Method for producing water resistant films from corn gluten meal

Abstract

The present invention relates mainly to a method for producing a plastic material, the method comprising the steps of: (i) providing a corn gluten source and a first liquid phase comprising an organic solvent; (ii) extracting solvent-soluble components of the corn gluten source into the first liquid phase; (iii) precipitating a first portion of the solvent-soluble components from the first liquid phase, resulting in a second solid phase comprising the first portion of the solvent-soluble components and a second liquid phase comprising a second portion of the solvent-soluble components; (iv) separating the second solid phase and the second liquid phase, and (v) recovering a flexible plastic material from the second liquid phase or a hard plastic material from the second solid phase.

Description

Technical Field

[0001] This invention relates to the field of biopolymers, and more particularly to bio-based and biodegradable plastics. More specifically, this invention relates to a method for producing plastic materials from corn gluten. Background Technology

[0002] Most plastics today are made from fossil raw materials and are non-biodegradable. The environmental problems caused by plastic pollution are well known. The reason why conventional plastics and many bioplastics lack biodegradability is that they are synthesized from monomers. Microorganisms in the environment have only a limited ability to break down these synthetic polymer chains. Another alternative is to use polymers that already exist in nature, such as starch, cellulose, lignin, or proteins, which are easily degraded by natural microorganisms.

[0003] To avoid conflicts with food, these natural polymers should also be obtained from second-generation biomass, such as agricultural residues. One example of such residue is corn gluten meal, a byproduct of starch production obtained through wet milling of corn. Wet milling of corn is a two-stage process involving soaking to soften corn kernels and wet milling to produce pure starch and corn gluten meal. Currently, corn gluten meal is used as animal feed. However, due to its limited content of essential amino acids, corn gluten meal, also known as corn gliadin, has poor nutritional quality. Alternatively, corn gluten meal can be used as a raw material for producing bio-based, biodegradable, and waterproof films, serving as a substitute for traditional plastic films.

[0004] The film-forming properties of zein are well-known in the literature. Zein is the prolysin moiety of corn protein and is soluble in aqueous ethanol. Zein molecules have a hydrophobic surface, thus exhibiting good intermolecular interactions, while also being hydrophobic. Therefore, they hold great potential for materials applications.

[0005] A method for producing purified and dried zein powder from corn is disclosed in WO2016 / 154441(A1) and EP0648078B1. The process is based on multiple extraction steps using 75% to 100% ethanol, followed by solid-liquid separation and liquid-phase drying. Purification aims to remove all fatty acids and pigments. Although purified zein is relatively expensive due to its wide range of market prices, it is commercially available.

[0006] Standard methods for preparing films, resins, or coatings from purified zein are known from US663,520,6B1, CN101024725 B, US 5,585,060 A, US 5,324,351 A, US 2,285,758 A, CN 104397828B, CN1302550A, or CN 103382255B. All these methods share a common concept: mixing dry zein powder with aqueous ethanol and fatty acids (primarily oleic acid). The latter is necessary because purified zein is very brittle, and a plasticizer must be added to form a flexible film or resin. The mixture is then poured into cold water to precipitate a moldable resin or vacuum-dry it at a moderate temperature to form a film.

[0007] One drawback of known methods is their economic infeasibility. They either rely on food crops such as corn or on purified zein as a raw material. Food crops are valuable resources, and purified zein is expensive. Furthermore, known methods rely on adding fatty acids as plasticizers, which again increases the cost of producing plastics from or through zein. For these reasons, until today, there are no film products on the market made from corn, zein, or corn gluten as alternatives to plastics. Summary of the Invention

[0008] The main problem this invention aims to solve is a method for producing plastic materials that at least partially overcomes the aforementioned drawbacks. In particular, the object is to provide a simple method for producing biological-based and biodegradable plastics that is economically feasible, especially inexpensive and operable on a large scale.

[0009] This problem is solved by the subject matter of claim 1. Other aspects and preferred embodiments of the invention are derived from the following description, the appended embodiments, and in particular the other appended patent claims.

