AU2006259799A2 - Process for the production of high quality fibers from wheat proteins and products made from wheat protein fibers - Google Patents

Description

WO 2006/138039 PCT/US2006/020430 PROCESS FOR THE PRODUCTION OF HIGH QUALITY FIBERS FROM WHEAT PROTEINS AND PRODUCTS MADE FROM WHEAT PROTEIN FIBERS CROSS REFERENCE TO RELATED APPLICATIONS ooo001] The present application claims the benefit under 35 U.S.C. 119(e) of U.S.

Provisional Patent Application Serial No. 60/691,816, entitled "100% Regenerated Protein Fibers and Products Made From Wheat Gluten," filed June 17, 2005 which is herein incorporated by reference in its entirety.

FIELD OF THE INVENTION [00021 The present invention relates generally to protein fiber production, and particularly to a method of producing protein fibers from proteins in wheat grains to be used in various products including textiles, films, composites, and the like.

BACKGROUND OF THE INVENTION [0003] Protein fibers are commonly preferred over synthetics and natural cellulose fibers for several applications. The unique properties of protein fibers such as their high extensibility, moisture absorption, better warmth retention, soft hand, luxurious appearance and durability make them preferred fibers for several applications. However, wool and silk are the only two natural protein fibers available on the market. The total world production of protein fibers is about 2.5 million tons, only about 4% of the total world fiber production. The limited availability of wool and silk makes them to be relatively expensive fibers. For instance,, medium quality wool costs about $5 per pound and silk costs about $12 per pound competing against cotton selling at $0.60 per pound and most synthetic fibers selling at less than $1 per pound. This makes wool and silk to be premium fibers used for high value applications.

[0004] Over the past several years, numerous attempts have been made to produce fibers with properties similar to that of the protein fibers, but by using a more cost effective material.

First, the regenerated cellulose fiber rayon often referred to as "artificial silk" was employed 00 to produce products with similar qualities as those with protein fibers from silk and wool.

O However, limitations in the quality of the fibers, introduction of cheap synthetic fibers and environmental concerns on the production of rayon led to a gradual decline in rayon o production and use. In addition, attempts have been made to use proteins in the agricultural products and byproducts such as soybeans, corn, milk and peanuts as a source for protein fibers. For instance, regenerated protein fibers generally called "Azlons" were commercially produced from proteins in corn, soybean, peanuts and milk. The poor quality of such protein fibers coupled with the use of toxic chemicals formaldehyde) t during fiber production and the introduction of cheap regenerated cellulose and synthetic IDfibers caused such fibers to fall out of favor.

100051 Thus, despite the several attempts to produce protein fibers with properties similar to those of protein fibers found in silk and wool from more cost effective agricultural products and byproducts, the need remains. Therefore, it would be desirable to provide a method of production of protein fibers which produces fibers that have similar properties to that of wool or silk and is cost effective.

SUMMARY OF THE INVENTION [0006] Accordingly, the present invention provides a process of fiber production and modification that produces fibers from wheat proteins that have mechanical properties similar to that of wool, and appearance and handle similar to that of silk. The unique properties and low cost advantage of wheat gluten and other wheat proteins have been utilized to produce high quality 100% protein fibers. There are several advantages of using wheat proteins when compared to the other common protein sources such as zein and soy proteins. Wheat proteins, particularly wheat gluten, are relatively low cost in comparison to soy proteins and zein. Purified zein is reported to cost $8 to $12 per pound and soy protein costs about $1.20 per pound. Wheat gluten costs about $0.50 per pound.

Other advantages of wheat proteins include excellent water and thermal stability and oxygen barrier properties. In addition, wheat proteins have excellent spinnability and can be used to form fine fibers.

00 [0007] In a first aspect, a method for production of wheat protein fibers is provided. The

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method comprises dissolving wheat proteins in a solution that comprises a solvent and a N reducing agent, wherein said dissolution involves breaking intramolecular linkages and O intermolecular linkages of the wheat proteins without substantially hydrolyzing the wheat proteins; and extruding the dissolved wheat proteins into a coagulation bath that comprises a salt to reform intramolecular linkages and intermolecular linkages of the wheat proteins, thereby precipitating the dissolved wheat proteins and forming the wheat protein fibers.

