Off-flavor reducer containing ergothioneine as active ingredient

Abstract

Problem: To provide an off-flavor reducer that reduces off-flavors from bitter substances and seasonings, and to provide a food or beverage product that has reduced off-flavors as a result of adding the off-flavor reducer. Solution: Provided is an off-flavor reducer that contains ergothioneine as an active ingredient. A food or beverage product containing ergothioneine as a bitterness reducer has reduced bitterness, seasonings having a pungent taste have reduced pungency, and the beany taste of soymilk and the like can be reduced.

Description

An agent for reducing unpleasant flavors containing ergothioneine as an active ingredient

[0001] The present invention relates to an agent for reducing unpleasant flavors for bitter substances and seasonings, and to foods and beverages with reduced unpleasant flavors.

[0002] Ergothioneine was discovered as a hydrophilic sulfur-containing amino acid isolated from the rye ergot fungus (Clavices purpurea), and its presence in plants and animals has been confirmed. However, plants and animals cannot synthesize ergothioneine, and ergothioneine in living organisms is thought to be derived from ergothioneine synthesized by microorganisms such as basidiomycetes. Ergothioneine has high antioxidant properties and has been reported to have elastase and tyrosinase inhibitory effects, attracting particular attention in the beauty and food fields for whitening and wrinkle prevention. Furthermore, it has been found that ERG is involved in the body's oxidation defense system, and its application in the medical field has also been attempted.

[0003] Although supplements containing ergothioneine are useful for maintaining and improving health, ergothioneine has a unique flavor, particularly a bitter taste. In order to suppress this bitterness, it has been reported that an oral composition in which the bitterness derived from ergothioneine is suppressed can be obtained by compounding ergothioneine with vitamin E (Patent Document 1), arachidonic acids (Patent Document 2), or theanine (Patent Document 3).

[0004] On the other hand, potassium chloride is used as a substitute for sodium chloride, but its bitterness is problematic. In koji-fermented beverages such as sake, the bitterness of arginine is an issue, and efforts are being made to reduce it. In soybean hydrolysates, the bitterness caused by soybean peptides is also an issue.

[0005] International Publication No. 2023 / 120370 International Publication No. 2023 / 120378 International Publication No. 2023 / 120367 International Publication No. 2019 / 240243 International Publication No. 2023 / 234307

[0006] The problem to be solved by the present invention is to provide an off-flavor reducer that reduces the off-flavors of bitter substances and seasonings, or to provide foods and beverages in which the off-flavors have been reduced by adding an off-flavor reducer.

[0007] As a result of intensive research, the present inventors have found that by adding a small amount of ergothioneine, which can have a bitter taste, to a food or beverage containing a bitter substance, the bitterness of the bitter substance can be reduced, thereby reducing the bitterness of the food or beverage.They have also found that ergothioneine can reduce the pungent taste of seasonings and the beany smell of soy milk, etc., and have thus completed the present invention.

[0008] The present invention relates to the following off-flavor reducers (1) to (4): (1) An off-flavor reducer for bitter substances, containing ergothioneine as an active ingredient. (2) The off-flavor reducer according to (1) above, wherein the off-flavor reduction is the reduction of the bitterness of soybean peptides or mycoproteins, which are bitter substances. (3) An off-flavor reducer for beverages containing beans as an ingredient, containing ergothioneine as an active ingredient. (4) The off-flavor reducer according to (3) above, wherein the off-flavor reduction is the reduction of the beany smell of soy milk.