[0010] According to a first aspect of the present invention, a method for producing a plastic material includes the following steps:

[0011] (i) providing a first solid phase comprising a source of corn gluten and a first liquid phase comprising an organic solvent;

[0012] (ii) Extracting the solvent-soluble component of the corn gluten from the first solid phase into the first liquid phase;

[0013] (iii) Precipitating the first liquid phase to provide a second solid phase and a second liquid phase, the second solid phase comprising a portion of the solvent-soluble component, the second liquid phase depleting said portion of the solvent-soluble component; and

[0014] (iv) Separate the second solid phase and the second liquid phase.

[0015] (v) Recovering flexible plastic materials from the second liquid phase or recovering hard plastic materials from the second solid phase.

[0016] This invention is based on the inventor's innovation that allows for the formation of plastic materials with different physicochemical properties from a single, inexpensive biological waste product using simple process steps. Therefore, this invention reflects a comprehensive method for producing various plastic materials. The plastic materials obtained through this process possess desired properties. In particular, the flexible plastic material exhibits physicochemical and mechanical properties that make it especially suitable for use as a flexible plastic film in packaging or as a coating. The rigid plastic material produced by this method can be used for packaging or single-use products such as trays, cups, straws, cutlery, etc.

[0017] Another advantage of this invention is that it can produce entirely biological and biodegradable plastic materials. These plastic materials can be entirely based on corn gluten sources. This means that the corn gluten source contains all the components required to produce the plastic material having the advantageous properties described herein. Therefore, it is generally unnecessary to add external components, i.e., components not derived from corn gluten sources.

[0018] Therefore, another advantage of the present invention includes the ability to obtain plastic materials with desired properties without the need for adding external plasticizers. Thus, in some embodiments of the invention, the amount of external plasticizer contained in the produced plastic material is less than 5% (w / w), preferably less than 2% (w / w), more preferably less than 1% (w / w), more preferably less than 0.5% (w / w), and most preferably less than 0.1% (w / w), relative to the total weight of the plastic material. However, this should not be construed as excluding the possibility of adjusting or fine-tuning the properties by adding external plasticizers or other components in other embodiments of the invention.

[0019] Other aspects, embodiments, and advantages of the invention will become apparent from the following detailed description, embodiments, drawings, and claims, which follow a brief description of the drawings. Attached Figure Description

[0020] In the attached diagram:

[0021] Figure 1 A method according to a preferred embodiment of the present invention is shown.

[0022] Figure 2 It shows the way Figure 1 A photograph of the flexible membrane obtained by the method shown.

[0023] Figure 3 A method of the prior art is shown.

[0024] Figure 4 Another prior art method is shown.

[0025] Figure 5 It shows the way Figure 4 A photograph of the plastic film obtained by the method described.

[0026] Figure 6 A method according to another preferred embodiment of the present invention is shown.

[0027] Figure 7 A process scheme for an integrated method for producing different plastics according to another preferred embodiment of the present invention is shown. Detailed Implementation

[0028] The method according to the present invention produces a plastic material with good physicochemical and mechanical properties from corn gluten. As understood herein, a plastic material refers to a material comprising all the components required to form a (flexible) plastic film, (flexible) plastic coating, or (rigid) plastic article. In some embodiments, all components of the plastic material are derived from corn gluten and no external components are added. In some embodiments, the plastic material also includes external components.

[0029] The term "flexible plastic material" refers to a plastic material that can be used as a flexible film or coating. Conversely, the term "rigid plastic material" refers to a plastic material that can be made into rigid plastic articles.

[0030] The first solid phase comprises a corn gluten source. The corn gluten source, as defined herein, is a source comprising corn gluten. In a preferred embodiment of the invention, the corn gluten source is a corn gluten slurry. The term "corn gluten slurry" as understood herein refers to wet corn gluten. Wet corn gluten can be obtained when corn is used for starch extraction. When dried and optionally milled, wet corn gluten produces corn gluten powder. Therefore, corn gluten slurry is a common byproduct of wet corn starch production. It is further envisioned that the corn gluten slurry be treated prior to extraction. For example, a preferred corn gluten source is a corn gluten slurry that has been dried and optionally milled prior to extraction.