(Ni N [0008] In further aspects, a textile product or a composite product is provided. The textile Oor composite product may include extracted wheat protein fibers, wherein the extracted wheat protein fibers include at least one of a fineness ranging from approximately eight deniers to one hundred and fifty deniers, a strength ranging from approximately 0.1 grams to five grams per denier or elongation from two percent to fifty percent. The textile product may be yarn, woven material, non-woven material, apparel, carpet, automotive fabric, or a medical textile.

[0009] In an additional aspect, a protein fiber production kit is provided. The kit comprises a dissolving solution that comprises a solvent and a reducing agent that may be used to dissolve wheat proteins, wherein said dissolution involves breaking intramolecular linkages and intermolecular linkages of the wheat proteins without substantially hydrolyzing the wheat proteins; and a coagulation solution that comprises a salt, that may be used to reform intramolecular linkages and intermolecular linkages of dissolved wheat proteins extruded into a bath of said coagulation solution thereby precipitating the dissolved wheat proteins and forming wheat protein fibers. The yielded protein fibers are suitable for use in a variety of products including, but not limited to, woven fabrics, non-woven materials, composites, powders and films. Further, the products may include varying amounts of wheat protein fibers ranging from one hundred percent form or as blends with other fibers or polymers in ratios ranging from approximately five percent to ninety five percent.

1000101 It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive 00 of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention.

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BRIEF DESCRIPTION OF THE DRAWINGS [00011] The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which: t FIG. 1 is a flow chart of a method of production of wheat protein fibers in accordance INO with an exemplary embodiment of the present invention; FIG. 2 is a graphical depiction of the effect of wheat gluten concentration on the strength of the fibers in accordance with an exemplary embodiment of the present invention; FIG. 3 is a graphical depiction of the effect of aging time on the strength of the fibers in accordance with an exemplary embodiment of the present invention; FIG. 4 is a graphical depiction of the effect of aging temperature on the strength of wheat fibers in accordance with an exemplary embodiment of the present invention; FIG. 5 is a scanning electron microscope image of a wheat protein fiber in accordance with an exemplary embodiment of the present invention, wherein the wheat protein fiber includes a smooth outer surface; FIG. 6 is a scanning electron microscope image of a wheat protein fiber in accordance with an exemplary embodiment of the present invention, wherein the wheat protein fiber includes a solid cross-section; FIG. 7 is a graphical depiction of the X-ray diffraction pattern of wheat gluten, wheat gluten fibers in comparison to wool in accordance with an exemplary embodiment of the present invention; and FIG. 8 is an X-ray diffraction image of a wheat gluten fiber in accordance with an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION 10011.11 In general, the method of the present invention for producing wheat protein fibers comprises dissolving wheat proteins in a solution that comprises a solvent and a reducing agent and the dissolved wheat proteins are extruded into a coagulation bath that 00 comprises a salt to reform intramolecular linkages and intermolecular linkages of the O wheat proteins, thereby precipitating the dissolved wheat proteins and forming the wheat protein fibers.

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10011.2] The configuration of proteins, such as those of wheat, is the result of inter- and intra-molecular forces disulfide linkages, hydrogen bonds and van der Waals forces) and ionic interactions. These inter- and intra-molecular forces are to be broken and the ionic interaction reduced to make the proteins to be soluble and provide a spinnable t solution with the required viscosity to extrude the fibers. After fiber extrusion, these IDinter- and intra-molecular forces should be reformed in order to make the fibers stable in hot water with weak acids or alkalis and to provide the strength and elongation required (Ni for fibrous applications. The conditions used to dissolve the proteins are important to obtain high quality fibers. They should be selected to ensure that the proteins do not hydrolyze during dissolution and the coagulating bath chemicals are able to reform the inter- and intra-molecular forces. Without proper protein dissolution and coagulation conditions, fibers formed will be brittle and/or weak and will not be suitable for textile and other high quality fibrous applications.

[000121 Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings.

[000131 Referring to FIG. 1, a method 100 for production of wheat protein fibers from wheat proteins including gluten, glutenin, gliadin or other like wheat proteins is provided.

Commercially available wheat gluten in "as is" form is preferred for producing fibers to avoid additional costs in purifying the wheat proteins. However, the wheat gluten may be purified to separate the two major components glutenin and gliadin and these components may be used separately or in any combination to produce the protein fibers.

