Method for producing modified pea protein

Abstract

The present invention addresses the issue of providing: a production method for modified pea protein (pea protein having increased viscosity); a modified pea protein (pea protein having increased viscosity) obtained using said method; and a method for increasing the viscosity of pea protein.　A modified pea protein production method and a modified pea protein obtained using same, said production method including: a step (1) in which peas are dried, ground, and mixed with water or peas are wet-ground in water, to obtain a water dispersion of ground peas; a step (2) in which transglutaminase is added to the water dispersion obtained in step (1) or a solution having solids removed from the water dispersion obtained in step (1) and an enzymatic reaction solution is obtained; and a step (3) in which acid is added to the enzymatic reaction solution obtained in step (2) and precipitate is recovered. Also provided is a method for increasing the viscosity of pea protein that includes steps (1)–(3).

Description

[Technical Field]

[0001] The present invention relates to a method for producing a modified pea protein (particularly a pea protein with increased viscosity), which is characterized by adding transglutaminase at a specific stage of production; a modified pea protein (particularly a pea protein with increased viscosity) obtainable by the production method; and a method for increasing the viscosity of a pea protein. [Background technology]

[0002] The market for pea protein has expanded in recent years, but its viscosity when dissolved is much weaker than that of soy protein, the main vegetable protein, making it less thickening capable and limiting its range of applications. Therefore, there is a need to develop pea protein with increased viscosity.

[0003] Patent Document 1 discloses that the gelling ability of a pea protein solution is improved by adding transglutaminase to the solution to cause an enzymatic reaction, but does not describe the addition of transglutaminase in a specific step in the present invention. Patent Document 2 discloses a method for producing linked soybean proteins by adding transglutaminase to the supernatant of soybean slurry to carry out an enzymatic reaction. However, Patent Document 2 only describes soybean proteins as vegetable proteins, and does not mention pea proteins. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Chinese Patent Application Publication No. 101703147 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-283173 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a method for producing a modified pea protein (particularly, a pea protein with increased viscosity); a modified pea protein (particularly, a pea protein with increased viscosity) obtainable by the production method; and a method for increasing the viscosity of a pea protein. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems and have found that adding transglutaminase in a specific production step makes it possible to produce pea protein with increased viscosity. Based on this finding, the present inventors have conducted further research and have completed the present invention.

[0007] That is, the present invention provides the following. [1] (1) A step of dry-grinding peas and mixing with water, or wet-grinding peas in water to obtain an aqueous dispersion of pea pulverized material; (2) adding transglutaminase to the aqueous dispersion obtained in step (1) or to a solution obtained by removing solid substances from the aqueous dispersion obtained in step (1) to obtain an enzyme reaction solution; and (3) adding an acid to the enzyme reaction solution obtained in step (2) and recovering the precipitate; A method for producing a modified pea protein, comprising: [2] The method according to [1] above, wherein the amount of transglutaminase added is 0.01 to 100 units per 1 g of protein. [3] Modified pea protein obtained by the manufacturing method described in [1] or [2] above. [4] (1) A step of dry-grinding peas and mixing with water, or wet-grinding peas in water to obtain an aqueous dispersion of pea pulverized material; (2) adding transglutaminase to the aqueous dispersion obtained in step (1) or to a solution obtained by removing solid substances from the aqueous dispersion obtained in step (1) to obtain an enzyme reaction solution; and (3) adding an acid to the enzyme reaction solution obtained in step (2) and recovering the precipitate; 10. A method for increasing the viscosity of pea protein, comprising: [5] The method according to [4] above, wherein the amount of transglutaminase added is 0.01 to 100 units per 1 g of protein. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a method for producing a modified pea protein (particularly, a pea protein with increased viscosity); a modified pea protein (particularly, a pea protein with increased viscosity) obtainable by the production method; and a method for increasing the viscosity of a pea protein. The modified pea protein (particularly pea protein with increased viscosity) obtained by the production method of the present invention is advantageous in that it can be used in a wider range of applications than conventional isolated pea protein.