[0009] The present invention also relates to the following foods and beverages (5) and (6), soy milk or fermented soy milk products (7) and (8), mycoprotein (9), or a method for reducing the unpleasant taste of foods and beverages (10), as well as other foods and beverages (11) to (16). (5) A food and beverage containing a bitter substance, characterized in that the bitterness of soy peptides is reduced, characterized by containing 0.005% by weight or more of ergothioneine relative to the soy peptide content. (6) The food and beverage described in (5) above, which is not a soy sauce for retort foods, a retort food containing soy sauce, a beverage with enhanced acidity, or a food and beverage containing an ergothioneine-producing fungal fermentation biomass or its supernatant colored with a dye. (7) Soy milk or fermented soy milk products containing 10 ppm or more of ergothioneine. (8) Soy milk or fermented soy milk products described in (7) above, which is not a beverage with enhanced acidity. (9) Mycoprotein containing 300 ppm or more of ergothioneine. (10) A method for reducing the unpleasant taste of a food or beverage by adding ergothioneine to the food or beverage having an unpleasant taste. (11) Ergothioneine for use in reducing the unpleasant taste of a beverage containing beans as an ingredient. (12) A koji mold fermentation product containing ergothioneine for use in reducing the unpleasant taste of a beverage containing beans as an ingredient. (13) Use of ergothioneine for reducing the unpleasant taste of a beverage containing beans as an ingredient. (14) Use of a koji mold fermentation product containing ergothioneine for reducing the unpleasant taste of a beverage containing beans as an ingredient. (15) Use of ergothioneine in the production of an agent for reducing an unpleasant taste for a beverage containing beans as an ingredient. (16) Use of a koji mold fermentation product containing ergothioneine in the production of an agent for reducing an unpleasant taste for a beverage containing beans as an ingredient.

[0010] According to the unpleasant flavor reducer of the present invention, the addition of ergothioneine can reduce the bitterness of bitter substances such as caffeine, potassium chloride, arginine, or soybean peptides, or can reduce the spiciness of seasonings such as sauces and the beany smell of soy milk, etc. Therefore, by adding a very small amount of ergothioneine to foods and beverages containing these bitter substances, these foods and beverages can be obtained with improved flavor.

[0011] The present invention relates to an off-flavor reducer containing ergothioneine as an active ingredient, specifically an agent for reducing the bitterness of bitter substances such as caffeine, potassium chloride, arginine, or soybean peptides, or an agent for reducing the irritating taste of seasonings such as sauces, or an agent for reducing the beany smell of soy milk, etc. The present invention also relates to foods and beverages in which off-flavors are reduced by containing the off-flavor reducer ergothioneine. Note that in the present invention, "%" means "% by weight" even if the unit is not specified, and 1 ppm is 0.0001% by weight.

[0012] Ergothioneine (hereinafter also referred to as "ERG") is contained in some edible mushrooms of the basidiomycete fungi, such as oyster mushroom, shiitake mushroom, maitake mushroom, and king oyster mushroom, and is particularly abundant in Pleurotus culotte. It is also known that Aspergillus oryzae produces ERG. Methods for producing ERG include extraction from basidiomycetes such as Pleurotus culotte, chemical synthesis, and fermentation using microorganisms. Preferred mushrooms used for ERG extraction include Pleurotus cornucopiae var. citrinopileatus, Pleurotus ostreatus, Lentinula edodes, and Grifola frondosa, which belong to the Pleurotus genus of the Pleurotus family, due to their high ERG content. These mushrooms may be used alone or in combination.

[0013] Extraction from basidiomycetes such as Pleurotus cornucopius takes time to obtain raw materials and is not suitable for mass production. Chemical synthesis is suitable for mass production, but requires the use of expensive synthetic reagents. Therefore, research is being conducted on fermentation production methods such as fermentation using bacteria or yeast that can assimilate C1 compounds, fermentation using microorganisms that overexpress ERG biosynthesis genes, and solid culture using koji mold that has been introduced with ERG biosynthesis genes and overexpresses ERG.

[0014] As the koji mold that produces ERG, any fungus belonging to the genus Aspergillus can be used. Examples include Aspergillus oryzae, Aspergillus sojae, Aspergillus niger, Aspergillus luchuensis, and Aspergillus tamarii. In addition to the wild-type strains mentioned above, mutant strains that produce high levels of ERG can also be isolated using a general mutagenesis method and used as the koji mold that produces ERG.

