Gluten-improving enzymes

Abstract

To provide a gluten-modifying enzyme, and a method for producing an improved gluten using such an enzyme, and a method for improving the physical properties of gluten-containing food.SOLUTION: Use of an enzyme having a specific amino acid sequence results in a composition having a superior gluten-modifying effect.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an enzyme capable of improving gluten in food dough, a method for producing improved gluten using the enzyme, and a method for improving the physical properties of gluten-containing foods. [Background technology]

[0002] Gluten, a type of protein obtained from wheat, rye, etc., has both flexibility and viscoelasticity, and its quantity and structure are important factors that determine the shape, volume, and texture of food. Therefore, strengthening the gluten strength of wheat flour itself is one way to improve dough properties, and this can be done by adding vitamin C (L-ascorbic acid) or salt to the dough or dough ingredients, adjusting the moisture content and pH of the dough, or adjusting the amount of sugar or fat in the dough.

[0003] However, the above method may not be effective depending on the amount of gluten in wheat flour, etc., and there is also a method of strengthening by adding gluten itself separately from wheat flour, etc. Also, methods of improving the added gluten itself to enhance the effect have been studied. For example, Patent Document 1 discloses a method of producing a gluten-modified product with water absorption and emulsifying properties by adding gluten to an acidic aqueous solution to prepare a gluten dispersion and then heat-treating it, and describes that foods in which a gluten-modified product prepared using a lactic acid aqueous solution is added to dough have excellent extensibility and a soft texture. Furthermore, Patent Document 2 describes a method of producing a gluten-modified product with a pH greater than 2.0 and less than 5.0. A method for producing modified gluten powder is disclosed in which a charged thickener is added to an acidic dispersion of gluten (e.g., gluten-containing thickener), to obtain aggregates with gluten, and the aggregates are then dried and pulverized. It is described that when the modified gluten powder is used in bread, noodles, etc., an elastic texture can be maintained even at a low pH. Patent Document 3 also discloses a method for producing a dry gluten powder with excellent processability, in which gluten is dispersed in an acidic solution of pH 2.0 to 6.0, subjected to a heat denaturation treatment at 60 to 160°C, and then dried. Other known methods include a method for producing hydrolyzed gluten by treating gluten with protease (Patent Document 5), an enzyme composition for baking containing a protease at least partially inactivated by oxidation with an oxidizing agent (Patent Document 6), and a bread quality improver for frozen dough containing transglutaminase, L-ascorbic acid, and an emulsifier for bread (Patent Document 7).

[0004] On the other hand, it is known that polypeptides containing specific amino acid sequences have proteolytic activity (Patent Document 8).

[0005] However, it was not known that gluten could be modified by enzymes containing specific amino acid sequences, and that such enzymes could improve the physical properties of gluten-containing foods. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-198037 [Patent Document 2] Patent No. 4168102 [Patent Document 3] Special Publication No. 52-24579 [Patent Document 4] Japanese Patent Application Publication No. 63-079552 [Patent Document 5] Japanese Patent Application Publication No. 03-143355 [Patent Document 6] Japanese Patent Application Publication No. 10-004958 [Patent Document 7] WO2014 / 157577 publication [Patent Document 8] Japanese Patent Application Publication No. 2019-187269 [Non-patent literature]

[0007] [Non-Patent Document 1] Kyoto Women's University Food Science Journal 18 (1966), 1-5 [Non-patent document 2] Seiichi Yoshino, "The Science of Bread", Kodansha, 2018, p. 53 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a gluten-improving enzyme containing a specific amino acid sequence, a method for producing improved gluten using such an enzyme, and a method for improving the physical properties of gluten-containing foods. [Means for solving the problem]

