Agent and method for suppressing unpleasant odor and taste of beans, and method for producing food containing beans

Abstract

To provide a technology to suppress unpleasant odors and tastes of beans.SOLUTION: An unpleasant odor and taste suppressing agent contains exopeptidase as an active ingredient and suppresses one or more of bean odors, bitterness of beans, and harsh taste of beans. According to the present invention, unpleasant odors and taste originating from beans can be suppressed through a simple process of contacting beans or their processed products with exopeptidase, endopeptidase, and / or asparaginase, thereby enhancing the commercial value of food products containing beans.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to novel uses of glutaminase, exopeptidase, endopeptidase, and asparaginase, and more particularly to an agent and method for suppressing unpleasant odors and tastes selected from the group consisting of beany odor, bitterness of beans, and harsh taste of beans, using these enzymes, as well as a method for producing a bean-containing food. [Background technology]

[0002] Beans are nutritious foods that are rich in protein and B vitamins, as well as a balanced amount of minerals such as calcium, phosphorus, potassium, magnesium, iron, and zinc, and also contain functional components such as dietary fiber and polyphenols (Non-Patent Document 1).Beans are eaten in their original form, such as boiled or roasted beans, or processed into various forms.

[0003] For example, soybeans, among legumes, are particularly high in lipids (approximately 20% of the weight of dry beans is lipids), and are therefore widely used worldwide as a source of soybean oil (Non-Patent Document 1). They also contain an extremely high amount of protein, at over 30% (Non-Patent Document 1). Soy protein, which is obtained by concentrating, separating, or extracting protein from soybeans, is used as a food ingredient in a wide range of processed foods, including processed meat products, fish paste products, frozen foods, chilled prepared foods, health foods, confectioneries, bread, and beverages. Furthermore, soy protein has recently attracted attention for its health benefits and high nutritional value, and is often used in place of meat as a meat substitute (soy meat). Other legumes also contain approximately 20% of the protein of dry beans, making them a rich source of protein for plant-based foods (Non-Patent Document 1). Therefore, soy flour and bean-derived protein concentrates and isolates are used as plant-based proteins.

[0004] On the other hand, beans have a characteristic unpleasant odor (a grassy smell, or so-called beany smell) that impairs their taste, which is one of the factors that hinders their utilization. For example, it has been reported that the main component of the unpleasant odor (soybean smell) of soybeans, which contain a lot of lipids, is n-hexanal, which is produced by oxidation of linoleic acid, which is contained in large amounts in soybeans. In order to suppress the soybean smell, breeding of soybeans lacking lipoxygenase, an enzyme that catalyzes the conversion of linoleic acid to n-hexanal, and screening of enzymes that can decompose n-hexanal (aldehyde dehydrogenase) have been conducted (Non-Patent Document 2).

[0005] Another problem with beans is that they can exhibit unpleasant tastes, such as bitterness and astringency. It has been reported that the main substances causing such unpleasant tastes are saponins and polyphenols (Non-Patent Documents 3 and 4). For example, soybean saponins share a common structure in which glucuronic acid is bound to the 3-position of the aglycone soyasapogenol A or B. Compared to saponins, the aglycones have a higher taste threshold, so it is expected that the unpleasant taste of soybean foods can be reduced by degrading the saponin sugar chain to the aglycone, and glucuronidase derived from Aspergillus oryze has been purified and isolated (Non-Patent Document 4). [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Japan Bean Association, HOME > Nutrition of Beans > Main Nutrients of Beans, [online], [Searched February 5, 2025], Internet<https: / / www.mame.or.jp / eiyou / eiyou.html> [Non-patent document 2] Hideyuki Suzuki and Daisuke Toyama, Screening of aldehyde dehydrogenase capable of decomposing n-hexanal, the cause of the grassy smell of soybeans, Soy Protein Research, Vol. 11 (2008), pp. 67-70 [Non-patent document 3] Japan Bean Association, HOME > Nutrition of Beans > Main Functional Components of Beans, [online], [Searched February 5, 2025], Internet<https: / / www.mame.or.jp / eiyou / kinou.html> [Non-patent document 4] Shigemitsu Kudo, Teiji Uchida, Kazuyoshi Okubo, Unpleasant Taste Components in Soybeans and Fermented Foods, Jyokyo, Vol. 87, No. 1 (1992), pp. 29-35 Summary of the Invention [Problem to be solved by the invention]

[0007] The present inventors conducted extensive research aimed at finding a simpler method for suppressing the unpleasant odor and taste of beans during food processing. As a result, they discovered that the beany odor and the bitter and harsh taste of beans can be suppressed by the action of glutaminase, exopeptidase, or asparaginase. They also discovered that the beany odor and unpleasant taste can be significantly suppressed by using endopeptidase and exopeptidase in combination. Based on these findings, they have completed the following inventions. [Means for solving the problem]

[0008] (1) A first aspect of the agent for suppressing unpleasant odors and unpleasant tastes according to the present invention, which suppresses one or more of beany odor, bitterness of beans, and harsh taste of beans, contains glutaminase as an active ingredient.

