the substrate material is a cellulose material.

[0154] More preferably, the base material is selected from the group consisting of: wood, wood pulp, cotton fiber, hemp fiber, jute fiber, sisal fiber, flax fiber, cellulose-based fiber, silica-based fiber, fruits, vegetables and seeds.

[0155] More preferably, the substrate material is selected from the group consisting of: paper, paperboard, and corrugated paperboard.

[0156] Depending on the substrate being coated, a variety of coating methods can be used.

[0157] For physically brittle and / or heat-sensitive substrates (e.g., fruits and vegetables), coating is typically achieved by dip coating or spray coating, and drying at a temperature of 4°C to 50°C, preferably ambient temperature to 30°C, more preferably ambient temperature. Drying at lower temperatures may require several hours.

[0158] For seeds, coating is typically carried out in a drum coater, spray coater, rotary coater, fluidized bed, or extruder. Drying is usually done at ambient temperature.

[0159] In a preferred aspect of the invention, the application of the first mixture and / or the second mixture to the substrate is achieved by roller coating, dip coating, slot coating, air knife coating or spraying.

[0160] For materials insensitive to heat, pressure, or shear (such as paper or fabric), a variety of equipment can be used for coating, including reverse rollers, direct rollers, gravure rollers (forward and reverse), on-roll doctor blades, flexographic printing equipment, offset printing equipment, slot die, air knife, spraying, or dip coating. After coating, the wet coated sample is exposed to temperatures of 50°C to 200°C, preferably 70°C to 150°C, more preferably 80°C to 130°C, to dry it, including equipment such as cylinders, Yankee dryers, Flakt dryers, infrared dryers, non-contact dryers (fans), or air flotation dryers.

[0161] In another preferred aspect of the invention, the drying of the first coating and / or the second coating is achieved by exposing the coating to air at a temperature of 50°C to 250°C for 0.1 seconds to 10 minutes, more preferably at a temperature of 60°C to 200°C for 2 seconds to 5 minutes, and most preferably at a temperature of 80°C to 150°C for 6 seconds to 3 minutes. Preferably, the drying of the first coating and / or the second coating is achieved by non-contact drying, preferably by using a fan.

[0162] When the substrate is paper or cardboard, the drying of the first coating and / or the second coating is preferably achieved by exposing the coating to an elevated temperature for a period of 10 seconds or less, preferably 5 seconds or less, and most preferably 2 seconds or less.

[0163] In another preferred aspect of the invention, when the first mixture and / or the second mixture are in the form of solid powders, they can be dried by heating the powders to reduce the level of liquid material present without altering the physical state of the mixtures.

[0164] Many substrates (such as paper, cardboard, fabric, or textiles) are printed with background colors, branding, or packaging information. For example, industrial offset printing, lithography, digital printing, gravure printing, screen printing, or aniline printing can be used for printing on paper. All these methods use roll pressing techniques to apply single-color inks or pigments to the substrate one at a time. Therefore, bleeding between color layers needs to be minimized to prevent blurring and distortion of the printed image. The coating of this invention prevents ink or pigment bleeding by providing a less permeable printing surface, especially when used on low-density substrates such as tissues, blotting paper, or porous paper. The coating of this invention can be used in conjunction with overprint varnish (OPV) to impart a glossy, satin, or matte finish to the print.

[0165] In another aspect, the present invention relates to coated substrates obtained by the methods described herein.

[0166] In a preferred aspect of the invention, the average thickness of the first coating is 1 to 20 micrometers, more preferably 2 to 15 micrometers.

[0167] In an optional preferred aspect of the invention, the average density of the first coating is 0.1 to 20 g / m³. 2 .

[0168] In another preferred aspect of the invention, the average thickness of the second coating is 1 to 20 micrometers, more preferably 2 to 15 micrometers.

[0169] In an optional preferred aspect of the invention, the average density of the second coating is 0.1 to 20 g / m³. 2 .

[0170] In a preferred aspect of the invention, the presence of two different coatings on the substrate can be observed using a microscope (preferably a scanning electron microscope).

[0171] In a preferred aspect of the invention, the first dried coating has at least 30% intermolecular β-sheet, 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, and the second dried coating has less than 40% intermolecular β-sheet, less than 30% intermolecular β-sheet, less than 20% intermolecular β-sheet, or less than 10% intermolecular β-sheet. To investigate the secondary structure of the plant-based protein in the first or second coating, Fourier transform infrared (FTIR) analysis was performed. FTIR spectral data were collected using a Bruker VERTEX 70 spectrometer with a diamond attenuated total reflectance (ATR) element. The first or second coating containing the plant-based protein needs to be in direct contact with a diamond ATR cell. A 4 cm⁻¹ anode was used. -1 Data were collected after 128 scans at high resolution with background subtraction. For protein structure analysis, spectra were smoothed and normalized using a second-order and seven-point window Savitzky-Golay filter. Amide I band (1600-1700 cm⁻¹) -1 The second derivative of the data is calculated from the smoothed data to deconvolve and quantize the contributions of the second- and fourth-level structures.

[0172] Recyclable articles made from coated substrates can be easily recycled because the coating can be easily or partially removed from the substrate. This is because the coating is not covalently bonded to the substrate (e.g., paper). Furthermore, the ease of coating removal facilitates the recycling of the coated substrate in a single recycling stream (e.g., a paper recycling stream).

[0173] A method for recycling a coated substrate includes extracting the coating in one or more aqueous extraction media having a pH value sufficient to sequentially or in a single step to separate the coating from the substrate.

[0174] The recycling method can further include a size reduction process on the coated substrate before extraction into the aqueous extraction medium. Size reduction can include pulping, grinding, or any other type of destructive mechanical process to break the coated substrate into smaller fragments, particularly increasing the surface area exposure of the interface region between the substrate and the coating, thereby enhancing the contact between the aqueous extraction medium and the coating. Generally, smaller fragment sizes can improve extraction efficiency.

[0175] The coating material can be washed off the coated substrate, for example, from the pulp during repulping. For instance, the first and second coatings can be removed from the coated paper using an acidic solution (e.g., a 40% v / v acetic acid solution). Alternatively, the pulp can be first rinsed with a 70-90 vol% ethanol aqueous solution to remove the second coating from the coated paper, followed by a second rinse with a NaOH aqueous solution adjusted to pH 11 to remove the first coating.

[0176] The recycling method may further include separating the substrate from the aqueous extraction medium and recovering and / or reforming the substrate. Separation of the substrate from the aqueous extraction medium can be carried out by any suitable solid / liquid separation method (e.g., filtration or decantation) to retain the substrate and remove the aqueous extraction medium containing components of a first mixture and a second mixture. Optionally, one or more washing steps may be performed after separation to remove any residual coating material retained in and / or on the substrate. If the coated material is pulped, milled, or otherwise reduced in size prior to extraction, the resulting substrate fragments can be recovered after separation from the aqueous extraction medium and then reformed into new recycled substrate, such as recycled paper or other cellulose substrate. In embodiments, the recovered or reformed porous substrate is substantially free of coating, for example, having 5 wt.% or less of residual coating material relative to the initial coating material before extraction. For example, the recovered or reformed substrate may have a reduced coating material of up to 1 wt.%, 2 wt.%, or 5 wt.% relative to the initial coating material before extraction. Optionally or additionally, the recycled or reformed substrate may have 0.1 wt.% or less of coating material relative to the substrate material. For example, the recycled or reformed substrate material may have at least up to 0.001 wt.%, 0.01 wt.%, or 0.1 wt.% of reduced coating material relative to the substrate material.

[0177] Extraction can remove substantially all coatings from a substrate, such as at least 95 wt.%, 98 wt.%, or 99 wt.% and / or up to 90 wt.%, 95 wt.%, 98 wt.%, 99 wt.%, or 100 wt.% of the coating that was originally present on the coated substrate.

[0178] Optionally or additionally, if the pulp is not washed or extracted or is partially washed / extracted, the remaining coating material may become part of the recycled paper.

[0179] Adhesives are substances that functionally hold materials together by adhering to surfaces (which resist separation). Adhesives are commonly used in the manufacture of items such as boxes made of cardboard and bags made of paper.