[0014] In an exemplary embodiment, the method 100 comprises dissolving wheat proteins 102 in the aforementioned dissolving solution, which comprises one or more wheat protein solvents and one or more reducing agents. The dissolving solution dissolves the proteins by breaking the disulfide linkages and hydrogen bonds in the wheat proteins without substantially hydrolyzing the wheat proteins. This is accomplished by 00 controlling/selecting the pH of the dissolving solution so that it is relatively mild or moderate such as within the range of about 7.0 to about 10.0 (if necessary alkalis such as N sodium hydroxide, sodium carbonate and sodium bicarbonate may be included in or

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O added to the dissolving solution to attain the desired pH). Examples of wheat gluten solvents include, but are not limited to ethanol, isopropyl alcohol, urea, mercaptoethanol, (Ni sodium hydroxide, formaldehyde, and like reagents. These solvents may be used alone or in combinations to achieve complete dissolution of the proteins and form a highly viscous and spinnable solution. Typically, the amount of the solvent used to the dissolve the t proteins in the range of approximately 0.5 percent to fifty percent of the weight of wheat IDproteins to be dissolved. Typically, the amount of wheat protein that is dissolved is in the range of 25 to 35% by weight of the dissolving solution. Examples of suitable reducing agents include sulfites sodium sulfite and sodium bisulfite), sulfides and polysulfides, dithionites, dithiodiglycolates, hydroxyacetone (acetol), thiourea, mercaptoethanol, dithiothreitol and cysteine. Typically, the concentration of reducing agent(s) in the solution is in the range of 0.05 to twenty percent based on the weight of the proteins being dissolved. In addition to the solvents and reducing agents, other chemicals such as plasticizers may also be added to the dissolving solution to improve the spinnability and properties of the fibers. Examples of plasticizers include but are not limited to glycerol and ethanol. If used, the concentration of plasticizers is typically in the range of 0.1 to fifty percent, preferably between approximately one and twenty percent and more preferably between approximately one and ten percent of the weight of proteins used. The protein dissolution can be carried out at temperatures ranging from approximately minus thirty degrees Celsius and one hundred degrees Celsius, preferably at room temperature and more preferably between approximately fifty and ninety degrees Celsius.

10014.1] Further, non-covalent interaction disruptors such as urea and guanidine hydrochloride may be included in the dissolving solution to decrease the intra- and intermolecular forces and assist in reduction of disulfide bonds to solubilize the proteins. If present, the concentration of such disruptors is typically between 20 and 80% by weight of the wheat protein being dissolved.

00 100151 As illustrated in FIG. 1, the method 100 may include aging the dissolved wheat O proteins 104 at temperatures from approximately minus thirty degrees Celsius (-30 to one hundred and fifty degrees Celsius (150 for approximately one to eighty hours, C more preferably between approximately twenty and forty hours, and more preferably between approximately twenty-four and thirty-eight hours, in order to form a viscous, spinnable solution.

10016] In addition, as demonstrated in FIG. 1, the method 100 comprises extruding the n dissolved wheat proteins into a coagulation bath 106 that comprises a salt to reform IDintramolecular linkages and intermolecular linkages of the wheat proteins, thereby precipitating the dissolved wheat proteins and forming the wheat protein fibers.

Examples of suitable salts include sodium chloride, sodium sulfite, sodium sulfate, ammonium sulfate, and aluminum sulfate. Typically, the concentration of the salt(s) in the coagulation solution is in the range of 2 to 40% by weight. The aged solution will be used to produce fibers using the dry or wet spinning system depending on the protein solvent used. For wet spinning, a suitable coagulation bath will be formulated to precipitate the solvents and obtain the fibers. Spinning of the fibers can be carried out at atmospheric or elevated temperatures. Most suitable temperatures are about twenty-five to eighty-five degrees Celsius and more preferably between approximately sixty and one hundred degrees Celsius. Moreover, the fibers from the spinning system can be air dried in the case of dry spinning or treated in a coagulation bath for the fibers to precipitate if wet spinning is used. The coagulation bath may further comprise acids, alkalis, and other chemicals depending on the solvent system used. Examples of acids used include, but are not limited to sulfuric acid, hydrochloric acid and formic acid. The temperature of the coagulation bath may be between approximately zero and one hundred degrees Celsius, preferably between approximately twenty and fifty degrees Celsius and more preferably between approximately forty and eighty degrees Celsius. In an additional embodiment, wheat proteins may be used as a blend to produce bicomponent or multicomponent fibers using the wet or dry spinning system. Fibers in various configurations such as sheath core, island-in-sea or other configurations may also be produced.