[0009] Isolated pea protein powders obtained by extraction from peas are commercially available (e.g., Pisane C9 (trade name), manufactured by Cosucra). In the process of adding such conventional isolated pea protein powders to foods or beverages to produce final products, adding an enzyme to increase the viscosity of the protein requires complicated operations such as enzyme addition and reaction steps and additional management items. When the pea protein with increased viscosity obtained by the production method of the present invention is added to a food or beverage to produce a final product, there is no need to add enzymes during production of the final product, which is advantageous in that the production of the final product is simplified. Furthermore, when pea protein is actually added to foods or beverages for use, it is likely to undergo a sterilization process. As is clear from the results of Test Examples 1 to 3 described below, the modified pea protein obtained by the production method of the present invention can maintain or improve its viscosity even when heated, so that the sterilization process in actual use can be carried out without any problems. Furthermore, as is clear from the results of Test Examples 1 and 2 described below, the modified pea protein obtained by the production method of the present invention has the effect of increasing viscosity even without heating. Furthermore, the modified pea protein obtained by the production method of the present invention can be gelled at a low protein concentration, and is therefore useful in the production of foods from the standpoint of reducing raw materials, etc. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below. Transglutaminase is an enzyme that catalyzes an acyl transfer reaction in which a glutamine residue in a protein or peptide serves as a donor and a lysine residue serves as an acceptor. Transglutaminase derived from various sources, such as mammals, fish, and microorganisms, is known. The transglutaminase used in the present invention is not particularly limited in origin as long as it has the above-described activity, and transglutaminase derived from any source can be used. Recombinant enzymes may also be used. The transglutaminase used in the present invention may be a commercially available product; specifically, a microbial transglutaminase commercially available from Ajinomoto Co., Inc. under the trade name "Activa" TG can be used.

[0011] In the present invention, the activity unit of transglutaminase is measured and defined as follows: In a reaction system using benzyloxycarbonyl-L-glutamylglycine and hydroxylamine as substrates in a Tris buffer solution at 37°C and pH 6.0, transglutaminase is allowed to act, and the resulting hydroxamic acid is allowed to form an iron complex in the presence of trichloroacetic acid. The absorbance at 525 nm is then measured, and the amount of hydroxamic acid is determined using a calibration curve. One unit (1 U) is defined as the amount of enzyme required to produce 1 μmole of hydroxamic acid per minute (see Japanese Patent Laid-Open No. 27471 / 1989).

[0012] The method for producing the modified pea protein of the present invention comprises the following steps (1) to (3). Step (1): A step of dry-grinding peas and mixing with water, or wet-grinding peas in water to obtain an aqueous dispersion of pea pulverized material. Step (2): A step of adding transglutaminase to the aqueous dispersion obtained in step (1) or to a solution obtained by removing solid substances from the aqueous dispersion obtained in step (1) to obtain an enzyme reaction solution. Step (3): Adding an acid to the enzyme reaction solution obtained in step (2) and recovering the precipitate.

[0013] Process (1) In step (1), peas are dry-ground and mixed with water, or peas are wet-ground in water to obtain an aqueous dispersion of ground peas. The peas used in the present invention include yellow peas, red peas, etc., and any type can be used as long as they are fully ripe seeds of the genus Pisum in the family Leguminosae. Dry pulverization can be carried out by a known method, for example, an impact pulverizer, a pin mill, a jet mill, a ball mill, or the like. Water is added to the pea powder obtained by dry grinding and stirred to obtain an aqueous dispersion of the pea powder. The amount of water added is, for example, 60 to 1000 parts by weight per 15 parts by weight of the pea powder. Stirring can be carried out by a known method, for example, stirring at 20°C for 1 hour. Furthermore, an aqueous dispersion of ground peas can be obtained by wet grinding. Wet milling can be carried out by a known method, for example, a ball mill. The amount of water used can be selected appropriately. If necessary, water can be further added to the aqueous dispersion obtained by wet milling to obtain an aqueous dispersion of ground peas containing, for example, 60 to 1000 parts by weight of water per 15 parts by weight of ground peas. In the present invention, the ground peas may have a particle size distribution curve with a D95 value of 200 μm or less, which represents the particle size of the smallest 95% by volume. The particle size can be measured, for example, with a laser diffraction / scattering particle size distribution analyzer.