[0009] The present invention relates to the following (a) to (d). (a) a gluten-improving enzyme, The gluten improving enzyme is a polypeptide having the following amino acid sequence (1) or (2): (1) A polypeptide having the same sequence as an amino acid sequence selected from SEQ ID NO: 1 (2) A polypeptide comprising an amino acid sequence having at least 80% sequence identity with an amino acid sequence selected from SEQ ID NO: 1. (b) The gluten improving enzyme according to (a), wherein the polypeptide of the present invention is derived from the genus Streptomyces. (c) a method for producing improved gluten, comprising the step of contacting gluten with an enzyme, A method for producing improved gluten, wherein the enzyme is a polypeptide having the amino acid sequence (1) or (2) below: (1) A polypeptide having the same sequence as an amino acid sequence selected from SEQ ID NO: 1 (2) A polypeptide comprising an amino acid sequence having at least 80% sequence identity with an amino acid sequence selected from SEQ ID NO: 1; (d) A method for improving the physical properties of food using the gluten improving enzyme described in (a) or (b) above. [Effects of the Invention]

[0010] The present invention provides an enzyme capable of improving gluten, improved gluten in food dough using such an enzyme, and a method for producing the same. Furthermore, it also provides a method for improving the physical properties of gluten-containing foods by adding the improved gluten of the present invention to, for example, food dough. [Brief explanation of the drawings]

[0011] [Figure 1] Gluten degradability [Figure 2] Observation of gluten aggregation appearance [Figure 3] Scanning electron microscope observation (conditions: 200x (top), 800x (bottom)) [Figure 4] Spectral diagram obtained by a micro-Raman spectrometer [Figure 5] Bar graph of excitation wavelengths by a Raman microscope [Figure 6] Extensograph results DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention relates to an enzyme for improving gluten, which is a polypeptide having the amino acid sequence of (1) or (2) below: (1) A polypeptide having the same sequence as an amino acid sequence selected from SEQ ID NO: 1 (2) A polypeptide comprising an amino acid sequence having at least 80% sequence identity with an amino acid sequence selected from SEQ ID NO: 1. The present invention also provides a method for producing improved gluten, which comprises a step of contacting gluten with an enzyme, wherein the enzyme comprises a polypeptide having the amino acid sequence of (1) or (2) below: (1) A polypeptide having the same sequence as an amino acid sequence selected from SEQ ID NO: 1 (2) A polypeptide comprising an amino acid sequence having at least 80% sequence identity with an amino acid sequence selected from SEQ ID NO: 1. The present invention also relates to a method for improving the physical properties of gluten-containing foods using the gluten-improving enzyme. The gluten-improving enzyme is suitably used as a bread dough improver or noodle dough improver.

[0013] The gluten of the present invention is a protein formed by the interaction of gliadin and glutenin when water is added to cereal flour such as wheat or rye and kneaded. It is characterized by its viscoelasticity, water absorption, and extensibility. The gluten of the present invention can be separated by washing away starch from dough prepared by adding water to wheat flour and kneading it. The gluten used in the present invention may be any gluten, and the grain from which it is derived and the method of separation are not particularly limited. However, wheat-derived gluten is preferred. The separated gluten may be either a wet type (raw gluten) or a powdered form of vital gluten, such as that obtained by drying using various drying methods such as flash drying, spray drying, vacuum drying, or freeze drying. However, vital gluten is preferred. When vital gluten is used, its moisture content is preferably less than 10%, more preferably less than 9%, even more preferably less than 8%, and most preferably less than 6%.

[0014] The enzyme of the present invention exhibits molecular weights of approximately 18 kDa, approximately 14 kDa, and approximately 11 kDa in SDS-polyacrylamide gel electrophoresis, and may be composed of a single molecular weight, or may be composed of multiple molecular weights such as approximately 18 kDa, approximately 14 kDa, and approximately 11 kDa, approximately 18 kDa and approximately 14 kDa, 18 kDa and 11 kDa, or 14 kDa and 11 kDa.

[0015] The enzyme of the present invention comprises the amino acid sequence of SEQ ID NO: 1. The polypeptide of the present invention comprises an amino acid sequence having at least 80%, at least 90%, or at least 95% sequence identity to the amino acid sequence of SEQ ID NO: 1.