[0180] The coating of this invention can be heat-sealed and thus used as an adhesive when articles are made from the coated material. This eliminates the need for a separate adhesive that is typically non-biodegradable.

[0181] Alternatively, if additional sealing is required, the coating of the present invention is compatible with typical adhesives such as starch-based adhesives, polyvinyl acetate-based adhesives, and polyoxyethylene adhesives, or water-dispersible adhesives, including thermoplastic elastomer-based adhesives and polyvinyl acetate-based adhesives.

[0182] Furthermore, water-soluble adhesives used in the repulping or decomposition steps of the paper recycling process are particularly suitable for the articles of the present invention.

[0183] For articles of the invention intended to remain in the environment (e.g., seeds), or articles of the invention unintentionally discarded in the environment (e.g., paper packaging), it is important that they are biodegradable and do not exacerbate the growing microplastic pollution crisis.

[0184] The preferred coatings of this invention are highly biodegradable, leaving virtually no trace of their previous presence. Coatings for biodegradation evaluation can be prepared according to the methods described herein by drying a first coating, followed by a second coating, onto a substrate, where they can be mechanically scraped off or peeled off, for example, a polyester film or glass.

[0185] In the preferred coating of the present invention, the percentage of coating biodegradation based on O2 consumption after 28 days, as measured according to ISO-14851, is 70% to 100%, more preferably 80% to 100%, and most preferably 85% to 100%.

[0186] In the preferred coating of the present invention, the percentage of coating biodegradation based on CO2 after 28 days, as measured according to ISO-14851, is 70% to 100%, more preferably 75% to 100%, and most preferably 80% to 100%.

[0187] In another aspect, the present invention relates to a coated substrate comprising a first coating on at least a portion of at least a first surface of the substrate and a second coating on at least a portion of the first coating, the first coating comprising one or more biodegradable polymers and the second coating comprising one or more glutenins and one or more fatty acids.

[0188] The present invention also relates to the use of the coated substrate described herein for manufacturing articles selected from the group consisting of: plates, cups, containers, boxes, cartons, corrugated boxes, packaging materials, and bags.

[0189] On the other hand, articles intended for packaging or encapsulating products (e.g., food boxes or bags) can be sealed by heat sealing, where the coating itself acts as an adhesive. For heat sealing to occur, the coating at the interface must be at or above its thermal initiation temperature. Controlling the thickness of the coating and the substrate allows sufficient heat to be transferred to the interface within the available time. Coatings with an outer surface containing a plant-based protein such as glutenin can create a seal upon heating, thus eliminating the need for additional adhesive materials (i.e., self-sealing coatings). In a preferred embodiment of the coating, the coating may be present on one or both sides of the seal before heat and / or pressure is applied during heat sealing. Therefore, a coated substrate can be sealed to an uncoated substrate, or a coated substrate can be sealed to another coated substrate.

[0190] Preferably, after the coated article has been acclimatized at 55% relative humidity and 20°C for at least 1 hour and then sealed at 120°C with 3 bar pressure applied for 1 second, the coating of the present invention has a heat seal strength of at least 20 N / m, more preferably at least 40 N / m, more preferably at least 60 N / m, even more preferably at least 80 N / m, even more preferably at least 100 N / m, and most preferably at least 120 N / m, as measured by ASTM F88 / F88M-15 at 55% relative humidity and 20°C.

[0191] In another aspect, the present invention relates to a kit for coating a substrate, comprising: The first mixture comprises one or more liquids and one or more biodegradable polymers; The second mixture comprises one or more liquids and one or more plant-based gluten proteins and one or more fatty acids.

[0192] In a preferred kit for coating substrates according to the present invention, the first mixture contains 5% or more by weight of one or more biodegradable polymers.

[0193] In another preferred kit for coating a substrate according to the present invention, the first mixture comprises one or more proteins selected from the group consisting of: soybean protein, pea protein, rice protein, potato protein, rapeseed protein, sunflower protein, lentil protein, chickpea protein, kidney bean protein, broad bean protein, mung bean protein, sunflower seed protein, pumpkin seed protein, flaxseed protein, chia protein, canola protein, lupin protein, alfalfa protein, moringa protein, borage protein, hemp seed protein, and cottonseed protein, preferably selected from pea protein, potato protein, rapeseed protein, and / or sunflower protein, with pea protein being the most preferred.

[0194] In another preferred kit for coating a substrate according to the present invention, the first mixture further comprises one or more plant-based albumins or one or more glutenins.

[0195] In another preferred kit for coating a substrate according to the present invention, the second mixture contains 5% or more by weight of one or more plant-based glutenin.

[0196] In another preferred kit for coating a substrate according to the present invention, the second mixture comprises one or more proteins selected from the group consisting of: gliadin, barley gliadin, rye gliadin, zein, sorghum gliadin, and oat protein, with zein being the most preferred.

[0197] In another preferred kit for coating a substrate according to the present invention, the second mixture further comprises one or more plant-based glutenins.

[0198] In another preferred kit for coating a substrate according to the present invention, the first mixture further comprises one or more plasticizers selected from the group consisting of: glycerol, polyethylene glycol, propylene glycol, sorbitol, mannitol, xylitol, triethyl citrate, lipids, monoglycerides, diglycerides, triglycerides, glucose, glucose, mannose, fructose, sucrose, urea, lecithin, waxes, amino acids, and oleic acid.

[0199] In another preferred kit for coating a substrate according to the present invention, the first mixture comprises glycerol.

[0200] In another preferred kit for coating a substrate according to the present invention, the first mixture further comprises one or more organic acids selected from the group consisting of: acetic acid, lactic acid, citric acid, malic acid, maleic acid, glycolic acid, gluconic acid, tartaric acid, β-hydroxypropionic acid, β-hydroxybutyric acid, β-hydroxyβ-methylbutyric acid, 2-hydroxybenzoic acid, and carnitine.

[0201] In another preferred kit for coating a substrate according to the present invention, the first mixture comprises acetic acid.

[0202] In another preferred kit for coating a substrate according to the present invention, the first mixture comprises lactic acid.

[0203] In another preferred kit for coating a substrate according to the present invention, the second mixture further comprises one or more plasticizers selected from the group consisting of: glycerol, polyethylene glycol, propylene glycol, sorbitol, mannitol, xylitol, triethyl citrate, lipids, monoglycerides, diglycerides, triglycerides, glucose, glucose, mannose, fructose, sucrose, urea, lecithin, waxes, amino acids, and oleic acid.

[0204] In another preferred kit for coating a substrate according to the present invention, the second mixture comprises glycerol.

[0205] In another preferred kit for coating a substrate according to the present invention, the second mixture comprises oleic acid.

[0206] In another preferred kit for coating a substrate according to the present invention, the second mixture further comprises one or more organic acids selected from the group consisting of: acetic acid, lactic acid, citric acid, malic acid, maleic acid, glycolic acid, gluconic acid, tartaric acid, β-hydroxypropionic acid, β-hydroxybutyric acid, β-hydroxyβ-methylbutyric acid, 2-hydroxybenzoic acid, and carnitine.

[0207] In another preferred kit for coating a substrate according to the present invention, one or more liquids in the first mixture are water.

[0208] In another preferred kit for coating a substrate according to the present invention, one or more liquids in the second mixture are alcohols. Brief description of the attached diagram Figure 1a A box containing vegetable oil made from uncoated cardstock is shown, as described in Example 4.

[0210] Figure 1b A box containing vegetable oil, made of coated cardstock, is shown as described in Example 6.

[0211] Figure 2a The first mixture A after undergoing moderate shear treatment as described in Example 5 is shown.

[0212] Figure 2b The first mixture M after high-shear treatment, as described in Example 5, is shown.

[0213] Example Ingredients and materials Pea protein isolate (PPI) (80 wt% protein, 4 wt% carbohydrate) (ProEarth P16109) was purchased from Cambridge Commodities Ltd.

[0214] Purified zein (88-96% protein) was purchased from Fisher Scientific.