[0016.11 The solution of the coagulation bath may further comprise one or more oxidizing agents. Examples of suitable oxidizing agents include peroxygens, peroxides, peracids, 0 and hypochlorites. Typically, the concentration of the oxidizing agent(s) is in the range O of 0.1 to 5.0 g/l when the solution is at a temperature of at least about 50 At Stemperatures below about 50 hypochlorites may be used effectively at a concentration O that is in the range of 0.1 to 3.0 g/l. Peroxygens may also be used at a temperature below about 50 °C but they are preferably accompanied with an activator such as, for example, tetraacetyl ethylene diamine, nonanoyloxybenzene sulfonate, and N-acyl caprolactams.

Typically, the concentration of activator(s) in the solution is in the range of 0.1 to weight percent.

N1 [00017] In further embodiments, the method 100 may include subjecting the wheat 0protein fibers to various after treatments 108 to improve the properties of the fibers.

Several after treatments may be used to improve the properties of the wheat protein fibers.

One or more of these processes may be necessary to obtain fibers suitable for a particular end use. For example, wheat protein fibers may be crosslinked either during or after fiber production. Crosslinking agents can be dissolved during protein dissolution or in the coagulation bath as a one-step process or the fibers may be crosslinked after fiber formation as a two-step process. Examples of crosslinking agents that may be used for crosslinking wheat protein fibers include but not limited to Poly(carboxylic acids) containing more than two carboxylic groups such as Butanetetracarboxylic acid (BTCA) and citric acid, carbodiimides, aldehydes such as formaldehyde and gluteraldehyde, cysteine and enzymes such as peroxidase, glucose oxidase and transglutaminase (Tgase).

The concentration of the crosslinking agents used can be between approximately 0.001 to thirty percent based on the weight of the fibers, preferably between approximately 0.01 to twenty percent and more preferably between approximately three and ten percent.

Crosslinking can be performed between zero to one hundred degrees Celsius, preferably between twenty to seventy degrees Celsius. The time of crosslinking is usually between approximately one and three hundred and sixty minutes, preferably between ten and two hundred minutes. The crosslinked fibers may be dried and cured. Some of the crosslinking chemicals need to be cured for the crosslinking reaction to occur. Curing temperatures may be from one hundred to three hundred degrees Celsius depending on the crosslinking chemicals used. The time of curing is usually between approximately one and one hundred and twenty minutes, preferably between approximately one and thirty minutes and more preferably between approximately one and ten minutes depending on the type of chemicals and the concentration of chemicals used for crosslinking. The crosslinking chemicals and enzymes listed here may be used in combination with the Cothers. Any suitable catalyst may also be used to accelerate the crosslinking reaction.

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0 [00018] In an alternative embodiment, the wheat protein fibers may be subjected to heat treatment to improve the strength of the wheat protein fibers. For instance, wheat protein fibers are heated in dry air or in water at temperatures between ambient to approximately two- hundred degrees Celsius for approximately two to six-hundred minutes and preferably between eighty five to one hundred and forty degrees Celsius for sixty to one hundred and twenty minutes and more preferably between one hundred and one hundred

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0 and twenty degrees Celsius for about sixty to eighty minutes, in a further embodiment, drawing may be utilized to increase the alignment of the polymers along the fiber axis thereby leading to increased fineness, strength and elongation. For example, the wheat protein fibers formed may be drawn by hand or any suitable means to lengths from approximately two to five hundred percent of their original length after extrusion. The drawing may be carried out during extrusion or coagulation as a one step process or after fiber formation as a two step process. Moreover, drawing may be carried in the dry or wet state. The wet state could be achieved using water or any other solution that does not dissolve wheat proteins.

1000191 In another embodiment, wheat protein fibers may be subject to physical treatments such as ultra-violet (UV) light treatment and y-irradiation to improve the fiber properties. UV and y-irradiation can be done using standard equipment for any lengths of time as required to improve the properties of fibers.

100020] In accordance with an additional embodiment of the present invention, a protein fiber production kit is provided. In such aspect, the kit may include a dissolving solution as described above. The kit also includes an extruding or coagulating solution as described above for precipitating the dissolved protein source in a bath of said solution.