[0014] Process (2) In step (2), transglutaminase is added to the aqueous dispersion obtained in step (1) or to a solution obtained by removing solid substances from the aqueous dispersion obtained in step (1) to obtain an enzyme reaction solution. Methods for removing solid substances from the aqueous dispersion obtained in step (1) include, for example, centrifugation and filtration. Centrifugation can be carried out by a known method, for example, centrifugation at 20°C (6000g x 30 minutes). Filtration can be carried out by a known method, for example, filtration using a paper filter (e.g., Whatman, 520B 1 / 2 FF) or the like. Centrifugation and filtration may be combined. Transglutaminase is added to the solution from which the solid substances have been removed (the supernatant recovered by centrifugation or the filtrate recovered by filtration). The amount of transglutaminase added is preferably 0.01 to 100 units, more preferably 0.1 to 10 units, and particularly preferably 0.5 to 5 units per gram of protein in the target substance (the aqueous dispersion obtained in step (1) or the solution obtained by removing solid substances from the aqueous dispersion obtained in step (1)). In this specification, the "protein" in "per gram of protein" refers to the value obtained by multiplying the amount of nitrogen contained in the target substance by a nitrogen conversion factor of 5.7. The reaction time after adding transglutaminase, i.e., the time from adding the enzyme to adding the acid, is 10 minutes to 24 hours (preferably 1 hour), and the enzyme reaction temperature is 0 to 60°C (preferably 50°C). If the reaction time is less than 10 minutes, the effect of adding the enzyme will not be sufficient, and if it exceeds 24 hours, productivity will decrease, such as occupying a tank in the factory. If the reaction temperature is less than 0°C, the solution will freeze and the enzyme reaction will not proceed, and if it exceeds 60°C, the enzyme will be inactivated. It is more preferable to stir the solution during the enzyme reaction, and stirring can be performed by a known method.

[0015] The aqueous dispersion (pea slurry) obtained in step (1) or the solution obtained by removing solid materials from the aqueous dispersion (pea slurry supernatant or filtrate) contains proteins and water-soluble sugars that are soluble in water in the neutral pH range. The method of the present invention is characterized by adding transglutaminase to the dispersion or solution to carry out an enzymatic reaction. On the other hand, conventional commercially available isolated pea protein powders are usually extracted from pea powder, separated by the addition of acid, and then dried, and the components are mainly proteins that did not dissolve in the acid during the separation process. Therefore, the components of the dispersion or solution to which transglutaminase is added in the present invention and the components of conventional commercially available isolated pea protein powders are different. That is, a portion of the proteins contained in the dispersion or solution to which transglutaminase is added in the present invention and the enzymatic reaction is performed is removed from conventional commercially available isolated pea protein powders by the separation process involving the addition of acid.

[0016] Process (3) In step (3), an acid is added to the enzyme reaction solution obtained in step (2) and the precipitate (isolated pea protein curd) is collected to obtain the modified pea protein of the present invention. Examples of the acid include hydrochloric acid, sulfuric acid, phosphoric acid, etc. The acid is added to adjust the pH to 3.0 to 6.1 (preferably pH 4.5), and the mixture is stirred to produce a precipitate. Methods for recovering the precipitate include, for example, centrifugation, filtration, and decantation. Centrifugation can be carried out by a known method, for example, centrifugation (6000 g x 30 minutes) at 20°C. Filtration can be carried out by a known method, for example, filtration using a paper filter, etc. Centrifugation, filtration, and decantation may be performed in combination.