[0215] Soy protein isolate (SPI) was purchased from Fytomax Nutrition Pvt. Ltd.

[0216] Food-grade glycerin (APC pure, 99.5%) was purchased from APC.

[0217] Acetic acid (glacial acetic acid, food grade) was purchased from Fisher Scientific.

[0218] Lactic acid (85% solids) was purchased from Sigma Aldrich.

[0219] Oleic acid (90% industrial grade, Thermo Scientific Chemicals) was purchased from Fisher Scientific.

[0220] HCl Fisher Chemical hydrochloric acid solution 1M (1N) (NIST standard solution) was purchased from Fisher Scientific.

[0221] Tapioca starch α-Instant was purchased from BakeRite, UK.

[0222] D-sorbitol (98%, Thermo Scientific Chemicals) was purchased from Fisher Scientific.

[0223] Vivapure® FD-150 sodium alginate was purchased from Rettenmaier, UK.

[0224] Polysorbate 80 was purchased from Merck.

[0225] 210 gsm A3 white matte paper card (product code: 976434) purchased from The Range, UK.

[0226] 250 gsm brown natural kraft paper (a type of multi-layer kraft paperboard) is available from Sterling Paper Services Ltd.

[0227] Anhydrous ethanol (99.8+%) was purchased from Fisher Scientific.

[0228] Castor oil (Thermo Scientific Chemicals) was purchased from Fisher Scientific.

[0229] Toluene (99.85%) (further dried with molecular sieves, AcroSeal™, Thermo Scientific Chemicals) was purchased from Fisher Scientific.

[0230] n-Heptane (99%) (Thermo Scientific Chemicals) was purchased from Fisher Scientific.

[0231] The vegetable oil was purchased from Tesco UK Plc, a local supermarket.

[0232] 8M urea was purchased from Fisher Scientific.

[0233] 3M thiourea was purchased from Fisher Scientific.

[0234] Sodium dodecyl sulfate-polyacrylamide gel (SDS-PAGE) was purchased from BIO-RAD, UK.

[0235] Tris / glycine / SDS buffer (25 mM Tris, 192 mM glycine and 0.1% w / v SDS) was purchased from Fisher Scientific.

[0236] Sodium benzoate was purchased from Fisher Scientific.

[0237] In the examples below, all references to "ambient temperature" refer to a temperature of approximately 20°C. Furthermore, the weight percentages of the ingredients and materials used in the preparation of the examples refer to purchased ingredients and materials and do not consider their purity.

[0238] Measurement methods Kit method test According to TAPPI standard T 559 (Paper and Pulp Industry Technical Association), the test solution containing castor oil, toluene, and n-heptane is mixed as follows: Select a test paper sample and acclimate it at 50% relative humidity and 23°C for at least 24 hours. During extraction in a fume hood, add one drop of test solution 6 to the paper. After 15 seconds, wipe away any excess test solution and check the sample for dark spots indicating coating failure. Repeat this process 5 times for each test solution. If the sample does not show dark spots, it passes, and the test continues with solutions of higher numbers until the sample fails, or reaches the highest-numbered test solution. If the sample fails, the test continues with solutions of lower numbers until the sample passes, or reaches the lowest-numbered test solution. Once the highest-valued test solution that will not cause a failure has been identified, this is the kit grade for the sample.

[0239] The lowest rating is 0, indicating that the test paper sample has no oil resistance under these test conditions. The highest rating is 12, indicating that the test paper sample has very good oil resistance under these test conditions.

[0240] Cobb test The Cobb 60 value was determined according to TAPPI standard T441 om-09 (Technical Association of Paper and Pulp Industries). A 125 × 125 mm sample was cut from the test paper and equilibrated at 50% RH and 23°C for at least 24 hours. After equilibration, the sample was weighed and then placed in and clamped in an 11.3 mm diameter Cobb tester (CT / 100). 100 ml of water was added for 60 seconds, then removed, blotted dry with blotting paper and a 10 kg roller, and then weighed again. The Cobb value was calculated as follows: Dry paper GSM Cut a 125×125 mm sample from the paper sample, equilibrate at 50% RH and 23°C for at least 24 hours, and weigh to a depth of 0.001 g. GSM calculation is as follows: Dry coating GSM The same procedure as described above is used to determine the dry paper GSM after coating. The coating GSM is calculated as the coated paper GSM minus the uncoated paper GSM.

[0241] Dry paper thickness Cut a 125×125 mm sample from the paper pattern, equilibrate at 50% RH and 23°C for at least 24 hours, and measure the thickness using a micrometer accurate to 0.001 mm. Take 5 values ​​and calculate the average to obtain the sample thickness. The paper pattern can be coated or uncoated.

[0242] Dry coating thickness The total coating thickness is calculated by subtracting the dry uncoated paper thickness from the total dry coated paper thickness, where the paper is adapted and its thickness measured as described above. This can be done on paper after only the first coating has been applied and dried to obtain the dry first coating thickness. To obtain the dry second coating thickness, the dry first coating thickness is subtracted from the total coating thickness.

[0243] Methods for identifying the presence of globulins and glutenins First, place a 5×5 cm sample of the coated specimen into a beaker containing 25 ml of 80 vol% ethanol aqueous solution. Then, place the sample in an ultrasonic bath (Fisherbrand FB15051) at its maximum setting for 30 minutes to dissolve any glioprotein fractions. Filter the 80 vol% ethanol aqueous solution using a 0.22 µm filter and concentrate to dryness using a freeze dryer. Resuspend the recovered solid precipitate in an 8 M urea / 3 M thiourea aqueous solution and load it onto a sodium dodecyl sulfate-polyacrylamide gel (SDS-PAGE) using Mini-PROTEAN TGX 4 -15% gel and tris / glycine / SDS buffer for gel electrophoresis analysis. As a control, a standard 80% ethanol aqueous solution containing isolated glioproteins (e.g., α-zein) prepared according to the above method is loaded onto a polyacrylamide gel (SDS-PAGE). The presence of glioproteins is confirmed by comparing the test sample with the control.

[0244] First, place a 5×5 cm sample of the coated specimen into a beaker containing 25 ml of an aqueous solution adjusted to pH 11 with NaOH. Then, place the sample in a sonic bath (Fisherbrand FB15051) at its maximum setting for 30 minutes to dissolve any globulin fractions. Filter the alkaline aqueous solution using a 0.22 µm filter and concentrate to dryness using a freeze dryer. Resuspend the recovered solid precipitate in an 8 M urea / 3 M thiourea aqueous solution and load it onto a sodium dodecyl sulfate-polyacrylamide gel (SDS-PAGE) using Mini-PROTEAN TGX 4-15% gel and tris / glycine / SDS buffer for gel electrophoresis analysis. As a control, a standard aqueous solution containing globulin-rich plant-based proteins (e.g., pea protein isolate) prepared according to the above method is loaded onto a polyacrylamide gel (SDS-PAGE). The presence of glutenin is confirmed by comparing the test sample with the control.

[0245] viscosity Viscosity of the mixture was measured using an Anton Paar MCR 92 rheometer with a plate-cone measurement geometry (50 mm plate and 1 degree angle). The viscosity was measured at 0.1 s⁻¹. -1 up to 1000 s -1 The first mixture was tested by shear scanning, then at 1000 s. -1 Cut for 10 seconds and then scan again at 20°C. Report 50 seconds before and after cutting at 20°C. -1 value.

[0246] Particle size The particle size of the first mixture was measured using laser diffraction with an Anton Paar PSA 1190. Measurements were performed by diluting the mixture in an aqueous solution with acetic or lactic acid. It is important that the sample's pH be far from its isoelectric point to avoid misleading results due to coagulation. For example, the isoelectric point of pea protein isolates is 4.5, and the pH of the mixture was adjusted to 3 with acetic or lactic acid before measurement. The slurry was diluted to the desired concentration to obtain the optical density required for the measurement (typically 2-8% opacity). The referenced d50 refers to the volume distribution. The d10 and d5 values ​​for the volume distribution can also be obtained using laser diffraction in this manner.