[0031] The first liquid phase includes an organic solvent. More specifically, the first liquid phase includes at least one organic solvent. It may include a mixture of two or more organic solvents, or a mixture of at least one organic solvent and an aqueous solvent such as water. The amount and type of the organic solvent, and optionally the amount and type of the aqueous solvent, are selected such that the resulting component (i.e., the first liquid phase) can be used as an extraction solvent for certain components of the corn gluten source (referred to herein as solvent-soluble components).

[0032] The main purpose of extracting solvent-soluble components is to obtain a liquid phase (referred to here as the first liquid phase) that is rich in plastic-forming components, especially corn gluten protein and lipids, while being poor in carbohydrates, lignin and minerals.

[0033] Therefore, the first liquid phase is preferably selected based on its ability to dissolve corn gluten proteins, especially corn gliadin, and corn gluten lipids, especially corn gluten fatty acids. More preferably, the first liquid phase does not dissolve carbohydrates, lignin, and minerals to a large extent.

[0034] In a preferred embodiment, the organic solvent included in the first liquid phase is selected from aprotic polar organic solvents, protic organic solvents, and mixtures thereof. Preferably, the organic solvent is selected from the group consisting of alcohols, ketones, and mixtures thereof. More preferably, the organic solvent is selected from monovalent alcohols containing 1 to 6, 1 to 5, 1 to 4, or 1 to 3 carbon atoms, and mixtures thereof. Most preferably, the organic solvent is selected from ethanol, isopropanol, and mixtures thereof.

[0035] According to one embodiment, the first liquid phase may be an aqueous phase comprising 50% to 90%, preferably 55% to 85%, more preferably 60% to 80%, and most preferably 65% ​​to 75% (v / v) of ethanol. This ensures that the ethanol content is close to an optimal content, which has been determined to be 70% (v / v).

[0036] According to another embodiment, the first liquid phase may be an aqueous phase comprising 40% to 80%, preferably 45% to 75%, more preferably 50% to 70%, and most preferably 55% to 65% (v / v) of isopropanol. An optimal isopropanol content of 60% (v / v) was determined. Therefore, a preferred range was selected that is close to the optimal isopropanol content.

[0037] Regarding other solvents or combinations of solvents useful in the context of this invention, solvents having similar logP values ​​to ethanol and isopropanol, or as a first liquid phase comprising the amounts of ethanol or isopropanol described above, can be considered. Furthermore, as mentioned above, the tendency of a solvent to dissolve desired components while not dissolving undesired components can be considered.

[0038] As described above, solvent-soluble components derived from corn gluten are extracted from a first solid phase into a first liquid phase. The term "solvent-soluble component" refers to one or more components that are soluble in the first liquid phase under the conditions used in the extraction process. These components include corn gluten protein, preferably zein, and corn gluten lipids, preferably fatty acids. By simultaneously extracting corn gluten protein and lipids, a flexible plastic material can be produced without adding external fatty acids or other plasticizers to achieve the desired elasticity of the plastic film.

[0039] Extraction can be performed at ambient temperature, for example, about 20°C. In a preferred embodiment of the invention, extraction involves heating and / or mixing. Therefore, the method steps can be accelerated and its yield increased. For example, extraction can be performed at a temperature of at least 25°C, preferably at least 30°C, more preferably at least 40°C, more preferably at least 50°C, and most preferably at least 55°C. Limiting the maximum temperature may be desirable in terms of power consumption. Accordingly, extraction is preferably performed at a temperature of up to 90°C, preferably up to 80°C, more preferably up to 75°C, more preferably up to 70°C, and most preferably up to 65°C.

[0040] There is no particular time limit for extraction, which can usually be between 1 minute or several minutes, such as between 5 minutes and 24 hours.

[0041] Before precipitating the first liquid phase, the first solid phase and the first liquid phase are separated. This can be achieved by solid-liquid separation, preferably by centrifugation, filtration, decantation, precipitation, or a combination thereof, to remove the first solid phase (including undissolved solvent components from corn gluten) from the first liquid phase.

[0042] The subsequent precipitation step aims to adjust the composition, particularly the amount of gluten protein relative to the amount of gluten lipids, so that the plastic material with the desired properties can be recycled. In the recycled plastic material, a higher ratio of gluten lipids to gluten protein results in higher elasticity, and vice versa. Depending on the desired properties, conditions are altered so that the solubility of certain solvent-soluble components exceeds its limit, causing some of these components to precipitate and form a second solid phase. The remaining liquid, the second liquid phase, contains a correspondingly reduced amount of solvent-soluble components.