[0017] In the production method of the present invention, the precipitate (isolated pea protein curd) obtained in step (3) can also be dried to obtain the modified pea protein (dried product) of the present invention. Drying can be carried out, for example, by the following steps. The precipitate obtained in step (3) is redissolved in water (and, if necessary, neutralized by adding an alkali (adjusted to pH 7)) to obtain an isolated pea protein solution. Examples of alkali include sodium hydroxide and potassium hydroxide. The resulting isolated pea protein solution is then dried to obtain a dried isolated pea protein (the modified pea protein of the present invention). Drying methods include, for example, freeze drying, spray drying, drum drying, etc. Drying such as freeze drying, spray drying, and drum drying can be carried out by known methods. The enzyme (transglutaminase) can be inactivated by heating before the drying step. The heating temperature should be above 60°C.

[0018] In the process of adding conventional isolated pea protein powder to foods and beverages to produce final products, if an enzyme is added to increase the viscosity of the protein, the final product, which is produced without undergoing a deactivation process such as heating after adding the enzyme, is required to include the enzyme in its ingredient labeling. This results in disadvantages such as changes to packaging, reduced distribution and reduced consumer acceptance. In the production method of the present invention, the pea protein with increased viscosity obtained through the above-mentioned drying step is advantageous in that, if sufficient heating is performed between the enzyme addition step and the drying step to inactivate the enzyme, there is no need for a further inactivation step such as heating during production of the final product, or for the enzyme to be listed on the label of the final product.

[0019] The modified pea protein of the present invention can be obtained by the production method of the present invention described above. "Modified" means that the properties of the pea protein, such as viscosity, have been changed by an enzymatic reaction. The modified pea proteins of the present invention have increased viscosity (for example, the viscosity of a pea protein solution or dispersion when dissolved or dispersed in a solvent such as water).

[0020] The modified pea protein of the present invention can be safely ingested by humans and non-human animals (e.g., mammals and birds such as livestock, poultry, and laboratory animals) either as is or by adding it to food (feed). The intake amount of the modified pea protein of the present invention is not particularly limited, and may be appropriately selected in accordance with the protein intake amount of general food (feed). In this specification, food is a concept that broadly encompasses anything that can be taken orally (excluding pharmaceuticals), and includes not only so-called "food" but also beverages, health supplements, health functional foods (e.g., foods for specified health uses, foods with functional claims, foods with nutrient functions), supplements, etc.

[0021] The present invention also relates to a method for increasing the viscosity of pea protein, comprising the steps of: Step (1): A step of dry-grinding peas and mixing with water, or wet-grinding peas in water to obtain an aqueous dispersion of pea pulverized material. Step (2): A step of adding transglutaminase to the aqueous dispersion obtained in step (1) or to a solution obtained by removing solid substances from the aqueous dispersion obtained in step (1) to obtain an enzyme reaction solution. Step (3): Adding an acid to the enzyme reaction solution obtained in step (2) and recovering the precipitate. Steps (1) to (3) in the method for increasing the viscosity of pea protein of the present invention can be carried out in the same manner as steps (1) to (3) in the method for producing the modified pea protein of the present invention described above. The method for increasing the viscosity of pea protein of the present invention may also include a drying step as described in the production method. The method of the present invention increases the viscosity of the pea protein (for example, the viscosity of a pea protein solution or dispersion when dissolved or dispersed in a solvent such as water). In the present invention, the viscosity can be measured, for example, with an AR2 Rheometer (TA Instruments). [Example]

[0022] The present invention will be described in more detail below based on examples, comparative examples, and test examples, but the present invention is not limited to these. In the following Examples and Comparative Examples 2 and 6, Activa TG (trade name) (Ajinomoto Co., Inc.) was used as the transglutaminase.