Treatment of the wheat protein source with the dissolving solution followed by a protein aging time period and treatment with the extruding solution allows wheat protein fibers to be formed. The yielded wheat protein fibers are suitable for use in a variety of products including, but not limited to, woven fabrics, non-woven materials, composites, powders and films. Further, the products may include varying amounts of wheat protein fibers O ranging from one hundred percent form or as blends with other fibers or polymers in ratios ranging from approximately five percent to ninety five percent.

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[00021] Thus, the present method and kit yield high quality one hundred percent protein (Ni fibers and products which may be utilized to produce numerous products including, but not limited to, woven fabrics, non-woven materials, composites, powders and films, the products including wheat protein fibers in one hundred percent form or as blends with t other fibers or polymers in ratios ranging from approximately five percent to ninety five (Ni O percent. Wheat protein fibers obtained according to this invention have the fineness, length, strength and elongation required for textile yarn, woven material, non-woven (,i material, apparel, carpet, automotive fabric, or a medical textile) and other fibrous applications. For instance, wheat protein fibers with a fineness ranging from approximately eight deniers to one hundred and fifty deniers, a strength ranging from approximately 0.1 grams to five grams per denier or elongation from two percent to fifty percent may be produced by the presently disclosed method.

[00022] Some of the specific examples in accordance with exemplary embodiments of the present invention are provided below.

[00023j Example 1: Dissolving wheat proteins. The wheat proteins specifically, wheat gluten, glutenin and gliadin were dissolved using various solvents and reducing agents.

Wheat gluten and glutenin were dissolved using a urea solution with three percent sodium sulfite to form a twenty percent solution. The solution was aged for twenty-four hours and fibers extruded using a syringe and needle. Fibers were extruded into a coagulation bath including ten percent sodium sulfate and ten percent sulfuric acid in equal proportions.

The fibers were allowed to stay in the coagulation bath for fifteen minutes and were later dried under ambient conditions. Fibers obtained under these conditions had deniers of about two hundred and seventy, strength of 0.14 to 0.23 grams per denier and an elongation of 1.5 to three percent. Gliadin purified form wheat gluten was dissolved using aqueous alcohol. A twenty five percent gliadin solution was prepared using a seventy percent alcohol solution. The gliadin solution was aged for about 15 hours and later 00 extruded in air. Gliadin fibers obtained had strength of about 0.75 grams per denier and an elongation of eight percent.

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o [00024] Example 2. Addingplasticizers. Plasticizers such as glycerol were added into the wheat gluten solution and fibers were extruded. Adding the plasticizers increased the viscosity of the solution and fine fibers were produced. Fibers of seventy deniers with strength of 0.3 grams per denier and elongation of 1.5 to three percent were obtained.

1 [000251 Example Effect of drawing. Fibers obtained from Examples 1 and 2 were IND dipped in water and then stretched by hand to about two hundred to three hundred percent of their original length. The fibers were dried in tension to retain the extended length. The drawn fibers had increased fineness by about two hundred percent, strength of about one hundred percent and elongation by about three hundred to five hundred percent compared to the corresponding undrawn fibers.

100026] Example 4: Studying the effect of concentration of wheat gluten. Various concentrations of wheat gluten were prepared to study the effect of wheat gluten concentration on fiber properties. The solutions were aged for thirty-two hours at a temperature of twenty degrees Celsius. FIG. 2 shows the effect of increasing wheat gluten concentration on the strength of the fibers. As seen from the figure, increasing the concentration of wheat gluten increases the strength of the fibers up to thirty percent and the strength decreases upon further increase in concentration. A concentration of thirty percent was found to be optimum for obtaining fibers with high strength.

[00027] Example 5: Studying the effect of aging time. The aging time of the wheat gluten solution was varied from twenty-four to thirty-six hours to obtain a spinnable solution that could provide fibers with the highest possible strength. The effect of aging time on the strength of the fibers is shown in FIG. 3. As illustrated in FIG. 3, an aging time of thirty hours provides fibers with the highest strength. However, there is relatively less change in strength from thirty to thirty-three hours of aging and this interval of time is preferred in terms of obtaining fibers with the desired strength.

0 100028] Example 6: Studying the effect of aging temperature. Three temperatures, ten, 0 twenty, and thirty degrees Celsius were used to study the effect of temperature on the spinnability of the wheat gluten solutions and the strength of wheat gluten fibers. The ~O results of the temperature study are shown in FIG. 4. As illustrated in FIG. 4, a temperature of twenty degrees Celsius provides fibers with the best strength.