[0043] According to a preferred embodiment of the invention, precipitation in step (iii) includes cooling the first liquid phase (also referred to herein as cryoprecipitation). As a result of cryoprecipitation, flexible plastic material can be recovered from the second liquid phase. It is believed that cooling results in conditions where a small amount of solvent is soluble in the analyte. Furthermore, these conditions are considered to favor the precipitation of corn gluten protein relative to corn gluten lipids, such that the ratio of corn gluten protein to corn gluten lipids in the second liquid phase is reduced compared to the ratio in the first liquid. In this way, the remaining lipid concentration is relatively high, thereby producing a flexible plastic material.

[0044] Those skilled in the art can readily determine a suitable cooling temperature. Preferably, the cooling causes a temperature drop of at least 5°C in the first liquid phase, more preferably at least 10°C, more preferably at least 15°C, at least 20°C, at least 25°C, at least 30°C, at least 35°C, at least 40°C, and most preferably at least 45°C. Preferably, the cooling causes a temperature drop of 5°C or lower in the first liquid phase, more preferably 0°C or lower, more preferably -10°C or lower, and even more preferably -20°C or lower.

[0045] There is no particular time limit for cold precipitation, which can typically be between a few minutes and a few hours, for example, between 15 minutes and 32 hours.

[0046] In another preferred embodiment of the invention, the precipitation in step (iii) comprises adding an aqueous phase to the first liquid phase (also referred to herein as water precipitation). As a result, the hard plastic material can be recovered from the second solid phase. It is believed that the addition of the aqueous phase results in the precipitation of a considerable amount of solvent-soluble components. Furthermore, the precipitation rates of corn gluten protein and corn gluten lipids are similar, preventing the enrichment of corn gluten lipids in the second solid phase. In this way, the remaining lipid concentration is relatively low, resulting in a hard plastic material.

[0047] The amount of aqueous phase required for water precipitation can be determined through routine experiments. The preferred amount results in a final water concentration of 75% to 95% (v / v). This range is close to the optimal content of 85% (v / v), thus favoring high yields.

[0048] There are no particular restrictions on the temperature during the water sedimentation process; it can be between -5°C and 40°C, preferably 0°C and 30°C, more preferably 5°C and 25°C, and most preferably in the range of 10°C to 20°C.

[0049] Subsequently, the second solid phase and the second liquid phase are separated. This can be achieved through solid-liquid separation, preferably by centrifugation, filtration, decantation, precipitation, or a combination thereof.

[0050] After the separation of the second solid phase and the second liquid phase, flexible plastic materials can be recovered from the second liquid phase, or rigid plastic materials can be recovered from the second solid phase. As mentioned above, if the intention is to produce flexible plastic materials, materials with optimal properties are obtained when cold precipitation is performed as the precipitation step. If the intention is to produce rigid plastic materials, optimal results are obtained when water precipitation is performed as the precipitation step. The plastic materials can then be further processed to produce flexible plastic films, plastic coatings, or rigid plastic articles as disclosed herein.

[0051] Another aspect of the invention relates to a method for manufacturing plastic films, plastic coatings, or rigid plastic articles, the method comprising the steps of providing a plastic material by the methods disclosed herein and forming the plastic material into a plastic film, plastic coating, or rigid plastic article. Plastic films can be obtained by directly casting the plastic material into a film, or by molding the plastic material and rolling the mold into a film. Plastic coatings can be obtained by spraying. Rigid plastic articles can be obtained by molding, extrusion, or extrusion molding.

[0052] On the other hand, it relates to an apparatus for producing plastic materials. The apparatus includes:

[0053] (i) Containers for storing corn gluten and containers for storing organic solvents;

[0054] (ii) An extraction unit for extracting the solvent-soluble components of the corn gluten into a first liquid phase;

[0055] (iii) A precipitation unit for precipitating a first portion of the solvent-soluble component from the first liquid phase to produce a second solid phase including the first portion of the solvent-soluble component and a second liquid phase having the second portion of the solvent-soluble component;

[0056] (iv) A separation unit for separating the second solid phase and the second liquid phase; and

[0057] (v) Optional drying unit for drying a second solid phase or a second liquid phase.