[0009] (1) A second aspect of the agent for suppressing unpleasant odors and unpleasant tastes according to the present invention, which suppresses one or more of bean odor, the bitterness of beans, and the harsh taste of beans, contains exopeptidase as an active ingredient.

[0010] (2) In the present invention, an exopeptidase may be used in combination with an endopeptidase.

[0011] (4) A third aspect of the agent for suppressing unpleasant odors and unpleasant tastes according to the present invention, which suppresses one or more of bean odor, the bitterness of beans, and the harsh taste of beans, contains asparaginase as an active ingredient.

[0012] (5) A second aspect of the method of the present invention for suppressing one or more of bean odor, bitterness of beans, and harsh taste of beans includes a step of contacting beans or processed beans with glutaminase.

[0013] (6) A second aspect of the method of the present invention for suppressing one or more of bean odor, bitterness of beans, and harsh taste of beans includes a step of contacting beans or processed beans with an exopeptidase.

[0014] (7) A third aspect of the method of the present invention for suppressing one or more of beany odor, bitterness of beans, and harsh taste of beans includes a step of contacting beans or processed beans with asparaginase.

[0015] (8) A first aspect of the method for producing a bean-containing food product according to the present invention includes a step of contacting beans or processed bean products with glutaminase to suppress one or more of bean odor, bitterness of beans, and harsh taste of beans.

[0016] (9) A second aspect of the method for producing a bean-containing food product according to the present invention includes a step of contacting beans or processed bean products with an exopeptidase to suppress one or more of bean odor, bitterness of beans, and harsh taste of beans.

[0017] (10) A third aspect of the method for producing a bean-containing food product of the present invention includes a step of contacting beans or processed bean products with asparaginase to suppress one or more of bean odor, bean bitterness, and bean harshness. [Effects of the Invention]

[0018] According to the present invention, unpleasant tastes such as beany odor and bitterness / acidity derived from beans can be suppressed. According to the present invention, delicious bean-containing foods in which unpleasant odors and unpleasant tastes are suppressed can be produced. According to the present invention, unpleasant odors and unpleasant tastes derived from beans can be suppressed by the simple process of contacting beans or processed bean products with glutaminase, exopeptidase, endopeptidase, and / or asparaginase. Thus, this can contribute to improving the commercial value of foods containing beans. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a table showing the specifications of commercially available enzyme products used in the examples. [Figure 2] These figures show the results of a sensory evaluation of the "beany smell" of soy proteins treated with various enzymes. (I) is a table showing the scores of each panelist, their average scores, and standard errors. (II) is a bar graph showing the average scores and standard errors for the "beany smell" scores. [Figure 3] These figures show the results of a sensory evaluation of the "bitterness" of soybean proteins treated with various enzymes. (I) is a table showing the scores of each panelist, their average values, and standard errors. (II) is a bar graph showing the average values ​​and standard errors of the scores for "bitterness." [Figure 4] These figures show the results of a sensory evaluation of the "beany smell" of soy proteins treated with endopeptidase and exopeptidase, either singly or in combination. (I) is a table showing the scores of each panelist, their average scores, and standard errors. (II) is a bar graph showing the average scores and standard errors for the "beany smell" scores. [Figure 5] These figures show the results of a sensory evaluation of the "bitterness" of soy proteins treated with endopeptidase and exopeptidase, either singly or in combination. (I) is a table showing the scores of each panelist, their average values, and standard errors. (II) is a bar graph showing the average values ​​and standard errors of the scores for "bitterness." [Figure 6]This figure shows the results of a sensory evaluation of the "beany smell" of soy proteins in which peptidases (endopeptidase and exopeptidase) were reacted with 10 g of soy protein at 0 to 11 LAPU. (I) is a table showing the scores scored by each panelist and their average values. (II) is a bar graph showing the average scores for the "beany smell." [Figure 7] This figure shows the results of a sensory evaluation of the "beany smell" of soy protein obtained by treating 10 g of soy protein with glutaminase at 0 to 1 EGLU. (I) is a table showing the scores scored by each panelist and their average values. (II) is a bar graph showing the average scores for the "beany smell." [Figure 8] These figures show the results of a sensory evaluation of the "beany flavor" of pea proteins treated with various enzymes. (I) is a table showing the scores of each panelist, their average scores, and standard errors. (II) is a bar graph showing the average scores and standard errors for the "pea flavor" scores. [Figure 9] These figures show the results of a sensory evaluation of the "bitterness" of pea proteins treated with various enzymes. (I) is a table showing the scores of each panelist, their average values, and standard errors. (II) is a bar graph showing the average values ​​and standard errors of the scores for "bitterness." [Figure 10] These figures show the results of a sensory evaluation of the "harshness" of pea proteins treated with various enzymes. (I) is a table showing the scores of each panelist, their average scores, and standard errors. (II) is a bar graph showing the average scores and standard errors for the "harshness" scores. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention will be described in detail below.