[0023] [Example 1] 85 parts by weight of water was added to 15 parts by weight of yellow pea powder (particle size specification: D95, measured by a laser diffraction particle size distribution analyzer, of 149 μm or less) obtained by dry grinding yellow peas. The mixture was stirred at 20°C for 1 hour and centrifuged at 20°C (6000 g x 30 minutes). The supernatant was collected and filtered through a paper filter (Whatman, 520B 1 / 2 FF) to obtain a pea solution. Transglutaminase was added to the resulting pea solution at 1.0 unit per gram of protein and stirred at 50°C for 1 hour. Hydrochloric acid was added to this solution to adjust the pH to 4.5, and the solution was stirred at 20°C for 30 minutes. The precipitate was collected and centrifuged at 20°C (6000 g x 30 minutes). Isolated pea protein curd was obtained. To 1 part by weight of the obtained curd was added 3 parts by weight of water to disperse the curd, and sodium hydroxide was added to adjust the pH of the solution to 7.0 to dissolve the curd, thereby obtaining an isolated pea protein solution. The obtained solution was frozen and freeze-dried to obtain the dried isolated pea protein of Example 1.

[0024] [Comparative Example 1] The dried isolated pea protein of Comparative Example 1 was obtained in the same manner as in Example 1, except that the procedure in Example 1, "1.0 unit of transglutaminase per 1 g of protein was added to the obtained pea solution and stirred at 50°C for 1 hour," was changed to "The obtained pea solution was stirred at 50°C for 1 hour (without adding transglutaminase)."

[0025] Comparative Example 2 85 parts by weight of water was added to 15 parts by weight of yellow pea powder (particle size specification: D95, measured by a laser diffraction / scattering particle size distribution analyzer, of 149 μm or less) obtained by dry grinding yellow peas. The mixture was stirred at 20°C for 1 hour and centrifuged at 20°C (6000 g x 30 minutes). The supernatant was collected and filtered through a paper filter (Whatman, 520B 1 / 2 FF) to obtain a pea solution. Hydrochloric acid was added to the resulting pea solution to adjust the pH to 4.5, and the mixture was stirred at 20°C for 30 minutes. The precipitate was collected and centrifuged at 20°C (6000 g x 30 minutes). Isolated pea protein curd was obtained by adding 3 parts by weight of water to 1 part by weight of the resulting curd to disperse it. The pH of the solution was adjusted to 7.0 with sodium hydroxide, and the curd was dissolved to obtain an isolated pea protein solution. To the obtained isolated pea protein solution, 1.0 unit of transglutaminase per 1 g of protein was added, and the mixture was stirred for 1 hour at 50° C. The solution was frozen and freeze-dried to obtain the dried isolated pea protein of Comparative Example 2.

[0026] Comparative Example 3 The dried isolated pea protein of Comparative Example 3 was obtained in the same manner as Comparative Example 2, except that the procedure in Comparative Example 2 was changed from "1.0 unit of transglutaminase per 1 g of protein was added to the obtained isolated pea protein solution and stirred at 50°C for 1 hour" to "The obtained isolated pea protein solution was stirred at 50°C for 1 hour (without adding transglutaminase)."

[0027] [Test Example 1] 95 parts by weight of water was added to 5 parts by weight of each of the dried isolated pea protein products obtained in Example 1 and Comparative Examples 1 to 3 to obtain each isolated pea protein dispersion. Each isolated pea protein dispersion was heated at 90°C for 15 minutes, and then its viscosity (Pa·s) was measured at shear rates of 10 ( / s) and 100 ( / s) using an AR2 Rheometer (TA Instruments) at a sample temperature of 20°C. The results are shown in Table 1. Separately, the viscosity (Pa·s) of each isolated pea protein dispersion was measured at a shear rate of 10 ( / s) and 100 ( / s) using an AR2 Rheometer (TA Instruments) at a sample temperature of 20°C, without heating at 90°C for 15 minutes. The results are shown in Table 2.

