Equol-containing food composition and method for producing the same

Abstract

To provide a food composition containing equol and an organic acid and having improved flavor, especially aroma.SOLUTION: The food composition contains an organic acid and equol, particularly at least one organic acid selected from the group consisting of carbonic acid, hydrogen carbonate, citric acid, lactic acid, phosphoric acid, gluconic acid, acetic acid, malic acid, orotic acid, ammonium salts thereof, alkali metal salts thereof, alkaline earth metal salts thereof, and chelates thereof, and equol.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a food composition containing equol and an organic acid. In particular, the present invention relates to a food composition containing equol and an organic acid that has an improved flavor, particularly an improved aroma. The present invention also relates to a method for producing the food composition. [Background technology]

[0002] Equol-containing compositions are often used primarily as foods, and their flavor, particularly their aroma, is an important factor. To date, it has been known to add flavoring agents to food compositions containing equol to improve their flavor (Patent Document 1) and to add pH adjusters to control the pH (Patent Document 2), but it has not been known to use pH adjusters to improve flavor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-139424 [Patent Document 2] Patent No. 5769419 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made in view of these circumstances, and an object of the present invention is to provide a food composition containing equol and an organic acid that has an improved flavor, particularly an improved aroma. Another object of the present invention is to provide a method for producing a food composition containing equol and an organic acid, which has an improved flavor, particularly an improved aroma, in addition to or in addition to the above-mentioned object. [Means for solving the problem]

[0005] In order to solve the above problems, the present inventors have discovered the following invention. <1> A food composition comprising equol and an organic acid. <2> the above <1> In the food composition, the content of the organic acid is preferably 1.5 to 29% by weight, more preferably 1.7 to 25% by weight, and even more preferably 2.0 to 22% by weight, when the food composition is taken as 100% by weight.

[0006] <3> the above <1> or <2> In the above, the organic acid is preferably at least one selected from the group consisting of carbonic acid, hydrogen carbonate, citric acid, lactic acid, phosphoric acid, gluconic acid, acetic acid, malic acid, orotic acid, and ammonium salts, alkali metal salts, alkaline earth metal salts, and chelates thereof. In particular, the organic acid is preferably at least one selected from the group consisting of citric acid, lactic acid, acetic acid, malic acid, orotic acid, phosphoric acid, and gluconic acid, more preferably at least one selected from the group consisting of citric acid, lactic acid, phosphoric acid, gluconic acid, acetic acid, and malic acid, and most preferably at least one selected from the group consisting of citric acid, lactic acid, phosphoric acid, and acetic acid.

[0007] <4> the above <1> ~ <3> In any one of the above, the equol is preferably produced by utilizing a culture process of an anaerobic microorganism. <5> the above <4> In the method, the anaerobic microorganisms may be microorganisms belonging to the genus Asaccharobacter or Adlercreutzia. <6> the above <4> or <5> In either of the above, the pH of the culture solution after completion of the culture step is adjusted to 3.0 to 5.5, preferably 3.5 to 5.0, more preferably 4.0 to 5.0, with the organic acid.

[0008] <7> A method for obtaining an equol-containing food composition, comprising the steps of: culturing at least one equol raw material selected from the group consisting of daidzein glycoside, daidzein, and dihydrodaidzein with an anaerobic microorganism; A method for producing an equol-containing food composition, characterized in that during the culture process, at least one organic acid selected from the group consisting of carbonic acid, bicarbonate, citric acid, lactic acid, phosphoric acid, gluconic acid, acetic acid, malic acid, and orotic acid, as well as their ammonium salts, alkali metal salts, alkaline earth metal salts, and chelates thereof, is added. The organic acid is preferably at least one selected from the group consisting of citric acid, lactic acid, acetic acid, malic acid, orotic acid, phosphoric acid, and gluconic acid, more preferably at least one selected from the group consisting of citric acid, lactic acid, phosphoric acid, gluconic acid, acetic acid, and malic acid, and most preferably at least one selected from the group consisting of citric acid, lactic acid, phosphoric acid, and acetic acid.