[0021] The present invention is characterized by suppressing an unpleasant odor or taste selected from the group consisting of beany odor, bitterness of beans, and harsh taste of beans by using one or more enzymes selected from the group consisting of the following (a) to (d): (a) glutaminase, (b) exopeptidases, (c) Asparaginase. (d) exopeptidases and endopeptidases;

[0022] Enzymes that hydrolyze peptide bonds are called peptidases. Peptidases are classified into endo-type and exo-type, as shown in Table 1 (Takao Shirakane, Industry Trends: Enzyme Classification and Nomenclature, JAS Information 2017.10, pp. 8-13, Table 5). [Table 1]

[0023] Exopeptidases are peptidases that cleave protein (polypeptide) molecules sequentially from their termini to release amino acids, dipeptides, and tripeptides. They can be classified into aminopeptidases, which cleave from the amino terminus (N-terminus) of the substrate, and carboxypeptidases, which cleave from the carboxyl terminus (C-terminus).

[0024] Endopeptidases are enzymes that hydrolyze peptide bonds within protein (polypeptide) molecules to produce several peptides, and are also called proteases or proteinases. These enzymes can be classified into five types, as shown in Table 1, based on the amino acid at the active site. Serine endopeptidases include trypsin, chymotrypsin, and subtilisin. Cysteine ​​endopeptidases include papain and bromelain. Aspartic endopeptidases include pepsin and chymosin. Metalloendopeptidases include neutral proteases from bacteria, actinomycetes, and fungi.

[0025] Glutaminase (EC 3.5.1.2) is a type of amidohydrolase enzyme that catalyzes the reaction of glutamine and H2O to produce glutamic acid and ammonia (NH3).

[0026] Asparaginase (Glutaminase; EC 3.5.1.1) is a type of amidohydrolase enzyme that catalyzes the reaction of asparagine and H2O to produce aspartic acid and ammonia (NH3).

[0027] In the present invention, commercially available food-grade enzymes can be used as the enzyme. Commercially available exopeptidases include, for example, "Sumiteam DPP-G," "Sumiteam FLAP," "Sumiteam FL-G," and "Sumiteam ACP-G" (all manufactured by Shin-Nihon Chemical Industry Co., Ltd.), and "Protana Prime" (Novozymes). Commercially available endopeptidases include, for example, "Papain 300," "Bromelain 200GDU" (both manufactured by Nippon Biocon), "Softagen M2" (Taisho Technos), "Neutrase 1.5MG," "Alcalase 2.4LFG," "Protamex," "Neutrase 0.8L / 1.5MG," "Formia TL," and "Formia CTL" (all manufactured by Novozymes). Commercially available mixtures of endopeptidase and exopeptidase include, for example, "Flavorzyme 1000L / 500MG" (Novozymes).

[0028] Commercially available glutaminase products include, for example, "Glutaminase SD-C100S" (Amano Enzyme) and "Protana Uboost" (Novozymes).

[0029] Commercially available asparaginase products include, for example, "PREVENTASE" and "Preventase M" (both DSM Food Specialties), and "Acrylaway" (Novozymes).

[0030] In the present invention, the enzyme activity can be confirmed by a conventional method, for example, by the following method.

[0031] Protease activity (AU) Measurement principle: Hemoglobin is hydrolyzed by enzymes, and the resulting tyrosine-like substance is colored blue with a phenol reagent and measured at a wavelength of 640 nm. Definition: 1 AU is the amount of enzyme that liberates 1 milliequivalent of tyrosine per minute at an initial rate under the reaction conditions of 25°C, pH 7.5, a 10-minute reaction time, and hemoglobin as the substrate.

[0032] Protease activity (AU(A)) Definition: Relative value to the enzyme activity of the reference material "protease A standard" (Novozymes). Measurement principle: Dimethylcasein is used as a substrate and hydrolyzed by the enzyme. The resulting primary amino group reacts with trinitrobenzenesulfonic acid (TNBS) to form a colored substance. The absorbance of this colored substance is measured. The level of absorbance correlates with the level of enzyme activity, so activity can be determined based on this. Measurement method: Standard protease A was diluted to seven levels (0.072-0.216 mAU-A / mL, sodium sulfite solution) to prepare the enzyme solution. 180 μL of 0.25% dimethylcasein-containing sodium tetraborate / sodium dihydrogen phosphate / Brij 35 solution (pH 8.3) was incubated at 50°C for 480 seconds, after which 36 μL of 0.1% TNBS aqueous solution was added and incubated for 60 seconds. 18 μL of enzyme solution was then added and incubated for 60 seconds, after which the absorbance was measured at 405 nm for 120 seconds. A standard curve of activity concentration was created based on the results of the standard protease A assay. The results of similar assays of the sample enzyme were applied to the standard curve to determine the enzyme activity.