[0029] Example 7: Producing Fibers from glutenin and gliadin. The two major components of wheat gluten, glutenin and gliadin were separated and fibers were t produced from each of the individual components. Gliadin fibers were produced by \0 dissolving gliadin in alcohol and glutenin fibers were produced using an aqueous urea 0solution as a solvent. Gliadin fibers produced had strength of 0.75 grams per denier and

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an elongation of 8.6 percent. Similarly, fibers produce from glutenin had strength of 0.6 grams per denier and an elongation of eighteen percent.

[00030] Example 8: Crosslinking using poly(carboxylic acids). Wheat gluten fibers were crosslinked using butanetetracarboxylic acid (BTCA). A three percent BTCA solution with sodium hypophosphite as a catalyst was used for crosslinking. Fibers were allowed to stay in the crosslinking solution for thirty minutes and were later dried and cured.

Fibers were cured at a temperature of one hundred and seventy degrees Celsius for three minutes. The BTCA crosslinked fibers were of forty-two denier with strength of 0.60 grams per denier and an elongation of thirty-two percent.

[00031] Example 9: Crosslinking with gluteraldehyde. Wheat gluten fibers were crosslinked using gluteraldehyde at varying temperatures and pH's. In a typical experiment, about 0.02 grams of wheat gluten fibers were dipped in 6.5 ml of twenty-five percent of gluteraldehyde solution. The pH of the solution was adjusted to 5.1 using a buffer. The fibers in the solution were allowed to react at fifty degrees Celsius for fortyfive minutes in an oven. The crosslinked fibers were removed from the solution and redipped in a solution containing 3ml of twenty-five percent gluteraldehyde and allowed to stay in this solution for about thirty minutes at ambient temperature. The crosslinked fibers were then drawn by hand to about 100 to 200% of their original length. The drawn fibers were dried in a oven at eighty-five degrees Celsius for one hundred and twenty minutes and were later conditioned at twenty-one degrees Celsius and sixty five percent 00 relative humidity (RH) for twenty-four hours before testing for the fiber properties. A specific example of crosslinking wheat gluten with gluteraldehyde and the changes in the properties of the fibers are given in Table 1.

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r- Table 1 Properties ofgluteraldehyde crosslinked wheat gluten fibers (N Fiber Denier Strength (g/den) Elongation Modulas (g/den) Control 54 0.74 24.6 36.3 Gluteraldehyde 61 1.13 18.3 46.0 0 [100032] Example 10: Crosslinking using a single enzyme. Three types of enzymes, Speroxidase, glucose oxidase and Tgase were used for crosslinking wheat gluten fibers.

Crosslinking conditions such as the concentration of enzymes used, time and temperature of treatment were varied to obtain fibers with the highest possible strength and elongation without affecting other fiber properties. Either single enzymes or a combination of two or more enzymes was used to crosslink the fibers, in a typical example ofcrosslinking using a single enzyme, about 0.3 grams of anhydrous glucose and 0.08 grams of glucose oxidase or Tgase was dissolved in 20 ml of water and the pH of the solution was adjusted to 5.1. About 0.02 grams of wheat gluten fibers were added into the solution and the fibers were allowed to stay in the solution for 2.5 hours at a temperature of 25 0 C. The fibers were then drawn by hand to about 200% of their initial length, dried at 85 OC for 2 hours. The changes in the properties of the fibers after this treatment for each enzyme are given in Table 2.

Table 2 Properties of wheat gluten fibers crosslinked using single enzymes.

Denier Strength (g/den) Elongation Modulas (g/den) Control 62 0.61 24.4 26.6 Tgase 59 0.77 33.8 32.2 Glucose oxidase 52 0.72 23.6 31.2 1000331 Example 11: Crosslinking using multiple enzymes. Single enzymes i.e. glucose oxidase and Tgase used to crosslink wheat gluten did not improve the properties of the wheat gluten fibers to the required extent. It was desired to have wheat gluten fibers with strengths higher than 1 gram per denier. To achieve higher strength, a combination of 00 enzymes was used. After the initial treatment with a single enzyme as described in O example 10, the fibers were retreated with 0.5g of Tgase in 15mL of water for 2 hours at 45 The fibers were later dried at 85 0 C for 2 hours. The changes in the properties of the o fibers when a combination of enzymes was used are given in Table 3 below.