[0058] The various features and embodiments described in the context of the method of the present invention should be understood as defining the corresponding features and embodiments of the apparatus of the present invention, and vice versa.

[0059] Reference Figure 7 The process scheme shown is used to describe further embodiments of the present invention. Figure 7 An integrated method for producing various plastics is shown. The method can begin with a corn gluten slurry as a source of corn gluten. The slurry can then be dried and ground before extraction. The solvent-soluble components of the corn gluten source are extracted into a first liquid phase by combining this corn gluten source with a first liquid comprising an organic solvent. The first liquid phase can then be separated from the solid (here referred to as the first solid phase) by centrifugation. The solid can be removed from the process and used as animal feed, etc. The first liquid phase is then further processed.

[0060] The next step is sedimentation. Depending on whether cold sedimentation or water sedimentation is performed, the subsequent steps may differ.

[0061] Cold precipitation results in the formation of a solid phase (referred to herein as the second solid phase) and a liquid phase (referred to herein as the second liquid phase), with the second liquid phase being recovered to obtain a flexible plastic material. For this purpose, the second solid phase and the second liquid phase can be separated by centrifugation, and the second liquid phase can be used in a spraying technique to obtain a waterproof coating. Alternatively, the second liquid phase can be cast and dried to form a waterproof and weldable flexible plastic film. The organic solvents evaporated during casting can be recovered and added to the extraction step, such as... Figure 7 As shown by the dashed line on the left side of the middle section.

[0062] Water precipitation also leads to the formation of a second solid phase and a second liquid phase; however, the second solid phase is recovered to obtain a rigid plastic material. For this purpose, the second solid phase can be removed from the second liquid phase by filtration, kneading, and drying. The removed second liquid phase can be recovered. Organic solvents can be separated from the water by evaporation and added to the extraction step, such as... Figure 7 As shown by the dashed line on the right. Water can be used in the water sedimentation step.

[0063] The invention will now be explained in more detail through selected embodiments.

[0064] Example 1

[0065] Corn gluten slurry is obtained from a starch production plant. The slurry is prepared from corn by mechanical starch separation.

[0066] The corn gluten slurry was then mixed with ethanol to obtain a final ethanol concentration of 70% (v / v). The mixture was heated to 50°C and then stirred at 50°C for 1 hour. The solids were then removed by centrifugation at 5000 x g for 5 minutes without cooling. The recovered supernatant was cooled to -18°C and then placed at -18°C for 4 hours. The precipitated solids were removed by centrifugation at 5000 x g for 5 minutes at 4°C. The recovered supernatant was poured out in a casting form and dried at room temperature (18°C to 25°C) to form a 100 μm membrane. Figure 1 The method steps involved in Example 1 are shown in the figure.

[0067] The resulting membrane was found to be uniform and flexible. Figure 2 A photograph of the membrane is shown in the image.

[0068] Example 2

[0069] Commercially available zein was dissolved in 70% (v / v) ethanol. Oleic acid was then added to the solution at a concentration of 12% relative to the dry matter content of the mixture. The resulting solution was stirred for 1 hour, then poured out in a casting manner and dried at room temperature to form a 100 μm film. Figure 3 The method steps involved in Example 2 are shown in the figure.

[0070] The resulting membrane was found to be relatively brittle.

[0071] Example 3

[0072] Corn gluten powder was mixed with ethanol to obtain a final ethanol concentration of 70% (v / v). The mixture was heated to 50°C and then stirred at 50°C for 1 hour. The mixture was then centrifuged at 5000 x g for 5 minutes without cooling to remove solids. The supernatant was poured off in a casting form and dried at room temperature to form a 100 μm membrane. Figure 4 The method steps involved in Example 3 are shown in the figure.

[0073] The resulting film was found to be non-uniform and brittle. Figure 5 A photograph of the membrane is shown in the image.

[0074] Example 4

[0075] The method outlined in Example 1 was used for extraction at 25°C instead of 50°C. The resulting membrane was found to be flexible.