[0033] Serine endopeptidase activity (PROT) Definition: Relative value to the enzyme activity of the standard substance "Standard Enzyme" (Novozymes). Measurement principle: The synthetic substrate Suc-Ala-Ala-Pro-Phe-pNA is hydrolyzed by the enzyme, and the absorbance of the resulting pNA (a yellow colored substance) is measured. The level of absorbance correlates with the level of enzyme activity, and this is used to determine activity. Measurement method: Dilute the standard enzyme in seven steps (0.060-0.300 mKMCU / mL, 10 mM citrate buffer) to prepare the enzyme solution. Incubate 160 μL of 0.1 M Tris buffer (pH 9.0) containing 0.56 mg / mL Suc-Ala-Ala-Pro-Phe-pNA at 37°C for 480 seconds, then add 40 μL of the enzyme solution and incubate for 60 seconds. Next, measure the absorbance at 405 nm for 190 seconds. Create a standard curve of activity concentration based on the standard enzyme measurement results. Apply the results of similar measurements to the sample enzyme to the standard curve to determine the enzyme activity.

[0034] Leucine aminopeptidase activity (LAPU) Measurement principle: The synthetic substrate L-leucine-p-nitroanilide is hydrolyzed by the enzyme, and the absorbance of the resulting p-nitroaniline (a yellow coloring substance) is measured at a wavelength of 405 nm. The level of absorbance correlates with the level of enzyme activity, so activity is determined based on this.

[0035] (1) Definition: The amount of enzyme that hydrolyzes 1 μmole of L-leucine-p-nitroanilide in 1 minute is defined as 1 LAPU.

[0036] (2) Definition: Relative value to the enzyme activity of the standard substance "Standard Enzyme" (Novozymes). Measurement method: Dilute the standard enzyme in seven steps (0.021-0.083 LAPU / mL, zinc chloride / Brij L23 solution) to prepare the enzyme solution. Prepare an ethanol / Tris buffer solution containing 6.532 g / L L-leucine-p-nitroanilide to prepare the substrate solution. Add 40 μL of the enzyme solution to 150 μL of 0.1 M Tris buffer (pH 8.0) and incubate at 37°C for 594 seconds. Then add the substrate solution to a concentration of 1.136 g / L and incubate for 144 seconds. Next, measure the absorbance at 405 nm for 297 seconds. Create a standard curve of activity concentration based on the standard enzyme measurement results. Apply the results of similar measurements to the sample enzyme to the standard curve to determine the enzyme activity.

[0037] 《Glutaminase activity (EGLU)》 Definition: Relative value to the enzyme activity of the standard substance "Standard Enzyme" (Novozymes). Measurement principle: The synthetic substrate L-γ-glutamyl-p-nitroanilide is hydrolyzed by the enzyme, and the absorbance of the resulting p-nitroaniline (a yellow coloring substance) is measured. The level of absorbance correlates with the level of enzyme activity, and this is used to determine activity. Measurement method: The standard enzyme was diluted to seven levels (0.035-0.17 EGLU / mL, 0.01 M ACES buffer, 0.5% TWEEN® 20 pH 7.5) to prepare the enzyme solution. A 0.01 M ACES buffer solution containing 1.4 mM L-γ-glutamyl-p-nitroanilide, 0.5% TWEEN® 20 pH 7.5, was prepared to prepare the substrate solution. 180 μL of the substrate solution was incubated at 37°C for 594 seconds, followed by the addition of 30 μL of the enzyme solution and incubation for 297 seconds. The absorbance was then measured at 405 nm for 198 seconds. A standard curve of activity concentration was created based on the results of the standard enzyme assay. The results of similar assays of the sample enzyme were then applied to the standard curve to determine the enzyme activity.