[0247] The particle size of the second mixture was measured using dynamic light scattering (DLS) technology, operated according to the manufacturer's instructions using a Zeta Sizer Nano S from Malvern P Analytical. It is important that the mixture be adequately diluted to avoid misleading results due to particle agglomeration during testing. The mixture was diluted 100-fold with 80% ethanol. 200 μL of the diluted slurry was placed in a cuvette and placed in the device. The test was then performed according to standard device procedures. The measured d50 is for weight / volume distribution. DLS is generally available for measuring particle sizes up to 500 nm. The upper limit is primarily determined by the onset of sedimentation. For larger particle sizes, the laser diffraction technique described herein for the first mixture can also be used.

[0248] Example 1: Preparation of coating mixture Coating mixtures A to P are prepared according to the procedures described below.

[0249] (i) Preparation of pea protein mixture A At ambient temperature, using a top-mounted stirrer, mix 180 g of reverse osmosis water with 19.8 g of pea protein isolate in a 1 L glass beaker until homogeneous. Then place the beaker in a preheated water bath at 90°C and stir until the batch temperature reaches 80°C. After reaching 80°C, heat and stir the sample for 30 minutes. After 30 minutes, remove the sample from the water bath and mix with a Silverson mixer at 7000 RPM for 10 minutes. Then, stir the sample in an ice bath with a top-mounted stirrer until it reaches 40°C to prevent skin formation on the sample surface.

[0250] (ii) Preparation of pea protein mixture B At ambient temperature, using a top-mounted stirrer, mix 166.5 g of reverse osmosis water with 19.8 g of pea protein isolate in a 1 L glass beaker until homogeneous. Then place the beaker in a preheated water bath at 90°C and stir until the batch temperature reaches 80°C. Once at 80°C, add 13.5 g of acetic acid and heat and stir the sample for 30 minutes. After 30 minutes, remove the sample from the water bath and mix with a Silverson mixer at 7000 RPM for 10 minutes. Then, stir the sample in an ice bath with a top-mounted stirrer until it reaches 40°C to prevent skin formation on the sample surface.

[0251] (iii) Preparation of pea protein mixture C At ambient temperature, using a top-mounted stirrer, mix 180 g of reverse osmosis water with 19.8 g of pea protein isolate and 6.93 g of glycerol in a 1 L glass beaker until homogeneous. Add 14.18 g of 1M hydrochloric acid to adjust the pH to 3.5. Then place the beaker in a preheated water bath at 90°C and stir until the batch temperature reaches 80°C. After reaching 80°C, heat and stir the sample for 30 minutes. After 30 minutes, remove the sample from the water bath and mix with a Silverson mixer at 7000 RPM for 10 minutes. Then stir the sample in an ice bath with a top-mounted stirrer until it reaches 40°C to prevent skin formation on the sample surface.

[0252] (iv) Preparation of pea protein mixture D At ambient temperature, using a top-mounted stirrer, mix 166.5 g of reverse osmosis water with 19.8 g of soy protein in a 1 L glass beaker until homogeneous. Then place the beaker in a preheated water bath at 90°C and stir until the batch temperature reaches 80°C. Once at 80°C, add 13.5 g of acetic acid and heat and stir the sample for 30 minutes. After 30 minutes, remove the sample from the water bath and mix with a Silverson mixer at 7000 RPM for 10 minutes. Then, stir the sample in an ice bath with a top-mounted stirrer until it reaches 40°C to prevent a skin from forming on the sample surface.

[0253] (v) Preparation of pea protein mixture E At ambient temperature, using a top-mounted stirrer, mix 200 g of reverse osmosis water with 22 g of pea protein isolate and 7.7 g of glycerol in a 1 L glass beaker until homogeneous. Then place the beaker in a preheated water bath at 90°C and stir until the batch temperature reaches 80°C. After reaching 80°C, heat and stir the sample for 30 minutes. After 30 minutes, remove the sample from the water bath and mix with a Silverson mixer at 7000 RPM for 10 minutes. Then, stir the sample in an ice bath with a top-mounted stirrer until it reaches 40°C to prevent skin formation on the sample surface.

[0254] (vi) Preparation of pea protein mixture F At ambient temperature, using a top-mounted stirrer, mix 166.5 g of reverse osmosis water with 19.8 g of pea protein isolate and 6.93 g of glycerol in a 1 L glass beaker until homogeneous. Then place the beaker in a preheated water bath at 90°C and stir until the batch temperature reaches 80°C. Once at 80°C, add 13.5 g of acetic acid and heat and stir the sample for 30 minutes. After 30 minutes, remove the sample from the water bath and mix with a Silverson mixer at 7000 RPM for 10 minutes. Then, stir the sample in an ice bath with a top-mounted stirrer until it reaches 40°C to prevent skin formation on the sample surface.

[0255] (vii) Preparation of pea protein mixture G At ambient temperature, using a top-mounted stirrer, mix 166.5 g of reverse osmosis water with 20 g of pea protein isolate in a 1 L glass beaker until homogeneous. Then place the beaker in a preheated water bath at 90°C and stir until the batch temperature reaches 80°C. Dissolve 48.44 g of zein separately in 13.5 g of acetic acid, warm at 50°C and stir. Once the pea protein isolate mixture reaches 80°C, add the acetic acid and zein mixture, and heat and stir the sample for another 30 minutes. After 30 minutes, remove the sample from the water bath and mix with a Silverson mixer at 7000 RPM for 10 minutes. Then, stir the sample in an ice bath with a top-mounted stirrer until 40°C to prevent skin formation on the sample surface.

[0256] (viii) Preparation of zein mixture H Using a vortex mixer, mix 6 g of water with 24 g of ethanol in a Falcon tube. Add 7.5 g of zein and mix until homogeneous.

[0257] (ix) Preparation of zein mixture I Using a vortex mixer, mix 6 g of water with 24 g of ethanol and 2.01 g of glycerol in a Falcon tube. Add 8 g of zein and mix until homogeneous.

[0258] (x) Preparation of zein mixture J Using a vortex mixer, mix 6 g of water with 24 g of ethanol and 1.5 g of oleic acid in a Falcon tube. Add 7.5 g of zein and mix until homogeneous.

[0259] (xi) Preparation of zein mixture K Using a vortex mixer, mix 6 g of water with 24 g of ethanol and 3.75 g of oleic acid in a Falcon tube. Add 7.5 g of zein and mix until homogeneous.

[0260] (xii) Preparation of zein mixture L Using a vortex mixer, mix 6 g of water with 24 g of ethanol and 1.5 g of acetic acid in a Falcon tube. Add 7.5 g of zein and mix until homogeneous.

[0261] (xiii) Preparation of PPI mixture M At ambient temperature, 836.47 g of reverse osmosis water was mixed with 1 g of sodium benzoate and 99 g of pea protein isolate in a 1.5 L metal beaker using a top-mounted stirrer until homogeneous. Then, 63.53 g of lactic acid (85% solids) was added to the mixture under stirring and mixed until homogeneous. The resulting slurry was then mixed for 10 minutes at 7000 RPM at ambient temperature under moderate shear conditions using a Silverson mixer. The sheared slurry was then passed through a high-pressure homogenizer FPG12805 from Homogenising Systems Ltd. at a pressure of 100 MPa, which also resulted in an increase in slurry temperature at the nozzle. The slurry outlet temperature subsequently decreased to approximately 30°C with a cooling of 5°C.

[0262] (xiv) Preparation of zein mixture N At ambient temperature, using a top-mounted stirrer, mix 133 g of reverse osmosis water with 533 g of ethanol and 167 g of oleic acid (90% pure) in a 1.5 L metal beaker until homogeneous. Add 167 g of zein protein while stirring and mix until homogeneous. Then, use a Silverson mixer to mix the resulting slurry at 7000 RPM under moderate shear conditions for 5 minutes.

[0263] Preparation of (xv) starch mixture O At room temperature, 437.5 g of deionized water was mixed with 9.375 g of glycerol and 9.375 g of sorbitol at speed 4 in a Klarstein Grand Chef Edition food processor (KG12-1500-GrandPrix). 43.75 g of tapioca starch was gradually added, and the mixture was stirred for 45 minutes. During this time, the mixer walls were scraped every 10 minutes. The sample was then placed in a high-speed mixer and processed under vacuum at 1500 rpm for 3 minutes.