[0015] Furthermore, high-ERG-producing koji mold strains into which genes related to ERG biosynthesis have been introduced by genetic recombination can be used, including, but not limited to, koji mold mutant strains into which the egtA gene has been introduced (see Patent Document 4), and Aspergillus mutant strains into which the Aspergillus genus-specific AO090005000664 gene (encoded amino acid sequence: SEQ ID NO: 1) or its ortholog gene has been introduced, into which a specific gene mutation has been introduced, such as a G428S mutation or a C459F mutation, or a deletion of 1 to 112 amino acids in the W404 to Q515 region, has been introduced, thereby increasing ERG expression (see Patent Document 5).

[0016] As used herein, a high-ERG-producing koji mold strain refers to one that produces 5 to 10 times or more, preferably 20 times or more, of ERG when cultured in liquid culture at 20 to 30°C for 3 to 14 days (in Pafumin SM medium (a solution prepared by adding 5 to 10% Pafumin SM (manufactured by Kikkoman Corporation) to water and suspending it), pH unadjusted) compared to a non-mutated or non-transformed strain. Examples of such a strain include an Aspergillus sojae strain in which the egtA gene is forcibly expressed, and an Aspergillus oryzae mutant strain containing amino acid mutations or deletions in the W404 to Q515 region of the mutant AO090005000664 gene and its orthologous gene.

[0017] The ERG used in the present invention may be a commercially available chemically synthesized ERG, or an extract or purified product thereof from ERG-containing mushrooms, ERG-producing koji mold and its culture, or sake lees produced using koji mold. Furthermore, for foods and beverages that use koji mold as a raw material, the amount of ERG in the foods and beverages can be increased by using koji mold that produces a high amount of ERG without adding ERG.

[0018] Bitter substances whose bitterness can be reduced by the present invention include, but are not limited to, caffeine, potassium chloride, arginine, or soybean peptides. Furthermore, seasonings whose irritating taste can be reduced by the present invention include irritating seasonings containing spices, such as Worcestershire sauce and medium-thick sauce, but are not limited to these. Furthermore, beverages whose beany odor can be reduced by the present invention include beverages such as soy milk, which contain beans as at least a part of their ingredients. The food and beverage products of the present invention are foods, beverages, or seasonings, and contain one or more bitter substances. The foods, beverages, or seasonings that can be used include, but are not limited to, foods, beverages, or seasonings containing one or more bitter substances.

[0019] "Reduced unpleasant flavors" means that the unpleasant flavors are perceived as weaker compared to when the unpleasant flavor reducing agent is not present in the food or beverage. For example, it means that the addition of a bitterness reducing agent makes it possible to sense the same bitterness even if the caffeine or the like in the food or beverage is increased by, for example, 1 to 50%. It also means that the addition of a bitterness reducing agent makes it possible to sense the same bitterness as when, for example, 0.5 to 0.9 times the amount of caffeine or the like is contained. When ERG is added to a food or beverage in the process of producing a food or beverage, it may be added at any step, and the method of addition is not limited as long as the required amount is contained in the final food or beverage product.

[0020] For foods and beverages containing caffeine as a bitter substance, the bitterness of the food and beverage can be reduced by adding ERG at 0.1 wt% or more, e.g., 0.1, 0.2, 0.3, or 0.5 wt% or more, based on the caffeine content, or by adding ERG at 0.01 wt% or more, e.g., 0.01, 0.02, 0.03, or 0.05 wt% or more, based on the potassium chloride or arginine content, based on the soybean peptide content. In this way, when a food or beverage contains one or more bitter substances, such as caffeine, potassium chloride, arginine, or soybean peptide, the bitterness-reducing effect can be achieved by adding 0.005 to 0.1 wt % or more of ERG relative to the content of any one of the substances.