[0038] Asparaginase activity (ASNU) Measurement principle: L-asparagine is hydrolyzed using an enzyme, and the ammonia produced is reacted with α-ketoglutaric acid and NADH (which absorbs at 340 nm) in the presence of glutamate dehydrogenase. This reaction produces L-glutamic acid, and NADH is oxidized to NAD+ (which does not absorb at 340 nm). The amount of NADH consumed is measured by measuring the absorbance at 340 nm, and converted to the amount of ammonia produced. Definition: 1 ASNU is the amount of enzyme that produces 1 μmole of ammonia per minute under the following reaction conditions. Reaction conditions: The substrate solution was MOPS buffer (pH 7.0) containing 9.2 mg / mL L-asparagine, 2.3 mg / mL α-ketoglutaric acid, 0.405 mg / mL NADH, and 61.8 U / mL glutamate dehydrogenase. After adding the enzyme solution and incubating for 1.5 minutes, the absorbance at 340 nm was measured for 120 seconds. The reaction temperature was 37.0°C ± 0.5°C.

[0039] "Beans" refers to the edible parts of legumes, such as seeds and pods. Specific examples of beans include soybeans, peanuts, peas, adzuki beans, cowpeas, kidney beans, scarlet beans, broad beans, mung beans, chickpeas, and lentils.

[0040] "Processed beans" refers to processed beans. Specific examples of processed beans include dried beans, boiled beans, boiled beans, bean flour, bean paste, roasted beans, fried beans, sweetened simmered beans, sweetened adzuki beans, steamed beans, bean-derived protein concentrates (concentrated bean protein), and bean-derived protein isolates (isolated bean protein).

[0041] For example, specific examples of soybean processed products include soy milk, tofu, miso, soy sauce, natto, tempeh, soybean flour, yuba, boiled beans, roasted beans, okara, soybean oil, and soy protein (whole fat soy flour, defatted soy flour, granular soy protein, fibrous soy protein, powdered soy protein, concentrated soy protein, isolated soy protein, and textured soy protein (soy meat)).

[0042] Examples of commercially available soy protein products include the New Soyme (registered trademark) series (F 2010, S10, S11, S20F, S21F, S22F, S31B, S50) (The Nisshin Oillio Group, Ltd.), the New Comitex series (A-301, A-302, A-318, A-320) (The Nisshin Oillio Group, Ltd.), the New Fujinic series (58, 59, AR, 61N, BSN) (Fuji Oil Co., Ltd.), Apex (registered trademark) 650 (Fuji Oil Co., Ltd.), Response 4400 (DuPont), and earth meat (registered trademark) (Harada & Co., Ltd.). Examples of commercially available pea protein products include PP-CS (Organo Food Tech: protein content 77% by mass), Pisane C9 (Cosucra: protein content 84-88% by mass), HARVESTPRO PEA PROTEIN 85 x (Glanbia Japan: protein content 84-88% by mass), and Nutralys S85F (Rocket Japan: protein content 85% by mass).

[0043] "Bean-containing foods" refers to processed foods that contain beans or processed beans as ingredients. Examples of beans-containing foods include processed vegetables, processed fruit, tea, coffee, and cocoa preparations, noodles and breads, grain products, confectioneries, meat products, dairy products, processed egg products, other processed livestock foods, processed seafood foods, cooked foods, seasonings, soups, beverages, retort foods, instant foods, canned foods, prepared meals, frozen foods, health foods, and supplements.

[0044] "Beany smell" refers to an unpleasant odor (unpleasant smell) derived from beans, and is sometimes described as green bean smell, peculiar smell, strange smell, or grassy smell. As mentioned above, compounds that have been reported to cause beany smell in soybeans include carbonyl compounds such as n-hexanal, as well as C5-C7 medium-chain alcohols, furan, and ethyl vinyl ketone. Although aldehydes such as hexanal are the main contributors to beany smell, there are other odor components that are thought to also contribute to the beany smell.

[0045] "Bitterness of beans" refers to the bitter taste derived from beans. As mentioned above, saponins and polyphenols have been reported as the compounds that are the main cause of the bitterness of beans (Non-Patent Documents 3 and 4). In soybeans, soybean saponins (group A saponins, group E saponins, group B saponins) as well as their aglycones (soyasapogenol A, soyasapogenol E, soyasapogenol B) also exhibit bitterness. In addition, soybean isoflavones (genistin, daidzin, etc.), which are a type of polyphenol, as well as their aglycones (genistein, daidzein, etc.) also exhibit bitterness.

[0046] "The astringent taste of beans" refers to the astringent taste derived from beans. Astringent taste is generally a sensation similar to astringency, astringency, or bitterness, and is a complex sensation in which the tactile sensation of something being adsorbed to the tongue surface is felt simultaneously with bitterness. As mentioned above, saponin has been reported as the main cause of the astringent taste of beans (Non-Patent Document 3). In addition, it has been reported that the substances responsible for the astringent taste of soybeans are soybean saponin and soybean isoflavone (Non-Patent Document 4).