[0076] Example 5

[0077] The method outlined in Example 1 was performed using isopropanol at a final concentration of 60% (v / v) instead of ethanol. The resulting membrane was found to be flexible.

[0078] Example 6

[0079] The method outlined in Example 1 was performed using a cooling temperature of 2°C instead of -20°C. The resulting membrane was found to be flexible.

[0080] Example 7

[0081] The method outlined in Example 1 was performed using a membrane drying temperature of 30°C instead of 20°C. The resulting membrane was found to be flexible.

[0082] Example 8

[0083] The method outlined in Example 1 involves an additional drying step of the corn gluten paste at 80°C prior to extraction. The resulting membrane was found to be flexible.

[0084] Example 9

[0085] Two additional experiments were conducted according to the scheme described in Example 1, except that the supernatant in the casting form was dried at 30°C and 40°C, respectively. The results were comparable.

[0086] Example 10

[0087] Another experiment was conducted following the procedure described in Example 1, except that the mixture of corn gluten slurry and ethanol was heated to 60°C instead of 50°C. Higher yields were found. The resulting membranes exhibited comparable performance.

[0088] Example 11

[0089] The membranes obtained in Examples 1 to 8 were subjected to mechanical parameter tests. The test results are summarized in Table 1 below.

[0090] Table 1: Tensile strength and elongation at break of the membranes obtained in Examples 1 to 8.

[0091] Example 1 2 3 4 5 6 7 8 Tensile strength (MPa) 15 0 0 15 13 15 22 5 Elongation at break (%) 2.8 0 0 2.8 2.5 1.5 3.3 40 Uniformity yes yes no yes yes yes yes yes

[0092] Example 12

[0093] Corn gluten slurry was obtained from a starch production plant. The slurry was prepared from corn by mechanical starch separation. The slurry was mixed with ethanol to obtain a final ethanol concentration of 70% (v / v). The mixture was heated to 50°C and then stirred at 50°C for 1 hour. Then, without cooling, it was centrifuged at 5000 x g for 5 minutes to remove solids. The supernatant was poured into cold water at 15°C with a water-to-ethanol volume ratio of 4:1 under stirring. The precipitate was separated from the solvent by filtration (paper filter) and kneaded into a homogeneous substance. This substance was kneaded and injected into a mold to form a stable resin. Figure 6 The method steps involved in Example 12 are shown.

[0094] in conclusion

[0095] A comparison of Examples 1 and 3 shows that the method according to the embodiments of the present invention significantly improves film quality compared to prior art film casting methods. The film obtained by the embodiments has a significantly higher elongation at break and is therefore significantly more flexible, making it more suitable for use as a packaging material. A comparison between Examples 1 and 2 shows that the film quality obtained according to the embodiments of the present invention is even better in terms of elongation at break than films obtained by existing processes based on a mixture of commercially available zein and fatty acids. Furthermore, using corn gluten is much cheaper than using purified zein and fatty acids, thus making the industrial production of plastic packaging economically feasible.

Claims

1. A method for producing plastic materials, the method comprising the following steps: (i) Providing a source of corn gluten and a first liquid phase comprising organic solvents; (ii) Extracting the solvent-soluble components from the corn gluten into the first liquid phase; (iii) Precipitate a first portion of the solvent-soluble component from the first liquid phase to generate a second solid phase comprising the first portion of the solvent-soluble component and a second liquid phase comprising the second portion of the solvent-soluble component; (iv) Separating the second solid phase and the second liquid phase, and (v) Recovering flexible plastic material from the second liquid phase, Its features are, The precipitation process includes cooling the first liquid phase; The cooling results in the temperature of the first liquid phase being 0°C or lower; No external plasticizers were added.

2. The method according to claim 1, Its features are, The solvent-soluble components derived from corn gluten include corn gluten protein and lipids.

3. The method according to claim 1 or 2, in, The cooling causes the temperature of the first liquid phase to drop by at least 5°C.

4. The method according to claim 1 or 2, in, The cooling causes the temperature of the first liquid phase to drop by at least 10°C.

5. The method according to claim 1 or 2, in, The cooling causes the temperature of the first liquid phase to drop by at least 15°C.