[0009] <8> the above <7> When the equol-containing food composition is taken as 100% by weight, the content of the organic acid is preferably 1.5 to 29% by weight, more preferably 1.7 to 25% by weight, and even more preferably 2.0 to 22% by weight. <9> the above <7> or <8> In the method, the anaerobic microorganisms may be microorganisms belonging to the genus Asaccharobacter or Adlercreutzia. <10> the above <7> ~ <9> In any of the above, the pH of the culture solution after completion of the culture step is adjusted to 3.0 to 5.5, preferably 3.5 to 5.0, more preferably 4.0 to 5.0, with the organic acid. [Effects of the Invention]

[0010] According to the present invention, a food composition containing equol and an organic acid can be provided which has an improved flavor, particularly an improved aroma. Furthermore, the present invention can provide a method for producing a food composition containing equol and an organic acid that has an improved flavor, particularly an improved aroma, in addition to or in addition to the above effects. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention provides a food composition comprising equol and an organic acid. The present invention particularly provides a food composition comprising equol and an organic acid that has an improved flavor, particularly an improved aroma. The present invention also provides a method for producing the food composition.

[0012] <Food composition containing equol and organic acid> The present invention provides a food composition comprising equol and an organic acid. The present invention particularly provides a food composition comprising equol and an organic acid that has an improved flavor, particularly an improved aroma. In the present application, "flavor" refers to aroma, and in the case of edible food, taste, etc. In the present invention, the "aroma" in particular can be improved. The food composition of the present invention comprises an organic acid. The organic acid may be at least one selected from the group consisting of carbonic acid, hydrogen carbonate, citric acid, lactic acid, phosphoric acid, gluconic acid, acetic acid, malic acid, orotic acid, and their ammonium salts, alkali metal salts, alkaline earth metal salts, and chelates. In particular, at least one selected from the group consisting of citric acid, lactic acid, acetic acid, malic acid, orotic acid, phosphoric acid, and gluconic acid is preferred, more preferably at least one selected from the group consisting of citric acid, lactic acid, phosphoric acid, gluconic acid, acetic acid, and malic acid, and most preferably at least one selected from the group consisting of citric acid, lactic acid, phosphoric acid, and acetic acid.

[0013] The organic acid contains, when the food composition is taken as 100% by weight, It is 1.5 to 29% by weight, preferably 1.7 to 25% by weight, and more preferably 2.0 to 22% by weight.

[0014] Equol is preferably produced using an anaerobic microbial culture process. The anaerobic microorganism may be a microorganism belonging to the genus Asaccharobacter or Adlercreutzia. Furthermore, the pH of the final culture solution in the culture step is adjusted to 3.0 to 5.5, preferably 3.5 to 5.0, and more preferably 4.0 to 5.0, with the organic acid. The culturing step will be described in detail in the method for producing the food composition of the present invention.

[0015] The composition of the present invention may contain ingredients other than equol or organic acids, as long as the ingredients do not impair the flavor. Examples of the above-mentioned components include, but are not limited to, amino acids, sugars, vitamins, minerals, isoflavones, dietary fiber, and excipients.

[0016] <Method of manufacturing an equol-containing food composition> According to the present invention, the above-mentioned food composition, particularly a food composition having improved flavor, especially aroma, can be obtained, for example, by the following production method. The present invention also provides the production method. The production method includes a step of culturing at least one equol raw material selected from the group consisting of daidzein glycoside, daidzein, and dihydrodaidzein with an anaerobic microorganism, thereby obtaining an equol-containing food composition, The method is characterized in that the organic acid is added in the culturing step.

[0017] The method of the present invention comprises the step of culturing at least one equol source selected from the group consisting of daidzein glycoside, daidzein, and dihydrodaidzein with an anaerobic microorganism. The conditions for the culture step are not particularly limited as long as equol can be produced. For example, conventionally known conditions can be used, but the conditions are not limited to these.