[0047] Whether or not the "beany smell," "bitter taste of beans," or "harsh taste of beans" has been suppressed can be confirmed, for example, by conducting a sensory test to evaluate the unaltered odor and unpleasant taste after eating food X containing the active ingredient of the present invention and food Y not containing the active ingredient, and comparing the results. If the comparison result shows that food X has a "weaker beany smell," "bitter taste," or "harsh taste" than food Y, it can be determined that the unaltered odor and unpleasant taste have been suppressed by the active ingredient.

[0048] The active ingredient is used by contacting it with beans or processed beans. The contacting method and timing may be any method that can be used in food processing, and can be appropriately set depending on the type of food and the desired taste and texture. Examples of contacting methods include immersing beans / processed beans products in a solution of the active ingredient, adding the active ingredient to foodstuffs containing beans / processed beans products and mixing them, and coating or spraying the active ingredient on the beans / processed beans products.

[0049] Bean-containing foods can be produced by conventional methods other than contacting an active ingredient with beans / bean processed products. In addition to the beans / bean processed products and the active ingredient, the foods may contain any ingredients used in food production, such as meat, seafood, vegetables, fruits, mushrooms, seaweed, grains, salt, sugar, seasonings such as mirin (sweet sake) and sake, spices such as pepper and mustard, eggs, and, if necessary, thickening polysaccharides, starch, wheat flour, and other cereal flours, food additives such as sucrose fatty acid esters, and edible oils.

[0050] The amount of exopeptidase used can be appropriately determined depending on the type of food, the desired taste, texture, etc. For example, the amount used can be 1 to 1,000 LAPU per 100 g of soaking liquid. Furthermore, when mixed with food materials, the amount can be 0.25 to 200 LAPU per 10 g of beans / bean processed products.

[0051] The amount of endopeptidase used can be appropriately determined depending on the type of food, the desired taste, texture, etc. For example, the amount used can be 0.01 to 1.5 AU (A) or 200 to 60,000 PROT per 100 g of soaking solution. Furthermore, when mixed with food materials, the amount can be 0.0025 to 0.3 AU (A) or 40 to 12,000 PROT per 10 g of beans / bean processed products.

[0052] The ratio of exopeptidase to endopeptidase used can also be appropriately set depending on the type of food, the desired taste, texture, etc. Examples of the ratio include exopeptidase:endopeptidase = 1000 LAPU:0.01 AU(A) to 1 LAPU:1.5 AU(A), and exopeptidase:endopeptidase = 1000 LAPU:40 PROT to 1 LAPU:12000 PROT.

[0053] The amount of glutaminase used can be appropriately determined depending on the type of food, the desired taste, texture, etc. For example, the amount used can be 0.1 to 50 EGLU per 100 g of soaking liquid. Furthermore, when glutaminase is mixed with food materials, the amount used can be 0.025 to 10 EGLU per 10 g of beans / bean processed products.

[0054] The amount of asparaginase used can be appropriately determined depending on the type of food, the desired taste, texture, etc. For example, the amount used can be 10 to 2000 ASNU per 100 g of soaking liquid. Furthermore, when mixed with food materials, the amount used can be 2 to 400 ASNU per 10 g of beans / bean processed products.

[0055] In the present invention, the method for suppressing unpleasant odors and tastes and the method for producing legume-containing foods may include other steps as long as the features of the present invention are not impaired, such as cutting food materials, crushing food materials, mixing food materials, seasoning, forming, heating, pressurizing, sterilizing, cooling, containerizing, packaging, and freezing.

[0056] The present invention will be described below based on examples, but the technical scope of the present invention is not limited to the features shown in these examples. [Example]

[0057] <Test Method> (1) Test materials Six commercially available enzyme products (abbreviated as enzymes A to F) were used. The specifications of the enzymes are shown in Figure 1. Enzyme A and enzyme B are endopeptidases, enzyme C is an exopeptidase (a mixture of aminopeptidase and carboxypeptidase), enzyme D is a mixture of endopeptidase and exopeptidase, enzyme E is glutaminase, and enzyme F is asparaginase. The amount of enzyme used in each example is the weight of the product.

[0058] The soy products used were dried granular soy protein "Soy Protein New Soyme S" (Nissin Oillio) or dried granular protein derived from peas "Pea Granular Meat Large" (CBC).

[0059] (2) Sensory evaluation Sensory tests were conducted to evaluate "beany smell (soybean or pea smell)" and the "bitterness" and "acridity" of beans. The sensory tests were conducted by an analytical panel of 4 to 8 people (average from mild to spicy) tasting the samples and each panelist gave a score. Sample 1 (a control sample with no enzyme added) was given a score of 3, and scores were given on a scale of 1 to 5 in increments of 1 according to the criteria shown below. The scoring results were calculated by averaging the scores given by all panelists for each sample. As shown below, the lower the score for each evaluation item, the less beany smell (low, weak), the less bitterness (low, weak), or the less acridness (low, weak). <Grading criteria> "Beany smell" 5 points: stronger bean smell than sample 1, 4 points: stronger bean smell than sample 1, 3 points: same as sample 1, 2 points: less bean smell than sample 1, 1 point: much less bean smell than sample 1. "Bitterness": 5 points: more bitter than sample 1; 4 points: more bitter than sample 1; 3 points: same as sample 1; 2 points: less bitter than sample 1; 1 point: much less bitter than sample 1. "Astringent taste" 5 points: Astringent taste stronger than sample 1, 4 points: Astringent taste stronger than sample 1, 3 points: Same as sample 1, 2 points: Less astringent taste than sample 1, 1 point: Very less astringent taste than sample 1.