[0016] The enzymes of the present invention are polypeptides having molecular weights of approximately 18 kDa, approximately 14 kDa, or approximately 11 kDa, and comprising an amino acid sequence having at least 80%, at least 90%, or at least 95% sequence identity to the amino acid sequence of SEQ ID NO: 1. The sequence identity is a value calculated, for example, by appropriately aligning a query sequence (a sequence to be evaluated) with the sequence of SEQ ID NO: 1. Specifically, in the present application, the sequence identity is a value calculated using the CLUSTAL algorithm.

[0017] The enzyme having gluten-degrading activity of the present invention can be produced by genetic engineering. The gene encoding the polypeptide of the present invention can be selected from a nucleotide sequence encoding SEQ ID NO: 1 or a nucleotide sequence encoding an amino acid sequence having at least 80%, at least 90%, or at least 95% sequence identity to SEQ ID NO: 1. The sequence identity of the nucleotide sequence is calculated using the CLUSTA L algorithm.

[0018] The enzymes having gluten-degrading activity of the present invention can be produced using a carrier for expression of the polypeptide, for example, using actinomycetes such as Streptomyces as a host. Any vector for actinomycetes can be used, such as the vectors described in JP 2014-207898 A. The host actinomycete can be any commonly available actinomycete, but it is particularly desirable to use actinomycetes belonging to the genus Streptomyces. Specific examples include Streptomyces erythraeus, Streptomyces griseus, Streptomyces omiyaensis, Streptomyces fradiae, Streptomyces roseoflavus, Streptomyces septatus, Streptomyces lividans, Streptomyces lavendulae, Streptomyces virginia, and Streptomyces coelicolor. The recombinant polypeptides of the present invention can be produced efficiently by appropriately determining optimal conditions for medium composition, medium pH, culture temperature, culture time, etc.

[0019] In addition to recombinant genetic production, the enzyme of the present invention can be isolated from microorganisms of the genus Streptomyces, such as Streptomyces erythraeus, Streptomyces griseus, Streptomyces omiyaensis, Streptomyces fradiae, and Streptomyces roseoflavus. Typical proteins are isolated from the microorganism, and a polypeptide comprising the amino acid sequence of SEQ ID NO: 1, or a polypeptide comprising an amino acid sequence having at least 80%, at least 90%, or at least 95% sequence identity to the amino acid sequence of SEQ ID NO: 1, and having a molecular weight of approximately 18 kDa, approximately 14 kDa, or approximately 11 kDa is isolated.

[0020] The medium used in the culturing step may be a medium containing a carbon source, a nitrogen source, and inorganic salts that can be assimilated by the cells used in the present invention. Either a natural medium or a synthetic medium may be used.

[0021] The culture conditions may be appropriately selected depending on the type of medium, culture method, etc., and are not particularly limited as long as the conditions allow the cells to grow and produce the enzyme of the present invention.

[0022] After the culture, a culture supernatant is obtained by separating the cells from the medium components. The separation method may be a common method such as centrifugation or filter press. The culture supernatant can be used as the enzyme solution, but the enzyme solution may also be obtained by treating and purifying it by UF concentration, hydrophobic chromatography, ion exchange chromatography, gel filtration chromatography, or the like.

[0023] The enzyme solution can be used as it is as a gluten-degrading enzyme, or it can be dried. There are no limitations on the drying method, but an appropriate drying method that does not impair the enzyme activity should be selected.

[0024] The enzyme of the present invention obtained by the method described above is different from the enzyme obtained by the conventional gluten-decomposing method, and therefore exhibits a decomposing activity different from that obtained by the conventional method.

[0025] In the present invention, when gluten is contacted with an enzyme, the enzyme is preferably dissolved in a liquid medium, and the liquid medium is preferably water. The solution containing gluten and the enzyme may be prepared by dispersing gluten in a liquid and then adding the enzyme or an enzyme solution, adding an enzyme solution to gluten, adding a liquid to a mixture of gluten and the enzyme, or adding a mixture of gluten and the enzyme to a liquid.

