soy sauce

Abstract

To provide soy sauce having enhanced saltiness and umami taste. [Solution] By adding 10 ppm or more of ergothioneine to soy sauce, soy sauce with enhanced flavors such as saltiness and umami can be obtained.

Description

[Technical field]

[0001] The present invention relates to soy sauce with enhanced flavor. [Background technology]

[0002] In recent years, there has been a society-wide demand for reducing salt (sodium chloride) intake to prevent diseases such as high blood pressure, kidney disease, and heart disease, and there is a trend toward low-salt foods and beverages in general. Simply reducing the salt content from a conventional product results in a dull, unpalatable taste, so a known method of reducing salt content is to increase umami components to compensate for the reduction in saltiness and provide a satisfying taste, but in this case it is necessary to increase the umami components considerably.

[0003] Soy sauce, an essential ingredient in Japanese cuisine, is no exception to the trend toward low salt content, and technological development is underway to produce soy sauce that has a good salty taste and flavor even with a low salt content. For example, Patent Document 1 describes soy sauce in which the umami taste of glutamic acid is enhanced by the inclusion of methional, and Patent Document 2 reports a soy sauce that contains 0.5 to 5% (w / v) salt and 0.2 to 4% (w / v) ammonium ions and has a pH of 3.2 to 5.0, and has excellent saltiness and soy sauce-like flavor. Furthermore, Patent Document 3 describes that the saltiness and umami taste of sodium chloride can be enhanced by using a saltiness and / or umami taste enhancer containing trehalose as an active ingredient, resulting in the production of foods and beverages with rich, excellent flavor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-18146 A [Patent Document 2] Patent No. 5812864 [Patent Document 3] Japanese Patent Application Publication No. 10-66540 [Patent Document 4] International Publication No. 2019 / 240243 [Non-patent literature]

[0005] [Non-Patent Document 1] BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY(2019)Vol.83,No.1,p.181‐184 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a soy sauce having an enhanced salty taste without increasing the salt content of the soy sauce and also having enhanced flavors such as umami. [Means for solving the problem]

[0007] As a result of extensive research into substances capable of simultaneously enhancing the saltiness and umami taste of soy sauce, the present inventors discovered that ergothioneine, which can be produced only by certain microorganisms, such as fungi such as mushrooms, Aspergillus oryzae, actinomycetes, and cyanobacteria, can simultaneously enhance the saltiness and umami taste of soy sauce when present in small amounts in soy sauce, thereby completing the present invention.

[0008] The present invention relates to a soy sauce as set forth in the following (1) to (3) or a soy sauce-containing seasoning as set forth in (4). (1) Soy sauce containing 10 ppm or more of ergothioneine. (2) The soy sauce according to claim 1, wherein the soy sauce is reduced-salt soy sauce. (3) The soy sauce according to (1) or (2) above, which is produced using a highly ergothioneine-producing koji mold strain. (4) Soy sauce-containing seasonings containing 5 ppm or more of ergothioneine. Effect of the Invention

[0009] The present invention relates to a soy sauce as set forth in the following (1) to (3) or a soy sauce-containing seasoning as set forth in (4). (1) Ergothioneine: 10 ppm or more0.09% by weight or less Contains soy sauce (Excluding retort food manufacturing.) . (2) The soy sauce according to claim 1, wherein the soy sauce is reduced-salt soy sauce. (3) The soy sauce according to (1) or (2) above, which is produced using a highly ergothioneine-producing koji mold strain. (4) Ergothioneine: 5 ppm or more 0.09% by weight or less Contains soy sauce-containing seasonings ( Excluding retort food manufacturing. ). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention relates to a soy sauce containing ergothioneine and having enhanced tastes such as saltiness and umami. In the present invention, "%" means "% by weight" even if the unit is not specified, and 1 ppm is 0.0001% by weight.