6. The method according to claim 1 or 2, in, The cooling causes the temperature of the first liquid phase to drop by at least 20°C.

7. The method according to claim 1 or 2, in, The cooling causes the temperature of the first liquid phase to drop by at least 25°C.

8. The method according to claim 1 or 2, in, The cooling causes the temperature of the first liquid phase to drop by at least 30°C.

9. The method according to claim 1 or 2, in, The cooling causes the temperature of the first liquid phase to drop by at least 35°C.

10. The method according to claim 1 or 2, in, The cooling causes the temperature of the first liquid phase to drop by at least 40°C.

11. The method according to claim 1 or 2, in, The cooling causes the temperature of the first liquid phase to drop by at least 45°C.

12. The method according to claim 1 or 2, in, The cooling results in the temperature of the first liquid phase being -5°C or lower.

13. The method according to claim 1 or 2, in, The cooling results in the temperature of the first liquid phase being -10°C or lower.

14. The method according to claim 1 or 2, in, The cooling results in the temperature of the first liquid phase being -15°C or lower.

15. The method according to claim 1, in, The organic solvent is selected from the group consisting of aprotic polar organic solvents, protic organic solvents, and mixtures thereof.

16. The method according to claim 15, in, The organic solvent is selected from the group consisting of alcohols, ketones and mixtures thereof.

17. The method according to claim 15, in, The organic solvent is selected from the group consisting of monovalent alcohols containing 1 to 6 carbon atoms and mixtures thereof.

18. The method according to claim 15, in, The organic solvent is selected from the group consisting of monovalent alcohols containing 1 to 5 carbon atoms and mixtures thereof.

19. The method according to claim 15, in, The organic solvent is selected from the group consisting of monovalent alcohols containing 1 to 4 carbon atoms and mixtures thereof.

20. The method according to claim 15, in, The organic solvent is selected from the group consisting of monovalent alcohols containing 1 to 3 carbon atoms and mixtures thereof.

21. The method according to claim 1, in, The first liquid phase comprises 50% to 90% (v / v) of ethanol.

22. The method according to claim 21, in, The first liquid phase comprises 55% to 85% (v / v) of ethanol.

23. The method according to claim 21, in, The first liquid phase comprises 60% to 80% (v / v) of ethanol.

24. The method according to claim 21, in, The first liquid phase comprises 65% to 75% (v / v) of ethanol.

25. The method according to claim 1, in, The first liquid phase comprises 40% to 80% (v / v) of isopropanol.

26. The method according to claim 25, in, The first liquid phase comprises 45% to 75% (v / v) of isopropanol.

27. The method according to claim 25, in, The first liquid phase comprises 50% to 70% (v / v) of isopropanol.

28. The method according to claim 25, in, The first liquid phase comprises 55% to 65% (v / v) of isopropanol.

29. The method according to claim 1, in, The extraction involves heating and / or mixing.

30. The method according to claim 1, in, The extraction is carried out at a temperature of at least 20°C.

31. The method according to claim 1, in, The extraction is performed at a temperature of at least 30°C.

32. The method according to claim 1, in, The extraction is carried out at a temperature of at least 40°C.

33. The method according to claim 1, in, The extraction is carried out at a temperature of at least 50°C.

34. The method according to claim 1, in, The extraction is performed at a temperature of at least 55°C.

35. The method according to claim 1, in, The extraction is carried out at a temperature of up to 90°C.

36. The method according to claim 1, in, The extraction is carried out at a temperature of up to 80°C.

37. The method according to claim 1, in, The extraction is carried out at a temperature of up to 75°C.

38. The method according to claim 1, in, The extraction is carried out at a temperature of up to 70°C.

39. The method according to claim 1, in, The extraction is carried out at a temperature of up to 65°C.

40. The method according to claim 1, in, The corn gluten source is corn gluten slurry, which may optionally be dried before extraction.

41. A method for forming a flexible plastic film or plastic coating, the method comprising providing a flexible plastic material by the method of claim 1 or 2 and forming the plastic material into a flexible plastic film or plastic coating, wherein, The flexible plastic film is obtained by directly casting the plastic material into a film or by molding the plastic material and rolling the molded product into a film; wherein the plastic coating is obtained by spraying.

Images