[0060] <Example 1> Study of active ingredients 1 Immersion solutions were prepared with the formulations shown in Table 2. Sample 1 is an immersion solution containing no enzyme, Sample 2 is an immersion solution containing peptidase, Sample 3 is an immersion solution containing glutaminase, and Sample 4 is an immersion solution containing asparaginase. [Table 2]

[0061] Soy protein was rehydrated by adding 20 mL of soybean soybean soybean soybean oil to 10 g of dried granular soy protein and leaving the mixture to stand at room temperature for 20 minutes. The soy protein rehydrated using the soybean soybean oils for samples 1 to 4 was designated as samples 1 to 4. The rehydrated soy protein was placed in a frying pan heated to a surface temperature of 200°C and heated for 2 minutes. After cooling, a sensory evaluation was performed using the method described in test method (2). The evaluation results for "beany smell (soybean smell)" and "bitterness" of soybeans are shown in Figure 2 and Figure 3, respectively.

[0062] As shown in Figure 2, the scores for "soybean odor" were significantly lower for samples 2 to 4 than for sample 1. In other words, the soybean odor of soy proteins treated with peptidase, glutaminase, or asparaginase was significantly weaker. These results demonstrate that peptidase, glutaminase, and asparaginase can significantly suppress the beany odor.

[0063] Furthermore, as shown in Figure 3, the scores for the "bitterness" of soybeans for Samples 2 to 4 were significantly lower than for Sample 1. In other words, the soybean bitterness of soybean proteins treated with peptidase, glutaminase, or asparaginase was significantly reduced. These results demonstrate that peptidase, glutaminase, and asparaginase can significantly reduce the bitterness of beans.

[0064] <Example 2> Study of active ingredients 2 Regarding peptidases, we investigated which peptidases are effective in suppressing the beany odor and the bitterness of beans. First, we prepared soaking solutions with the formulations shown in Table 3. Sample 1 is a soaking solution containing no enzymes, Sample 2 is a soaking solution containing endopeptidase, Sample 3 is a soaking solution containing exopeptidase, and Samples 4 to 8 are soaking solutions containing both endopeptidase and exopeptidase. [Table 3]

[0065] Soy protein was rehydrated by adding 20 mL of soybean soybean soybean soybean oil to 10 g of dried granular soy protein and leaving the mixture to stand at room temperature for 20 minutes. The soy protein rehydrated using the soybean soybean oils for samples 1 to 8 was designated as samples 1 to 8. The rehydrated soy protein was placed in a frying pan heated to a surface temperature of 200°C and heated for 2 minutes. After cooling, a sensory evaluation was performed using the method described in test method (2). The evaluation results for "beany smell (soybean smell)" and "bitterness" of soybeans are shown in Figure 4 and Figure 5, respectively.

[0066] As shown in Figure 4, the "soybean odor" score for Sample 2 was equivalent to that of Sample 1, but Sample 3 was lower than that of Sample 1. Furthermore, Samples 4 to 8 all had significantly lower scores than Samples 1 to 3. In other words, the soybean odor of soy protein treated with endo-type peptidase alone was not suppressed, but the soybean odor of soy protein treated with exo-type peptidase alone was weak. Furthermore, the soybean odor of soy protein treated with a combination of endo-type and exo-type peptidases was significantly weaker. These results demonstrate that exopeptidase can suppress beany odor. Furthermore, it was also demonstrated that the beany odor can be significantly suppressed by using endopeptidase and exopeptidase in combination.

[0067] Furthermore, as shown in Figure 5, the score for the "bitterness" of soybeans was higher for sample 2 than for sample 1, but lower for sample 3. Furthermore, samples 4 to 8 all had significantly lower scores than samples 1 to 3. In other words, soy protein treated with endo-type peptidase alone exhibited a strong bitter soybean taste, while soy protein treated with exo-type peptidase alone exhibited a weaker bitter taste. Furthermore, soy protein treated with a combination of endo-type and exo-type peptidases exhibited a significantly weaker bitter taste. These results demonstrate that exopeptidase can suppress the bitterness of beans. Furthermore, it was also demonstrated that the bitterness of beans can be significantly suppressed by using endopeptidase and exopeptidase in combination.