Table 3 Properties of wheat gluten fibers crosslinked with single and multiple enzymes Denier Strength (g/den) Elongation Modulas (g/den) S Control 59 0.70 28.8 30.6 Glucose oxidase 51 0.81 25.2 38.7 Glucose oxidase 57 0.90 27.7 40.8 and TG [00034] Referring to FIGS. 5 and 8, examples of the morphological and physical structure of the fibers produced by the aforementioned methods are provided. First, the longitudinal and cross-sectional features of wheat gluten fibers were observed using a scanning electron microscope. FIGS. 5 and 6 show the longitudinal and cross-sectional view of a wheat gluten fiber, respectively obtained using scanning electron microscopes. Wheat gluten fiber has a smooth surface and a solid cross-section as seen from FIGS. 5 and 6, respectively. The physical structure of the wheat gluten fibers was studied using X-ray diffraction in terms of the percent crystallinity and orientation of the protein crystals in the fibers. FIG. 7 shows a picture of the diffraction pattern of wheat gluten, wheat gluten fibers in comparison to wool. As seen from the picture, wheat gluten fibers have the lowest percent crystallinity compared to gluten and wool. The fiber forming process may have hydrolyzed the wheat proteins leading to fibers with lower percent crystallinity. The wheat gluten fibers also have poor orientation as demonstrated by the weak and broad diffracting arcs in FIG. 8. Based on the diffraction presented in FIG. 7, wheat gluten fibers have a crystallinity of about twenty percent compared to thirty-five percent for the gluten powder and about twenty-five percent for wool.

[000351 It is believed that the present invention and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the 00 components thereof without departing from the scope and spirit of the invention or O without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof. Further, it is to be understood that the claims included below are merely exemplary of the present invention and are not intended to r- limit the scope of coverage which has been enabled by the written description.

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1000361 With reference to the use of the word(s) "comprise" or "comprises" or "comprising" in the foregoing description and/or in the following claims, unless the tt context requires otherwise, those words are used on the basis and clear understanding that IND they are to be interpreted inclusively, rather than exclusively, and that each of those words is to be so interpreted in construing the foregoing description and/or the following claims.

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Claims (24)

1. A method for production of wheat protein fibers, comprising: jO dissolving wheat proteins in a solution that comprises a solvent and a reducing agent, wherein said dissolution involves breaking intramolecular linkages and intermolecular linkages of the wheat proteins without substantially hydrolyzing the wheat proteins; and extruding the dissolved wheat proteins into a coagulation bath that comprises a tt salt to reform intramolecular linkages and intermolecular linkages of the wheat proteins, IN thereby precipitating the dissolved wheat proteins and forming the wheat protein fibers.

2. The method as claimed in claim 1, further comprising treating the wheat protein fibers with ultraviolet light, performing a thermal treatment, and combinations thereof to strengthen the wheat protein fibers.

3. The method as claimed in claim 1 or 2, further comprising treating the wheat protein fibers with a crosslinking agent selected from the group consisting of poly(carboxylic acids), carbodiimides, aldehydes, cysteine, enzymes, and combinations thereof, thereby crosslinking the wheat protein fibers.

4. The method as claimed in any one of claims 1 to 3, further comprising treating the wheat protein fibers with a bleaching solution, thereby bleaching the wheat protein fibers.

The method as claimed in any one of claims 1 to 4, further comprising treating the wheat protein fibers with a dye solution, thereby dyeing the wheat protein fibers.

6. The method as claimed in any one of claims 1 to 5, wherein the wheat proteins are selected from the group consisting of wheat gluten, wheat glutenin, wheat gliadin, and combinations thereof; the solvent is selected from the group consisting of ethanol, isopropyl alcohol, urea, mercaptoethanol, sodium hydroxide, formaldehyde, and combinations thereof; the reducing agent is selected from the group consisting of sulfites, sulfides and polysulfides, dithionites, dithiodiglycolates, hydroxyacetone (acetol), thiourea, mercaptoethanol, dithiothreitol, cysteine, and combinations thereof; and the salt O is selected from the group consisting of sodium chloride, sodium sulfite, sodium sulfate, ammonium sulfate, and aluminum sulfate. C)

7. The method as claimed in any one of claims 1 to 6, wherein the dissolving solution further comprises a chemical additive selected from the group consisting of a 0, plasticizer, a stabilizer, and combinations thereof.

S8. The method as claimed in any one of claims 1 to 7, wherein the wheat protein IDfibers are suitable for producing products selected from the group consisting of woven fabrics, non-woven materials, composites, powders and films.