[0021] Furthermore, since the bitterness-reducing effect is not enhanced even when a large amount of ERG is added, in consideration of economic efficiency, ERG can be added at 15% by weight or less, for example, 12, 9, 6, or 3% by weight or less, relative to the content of bitter substances in the food or beverage. That is, for caffeine-containing foods and beverages, ERG can be added at 0.1% by weight or more, for example, 0.1, 0.2, 0.3, or 0.5% by weight or more, and 15% by weight or less, for example, 12, 9, 6, or 3% by weight or less, relative to the caffeine content. Also, for potassium chloride or arginine-containing foods and beverages, ERG can be added at 0.01% by weight or more, for example, 0.01, 0.02, 0.03, or 0.05% by weight or more, and 15% by weight or less, for example, 12, 9, 6, or 3% by weight or less, relative to the potassium chloride or arginine content. The bitterness-reducing effect of the food or beverage can be achieved at all combinations of the lower and upper limits. Furthermore, by incorporating ERG in an amount of 0.005% by weight or more, for example, 0.005, 0.01, 0.05, or 0.08% by weight or more, and 15% by weight or less, for example, 12, 9, 6, or 3% by weight or less, relative to the soybean peptide content, the bitterness-reducing effect of the food or beverage is exerted at all combinations of the contents of these lower and upper limits.

[0022] For seasonings with a pungent taste containing the spices of the present invention, such as Worcestershire sauce and medium-thick sauce, the pungent taste can be reduced by adding ERG at 5 ppm or more, for example, 10 ppm or 15 ppm or more, or 20 ppm, 25 ppm, 30 ppm or more, 35 ppm, 40 ppm, 45 ppm, or 50 ppm or more. Furthermore, since the effect of reducing the pungent taste is not enhanced even when a large amount of ERG is added, in consideration of economic efficiency, ERG can be added to the seasoning at 0.15 wt % or less, for example, 0.12 or 0.09 wt % or less, or 0.06 or 0.03 wt % or less.

[0023] Furthermore, in soy milk and fermented soy milk products containing soy peptides, which are bitter substances, the inclusion of ergothioneine can reduce not only the bitterness but also the unpleasant bean-like flavor. In this embodiment, "soy milk" refers to a beverage containing a milky soy milk liquid obtained by eluting proteins and other components from soybeans (whole soybeans, defatted soybeans, powdered soybeans, etc.) with hot water or the like and removing fiber. Examples of soy milks include soy milks (soy milk, prepared soy milk, soy milk beverages) listed in the Soy Milk Quality Labeling Standards issued by the Consumer Affairs Agency, as well as soy milks other than those listed in the Soy Milk Quality Labeling Standards. Furthermore, the soy milk in this embodiment may contain other auxiliary ingredients (e.g., animal and vegetable oils and fats, seasonings such as sweeteners and salt, flavoring ingredients such as fruit juice, vegetable juice, coffee, and cocoa, emulsifiers, thickeners, flavorings, etc.). Furthermore, the soy milk of this embodiment also includes soybean liquid preparations prepared by suspending, dissolving, or homogenizing powder of dehulled soybeans or whole soybeans in water, as well as soybean beverages made from these as raw materials. The soy milk may be soy milk that has been pasteurized and sealed and packaged in a state where commercial sterility is maintained for the purpose of long-term storage.

[0024] The method for producing soy milk is not particularly limited, and soy milk can be produced using methods known to those skilled in the art, such as soaking soybeans overnight in water and then grinding them in a grinder. Soybeans may be pretreated, for example, by roasting. Commonly available commercially available soy milk may be used. When the final product is soy milk other than unadjusted soy milk, various additives commonly used in soy milk beverages may be added. Examples of additives include sugars such as sugar, salt, calcium lactate, emulsifiers, thickeners such as carrageenan, flavorings, colorings, oils and fats, preservatives, antioxidants, emulsifiers, spices, various extracts and pastes, proteins and their hydrolyzates, organic acids, starches, stabilizers, etc. Regarding soybean solids content, the Japanese Agricultural Standards define soy milk as having a soybean solids content of 8.0% or more, adjusted soy milk as having a soybean solids content of 6% or more, and soy milk beverages as having a soybean solids content of 4% or more. Any of these may be used as the soy milk in this embodiment.