[0028] [Table 1]

[0029] [Table 2]

[0030] [Example 2] 85 parts by weight of water was added to 15 parts by weight of yellow pea powder (particle size specification: D95, measured by a laser diffraction particle size distribution analyzer, of 149 μm or less) obtained by dry grinding yellow peas. The mixture was stirred at 20°C for 1 hour and centrifuged at 20°C (6000 g x 30 minutes). The supernatant was collected and filtered through a paper filter (Whatman, 520B 1 / 2 FF) to obtain a pea solution. Transglutaminase was added to the resulting pea solution at 1.0 unit per gram of protein and stirred at 50°C for 1 hour. Hydrochloric acid was added to this solution to adjust the pH to 4.5, and the solution was stirred at 20°C for 30 minutes. The precipitate was collected and centrifuged at 20°C (6000 g x 30 minutes). Isolated pea protein curd was obtained. To 1 part by weight of the obtained curd was added 3 parts by weight of water to disperse the curd, and sodium hydroxide was added to adjust the pH of the solution to 7.0 to dissolve the curd, thereby obtaining an isolated pea protein solution. The solution was spray-dried to obtain the dried isolated pea protein of Example 2.

[0031] [Example 3] The dried isolated pea protein of Example 3 was obtained in the same manner as in Example 2, except that the amount of transglutaminase added was changed from 1.0 unit per gram of protein to 0.5 unit per gram of protein.

[0032] Comparative Example 4 The dried isolated pea protein of Comparative Example 4 was obtained in the same manner as in Example 2, except that the procedure in Example 2, "1.0 unit of transglutaminase per 1 g of protein was added to the obtained pea solution and stirred at 50°C for 1 hour," was changed to "The obtained pea solution was stirred at 50°C for 1 hour (without adding transglutaminase)."

[0033] [Test Example 2] 95 parts by weight of water was added to 5 parts by weight of each of the dried isolated pea protein products obtained in Examples 2 and 3 and Comparative Example 4 to obtain each isolated pea protein dispersion. Each isolated pea protein dispersion was heated at 90°C for 15 minutes, and then the viscosity (Pa·s) was measured at shear rates of 10 ( / s) and 100 ( / s) using an AR2 Rheometer (TA Instruments) at a sample temperature of 20°C. The results are shown in Table 3. Separately, the viscosity (Pa s) of each isolated pea protein dispersion was measured at a shear rate of 10 ( / s) and 100 ( / s) using an AR2 Rheometer (TA Instruments) at a sample temperature of 20°C, without heating at 90°C for 15 minutes. The results are shown in Table 4.

[0034] [Table 3]

[0035] [Table 4]

[0036] [Example 4] 85 parts by weight of water was added to 15 parts by weight of yellow pea powder (powder with a particle size distribution measured by a laser diffraction / scattering particle size analyzer of 50 μm or less) obtained by dry grinding yellow peas. The mixture was stirred at 20°C for 1 hour and centrifuged at 20°C (6000 g x 30 minutes). The supernatant was collected and filtered through a paper filter (Whatman, 520B 1 / 2 FF) to obtain a pea solution. Transglutaminase was added to the resulting pea solution at a rate of 1.0 unit per gram of protein and stirred at 50°C for 1 hour. Hydrochloric acid was added to this solution to adjust the pH to 4.5, and the solution was stirred at 20°C for 30 minutes. The precipitate was collected and centrifuged at 20°C (6000 g x 30 minutes). Isolated pea protein curd was obtained. To 1 part by weight of the obtained curd was added 3 parts by weight of water to disperse the curd, and sodium hydroxide was added to adjust the pH of the solution to 7.0 to dissolve the curd, thereby obtaining an isolated pea protein solution. The obtained solution was frozen and freeze-dried to obtain the dried isolated pea protein of Example 4.

[0037] Comparative Example 5 The dried isolated pea protein of Comparative Example 5 was obtained in the same manner as in Example 4, except that the procedure in Example 4 was changed from "1.0 unit of transglutaminase per 1 g of protein was added to the obtained pea solution and stirred at 50°C for 1 hour" to "The obtained pea solution was stirred at 50°C for 1 hour (without adding transglutaminase)."