[0011] Soy sauce is typically produced by heat-treating vegetable raw materials such as soybeans and wheat, propagating koji mold on the raw materials, and then fermenting and maturing the soy sauce in salt water, and the salt concentration is generally 15 to 18% by weight. There are other types of soy sauce, such as chemical soy sauce made by decomposing vegetable raw materials with acids and enzymes, fish sauce made by fermenting seafood, and meat sauce made by fermenting livestock meat, but the soy sauce of the present invention is preferably brewed soy sauce made using koji mold. There are various types of brewed soy sauce depending on the manufacturing method, such as the ratio of soybeans and wheat, the method of processing the raw materials, and the salt concentration, and examples of these include koikuchi, usukuchi, tamari, shiro, saishikomi, etc. There is also reduced-salt soy sauce, which has nearly half the salt content of regular soy sauce, and the soy sauce of the present invention includes reduced-salt soy sauce.

[0012] Ergothioneine (hereinafter, also referred to as "ERG") was discovered as a sulfur-containing amino acid isolated from the rye ergot fungus (Claviceps purpurea), and it has been confirmed that it also exists in the living bodies of plants and animals. However, plants and animals cannot synthesize ergothioneine, and it is believed that ergothioneine in the living body is derived from ergothioneine synthesized by microorganisms such as basidiomycetes. It is known to be contained in some edible mushrooms of basidiomycetes, such as oyster mushrooms, shiitake mushrooms, maitake mushrooms, and king oyster mushrooms, and is particularly abundant in Tamogi mushrooms. It is also known that Aspergillus oryzae produces ERG.

[0013] It is known that ERG is synthesized from histidine in microorganisms, and the sulfur atom is supplied from cysteine. ERG has high antioxidant properties, and has been reported to have elastase and tyrosinase inhibitory effects, and is particularly attracting attention in the beauty and food fields, such as whitening and wrinkle prevention. It has also been found that ERG is involved in the biological oxidation defense system, and applications in the medical field are also being attempted. ERG has high thermal and pH stability and can maintain its antioxidant effect even at high temperatures, so it is incorporated into foods in the hope of its physiological effects, and is also expected to be used in foods as an antioxidant.

[0014] Methods for producing ERG include extraction from basidiomycetes such as Pleurotus cornucopiae, chemical synthesis, and fermentation using microorganisms. Extraction from basidiomycetes such as Pleurotus cornucopiae 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 production methods by fermentation, such as fermentation using bacteria or yeast that can assimilate C1 compounds, fermentation using microorganisms that have overexpressed the ERG biosynthesis gene, and solid culture using Aspergillus oryzae that has been introduced with the ERG biosynthesis gene and overexpressed ERG (Non-Patent Document 1).

[0015] As the EGR of the present invention, a commercially available ERG obtained by chemical synthesis may be used, or an extract or a refined product thereof may be used from mushrooms containing ERG, from koji mold producing ERG, or from a culture of the koji mold, or from sake lees produced using the koji mold. In addition, for soy sauce using koji mold as a raw material, the amount of ERG in soy sauce can be increased by using a koji mold that produces a high amount of ERG without adding ERG. Mushrooms used for extracting ERG include, preferably, Pleurotus cornucopiae var. citrinopileatus, Pleurotus ostreatus, Lentinula edodes, and Maitake mushroom (Grifola Frondosa), which are mushrooms of the Pleurotus genus in the Pleurotus family, due to their high ERG content. These may be used alone or in combination.

[0016] As the koji mold for producing ERG, any species belonging to the genus Aspergillus can be used. Examples include Aspergillus oryzae, Aspergillus sojae, Aspergillus niger, Aspergillus luchuensis, and Aspergillus tamarii. As the koji mold strain, for example, a strain available from a depository institution such as the Aspergillus oryzae RIB326 strain, a strain contained in a commercially available seed koji, or a strain obtained by isolating from a food and beverage production environment such as a sake or soy sauce brewery can be used.