[0025] Fermented soy milk refers to a fermented product obtained by fermenting soy milks using koji mold. The soy milks used as raw materials for producing fermented soy milks may be those classified as soy milk, prepared soy milk, or soy milk beverages under the Japanese Agricultural Standards, and are not particularly limited as long as they are obtained by conventional methods. Commercially available soy milks may be used, but solutions containing whole soybean flour, defatted soybean flour, etc. may also be used. The soy milks used as raw materials for producing fermented soy milks may also be beverages containing soybean-derived proteins, such as beverages in which soybeans are liquefied as is or in a fiber-containing state without removing the soybean fiber (okara) as in soy milk (whole soybean beverages, etc.), or beverages in which soybean fiber is added to soy milk (soy milk and okara beverages). The concentration of soybean-derived protein can be freely set as long as koji mold can grow. Furthermore, the soy milk used as raw material for producing fermented soy milks may be soy milk prepared by adjusting the soybean-derived protein concentration to a predetermined concentration, for example. Fermented soy milk is produced by fermenting soy milk and, if necessary, performing additional treatments other than fermentation, such as spray drying, retort sterilization, freeze drying, UHT sterilization, autoclaving, high-pressure steam sterilization, dry heat sterilization, electromagnetic wave sterilization, high-frequency sterilization, ultraviolet sterilization, and chemical sterilization (alcohol sterilization, electrolyzed water treatment), which are conventionally known methods for treating cultures.

[0026] By adding 10 ppm or more, preferably 20 ppm or more, of ERG to soy milk or fermented soy milk, the beany smell can be reduced and the bitterness of soy peptides can also be reduced. Since the effect of reducing the beany smell is not enhanced even if a large amount of ERG is added, in consideration of economic efficiency, ERG can be added to soy milk, etc. at 0.15 wt % or less, 0.12 or 0.09 wt % or less, 0.06 or 0.03 wt % or less.

[0027] Furthermore, in mycoprotein containing arginine, a bitter substance, the inclusion of ergothioneine not only reduces bitterness but also enhances umami. Mycoprotein is a food obtained by fermenting koji mold in a solid or liquid medium, and then adding seasonings as needed. By adding 300 ppm or more of ERG to mycoprotein, the bitterness of the arginine contained in the mycoprotein can be reduced and the umami can be enhanced. Furthermore, by producing an ERG-rich koji mold fermentation product using a high-ERG-producing koji mold strain without adding ERG, a koji mold fermentation product containing 50 ppm or more, 100, 300, 500, or 1,000 ppm or more of ERG and 5%, 4, 3, 2, or 1% or less of ERG can be obtained.

[0028] The ERG concentration is measured by LCMS under the following conditions: (HPLC conditions) HPLC analysis is performed under the following conditions: Apparatus: HPLC Apparatus: HPLC: Nexera series set (Shimadzu Corporation) Column: COSMOSIL 2.5 HILIC column 3.0 x 150 2.5 μm 3.0 mm I.D. × 15.0 cm (manufactured by Nakarai) Flow rate: 0.5 mL / min Temperature: 40°C Mobile phase: A) 0.1% (v / v) formic acid aqueous solution, B) 0.1% (v / v) formic acid acetonitrile Isocratic: 0-10 min (B: 80%) Injection volume: 5 μL (Mass spectrometry) Apparatus: LCMS-2020 (manufactured by Shimadzu Corporation) (Mass spectrometry (LC-MS) analysis conditions) Ionization conditions: ESI+ MS conditions: SIM ERG: m / z 230.1 ([M+H] ＋ ) Retention time: about 5 minutes

[0029] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. In the examples, "%" simply means "% by weight." For the sensory evaluation, room temperature samples were used.

[0030] [Test 1: Effect of Caffeine Bitterness Reduction in Bitterness Standard Substances by ERG] Caffeine was added to pure water to prepare four caffeine samples at concentrations of 0.01%, 0.03%, 0.05%, and 0.06%, and ergothioneine was added to these samples to give final concentrations of 0.05 ppm, 0.1 ppm, 0.25 ppm, and 0.5 ppm (ERG 0.05 to 0.5 in Table 1 below, and hereinafter, "ERGX" refers to a sample with X ppm of ERG added).