[0026] When gluten is contacted with the enzyme, the amount of enzyme relative to gluten is, for example, 0.5 parts by weight or more, preferably 1.0 parts by weight or more, more preferably 2.0 parts by weight or more, and even more preferably 4.0 parts by weight or more, per 100 parts by weight of gluten. The upper limit of the amount of enzyme relative to gluten is not particularly limited, but is, for example, less than 100 parts by weight, preferably less than 50 parts by weight, more preferably less than 15 parts by weight, even more preferably less than 13.5 parts by weight, even more preferably less than 12 parts by weight, less than 11 parts by weight, and most preferably 10 parts by weight or less, per 100 parts by weight of gluten.

[0027] The pH when the gluten of the present invention is brought into contact with the enzyme is 4.0 to 10.0, more preferably 5.0 to 7.5.

[0028] The temperature when the gluten of the present invention is brought into contact with the enzyme is preferably 15°C or higher, more preferably 20°C or higher. At 40°C, the gluten and the like will form clumps, making it impossible to obtain the desired improved gluten. There is no particular upper limit to the temperature for the heat treatment, but considering that the reaction is in an aqueous solution and the reactant is a protein that is subject to thermal denaturation, the temperature should be 100°C or lower, preferably less than 100°C, more preferably less than 95°C, and even more preferably 40°C or lower.

[0029] The time for the contact may be adjusted appropriately depending on the temperature, but is 30 minutes or more, preferably 60 minutes or more, more preferably 90 minutes or more, even more preferably 120 minutes or more, and even more preferably 150 minutes or more. There is no particular upper limit to the time for the heat treatment, but in consideration of industrial productivity, it is preferably 1,440 minutes or less, more preferably 1,080 minutes or less, even more preferably 720 minutes or less, even more preferably 600 minutes or less, and most preferably 480 minutes or less.

[0030] The gluten obtained by contacting the gluten with an enzyme (hereinafter referred to as "improved gluten") may be used as is, or may be dried and solidified or powdered before use. The drying method is not particularly limited, and various drying methods such as flash drying, spray drying, drum drying, vacuum drying, and freeze drying can be used.

[0031] The improved gluten of the present invention can also be used as a raw material for gluten-based foods such as wheat gluten confectionery, gyoza wrappers, gluten meat, etc. In addition, to strengthen the gluten network, it can also be used as a texture improver for noodles and the like, and may also be used as a bread dough improver.

[0032] The improved gluten of the present invention is characterized by the promotion of the formation of higher-order gluten structures such as disulfide bonds, resulting in the formation of a fine network structure. Therefore, by adding the improved gluten of the present invention to food dough, it is possible to suppress the deterioration of the gluten network in the dough.

[0033] The gluten-improving enzyme of the present invention can be used alone as a food dough improving agent, but it may also be formulated by mixing it with other food ingredients, additives, flavorings, colorants, etc. that are commonly used in food production. For example, the food dough improving agent may contain various edible fats and oils, dairy products, fruit juice, grain flour, etc., emulsifiers such as monoglycerides, succinic acid monoglycerides, diacetyltartaric acid monoglycerides, sucrose fatty acid esters, lecithin, enzymatically hydrolyzed lecithin, sodium stearoyl lactylate and calcium stearoyl lactylate, enzymes such as α-amylase, β-amylase, glucoamylase, hemicellulase (pentosanase), cellulase, glucose oxidase, protease, amino acids such as cysteine, cystine, methionine, alanine, aspartic acid, glycine, collagen, soy protein, etc. The dough improving agent may contain, for example, carbohydrates and peptides, inorganic salts such as sodium chloride, potassium chloride, ammonium chloride, calcium sulfate, calcium carbonate, and calcium dihydrogen phosphate, nucleic acids such as sodium inosinate and sodium guanylate, vitamins such as vitamin B1, vitamin B2, vitamin C (L-ascorbic acid), and vitamin E, alcohols such as ethanol and glycerol, sugars such as sucrose, glucose, maltose, and lactose, thickening polysaccharides such as gum arabic, alginic acid, carrageenan, xanthan gum, guar gum, tamarind gum, and pectin, excipients such as dextrin and various starches, etc. The form of the food dough improving agent is not particularly limited, and it may be in any of the forms of liquid, granules, paste, and emulsion.