[0017] In addition to the wild-type strains mentioned above, mutant strains that produce high levels of ERG can be isolated and used as ERG-producing Aspergillus oryzae by using common mutagenesis methods, such as ultraviolet (UV) or X-ray irradiation, which physically damage DNA and introduce mutations, or treatment with alkylating agents such as N-methyl-N'-nitro-N-nitrosoguanidine (NTG) or ethyl methanesulfonate (EMS), which chemically damage DNA and introduce mutations.

[0018] Furthermore, an ERG-high-producing koji mold strain into which a gene related to ERG biosynthesis has been introduced by genetic recombination can be used. Examples of such koji mold strains include, but are not limited to, koji mold mutants into which the egtA gene has been introduced (see Patent Document 4 and Non-Patent Document 1), and Aspergillus mutants into which the expression of ERG has been increased by introducing the AO090005000664 gene (encoded amino acid sequence: SEQ ID NO: 1) specific to the Aspergillus genus and into which a specific gene mutation 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 (see PCT / JP2023 / 020131).

[0019] As used herein, a koji mold strain highly producing ERG refers to one that produces 5 to 10 times or more, preferably 20 times or more, of ERG produced by liquid culture at 20 to 30°C for 3 to 14 days (Puffmin SM medium (a solution prepared by adding 5 to 10% Puffmin SM (Kikkoman Corporation) to water and suspending it therein), pH unadjusted) compared to a non-mutated or non-transformed strain. Examples of this include an Aspergillus sojae strain in which the above-mentioned egtA gene is forcibly expressed, or an Aspergillus oryzae mutant strain having amino acid mutations or deletions in the W404 to Q515 region of the above-mentioned mutant AO090005000664 gene and its orthologous gene.

[0020] In addition, because soy sauce is made from a product fermented with koji mold, the ERG content in soy sauce can be increased by making koji using an ERG-rich koji mold strain without adding ERG during production. In addition, using an ERG-rich koji mold strain in soy sauce production has the advantage of improving filterability during the soy sauce production process compared to when ERG is added.

[0021] The term "enhanced umami and / or saltiness" means that the umami and saltiness are felt more strongly than in the absence of the umami-salty enhancer of the present invention. Specifically, it means that the addition of ERG allows the same saltiness or umami to be felt even if the amount of salt or umami component is reduced by, for example, 1 to 50%. It also means that the addition of ERG allows the same saltiness or umami to be felt as in the case of containing, for example, 1.1 to 2 times the amount of salt or umami component. Alternatively, it means that in the case where a small amount of salt or umami component is contained but cannot be felt, the addition of the umami-salty enhancer allows the saltiness or umami to be felt for the first time.

[0022] The taste of soy sauce, such as saltiness and umami, is enhanced by adding the ERG of the present invention to soy sauce at 5 ppm or more, for example, 10 ppm, 15 ppm, 25 ppm, 30 ppm or more, or 35 ppm, 40 ppm, 45 ppm, 50 ppm or more. Similarly, the taste of reduced-salt soy sauce, such as saltiness and umami, is enhanced by adding the ERG of the present invention to reduced-salt soy sauce at 5 ppm or more, for example, the above-mentioned concentration or more. Furthermore, for soy sauce-containing seasonings, including soy sauce, by adding 5 ppm or more of ERG, the tastes such as saltiness and umami are enhanced. Furthermore, since the inclusion of a large amount of ERG does not increase the umami and saltiness enhancing effect of soy sauce, in consideration of economic efficiency, the soy sauce can contain ERG at 0.15% by weight or less, for example, 0.12, 0.09% by weight or less, or 0.06% by weight or less.