[0264] (xvi) Preparation of alginate mixture P 171.47 g of deionized water, 1.39 g of oleic acid, and 0.685 g of polysorbate 80 were added to a plastic container. The mixture was treated with a Bandelin acoustic treatment instrument at 50% for 5 minutes to produce a homogenized emulsion. The mixture was then added to a Klarstein GrandChef Edition food processor (KG12-1500-GrandPrix) and mixed at speed 4, while simultaneously adding 257.205 g of deionized water, 12.12 g of glycerol, and 12.12 g of sorbitol. After homogenization, 45.01 g of alginate was added, and the food processor was set to speed 4 at 85°C for 60 minutes. The mixer walls were scraped every 10 minutes. After combining, the sample was placed in a high-speed mixer and treated under vacuum at 2000 rpm for 3 minutes. 95 g of deionized water was added to 200 g of the prepared alginate formulation, and then mixed under vacuum at 1500 rpm for 3 minutes.

[0265] The composition of each coating mixture is shown in Table 1. Table 1 The dispersion particle size distribution of the first mixture was measured using the method described herein. For Example A, d50 was 49.4 μm; for Example B, it was 13.5 μm; for Example E, it was 6.3 μm; and for Example F, it was 13.0 μm.

[0266] The viscosity of the first mixture was measured using the method described herein. For Example B, the viscosities before and after Silverson were 473 MPa and 225 MPa, respectively, and for Example F, the viscosities before and after Silverson were 436 MPa and 188 MPa, respectively.

[0267] Example 2: Coating of Paper Cards The first and second coating mixtures provided in Tables 2a-f are applied to the paper card using the two-step method described below. The choice of Kbar determines the wet thickness of each coating.

[0268] (i) Preparation of the first coating The samples were prepared by firmly attaching paper cards to a glass slide to reduce wrinkling. 50 g of the first coating mixture was rapidly mixed under vacuum at 1500-2000 RPM for 3 to 2 minutes for shearing and degassing. Approximately 5 ml of each A5 card was then aspirated to one end of the sample, and the sample was coated with the desired thickness according to the table below using a suitable Kbar from RK Print Coat Instruments in a continuous and smooth motion; any excess was spread off from the end of the sample. The sample was then placed in a preheated 120°C oven for 10 minutes until dry.

[0269] The thickness of the dry coating depends on the solids content of the coating mixture.

[0270] (ii) Preparation of the second coating After the first coating has dried, allow the sample to cool to ambient temperature. If the sample wrinkles during the first coating, reattach it to the slide as smoothly as possible. Then, rapidly mix 50 g of the second coating mixture under vacuum at 1500-2000 RPM for 3 to 2 minutes to shear and degas. Then, pipette approximately 5 ml onto one end of each A5 card and, using a suitable Kbar from RK Print Coat Instruments, coat the sample with a continuous and smooth motion to the desired thickness as shown in the table above, spreading any excess material from the end of the sample. Then, place the sample in a preheated 120°C oven for 10 minutes until dry.

[0271] The paper samples were then tested according to the Kit method and Cobb 60 test described herein, and the results are shown in Tables 2a to 2f. Table 2a: Examples of comparative single-layer coatings In Example I, an uncoated paper sample was tested and found to have very poor oil resistance, with a Kit test value of 0, and it absorbed some water with a Cobb 60 value of 17.8.

[0272] In Example II and Example II *In this study, paper samples were coated with single coatings of mixtures B and M of pea protein and organic acids, respectively, according to the methods described herein, and were found to have moderate to poor oil resistance, with Kit test values ​​of 9 and 8, respectively. Without being bound by theory, it is believed that the partial unfolding of the plant-based protein due to the addition of pea protein to an aqueous organic acid solution and subsequent heating and shearing exposes hydrophobic amino acids initially embedded in the protein's native structure. Once partially unfolded, the organic acid more readily protonates the amino acid residues, enabling the formation of anionic salt bridges with stable hydrophobic interactions. Furthermore, protein-protein non-covalent molecular contacts are disrupted upon heating at elevated temperatures. Additionally, the application of mechanical stirring (e.g., sonication) is believed to break down large colloidal protein aggregates into smaller aggregates and disrupt intermolecular protein interactions. Furthermore, it is believed that cooling the protein mixture facilitates protein-protein non-covalent molecular contacts, thereby promoting the self-assembly of plant-based protein molecules into interconnected protein aggregates. Drying the colloidal suspension of pea protein aggregates on a cellulose substrate results in the formation of a dense protein coating with acceptable oil resistance. However, the coating exhibits very poor water resistance, with Cobb 60 test values ​​of 42.2 and 31.5, respectively, worse than the uncoated paper sample. To avoid being bound by theory, it is assumed that water is retained in the coating due to the hydrophilic nature of the globulin, resulting in the higher Cobb test values.

[0273] In Example III, a paper sample was coated with a single layer of a mixture C of pea protein and inorganic acid, following the method described herein, and was found to have very poor oil resistance, with a Kit test value of 0. Not wanting to be bound by theory, it is assumed that when pea protein is added to an aqueous solution of inorganic acid and subjected to heating and shearing, the plant-based protein does not fully unfold, resulting in a colloidal suspension of pea protein particles with a lower degree of protein-protein non-covalent intermolecular interactions compared to mixtures B and M. After drying, the colloidal suspension of pea protein particles forms an incompletely homogeneous coating, thus allowing oil penetration. Furthermore, the coating exhibits very poor water resistance, with a Cobb 60 test value of 35.5, worse than the uncoated paper sample.

[0274] In Example IV, a paper sample was coated with a single layer of a mixture H of zein, ethanol, and water according to the method described herein, and it was found to still exhibit very poor oil resistance, with a Kit test value of 0. Furthermore, the coating was found to have very poor water resistance, with a Cobb 60 test value of 45.4, similar to Example II, and worse than the uncoated sample. It is not desirable to be bound by theory; it is assumed that the zein-ethanol solution penetrates the paper very rapidly and cannot form a uniform and defect-free coating.

[0275] In Example V, a paper sample was coated with a single layer of a mixture G of pea protein, organic acid, and zein, according to the method described herein, and it was found to have very good oil resistance, with a Kit test value of 12. However, the coating was found to have very poor water resistance, with a Cobb 60 test value of 44.7, similar to Example II. Not wanting to be bound by theory, it is assumed that this low level of zein slightly enhances the oil barrier properties of Example II, but it is insufficient to alter the hydrophilic properties of pea protein, resulting in the high Cobb test value.

[0276] In Example CC, a paper sample was coated with a single layer of a mixture of starch and plasticizer O according to the method described herein, and it was found to have poor oil resistance, with a Kit test value of 8. The coating was also found to have very poor water resistance, with a Cobb 60 test value of 46.0. Not wanting to be bound by theory, it is assumed that the hydrophilic nature of starch leads to the very high Cobb test value.

[0277] In Example DD, a paper sample was coated with a single layer of alginate and plasticizer mixture P according to the method described herein, and it was found to have poor oil resistance, with a Kit test value of 9. The coating was also found to have very poor water resistance, with a Cobb 60 test value of 47.0. Not wanting to be bound by theory, it is assumed that the hydrophilic nature of alginate leads to the very high Cobb test value.

[0278] Therefore, it can be seen that a single coating cannot provide the oil and water barrier properties required for multifunctional coated paper. Table 2b: Examples of Comparative Double Coatings In Examples VI, VII, and VIII, paper samples were coated with two coatings according to the method described herein: a first coating of pea protein from mixture A, B, or C, and a second coating of zein-based mixture H. All of these coated paper samples exhibited very good oil resistance, with a Kit test value of 12. Furthermore, Example VI showed good water resistance, with a Cobb 60 test value of 8.3, lower than the uncoated paper; however, a relatively thick coating, calculated to be approximately 15 micrometers, was required to achieve this. Examples VII and VIII exhibited moderate water resistance, with Example VII at 20, similar to the uncoated paper, and Example VIII at 15.3, slightly better than the uncoated paper. Both of these had relatively thick coatings, calculated to be approximately 15 to 16 micrometers.