[0034] The preparation of dough and the production of food using the gluten-improving enzyme of the present invention can be carried out by conventional methods, except that the gluten-improving enzyme of the present invention is added to a food-grade cereal flour dough raw material. Alternatively, the gluten-improving enzyme of the present invention may be mixed with wheat flour or the like in advance to prepare a flour mix.

[0035] The flour used to prepare the food dough is not particularly limited as long as it contains gluten, but examples include flour obtained from grains such as wheat, barley, and rye, and wheat flour is preferably used. As wheat flour, any type and grade of flour may be used, including hard flour, semi-hard flour, medium-strength flour, and soft flour.

[0036] The amount of the gluten-improving enzyme of the present invention to be added to flour dough is usually 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 1 to 5 parts by weight, per 100 parts by weight of flour.

[0037] The types of foods produced in the present invention are not particularly limited as long as they contain gluten, and include breads such as noodles (soba, udon, ramen, pasta, etc.), gyoza wrappers, rice crackers, cookies, and other snacks, breads such as white bread, rolls, hard-baked bread, sweet breads (chocolate paste-filled cornet, jam-filled bread, etc.), cooked breads (sandwiches, hamburgers, curry bread, etc.), and steamed bread, as well as confectioneries such as manju, donuts, cookies, crackers, pies, pizza, pancakes, and sponge cakes.

[0038] The ingredients for dough include grain flour (wheat flour, rye flour, rice flour, corn flour, etc.) as the main ingredient, and secondary ingredients such as water, yeast, salt, sugars, fats and oils (shortening, lard, margarine, butter, etc.), dairy products (milk, skim milk powder, whole milk powder, condensed milk, etc.), eggs, and yeast food.

[0039] The gluten-improving enzyme of the present invention may be added at any time during the food production process. For example, it may be added to the food dough ingredients to prepare the dough, or it may be added when the ingredients are mixed and kneaded (mixed) to make the dough. Furthermore, when adding the gluten-improving enzyme to the dough ingredients or dough, if the gluten-improving enzyme is dried, it may be mixed with flour, or it may be dissolved or dispersed in a liquid such as water and then added.

[0040] The present invention will be described below using examples, although the technical scope of the present invention is not limited to these examples. [Example]

[0041] (Enzyme production) (1) Spore suspension of Streptomyces nanshensis (JCM 16226) (107 One loopful of the culture medium (30 g / L of soluble cornstarch, 30 g / L of corn steep liquor, 1 g / L of ammonium sulfate, 0.5 g / L of magnesium sulfate, 3 g / L of calcium carbonate, pH 7.0) was inoculated with the culture medium and cultured in a 200 mL Erlenmeyer flask at 28°C and 200 rpm for 12 hours to obtain a completed seed culture solution. (2) 1 ml of the resulting seed culture solution was transferred to 2000 ml of main medium (soluble corn starch 300 g / l, corn steep liquor 150 g / l, defatted soybean flour 250 g / l, ammonium sulfate 10 g / l, magnesium sulfate 5 g / l, calcium carbonate 30 g / l, pH 7.0), and cultured in a 10-liter flask at 28°C and 200 rpm for 40 hours to obtain a main culture solution. (3) The enzyme-treated solution was filtered through a filter press to remove solid matter such as bacterial cells, and then treated with a UF membrane with a molecular weight cutoff of 6000. The concentrated solution fraction was collected and spray-dried to obtain a polypeptide.