[0023] The concentration of ERG is measured by LCMS under the following conditions. (HPLC conditions) The HPLC analysis is carried out under the following conditions. Equipment: HPLC equipment: HPLC: Nexera series (Shimadzu Corporation) Column: COSMOSIL 2.5HILIC column 3.0 x 150 2.5 μm 3.0 mm I.D. x 15.0 cm (Nacalai) Flow rate: 0.5mL / min Temperature: 40℃ Mobile phase: A) 0.1% (v / v) formic acid in water, B) 0.1 (v / v) formic acid in acetonitrile Isocratic: 0-10 minutes (B:80%) Injection volume: 5μL (Mass spectrometry) Equipment: LCMS-2020 (Shimadzu Corporation) (Mass spectrometry (LC-MS) analysis conditions) Ionization conditions: ESI+ MS conditions: SIM ERG: m / z230.1([M+H] + ) Retention time: Around 5 minutes

[0024] Furthermore, when the ERG of the present invention is added to soy sauce during the process of producing soy sauce, it may be added at any step, and there are no limitations on the method of addition as long as the required amount is contained in the final product, soy sauce. EXAMPLES

[0025] 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, samples at room temperature were used.

[0026] [Test 1: Amount of ERG added to enhance the saltiness of soy sauce] (1) Specially selected whole soybean soy sauce Samples were prepared by adding ergothioneine (manufactured by Tetrahedron Corporation) to commercially available special whole soybean soy sauce (Kikkoman Corporation) to concentrations of 5 ppm, 20 ppm, and 50 ppm (ERG5 to 50 in Table 1 below, and hereinafter "ERGX" refers to a sample with X ppm of ERG added). A panel of five experts conducted a drinking test of specially selected whole soybean soy sauces containing various concentrations of ERG (concentrations not disclosed to the panel) with soy sauce without added ergothioneine as a control. The expert panel was presented with pairs of the control soy sauce and soy sauces containing various concentrations of ergothioneine, and the panel conducted a two-point discrimination test to determine which of the pairs they perceived as saltier. The results are shown in Table 1.

[0027] <Evaluation method for the two-point discrimination test> Evaluation results of saltiness of test products compared to the control ○: Saltiness is enhanced compared to the control. ◇: Same saltiness as the control. The evaluation method for the two-point discrimination test and the display of the evaluation results are the same as those for other tests.

[0028] [Table 1] All panelists rated soy sauce containing 5 ppm or more of ERG as having an enhanced saltiness.

[0029] (2) In the case of light soy sauce A similar two-point discrimination test was also carried out on commercially available light soy sauce. The results are shown in Table 2. [Table 2] All panelists rated the light soy sauce containing 5 ppm or more of ERG as having an enhanced saltiness.

[0030] (3) In the case of reduced-salt soy sauce A similar two-point discrimination test was also conducted on commercially available reduced-salt soy sauce. The results are shown in Table 3. [Table 3] All panelists rated the reduced-salt soy sauce containing 5 ppm or more of ERG as having an enhanced saltiness.

[0031] [Test 2: Amount of ERG added to enhance the umami taste of soy sauce] (1) In the case of dark soy sauce Samples (ERG5-200) were prepared by adding ergothioneine to a dark soy sauce concentrate at concentrations of 5 ppm, 10 ppm, 50 ppm, 100 ppm, and 200 ppm. A panel of five experts conducted a drinking test of dark soy sauces containing various concentrations of ERG (concentrations not disclosed to the panel) with soy sauce without added ergothioneine as a control. The expert panel was presented with pairs of the control soy sauce and soy sauces containing various concentrations of ergothioneine, and the panel evaluated which of the pairs they perceived as umami by a two-point discrimination test. The results are shown in Table 4.

[0032] <Evaluation method for the two-point discrimination test> Evaluation results of the umami taste of the test product compared to the control ◯: The flavor is enhanced compared to the control. ◇: Taste similar to the control. The evaluation method for the two-point discrimination test and the display of the evaluation results are the same as those for other tests.

[0033] [Table 4] Four panelists rated soy sauce containing 5 ppm or more of ERG as having enhanced umami flavor, while all panelists rated soy sauce containing 10 ppm or more as having enhanced umami flavor.