[0279] In Example IX, a paper sample was coated with two coatings according to the method described herein: a first coating of soy protein and organic acid mixture D and a second coating of zein-based coating mixture H. The coated paper sample (calculated to have a total thickness of approximately 15 micrometers) exhibited moderate oil resistance, with a Kit test value of 10. Additionally, the coated paper was found to have moderate water resistance, with a Cobb 60 test value of 20.7, similar to the uncoated paper sample.

[0280] In contrast, in Example X, the coatings were applied in the reverse order: a first coating of zein blend H, followed by a second coating of pea protein blend B. Oil resistance was poor, with a Kit test grade of 8, lower than in Example VII; similarly, water resistance was poor, with a Cobb test grade of 41.8, significantly lower than in Example VII. This demonstrates that applying the coating blends in the reverse order specified in this method does not lead to improved performance. Without being bound by theory, it is assumed that the first blend containing non-zein biopolymers achieves good oil resistance and provides a surface suitable for the good spreading of the second blend of plant-based zein. Table 2c: Comparative examples using a double-layer thin coating. Cobb 60 tests were performed in triplicate. In Example XI, following the method described herein, a paper sample was coated with a first coating of a thinner mixture of pea protein B and a second coating of a zein mixture H. The coated paper sample exhibited very good oil resistance, with a Kit test value of 11.5. However, the coating only showed moderate water resistance, with a Cobb 60 test value of 15.4, only slightly better than the uncoated paper.

[0281] In Example XII, following the method described herein, paper samples were also coated with thinner coatings of two mixtures: a thin coating of pea protein mixture B and a second thin coating of zein mixture H. The coated paper samples exhibited only moderate oil resistance, with a Kit test value of 9. Water resistance decreased, with a Cobb 60 test value of 24.8, slightly higher than the uncoated paper.

[0282] This demonstrates that it is impossible to achieve both very good oil and water resistance with a thin coating in which the zein mixture does not contain fatty acids (such as oleic acid). Table 2d: Examples of comparative double-layer coatings containing plasticizers In Examples XIII and XIV, paper samples were coated with a first coating of a pea protein mixture E also containing glycerol and a second coating of a zein mixture H, according to the method described herein. The coated paper sample XIII exhibited very good oil resistance (Kit test value 12) and good water resistance (Cobb 60 test value 6.4), with a calculated thickness of 15 micrometers. Barrier properties deteriorated when the coating thickness decreased to 8 micrometers; therefore, in Example XIV, the Kit test value decreased slightly to 11, while the Cobb 60 test value increased to 15.3.

[0283] In Examples XV and ZZ, another paper sample was coated with a first coating of pea protein mixture F or M and a second coating of zein mixture I, which also contains glycerol, according to the method described herein. The coated paper samples all exhibited very good oil resistance (Kit test value 12), but only moderate water resistance, worse than the uncoated paper, with Cobb 60 test values ​​of 23.5 and 18.1, respectively. Table 2e: Examples of double-layer oleic acid coatings In Examples XVI to YY, paper samples were coated with a first coating of pea protein mixtures F and M containing glycerol and a second coating of zein mixtures J, K, and N with different levels of oleic acid, according to the method described herein. The coated paper samples exhibited very good oil resistance, with a Kit test value of 12. The coated paper samples also exhibited moderate to very good water resistance, with Cobb 60 test values ​​ranging from 17.3 to 3.6, which was better than the uncoated paper of Example I. Higher oleic acid levels correlated with greater water resistance.

[0284] Very good water resistance was achieved in Example YY, with Cobb 60 test values ​​significantly lower than those of similar thickness coatings in Examples VI and XIII, which do not contain oleic acid.

[0285] Furthermore, for the coatings of examples YY and ZZ, both have a first coating of mixture M, and example ZZ has a second coating of mixture I containing zein and glycerol, resulting in a very good Kit test value of 12 and a moderate Cobb 60 test value of 18.1, slightly worse than the uncoated paper. In contrast, YY, where the second coating is a mixture N containing zein and oleic acid, produced a very good Kit test value of 12 and a very good Cobb 60 test value of 3.6.

[0286] In Examples AA and BB, paper samples were coated with a first coating of starch mixture O and alginate mixture P, and a second coating of zein mixture N, respectively, according to the method described herein. The coated paper samples exhibited very good oil resistance, with a Kit test value of 12. The coated paper samples also exhibited moderate and good water resistance, with Cobb 60 test values ​​of 14 and 11, respectively.

[0287] Examples XVI, XVII, YY, AA, and BB illustrate how the present invention can provide a coated substrate with good water and oil resistance when combined with a second coating mixture containing gluten and fatty acids for various first coating mixtures.

[0288] Adding fatty acids (such as oleic acid) to a second mixture containing glutenin (such as zein) results in the formation of a coating with good oil and water resistance. Not wanting to be bound by theory, it is assumed that zein and oleic acid are miscible in liquid form in an aqueous ethanol solution. When the coating dries, the resulting strong interaction prevents phase separation. This leads to a uniform oleic acid-plasticized zein coating with improved water barrier properties.

[0289] Adding fatty acids (such as oleic acid) to the second mixture containing zein also resulted in a reduction in the zein level required to achieve the desired performance, while simultaneously increasing the solids content of the second mixture and reducing the ethanol level. This demonstrates that good oil and water resistance is achieved with reduced amounts of undesirable non-aqueous solvents, which reduces evaporation and recycling, and thus lowers associated processing costs. Furthermore, minimizing the zein level minimizes any potential yellowing issues with the coating. Table 2f: Examples of comparative use of double-coated zein solvent In Example XX, a paper sample was coated with a first coating of pea protein mixture F and a second coating of zein mixture M, according to the method described herein. The coated paper sample exhibited very good oil resistance, with a Kit test value of 12, but poor water resistance, with a Cobb 60 test value of 25.0, which was worse than the uncoated paper.

[0290] Comparative Example 4: Use as a food container The uncoated card from Example I was manually cut into 170mm x 170mm squares. Each square was manually folded to form a box shape and stapled at the corners. Figure 1a The box of instance I is displayed.

[0291] Place the test kit on an absorbent paper towel and gently pour approximately 50 ml of vegetable oil into each kit. Initially observe the kits at time zero, and as shown... Figure 1a As shown in the top photo, the oil has begun to seep into and stain the uncoated card in Example I. Place the box at ambient temperature and observe again after 30 minutes. Figure 1a As shown in the middle row of the photographs, the uncoated card in Example I was stained with oil. When the box was removed from the absorbent paper, as can be seen in the bottom row of the photographs, it was observed that the oil had penetrated the uncoated card and reached the absorbent paper underneath.

[0292] Example 5: Effect of shear on the first mixture According to the composition in Table 1, the first mixture A and the first mixture M are prepared and processed by methods with different shear degrees (low, medium and high).

[0293] At ambient temperature, a first mixture A was prepared by mixing 2000 g of reverse osmosis water with 220 g of pea protein isolate in a 3-liter metal beaker until homogeneous using a top-mounted stirrer. The slurry was then mixed for 10 minutes at 7000 RPM using a Silverson mixer at an ambient temperature of approximately 22°C. The slurry was then processed at 100 MPa using a high-pressure homogenizer FPG12805 from Homogenising Systems Ltd., which also resulted in an increase in slurry temperature at the nozzle. The slurry outlet temperature subsequently decreased to approximately 30°C with a cooling of 5°C.

[0294] The first mixture M was prepared according to the method in Example 1 (xiii).

[0295] In both cases, after adding all materials and mixing with a top-mounted agitator, take the first "low-shear" sample. After mixing with a Silverson mixer, take the second "medium-shear" sample. After passing through a high-pressure homogenizer, take the third "high-shear" sample.

[0296] The viscosity and particle size distribution of protein aggregates in the slurry samples were measured according to the method described in this paper, and are shown in Table 3: Table 3 Medium shear significantly reduces slurry viscosity. High pressure does not further reduce viscosity. Lower slurry viscosity is advantageous because it makes pumping and spraying easier and reduces energy consumption.