[0038] Comparative Example 6 85 parts by weight of water was added to 15 parts by weight of yellow pea powder (powder with a particle size distribution measured by a laser diffraction / scattering particle size analyzer of 50 μm or less) obtained by dry grinding yellow peas. The mixture was stirred at 20°C for 1 hour and centrifuged at 20°C (6000 g × 30 minutes). The supernatant was collected and filtered through a paper filter (Whatman, 520B 1 / 2 FF) to obtain a pea solution. Hydrochloric acid was added to the resulting pea solution to adjust the pH to 4.5, and the mixture was stirred at 20°C for 30 minutes. The precipitate was collected and centrifuged at 20°C (6000 g × 30 minutes). Isolated pea protein curd was obtained by adding 3 parts by weight of water to 1 part by weight of the resulting curd to disperse it. The pH of the solution was adjusted to 7.0 with sodium hydroxide, and the curd was dissolved to obtain an isolated pea protein solution. To the obtained isolated pea protein solution, 1.0 unit of transglutaminase per 1 g of protein was added, and the mixture was stirred for 1 hour at 50° C. The solution was frozen and freeze-dried to obtain the dried isolated pea protein of Comparative Example 6.

[0039] Comparative Example 7 The dried isolated pea protein of Comparative Example 7 was obtained in the same manner as in Comparative Example 6, except that the procedure in Comparative Example 6 was changed from "1.0 unit of transglutaminase per 1 g of protein was added to the obtained isolated pea protein solution and stirred at 50°C for 1 hour" to "The obtained isolated pea protein solution was stirred at 50°C for 1 hour (without adding transglutaminase)."

[0040] [Test Example 3] 95 parts by weight of water was added to 5 parts by weight of each of the dried isolated pea protein products obtained in Example 4 and Comparative Examples 5 to 7, to obtain each of the isolated pea protein dispersions (solution concentration 5%). Separately, 90 parts by weight of water was added to 10 parts by weight of each of the dried isolated pea protein products obtained in Example 4 and Comparative Examples 5 to 7, to obtain each of the isolated pea protein dispersions (solution concentration 10%). Each isolated pea protein dispersion was heated at 90°C for 15 minutes, and then its viscosity (Pa·s) was measured at shear rates of 10 ( / s) and 100 ( / s) using an ARES G2 Rheometer (TA Instruments) at a sample temperature of 20°C. The results are shown in Table 5. In Example 4, gelation occurred as a result of an increase in viscosity at a solution concentration of 10%. Gelling at a low protein concentration is useful in food production from the perspective of reducing raw materials, etc.

[0041] [Table 5] [Industrial Applicability]

[0042] According to the present invention, a method for producing a modified pea protein (particularly a pea protein with increased viscosity) can be provided.

[0043] This application is based on patent application No. 2019-124835 filed in Japan, the contents of which are incorporated in full herein.

Claims

1. (1) A step of dry-grinding peas and mixing them with water, or wet-grinding peas in water to obtain an aqueous dispersion of pea pulverized material; (2) adding transglutaminase to the aqueous dispersion obtained in step (1) or to a solution obtained by removing solid substances from the aqueous dispersion obtained in step (1) to obtain an enzyme reaction solution; and (3) adding an acid to the enzyme reaction solution obtained in step (2) and recovering the precipitate; A method for producing a modified pea protein, comprising: A method for producing a modified pea protein, wherein the viscosity is increased compared to a pea protein produced by the same method except that transglutaminase is not added.

2. 2. The method according to claim 1, wherein the amount of transglutaminase added is 0.01 to 100 units per 1 g of protein.

3. (1) A step of dry-grinding peas and mixing them with water, or wet-grinding peas in water to obtain an aqueous dispersion of pea pulverized material; (2) adding transglutaminase to the aqueous dispersion obtained in step (1) or to a solution obtained by removing solid substances from the aqueous dispersion obtained in step (1) to obtain an enzyme reaction solution; and (3) adding an acid to the enzyme reaction solution obtained in step (2) and recovering the precipitate; 10. A method for increasing the viscosity of pea protein, comprising:

4. 4. The method according to claim 3, wherein the amount of transglutaminase added is 0.01 to 100 units per 1 g of protein.

Images