[0034] Samples (ERG5-200) were prepared by adding ergothioneine to dark soy sauce at concentrations of 5 ppm, 10 ppm, 50 ppm, 100 ppm, and 200 ppm, and each was diluted 10-fold with pure water. The same five expert panel members conducted a drinking test on the soy sauces to which ERG had been added at each concentration, and the umami taste was evaluated. The five expert panel members were presented with pairs of soy sauces with ERG added at successively different concentrations (for example, a pair of ERG 10 ppm and 50 ppm), and the panel members performed a two-point discrimination test to determine which of the pairs they felt had the umami taste. The results are shown in Table 5.

[0035] [Table 5] The four-member panel evaluated soy sauce with 200 ppm ERG added as having the same umami flavor as soy sauce with 100 ppm ERG added, indicating that the degree of umami flavor enhancement with the addition of 200 ppm ERG is no different from that with 100 ppm ERG added. From the above, it was evaluated that when ERG was added to dark soy sauce at 5 ppm to 100 ppm, the umami flavor was enhanced as the amount added increased. When the amount exceeded 100 ppm, the umami flavor enhancement effect was not different from that of the 100 ppm addition.

[0036] (2) In the case of reduced-salt soy sauce 1 ml of ERG aqueous solution was added to 4 ml of commercially available Honjozo reduced-salt soy sauce (50% salt reduction, Kikkoman Corporation), and ergothioneine was added to concentrations of 5 ppm, 10 ppm, 50 ppm, 100 ppm, and 200 ppm to prepare samples (ERG5-200). To prepare reduced-salt soy sauce without added ergothioneine (ERG0), 1 ml of water was added to 4 ml of reduced-salt soy sauce. For reduced-salt soy sauces containing ERG at various concentrations (concentrations not disclosed to the panel), pairs of reduced-salt soy sauces containing ERG at successively different concentrations (for example, a pair containing ERG at 10 ppm and 50 ppm) were presented to a panel of five experts, who were asked to evaluate which of the pairs they perceived as umami or salty by a two-point discrimination test. The results are shown in Table 6 (umami) and Table 7 (saltiness).

[0037] <Evaluation method for the two-point discrimination test> Evaluation results of umami (saltiness) of the test product compared with the control ○: The umami (saltiness) is enhanced compared to the control. ◇: Same umami (salty) taste as the control.

[0038] [Table 6]

[0039] [Table 7]

[0040] All panelists agreed that the reduced-salt soy sauce containing 5 ppm ERG had enhanced umami and saltiness. In addition, when ERG was added to reduced-salt soy sauce at levels between 5 ppm and 200 ppm, it was evaluated that the umami and saltiness were enhanced as the amount added increased. Sample ERG200, made by adding 1 ml of ERG aqueous solution to 4 ml of reduced-salt soy sauce to give an ERG concentration of 200 ppm, was compared with a control made by mixing 2 ml of honjozo soy sauce, 2 ml of reduced-salt soy sauce, and 1 ml of water. ERG200 was rated as having the same umami and saltiness as the control.

[0041] (3) Specially selected whole soybean soy sauce or light soy sauce Samples (ERG5-200) were prepared by adding ergothioneine to commercially available special whole soybean soy sauce (Kikkoman Corporation) at concentrations of 5 ppm, 10 ppm, 50 ppm, 100 ppm, and 200 ppm, and, as in (1) above, a drinking test was conducted by a five-member expert panel, who were presented with pairs of control soy sauce without added ergothioneine and soy sauce with various concentrations of ergothioneine added. The panel conducted a two-point discrimination test to determine which of the pairs of samples they perceived as umami. A similar two-point discrimination test was also conducted on commercially available light soy sauce. The results showed that all panelists rated the soy sauce containing 5 ppm or more of ERG as having enhanced umami flavor, both for the special whole soybean soy sauce and the light soy sauce.

[0042] [Test 3: Sweetness enhancement effect of soy sauce] (1) Specially Selected Whole Soybean Soy Sauce Soy sauce samples were prepared by adding ergothioneine to commercially available special whole soybean soy sauce (Kikkoman Corporation) at concentrations of 10 ppm, 20 ppm, and 50 ppm (EGR 10, 20, and 50). A panel of three experts conducted a drinking test of soy sauce containing various concentrations of ERG (concentrations not disclosed to the panel) against soy sauce without added ergothioneine (ERG0) as a control, and evaluated the sweetness using a two-point discrimination test. The results are shown in Table 8.