[0042] (enzyme activity) The purified enzyme was analyzed for molecular weight by SDS-polyacrylamide gel electrophoresis. After electrophoresis, the gel was stained with Coomassie Brilliant Blue (Sigma). Bands of the obtained enzyme were confirmed at approximately 18 kDa, 14 kDa, or 11 kDa.

[0043] (activity expression) The internal amino acid sequences and N-terminal amino acid sequences of the approximately 18 kDa, 14 kDa, and 11 kDa proteins were analyzed by standard methods, and it was found that all of them were identical proteins that had been shortened by processing from the N-terminus.

[0044] (Examination of substrate properties) The gluten decomposition ability was investigated using the enzyme prepared in Example 1. Gluten decomposition activity was measured using gluten (manufactured by Mitsubishi Corporation Life Sciences) as a substrate, and 1 U was defined as the enzyme activity that caused a 1-unit change in absorbance at 495 nm per hour. As a result, as shown in Figure 1, it was revealed that the gluten decomposition ability of the enzyme was weaker than that of four commercially available neutral and alkaline proteases (Biophrase OP, Bioprase SP-20FG (both manufactured by Nagase ChemteX Corporation), Alcalase (manufactured by Novozymes), and Protin SDNY10 (manufactured by Amano Enzyme Inc.)), Amano A (manufactured by Amano Enzyme Inc.), Amano P (manufactured by Amano Enzyme Inc.), and Orientase (manufactured by HI). [Example]

[0045] (Consideration of gluten modification) (1) Sample preparation 7.00 mg of the enzyme prepared in Example 1 was added to 1 mL of distilled water and mixed to obtain a mixture. 900 μL of a 20 mg / mL aqueous solution of activated gluten was added to 100 μL of the mixture, and the activated gluten and the enzyme were reacted under conditions of reaction pH: 6.0, reaction temperature: 25°C, and reaction time: 3.0 hours while thoroughly stirring. The reaction solution was allowed to stand for 30 minutes, and the appearance of gluten aggregation was observed. Furthermore, the gluten in the reaction solution was observed using a scanning electron microscope (Hitachi High-Technologies Corporation, conditions: 200x, 800x) and a Raman microscope (Renishaw, conditions: 100x, excitation wavelength: 785 nm).

[0046] Comparative Examples of the present invention will be explained below, but the amount of enzyme added was determined based on the gluten decomposition activity measured above (FIG. 1).

[0047] (Comparative Example 1) The same procedure was followed as in Example 1 above, except that 7.00 mg of the enzyme prepared in Example 1 was replaced with 2.5 mg of Orientase (manufactured by HIV).

[0048] (Comparative Example 2) The same procedure was followed as in Example 1 above, except that 7.00 mg of the enzyme prepared in Example 1 was replaced with 2.5 mg of Fungal protease (manufactured by Shin Nippon Chemical Co., Ltd.).

[0049] (Comparative Examples 3 to 8) The same procedure was followed as in Example 1 above, except that the 7.00 mg of enzyme prepared in Example 1 was replaced with 2.5 mg of commercially available Alcalase (Novozymes) (Comparative Example 3), 2.5 mg of Bioprase OP (Nagase ChemteX) (Comparative Example 4), 2.5 mg of Bioprase SP-20FG (Nagase ChemteX) (Comparative Example 5), 2.5 mg of Protin SDNY10 (Amano Enzyme) (Comparative Example 6), 2.5 mg of Amano A (Amano Enzyme) (Comparative Example 7), or 2.5 mg of Amano P (Amano Enzyme) (Comparative Example 8).

[0050] (2) Evaluation results The results of the external observation are shown in Figure 2, the results of the scanning electron microscope observation are shown in Figure 3, and the spectrum diagram and bar graph of the excitation wavelength obtained by the micro-Raman spectrometer are shown in Figures 4 and 5, respectively.