[0297] Increasing the shear level exposed to the slurry reduces the average particle size of the protein aggregates. This is advantageous because it allows for easier suspension of the protein aggregates and more uniform coating of the substrate. The combination of organic acids in the formulation with high shear results in the smallest average particle size of the protein aggregates. As demonstrated in comparison to Example A(i), for the same level of shear, increased heat also leads to a reduction in average particle size.

[0298] The slurries were placed in glass bottles and stored in a refrigerator at 5°C overnight, and observed in the morning. The first mixture A treated with low or medium shear showed obvious separation, while the first mixture A treated with high shear appeared homogeneous. The first mixture M treated with low shear showed obvious separation, while the first mixture M treated with medium or high shear appeared homogeneous. Figure 2a The first mixture A, treated with moderate shear, shows clear separation. Figure 2b The first mixture M treated with high shear is shown to be homogeneous.

[0299] The degree of separation was quantified by stirring the sample with a top stirrer for 15 minutes, and then centrifuging 40 ml of the sample in a 50 ml Flacon tube at 5000 rpm for 2 minutes, and observing how much clear supernatant was formed.

[0300] For mixture A, 22 ml of supernatant was obtained after low-shear treatment. 27 ml of supernatant was obtained after medium-shear treatment. No clear supernatant was obtained after high-shear treatment.

[0301] For the first mixture M, 24 ml of supernatant was obtained after low and medium shear treatment. No clear supernatant was obtained after high shear treatment.

[0302] This demonstrates that increased shear (especially high-pressure homogenization) results in a more physically stable slurry, and therefore easier to process. If left to stand before the coating process, it exhibits a lower tendency to separate and thus requires no additional treatment to resuspend it as a homogeneous mixture.

[0303] Example 6: Large-scale plate coating Preparation of PPI mixture M 8.3647 kg of water was added to a 10-liter tank. 10 g of sodium benzoate was added while stirring with a top-mounted agitator and mixed until dissolved. 990 g of pea protein isolate was gradually added. Once visually dispersed, 635.3 g of lactic acid (85% solids) was added and mixed to form a slurry. The homogenized slurry was then transferred to a pressurized feed vessel where it was continuously stirred. The slurry was then high-pressure homogenized at 250 MPa and 75 liters per hour using an FPG7575 from Homogenising Systems Ltd., and cooled at 5°C at the outlet to form a stable dispersion. Inlet temperature readings were 17°C to 21°C, temperature readings at the homogenizing nozzle were 74°C to 81°C, and outlet temperature readings after cooling the coil were 19°C to 20°C.

[0304] Preparation of zein mixture N At ambient temperature, using a top-mounted agitator, 1.04 kg of reverse osmosis water, 4.16 kg of ethanol, and 1.3 kg of oleic acid (90% pure) were mixed in a 10-liter tank under extraction conditions until homogeneous. Then, 1.3 kg of zein was gradually added under stirring and mixed until homogeneous. The resulting slurry was then mixed for 10 minutes at 7000 RPM under moderate shear conditions using a Silverson mixer.

[0305] Coating Brown natural kraft paper (a type of multi-layer kraft paperboard) is coated with PPI mixture M at a linear speed of 30 meters per second using a reverse gravure process and dried in an oven set to 110°C to 120°C. The dried coated paper is then coated with an outer layer of zein mixture N using the same reverse gravure process and dried in a similar manner.

[0306] The resulting coated board has a coating weight of 4 gsm, a Cobb 60 test value of 10.5 and a Kit test value of 12, indicating that the board has good oil and water resistance and is suitable for use in the preparation of packaging articles such as boxes for food service applications.

[0307] Test specimens, 25 mm wide, were cut to dimensions provided in ASTM F88 / F88M-15 and acclimatized 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) on a Tinnius Olsen tensile testing machine. A sealing temperature of 130°C, a residence time of 1 second, and a pressure of 4 bar were used. The maximum force encountered when each specimen was stressed to failure was reported as 92.4 N / m; paper failure indicates that the seal is stronger than the substrate material itself.

[0308] The uncoated cards from Example 6 (with a first coating of first mixture F and a second coating of second mixture N) were manually cut into 170 mm × 170 mm squares. Each square was manually folded to form a box shape and stapled at the corners. The test boxes were placed on absorbent paper towels, and approximately 50 ml of vegetable oil was gently poured into each box. The boxes were initially observed at time zero, and as shown... Figure 1b As shown in the image above, the box in Example 6 was unaffected by the presence of oil. The box was placed at ambient temperature and observed again after 30 minutes. Figure 1b As shown in the middle photo, the box remained unchanged. After 30 minutes, the coated card box of Example 6 showed only a very small amount of oil stains at the creases where the cards were folded, such as... Figure 1b As shown in the photo below.

Claims

1. A method for coating a substrate, the method comprising the following steps: a. To prepare a first mixture comprising one or more liquids and one or more biodegradable polymers; b. Prepare a second mixture comprising one or more liquids, one or more plant-based glutenins, and one or more fatty acids; c. Applying the first mixture to at least a portion of at least a first surface of a substrate to produce a first coating; d. Optionally, dry the first coating; e. Apply the second mixture onto at least a portion of the first coating to create a second coating; f. Dry the first coating and / or the second coating.

2. The method according to claim 1, wherein the substrate comprises a fiber-based material.

3. The method according to claim 2, wherein the material is a cellulose material.

4. The method according to claim 2 or claim 3, wherein the material is selected from wood, wood pulp, cotton fiber, hemp fiber, jute fiber, sisal fiber, flax fiber, cellulose-based fiber, silica-based fiber, fruits, vegetables and seeds.

5. The method according to any one of claims 1 to 4, wherein the substrate is selected from paper, paperboard, corrugated paperboard.

6. The method according to any one of claims 1 to 5, wherein one or more liquids in the first mixture is water.

7. The method according to any one of claims 1 to 6, wherein one or more liquids in the second mixture is an alcohol.

8. The method according to any one of claims 1 to 7, wherein the first mixture comprises 5% or more by weight of one or more of the biodegradable polymers.

9. The method according to any one of claims 1 to 8, wherein the first mixture comprises one or more biodegradable polymers selected from plant-derived polysaccharides, algae-derived polysaccharides, fungal-derived polysaccharides, microbial-derived polysaccharides and naturally derived polymers, preferably wherein the first mixture comprises one or more biodegradable polymers selected from starch, alginate, cellulose and lignin.

10. The method according to any one of claims 1 to 8, wherein the first mixture comprises one or more proteins; preferably, wherein the first mixture comprises one or more plant-based globulins; more preferably, wherein the first mixture comprises one or more plant-based globulins selected from soybean protein, pea protein, rice protein, potato protein, rapeseed protein, sunflower protein, lentil protein, chickpea protein, common bean protein, broad bean protein, mung bean protein, sunflower seed protein, pumpkin seed protein, flaxseed protein, chia protein, canola protein, lupin protein, alfalfa protein, moringa protein, borage protein, hemp seed protein, and cottonseed protein, preferably selected from pea protein, potato protein, rapeseed protein, and / or sunflower protein; most preferably, wherein the first mixture comprises pea protein.

11. The method according to any one of claims 1 to 10, wherein the first mixture further comprises one or more plant-based albumins.

12. The method according to any one of claims 1 to 11, wherein the second mixture comprises 5% or more by weight of one or more plant-based glutenins.

13. The method according to any one of claims 1 to 12, wherein the second mixture comprises one or more proteins selected from gliadin, barley gliadin, rye gliadin, zein, sorghum gliadin, and oat protein.

14. The method according to any one of claims 1 to 13, wherein the second mixture comprises zein.

15. The method according to any one of claims 1 to 14, wherein the second mixture further comprises one or more plant-based glutenins.

16. The method according to any one of claims 1 to 15, wherein the first mixture further comprises one or more plasticizers selected from glycerol, polyethylene glycol, propylene glycol, sorbitol, mannitol, xylitol, triethyl citrate, monoglyceride, diglyceride, triglyceride, glucose, glucose, mannose, fructose, sucrose, urea, lecithin, waxes, and amino acids.