9. The method as claimed in any one of claims 1 to 8, wherein the wheat protein fibers have a fineness that is at least about eight deniers and no greater than about one hundred and fifty deniers, a strength that is at least about 0.1 grams per denier and no greater than about five grams per denier, and an elongation that is at least about two percent and no greater than about fifty percent.

A textile comprising: wheat protein fibers that have a fineness that is at least about eight deniers and no greater than about one hundred and fifty deniers, a strength that is at least about 0.1 grams per denier and no greater than about five grams per denier, and an elongation that is at least about two percent and no greater than about fifty percent.

11. The textile as claimed in claim 10, wherein the textile is selected from the group consisting of a yarn, a woven material, a non-woven material, an apparel, a carpet, an automotive fabric, or a medical textile.

12. A composite product, comprising: wheat protein fibers that have a fineness that is at least about eight deniers and no greater than about one hundred and fifty deniers, a strength that is at least about 0.1 grams per denier and no greater than about five grams per denier, and an elongation that is at least about two percent and no greater than about fifty percent. 00

13. A wheat protein fiber with a fineness that is at least about eight deniers and no O greater than about one hundred and fifty deniers, a strength that is at least about 0.1 grams per denier and no greater than about five grams per denier, and an elongation that is at O least about two percent and no greater than about fifty percent. (.i

14. A wheat protein fiber production kit, comprising: a dissolving solution that comprises a solvent and a reducing agent that may be used to dissolve wheat proteins, wherein said dissolution involves breaking t intramolecular linkages and intermolecular linkages of the wheat proteins without IND substantially hydrolyzing the wheat proteins; and a coagulation solution that comprises a salt, that may be used to reform intramolecular linkages and intermolecular linkages of dissolved wheat proteins extruded into a bath of said coagulation solution thereby precipitating the dissolved wheat proteins and forming wheat protein fibers.

The kit as claimed in claim 14, wherein the dissolving solution further comprises a chemical additive selected from the group consisting of a plasticizer, a stabilizer, and combinations thereof.

16. The method as claimed in any one of claims 1 to 9, wherein the solvent is at a concentration that is at least 0.5 and no greater than 50 percent of the weight of wheat proteins being dissolved; wherein the reducing agent is at a concentration that is at least 0.05 and no greater than 20 percent of the weight of the wheat proteins being dissolved; and wherein the salt is at a concentration that is at least 2 and no greater than 40 percent by weight of the coagulation bath.

17. The method as claimed in any one of claims 1 to 9 or 16, wherein the dissolving solution has a pH that is at least 7 and no greater than

18. The method as claimed in any one of claims 1 to 9, 16 or 17, wherein the coagulation bath further comprises an oxidizing agent selected from the group consisting ofperoxygens, peroxides, peracids, hypochlorites, and combinations thereof.

19. The method as claimed in any one of claims 1 to 9 or 16 to 18, wherein the wheat 00 O protein being dissolved is at least 25% and no greater than 35% by weight of the dissolving solution.

C) O The method as claimed in any one of claims 1 to 9 or 16 to 19, further comprising aging the dissolved wheat proteins before extruding them into the coagulation bath, wherein the aging is for a duration that is at least about 1 hour and no greater than about hours and during aging the dissolving solution comprising the dissolved proteins is at a t temperature that is at least about -30 'C and no greater than about 150 'C.

21. The method as claimed in claim 22, wherein the wheat protein are at an aging temperate that is no greater than about 20 C and the duration of the aging is no greater than about 30 hours.

22. The wheat protein fiber production kit as claimed in claim 14 or 15, wherein the solvent is at a concentration that is at least 0.5 and no greater than 50 percent of the weight of wheat proteins that are to be dissolved; wherein the reducing agent is at a concentration that is at least 0.05 and no greater than 20 percent of the weight of the wheat proteins that are to be dissolved; and wherein the salt is at a concentration that is at least 2 and no greater than 40 percent by weight of the coagulation solution.

23. The wheat protein fiber production kit as claimed in any one of claims 14, 15 or 22, wherein the dissolving solution has a pH that is at least 7 and no greater than

24. The wheat protein fiber production kit as claimed in any one of claims 14, 15, 22 or 23, wherein the coagulation solution further comprises an oxidizing agent selected from the group consisting ofperoxygens, peroxides, peracids, hypochlorites, and combinations thereof. BA.6648C