[0051] As shown in Figure 2, even when gluten decomposition activity was measured, no gluten aggregation was observed with the commercially available enzyme, whereas clear gluten aggregation occurred in the enzyme-treated area of ​​the present invention. Furthermore, Figures 3, 4, and 5 confirm that a fine gluten network structure was formed in the enzyme-treated area of ​​the present invention, with the spectra corresponding to α-helix and β-sheet being more intense than in the control. This suggests that the large molecular weight gluten fragments somehow promote the formation of higher-order gluten structures, such as disulfide bonds. [Example]

[0052] (Study on the evaluation of the physical properties of wheat dough) To evaluate the physical property modification of wheat flour dough by the enzyme prepared in Example 1, a Farinograph (registered trademark, manufactured by Brabender) and an Extensograph (registered trademark, manufactured by Brabender) were used. The Farinograph mixes wheat flour and a test solution in a mixer maintained at a constant temperature, and can measure and adjust the viscosity of the dough based on the resistance force applied to the mixer blades attached to the mixer. The Extensograph can measure the extension resistance and degree of elongation of wheat flour dough after a certain time has passed since kneading. (1) Preparation of dough The dough was prepared as follows: 1) 300 g of strong flour (Camelya, manufactured by Nisshin Seifun Co., Ltd.) was placed in a Farinograph mixer set to 30°C and mixed for 1 minute. The amount of gluten contained in the strong flour was estimated to be approximately 30 g based on the Standard Tables of Food Composition in Japan (8th edition) and Non-Patent Document 2. 2) A 2% NaCl aqueous solution heated to 30°C was added to the bread flour in an amount that would make the dough firmer to 500 BU (BU: Brabender units). 3) Simultaneously with the addition of the NaCl aqueous solution, a 1% aqueous enzyme solution was added so that the enzyme of the present invention was 31 ppm and the orientase was 6 ppm. 4) After mixing for 1 minute, the mixer was stopped for 5 minutes to allow the strong flour to hydrate, and then mixing was continued for 9 minutes. 5) The dough was divided into 150 g portions and formed into log shapes using the rounding and molding machine attached to the Extensograph. 6) The dough was placed in a 30°C fermentation chamber attached to an Extensograph. 7) The first measurement was taken after 45 minutes. Then, the same dough was used to measure twice, 45 minutes apart (results were taken at 90 and 135 minutes after the dough was made).

[0053] (2) Evaluation results The results of the extensographs are shown in Figure 6. The vertical axis of each graph shows the elongation resistance force, and the horizontal axis shows the degree of elongation. Since the extensograms show the resistance force that occurs when the fabric is stretched to a certain length, the larger the BU value on the vertical axis, the stronger the fabric's physical properties are evaluated to be.

[0054] As shown in FIG. 6, the physical strength of the dough decreased over time when the commercial enzyme was used, whereas the physical strength of the dough did not decrease over time when treated with the enzyme of the present invention. [Industrial Applicability]

[0055] As described above, modified gluten can be obtained by the enzyme of the present invention. By incorporating the improved gluten of the present invention into food dough, deterioration of the gluten network is suppressed, resulting in foods with a voluminous, chewy texture. Furthermore, by incorporating the improved gluten of the present invention into food dough, the amount of water absorption can be increased, thereby achieving effects such as cost reduction. Furthermore, the improved gluten of the present invention has a finely formed gluten network structure, and the extensibility and elasticity of the dough are well maintained. The improved gluten of the present invention can also be used as an ingredient in foods that use gluten, such as noodles, bread, gluten confectionery, dumpling wrappers, and gluten meat. According to the present invention, there are provided an enzyme capable of improving gluten, a method for producing improved gluten using such an enzyme, and a method for improving the physical properties of gluten-containing foods.

Claims

1. A method for producing gluten having a densified gluten network structure, comprising a step of contacting gluten with an enzyme that is a polypeptide having the amino acid sequence set forth in SEQ ID NO:

1.

2. A method for improving the physical properties of food including gluten-containing cereal flour dough using an enzyme that is a polypeptide having the amino acid sequence set forth in SEQ ID NO: 1, wherein the improvement in physical properties is the suppression of a decrease in the physical strength of the dough.

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