17. The method of claim 16, wherein the first mixture comprises glycerol.

18. The method according to any one of claims 1 to 17, wherein the first mixture further comprises one or more organic acids selected from acetic acid, lactic acid, citric acid, malic acid, maleic acid, glycolic acid, gluconic acid, tartaric acid, β-hydroxypropionic acid, β-hydroxybutyric acid, β-hydroxyβ-methylbutyric acid, 2-hydroxybenzoic acid, and carnitine.

19. The method of claim 18, wherein the first mixture comprises acetic acid and / or lactic acid; preferably, wherein the first mixture comprises lactic acid.

20. The method according to any one of claims 1 to 19, wherein the second mixture further comprises one or more plasticizers selected from glycerol, polyethylene glycol, propylene glycol, sorbitol, mannitol, xylitol, triethyl citrate, monoglyceride, diglyceride, triglyceride, glucose, glucose, mannose, fructose, sucrose, urea, lecithin, waxes, and amino acids.

21. The method of claim 20, wherein the second mixture comprises glycerol and / or oleic acid.

22. The method according to any one of claims 1 to 21, wherein the second mixture further comprises one or more organic acids selected from acetic acid, lactic acid, citric acid, malic acid, maleic acid, glycolic acid, gluconic acid, tartaric acid, β-hydroxypropionic acid, β-hydroxybutyric acid, β-hydroxyβ-methylbutyric acid, 2-hydroxybenzoic acid, and carnitine.

23. The method according to any one of claims 1 to 22, wherein the first mixture is prepared by applying high shear using a high-pressure homogenizer or a acoustic processor.

24. The method according to any one of claims 1 to 23, wherein the application of the first mixture and / or the second mixture to the material is achieved by roller coating, drum coating, spin coating, dip coating, slot coating, air knife coating, spraying, fluidized bed coating or extrusion.

25. The method according to any one of claims 1 to 24, wherein the drying of the first coating and / or the second coating is achieved by non-contact drying, preferably by using a fan.

26. The method of claim 25, wherein when the substrate is paper or paperboard, the drying of the first coating and / or the second coating is achieved by exposing the substrate to an elevated temperature for a period of 10 seconds or less, more preferably 5 seconds or less, and most preferably 2 seconds or less.

27. A coated material obtained by the method of any one of claims 1 to 26.

28. The coated material of claim 27, wherein the average thickness of the first coating is 1 to 20 micrometers.

29. The coated material according to claim 27 or claim 28, wherein the average weight of the first coating is 0.1 to 20 g / m³. 2 .

30. The coated material according to any one of claims 27 to 29, wherein the average thickness of the second coating is 1 to 20 micrometers.

31. The coated material according to any one of claims 27 to 30, wherein the average weight of the second coating is 0.1 to 20 g / m³. 2 .

32. The coated material according to any one of claims 27 to 31, wherein the percentage of coating biodegradation based on O2 consumption after 28 days is 70% to 100% as measured according to ISO-14851, or wherein the percentage of coating biodegradation based on CO2 generation after 28 days is 70% to 100% as measured according to ISO-14851.

33. The coated material according to any one of claims 27 to 32, wherein the coated material is composed of food-grade ingredients.

34. A coated material comprising a first coating on at least a portion of at least a first surface of a substrate and a second coating on at least a portion of the first coating, the first coating comprising one or more biodegradable polymers and the second coating comprising one or more plant-based glutenin.

35. A kit for coating a substrate, the kit comprising: a. A first mixture comprising one or more liquids and one or more biodegradable polymers; b. A second mixture comprising one or more liquids, one or more plant-based glutenin and one or more fatty acids.

36. The kit for coating a substrate according to claim 35, wherein the first mixture comprises 5% or more by weight of one or more of the biodegradable polymers.

37. The kit for coating a substrate according to claim 35 or claim 36, wherein the first mixture comprises one or more biodegradable polymers selected from plant-derived polysaccharides, algae-derived polysaccharides, fungal-derived polysaccharides, microbial-derived polysaccharides, and naturally derived polymers, preferably wherein the first mixture comprises one or more biodegradable polymers selected from starch, alginate, cellulose, and lignin.

38. The kit for coating a substrate according to claim 35 or claim 36, wherein the first mixture comprises one or more proteins; preferably, wherein the first mixture comprises one or more plant-based globulins; more preferably, wherein the first mixture comprises one or more plant-based globulins selected from soybean protein, pea protein, rice protein, potato protein, rapeseed protein, sunflower protein, lentil protein, chickpea protein, common bean protein, broad bean protein, mung bean protein, sunflower seed protein, pumpkin seed protein, flaxseed protein, chia protein, canola protein, lupin protein, alfalfa protein, moringa protein, borage protein, hemp seed protein, and cottonseed protein, preferably selected from pea protein, potato protein, rapeseed protein, and / or sunflower protein; most preferably, wherein the first mixture comprises pea protein.

39. The kit for coating a substrate according to any one of claims 35 to 38, wherein the first mixture further comprises one or more plant-based albumins.

40. The kit for coating a substrate according to any one of claims 35 to 39, wherein the second mixture comprises 5% or more by weight of one or more plant-based glutenins.

41. The kit for coating a substrate according to any one of claims 35 to 40, wherein the second mixture comprises one or more proteins selected from gliadin, barley gliadin, rye gliadin, zein, sorghum gliadin, and oat protein.

42. The kit for coating a substrate according to any one of claims 35 to 41, wherein the second mixture comprises zein.

43. The kit for coating a substrate according to any one of claims 35 to 42, wherein the second mixture further comprises one or more plant-based glutenins.

44. The kit for coating a substrate according to any one of claims 35 to 43, wherein the first mixture further comprises one or more plasticizers selected from glycerol, polyethylene glycol, propylene glycol, sorbitol, mannitol, xylitol, triethyl citrate, monoglyceride, diglyceride, triglyceride, glucose, glucose, mannose, fructose, sucrose, urea, lecithin, waxes, and amino acids.

45. The kit for coating a substrate according to claim 44, wherein the first mixture comprises glycerol.

46. ​​The kit for coating a substrate according to any one of claims 35 to 45, wherein the first mixture further comprises one or more organic acids selected from acetic acid, lactic acid, citric acid, malic acid, maleic acid, glycolic acid, gluconic acid, tartaric acid, β-hydroxypropionic acid, β-hydroxybutyric acid, β-hydroxyβ-methylbutyric acid, 2-hydroxybenzoic acid, and carnitine.

47. The kit for coating a substrate according to claim 46, wherein the first mixture comprises acetic acid and / or lactic acid.

48. The kit for coating a substrate according to any one of claims 35 to 47, wherein the second mixture further comprises one or more plasticizers selected from glycerol, polyethylene glycol, propylene glycol, sorbitol, mannitol, xylitol, triethyl citrate, monoglyceride, diglyceride, triglyceride, glucose, glucose, mannose, fructose, sucrose, urea, lecithin, waxes, and amino acids.

49. The kit for coating a substrate according to claim 48, wherein the second mixture comprises glycerol and / or oleic acid.

50. The kit for coating a substrate according to any one of claims 35 to 49, wherein the second mixture further comprises one or more organic acids selected from acetic acid, lactic acid, citric acid, malic acid, maleic acid, glycolic acid, gluconic acid, tartaric acid, β-hydroxypropionic acid, β-hydroxybutyric acid, β-hydroxyβ-methylbutyric acid, 2-hydroxybenzoic acid, and carnitine.

51. The kit for coating a substrate according to any one of claims 35 to 50, wherein one or more liquids in the first mixture is water.

52. The kit for coating a substrate according to any one of claims 35 to 51, wherein one or more liquids in the second mixture is an alcohol.

53. Use of the coated substrate according to any one of claims 27 to 34 for manufacturing articles, said articles being selected from plates, cups, containers, boxes, cartons, corrugated boxes, packaging materials, and bags.

54. The use according to claim 53, wherein the article is self-heat-sealed.

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