[0031] A sensory evaluation of bitterness was conducted by a four-person expert panel consisting of trained bitter-tasting subjects. A drinking test was conducted by the four-person expert panel for 0.01-0.06% caffeine samples (concentrations not disclosed to the panel) containing various concentrations of ERG, with a 0.01-0.06% caffeine sample without added ergothioneine as a control. The expert panel was presented with pairs of 0.01-0.06% caffeine control samples and 0.01-0.06% caffeine samples containing various concentrations of ergothioneine, and the panel conducted a two-point discrimination test to determine which of the presented pairs tasted more bitter. The results are shown in Table 2.

[0032] <Evaluation method for two-point discrimination test> Evaluation results of the taste (bitterness) of the test product compared to the control ▽: The taste (bitterness) is reduced compared to the control. ◇: The taste (bitterness) is the same as the control. ○: The taste (bitterness) is enhanced compared to the control. The evaluation method for the two-point discrimination test and the display of the evaluation results are the same for other tests.

[0033]

[0034] The results of the sensory evaluation showed that for caffeine samples containing 0.01% to 0.05%, all panelists evaluated that the bitterness was reduced when ERG was added to a final concentration of 0.1 ppm or more. For the 0.06% caffeine sample, all panelists evaluated that the bitterness was reduced when ERG was added to a final concentration of 0.5 ppm or more. For the 0.01% caffeine sample, the bitterness was reduced when ERG was added to a final concentration of 0.1 ppm or more, so the amount of ERG that has a bitterness-reducing effect relative to the caffeine content in a food or beverage corresponds to an ERG of 0.1 wt% or more.

[0035] [Test 2: Effect of ERG on Potassium Chloride Bitterness Reduction] A 5.0% potassium chloride sample (ERG5) was prepared by adding ergothioneine to a final concentration of 5 ppm (Table 3) (Table 3). A panel of five trained, bitter-tasting subjects was presented with a pair of samples: a control 5% potassium chloride sample (ERG0) without ERG and a 5% potassium chloride sample with ergothioneine added to a final concentration of 5 ppm. The panel conducted a two-point discrimination test to determine which of the paired samples they perceived as bitter and salty. The results are shown in Table 4.

[0036]

[0037] The results showed that four out of five panelists evaluated the 5% potassium chloride aqueous solution with 5 ppm ERG as having a reduced bitterness, and all five panelists evaluated the 5% potassium chloride aqueous solution with 5 ppm ERG as having an increased saltiness. Since the bitterness of a 5% potassium chloride aqueous solution is reduced when 5 ppm or more of ERG is added, the amount of ERG that has a bitterness-reducing effect relative to the potassium chloride content in a food or beverage corresponds to an ERG content of 0.01 wt% or more.

[0038] [Test 3: Effect of ERG on Bitterness Reduction of Potassium Chloride Processed Products] A sample (ERG5) was prepared by adding ergothioneine to a potassium chloride processed product sample containing 5.0% Cell Salt I (a potassium chloride bitterness-masking processed product: Mitejima Chemical) to a final concentration of 5 ppm (Table 5). The same five expert panel members as in Test 2 evaluated the sample using the same two-point discrimination test as in Test 2. The results are shown in Table 6.

[0039]

[0040] The results showed that all five panelists rated the 5% potassium chloride processed product aqueous solution to which ERG was added to reach a final concentration of 5 ppm as having a reduced bitter taste, and rated the 5% potassium chloride processed product aqueous solution to which ERG was added to reach a final concentration of 5 ppm as having an increased saltiness.

[0041] Test 4: Effect of ERG on Arginine Bitterness Reduction. An arginine sample containing 5.0% arginine, a bitter amino acid, was supplemented with ergothioneine to a final concentration of 5 ppm to prepare a sample (ERG5) (Table 7). A panel of four experts was presented with a pair of a 5% arginine control sample (ERG0) without ERG and a 5% arginine sample containing ergothioneine to a final concentration of 5 ppm. The panel conducted a two-point discrimination test to determine which of the presented samples perceived the bitterness and umami. The results are shown in Table 8.