[0018] <<Equol ingredient>> The equol raw material used in the production method of the present invention may be in any form as long as it can be used as a raw material for equol. The equol raw material may be at least one selected from the group consisting of daidzein glycoside, daidzein, and dihydrodaidzein, and may be in any form, such as daidzein glycoside itself, daidzein itself, or dihydrodaidzein itself, or a substance containing any of these, such as soybeans, processed soybeans, soybean hypocotyls, processed soybean hypocotyls, e.g., soybean hypocotyl extracts, or, more specifically, commercially available isoflavones.

[0019] <<Anaerobic microorganisms>> The equol-utilizing microorganism used in the production method of the present invention is not particularly limited as long as it is an anaerobic microorganism that produces equol from the above-mentioned equol raw material. Anaerobic microorganisms can produce equol at temperatures around 37°C (eg, 30 to 42°C), for example. The equol assimilation ability can be confirmed by quantifying daidzein, dihydrodaidzein, equol, etc. in the culture. These quantifications can be performed by those skilled in the art based on the descriptions in, for example, WO2012 / 033150, JP 2012-135217, JP 2012-135218, JP 2012-135219, etc. An example of these quantification methods is shown below.

[0020] For example, ethyl acetate is added to the culture medium, which is then vigorously stirred and centrifuged to separate the ethyl acetate layer. The same procedure can be repeated several times as necessary, and the combined ethyl acetate layers can be used to obtain an equol extract. This extract is concentrated to dryness under reduced pressure using an evaporator and dissolved in methanol. This is then filtered using a membrane such as a polytetrafluoroethylene (PTFE) membrane to remove insoluble matter, and the resulting solution can be used as a sample for high-performance liquid chromatography analysis. Examples of high-performance liquid chromatography conditions include, but are not limited to, the following:

[0021] [High-performance liquid chromatography conditions] Column: Phenomenox Luna 5uC18, 2.0mm x 150mm (Shimadzu GLC) Mobile phase: water / methanol [55:45, v / v] Flow rate: 0.2mL / min Column temperature: 40℃ Detection: UV280nm Retention times: dihydrodaidzein 13.8 minutes, daidzein 19.6 minutes, glycitein 22.5 minutes, equol 25.6 minutes, genistein 35.0 minutes

[0022] Anaerobic microorganisms include, but are not limited to, microorganisms classified into the following genera: Genus Adlercreutzia Genus Asaccharobacter Bacteroides genus Bifidobacterium Clostridium Genus Eggerthella Enterococcus genus Genus Enterorhabdus Eubacterium genus Genus Finegoldia Lactobacillus Lactococcus genus Genus Paraeggerthella Pediococcus genus Genus Sharpea Genus Slackia Streptococcus genus Veillonella genus

[0023] Specific examples of anaerobic microorganisms include, but are not limited to, the following microorganisms: Asaccharobacter celatus Adlercreutzia equolifaciens Bacteroides ovatus Bifidobacterium breve Bifidobacterium longum Clostridium sp. Eggerthella sp. Enterococcus faecalis Enterococcus faecium Enterorhabdus mucosicola Eubacterium sp. Finegoldia magna Lactobacillus fermentum Lactobacillus mucosae Lactobacillus paracasei Lactobacillus plantarum Lactobacillus rhamnosus Lactobacillus sp. Lactococcus garvieae Paraeggerthella sp. Pediococcus pentosaceus Sharpea azabuensis Slackia equolifaciens Slackia isoflavoniconvertens Slackia sp. Streptococcus constellatus Streptococcus intermedius Veillonella sp.

[0024] Among the microorganisms described above, any of the microorganisms described below or related microorganisms having properties as species similar to these microorganisms can be cited as more preferred anaerobic microorganisms. Microorganisms belonging to the genera Asaccharobacter or Adlercreutzia. In particular, it is preferable that: Asaccharobacter celatus DSM 18785 strain Adlercreutzia equolifaciens DSM 19450 strain

[0025] The above anaerobic microorganisms can be obtained from the depository institutions indicated by their accession numbers. Each accession number indicates that the anaerobic microorganism has been deposited at the following depository institution. FERM International Patent Organism Depositary (IPOD) http: / / unit.aist.go.jp / pod / ci / index.html DSM German Collection of Microorganisms and Cell Cultures (DSMZ) http: / / www.dsmz.de / KCCM Korean Culture Center of Microorganisms