[0043] <Evaluation method for the two-point discrimination test> Sweetness evaluation results of the test product compared to the control ○: Sweeter than the control. ◇: Same sweetness as the control. The evaluation method for the two-point discrimination test and the display of the evaluation results are the same as those for other tests.

[0044] [Table 8] All panelists rated soy sauce containing 10 ppm or more of ERG as having an enhanced sweetness.

[0045] (2) Sweet soy sauce ERG was added to a commercially available sweet soy sauce (Golden Purple, Fundokin Soy Sauce) and the same test as in (1) above was carried out. The results are shown in Table 9. [Table 9] All panelists rated sweet soy sauce containing 10 ppm or more of ERG as having an enhanced sweetness.

[0046] [Test 4: Soy sauce production] Equal amounts of steamed and denatured defatted soybeans and crushed roasted wheat were mixed, inoculated with seed koji, and koji was produced for 42 hours by a conventional method to obtain soy sauce koji. For the seed koji, an Aspergillus sojae mutant strain (Example 1) into which 4 copies of the egtA gene were introduced and the inserted gene was overexpressed, and an Aspergillus oryzae strain (Example 2) into which the G428S mutation was introduced into the AO090005000664 gene were used. 100 parts by mass of the obtained soy sauce koji were added to 130 parts by mass of salt solution (salt concentration 26% (w / v)), and fermented and aged at 25 to 30 ° C. for 150 days while appropriately stirring, by conventional moromi management. The obtained aged moromi was squeezed and filtered to obtain raw soy sauce. The obtained raw soy sauce was pasteurized at 80 ° C. for 1 hour, and then clarified and filtered to obtain soy sauce. The ERG concentrations in the soy sauces obtained by the clarification filtration were 566 ppm in Example 1 and 250 ppm in Example 2. The soy sauce of the Example had enhanced umami, saltiness, and sweetness compared to the commercially available product. Furthermore, the soy sauce of Example 2 had improved compressibility and workability during the filtration process during its production.

[0047] [Test 5: Effect of ERG on taste enhancement of soy sauce-containing seasonings] A panel of experts conducted a two-point discrimination test to evaluate the taste (umami, sweetness, and bitterness) of the test product, which was a soy sauce-containing seasoning with ERG added, and the control soy sauce-containing seasoning without ERG added, in comparison with the control. The results of the sensory evaluation are shown in Tables 10 and 11 below. The test sample "ERGX" means that the test sample contained X ppm of ERG. Sensory evaluation ○: The taste is enhanced compared to the control. ◇: Tastes the same as the control.

[0048] (1) Hontsuyu After adding 5 ppm of ERG to the original solution of Hontsuyu (Kikkoman Corporation), the solution was diluted 4-fold and subjected to a sensory test. [Table 10] The addition of 5 ppm of ERG enhanced the umami and sweetness of the soup.

[0049] (2) Zaru soba soup A sensory test was conducted after adding 5 ppm of ERG to Zaru Soba Soba Soup (straight soup: Kikkoman Corporation). [Table 11] The addition of 5 ppm ERG enhanced the umami, sweetness, and saltiness of the zaru soba soup.

Claims

1. Soy sauce (excluding that for use in retort food production) containing not less than 10 ppm and not more than 0.09% by weight of ergothioneine.

2. The soy sauce of claim 1 , wherein the soy sauce is a reduced-salt soy sauce.

3. 3. The soy sauce according to claim 1 or 2, which is produced using an ergothioneine-rich Aspergillus oryzae strain.

4. Soy sauce-containing seasonings (excluding those for use in retort food production) containing 5 ppm or more and 0.09% or less by weight of ergothioneine.

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