[0042]

[0043] As a result, all four panelists evaluated that the 5% arginine aqueous solution containing ERG at a final concentration of 5 ppm reduced bitterness, and the 5% arginine aqueous solution containing ERG at a final concentration of 5 ppm increased umami. Since the bitterness of a 5% arginine aqueous solution is reduced when ERG is added to a final concentration of 5 ppm or more, the amount of ERG that has a bitterness-reducing effect relative to the arginine content in a food or beverage corresponds to an ERG of 0.01% by weight or more.

[0044] Test 5: Effect of ERG on the Bitterness Reduction of Soybean Peptides. A soybean peptide sample containing 1.0% HINUTE S (Fuji Oil Co., Ltd.) was supplemented with ergothioneine at final concentrations of 0.5 ppm, 1 ppm, 3 ppm, 5 ppm, and 10 ppm (ERG 0.5-10) to prepare samples (Table 9). A panel of four trained bitter-tasting subjects was presented with a pair of samples: a control 1% soybean peptide sample (ERG 0) without ERG and a 1% soybean peptide sample containing ergothioneine at final concentrations of 0.5-10 ppm. The panel conducted a two-point discrimination test to determine which of the paired samples they perceived as more bitter. The results are shown in Table 10.

[0045]

[0046] As a result, all four panelists evaluated that the bitterness of the 1% soybean peptide aqueous solution to which ERG was added to a final concentration of 0.5 ppm was reduced. Since the bitterness of a 1% soybean peptide aqueous solution was reduced when ERG was added to a final concentration of 0.5 ppm or more, the amount of ERG that has a bitterness-reducing effect relative to the soybean peptide content in a food or beverage corresponds to an ERG content of 0.005% by weight or more.

[0047] Test 6: Effect of ERG on Reducing the Irritating Taste of Sauces A sample (ERG5) was prepared by adding ergothioneine to a medium-thick sauce (Kikkoman Delicious Sauce Medium-Thick Sauce: Kikkoman Corporation) to a final concentration of 5 ppm. Two expert panelists were presented with a pair of samples: a control medium-thick sauce (ERG0) without added ERG and a medium-thick sauce sample with 5 ppm ergothioneine added. The panelists performed a two-point discrimination test to determine which of the paired samples they perceived as having the most irritating taste (hot and sour). The results are shown in Table 11.

[0048] The medium-thick sauce to which ERG was added so as to give a final concentration of 5 ppm was evaluated as having a reduced irritating taste.

[0049] Test 7: Effect of ERG on Reducing the Beany Odor of Soymilk Soymilk was prepared by adding ergothioneine to soymilk to final concentrations of 5 ppm, 10 ppm, 20 ppm, 40 ppm, 60 ppm, and 100 ppm (ERG 5-100) (Table 12). A trained expert panel of five members was presented with pairs of control soymilk without added ERG (ERG 0) and soymilk to which ergothioneine had been added to final concentrations of 5-100 ppm, and the panel conducted a two-point discrimination test to determine which of the pairs of samples they perceived had the beany odor. The results are shown in Table 13.

[0050] All panelists evaluated soy milk to which ergothioneine was added so that the concentration was 20 ppm or more as having a reduced beany smell, and two panelists evaluated soy milk to which ergothioneine was added so that the concentration was 10 ppm or more as having a reduced beany smell.