[0068] Example 3: Examination of dosage (1) Peptidase Immersion solutions were prepared with the formulations shown in Table 4. Sample 1 was an immersion solution containing no enzyme, and samples 2 and 3 were immersion solutions containing 11 LAPU or 55 LAPU of enzyme D in 100 g (= 100 mL) of immersion solution. [Table 4]

[0069] 20 mL of soy protein soy soy soy soy soy soy soy soy protein was rehydrated by adding 20 mL of soy ...

[0070] As shown in Figure 6, the "soybean odor" scores for Samples 2 and 3 were significantly lower than for Sample 1. In other words, soybean odor was significantly reduced for soybean proteins treated with Enzyme D at 2.2 LAPU (Sample 2) or 11 LAPU (Sample 3) per 10 g of soy protein, regardless of the amount used. These results demonstrate that endopeptidase and exopeptidase can significantly suppress beany odor, regardless of the amount used.

[0071] (2) Glutaminase Immersion solutions were prepared with the formulations shown in Table 5. Sample 1 was an immersion solution containing no enzyme, and samples 2 and 3 were immersion solutions containing 1 EGLU or 5 EGLU of enzyme E in 100 g (= 100 mL) of immersion solution. [Table 5]

[0072] 20 mL of soy protein soy soy soy soy soy soy soy soy soy protein was rehydrated by adding 20 mL of soy ...

[0073] As shown in Figure 7, the "soybean odor" scores for Samples 2 and 3 were significantly lower than for Sample 1. That is, soybean odor was significantly reduced for soybean proteins treated with 0.2 EGLU (Sample 2) or 1 EGLU (Sample 3) of Enzyme E per 10 g of soy protein, regardless of the amount used. These results demonstrate that glutaminase can significantly suppress beany odor, regardless of the amount used.

[0074] <Example 4> Examination of types of plant proteins The test material, dry granular soy protein, was replaced with dry granular protein derived from peas, and the test was carried out as described in Example 1. The evaluation results for "beany smell (pea smell)" are shown in Figure 8, the evaluation results for "bitterness" of peas in Figure 9, and the evaluation results for "harshness" of peas in Figure 10.

[0075] As shown in Figure 8, the scores for "pea smell" were significantly lower for Samples 2 to 4 than for Sample 1. In other words, the pea protein treated with peptidase, glutaminase, or asparaginase had significantly weaker pea smell. This result demonstrates that peptidase, glutaminase, and asparaginase can significantly suppress the beany smell.

[0076] Furthermore, as shown in Figure 9, the scores for the "bitterness" of peas for Samples 2 to 4 were significantly lower than for Sample 1. In other words, the pea proteins treated with peptidase, glutaminase, or asparaginase had significantly less bitterness than the pea proteins treated with peptidase, glutaminase, or asparaginase. These results demonstrate that peptidase, glutaminase, and asparaginase can significantly reduce the bitterness of beans.

[0077] Furthermore, as shown in Figure 10, the scores for the "harsh taste" of peas were significantly lower for samples 2 to 4 than for sample 1. In other words, the harsh taste of peas was significantly reduced in the pea proteins treated with peptidase, glutaminase, or asparaginase. These results demonstrate that peptidase, glutaminase, and asparaginase can significantly suppress the harsh taste of beans.

Claims

1. An agent for suppressing unpleasant odors and unpleasant tastes that suppresses one or more of bean odor, bitterness of beans, and harsh taste of beans, said agent containing exopeptidase as an active ingredient.

2. The agent according to claim 1, further comprising endopeptidase as an active ingredient.

3. An agent for suppressing unpleasant odors and unpleasant tastes that suppresses one or more of bean odor, bitterness of beans, and harsh taste of beans, said agent containing asparaginase as an active ingredient.

4. A method for suppressing one or more of bean odor, bitterness of beans, and harsh taste of beans, which comprises a step of contacting beans or processed beans with exopeptidase.

5. The method according to claim 4, further comprising the step of contacting the beans or processed beans with an endopeptidase.

6. A method for suppressing one or more of bean odor, bitterness of beans, and harsh taste of beans, comprising the step of contacting beans or processed beans with asparaginase.

7. A method for producing a bean-containing food product, comprising a step of contacting beans or processed beans with an exopeptidase to suppress one or more of bean odor, bean bitterness, and bean harshness.

8. The method according to claim 7, further comprising the step of contacting the beans or processed beans with an endopeptidase to suppress one or more of bean odor, bitterness of beans, and harsh taste of beans.

9. A method for producing a bean-containing food, comprising a step of contacting beans or processed beans with asparaginase to suppress one or more of bean odor, bean bitterness, and bean harshness.

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