[0051] Test Example 8: Effect of ERG on Reducing the Bitterness of Mycoprotein Mycoprotein was produced using the following manufacturing method. Fermentation was carried out in a 30 L jar (Marubishi Bioengineering Co., Ltd.). 1.5 kg of okara powder was diluted to 15 L with water, and 2.25 g of Shin-Etsu Silicone® KM72F (Shin-Etsu Chemical Co., Ltd.), an antifoaming agent, was added and sterilized at 123°C for 60 minutes. An enzyme solution filtered through a 0.22 μm pore size filter was added to a final arabinase concentration of 0.6 U / ml and a final cellulase concentration of 0.1 U / ml, followed by stirring and reacting at 60°C for 2 hours. After the reaction, the mixture was cooled to 30°C. Preculture was carried out as follows: 5 g of okara powder and 100 ml of water were added to one 500 ml baffled Erlenmeyer flask for each strain, and the mixture was autoclaved (121°C, 30 minutes). A glycerol stock of Aspergillus oryzae strain (seed koji) was added in an amount of 0.5 ml each, and the initial number of spores in the preculture solution was adjusted to 5 × 10 ５The preculture solution was inoculated to a concentration of 1 / ml. This preculture solution was cultured for 24 hours with shaking (30°C, 160 rpm). This preculture solution was then inoculated into a 30 L jar and cultured at 30°C for 3 days. The aeration rate and stirring rate were initially set at 0.5 vvm and 250 rpm, and increased to 1 vvm and 330 rpm after 18 hours. After culture, the fermented product was heat sterilized (80°C, 30 minutes).

[0052] The heat-sterilized fermented product was dried for 1 minute in a drum dryer (manufactured by Katsuragi Kogyo Co., Ltd., product name "Drum Dryer D-00") set at a gap of 0.3 mm and a surface temperature of 150°C. This is referred to as fermented soy pulp. Using 16.7 g of the fermented soy pulp obtained by the procedure described above, the dried product was mixed with water in a 1:2 ratio by weight. This mixture was then mixed with 3% soy sauce and 1% yeast extract, and kneaded for 10 seconds in a kneading machine (manufactured by Tiger Corporation, product name "Microcomputer Food Processor SKF-H101"). At this time, samples with 330 ppm of ergothioneine added (Example) and samples without ergothioneine added (Comparative Example) were prepared. The kneaded samples were molded into a size of 1.8 cm thick and 7.5 cm inner diameter. 5 ml of oil was placed in a frying pan and the formed sample was baked over low heat for 1 minute 20 seconds on each side, for a total of 2 minutes 40 seconds. A sensory evaluation was performed to see how the taste of the test product of the example compared to the comparative example, which was the control. ◯: The taste is enhanced compared to the control. ◇: The taste is the same as the control. ▽: The taste is reduced compared to the control

[0053] The addition of 330 ppm of ERG reduced the bitterness of the mycoprotein and enhanced its umami flavor.

[0054] Test Example 9: Effect of ERG on reducing the beany odor of fermented soy milk Aspergillus oryzae strain in which the G428S mutation was introduced into the AO090005000664 ortholog gene was used as the seed culture. 60 ml of unadjusted soy milk was placed in a sterilized 300 ml Erlenmeyer flask, and the glycerol stock of the seed culture was added. The initial number of spores was 2.5 × 10 ４The culture medium was inoculated to a concentration of 1 / ml. This culture medium was cultured with shaking (26°C, 180 rpm) for 48 hours and then sterilized. The ergothioneine content was 37 ppm. A sensory evaluation of the soy milk before and after fermentation was conducted by a five-member expert panel, and all panelists evaluated that the soy milk after fermentation had a weaker beany smell.

Claims

1. An agent for reducing the unpleasant flavor of bitter substances, containing ergothioneine as the active ingredient.

2. The unpleasant flavor reducing agent according to claim 1, wherein the unpleasant flavor reduction is the reduction of the bitterness of bitter substances, such as soybean peptides or mycoproteins.

3. An agent for reducing unpleasant flavors in beverages containing beans as ingredients, containing ergothioneine as an active ingredient.

4. The unpleasant flavor reducing agent according to claim 3, wherein the unpleasant flavor reduction is the reduction of the beany smell of soy milk.

5. A food or beverage containing a bitter substance, characterized in that it contains 0.005% by weight or more of ergothioneine relative to the soy peptide content, and has a reduced bitterness of soy peptides.

6. Soy milk or fermented soy milk containing 10 ppm or more of ergothioneine.

7. Mycoprotein containing more than 300 ppm ergothioneine.

8. A method for reducing the unpleasant taste of food or beverage by adding ergothioneine to the food or beverage having an unpleasant taste.

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