[0026] In the present invention, anaerobic microorganisms capable of producing equol are cultured under conditions suitable for equol production. In the present invention, conditions suitable for equol production refer to conditions under which the survival and activity of anaerobic microorganisms capable of producing equol are maintained. More specifically, these conditions refer to maintaining gas-phase conditions (anaerobic conditions) that allow the survival of anaerobic microorganisms and providing nutrients to support the activity and growth of the anaerobic microorganisms. Various medium compositions suitable for the survival of anaerobic microorganisms are known. Therefore, those skilled in the art can select an appropriate medium composition for the anaerobic microorganisms capable of producing equol described above. For example, BHI medium manufactured by Difco and the medium used in the examples can be used, but are not limited to these.

[0027] Water-soluble organic substances can be added to the medium used in the present invention as a carbon source. Examples of water-soluble organic substances include, but are not limited to, the following compounds: sugars such as sorbose, fructose, and glucose; alcohols such as methanol; Organic acids such as valeric acid, butyric acid, propionic acid, acetic acid, formic acid, etc., or salts thereof.

[0028] The concentration of the organic matter added to the medium as a carbon source can be adjusted appropriately to efficiently grow anaerobic microorganisms in the medium. Generally, excess or deficiency can be avoided by selecting the amount added from the range of 0.1 to 10 wt / vol%.

[0029] In addition to the carbon source, a nitrogen source is added to the medium. In the present invention, various nitrogen compounds that can be used in conventional fermentation can be used as the nitrogen source. Preferred inorganic nitrogen sources are ammonium salts and nitrate salts. More preferred inorganic nitrogen sources are ammonium sulfate, ammonium chloride, ammonium phosphate, ammonium hydrogen phosphate, potassium nitrate, and sodium nitrate. On the other hand, preferred organic nitrogen sources are amino acids, yeast extract, peptones (e.g., polypeptone N), meat extract, liver extract, digested serum powder, etc. More preferred organic nitrogen sources are arginine, cysteine, citrulline, lysine, yeast extract, and peptones (e.g., polypeptone N).

[0030] In addition to carbon and nitrogen sources, other organic or inorganic substances suitable for equol production can also be added to the medium. For example, the growth and activity of anaerobic microorganisms can sometimes be enhanced by adding cofactors such as vitamins or inorganic compounds such as various salts to the medium. Examples of inorganic compounds, vitamins, and microbial growth cofactors derived from plants and animals include the following:

[0031] Inorganic compounds Vitamins Potassium dihydrogen phosphate Biotin Magnesium sulfate Folic acid Manganese sulfate pyridoxine Sodium chloride Thiamine Cobalt chloride Riboflavin Calcium chloride Nicotinic acid Zinc sulfate Pantothenic acid Copper sulfate Vitamin B12 Alum Thioctic acid Sodium molybdate p-aminobenzoic acid potassium chloride Boric acid etc. Nickel chloride Sodium Tungstate Sodium Selenite ferrous ammonium sulfate

[0032] Conventional methods can be used to prepare a culture medium by adding these inorganic compounds, vitamins, or growth cofactors. The medium can be liquid, semi-solid, or solid. In the present invention, the preferred form of the medium is a liquid medium. The medium of the present invention can contain dextrins. By culturing anaerobic microorganisms in a medium containing dextrins, a liquid containing equol and dextrins can be prepared without contacting the culture with dextrins again after the culture. Dextrins can be added to the medium before or during the cultivation of the microorganism.

[0033] In the present invention, anaerobic microorganisms can be cultured according to known microbial culture methods. For industrial production, a continuous fermentation system can be used, which can continuously supply the medium and substrate gas and is equipped with a mechanism for recovering the culture.

[0034] When using anaerobic microorganisms in the production of equol-containing food compositions, it is advisable to prevent oxygen from entering the continuous culture system. A commonly used culture tank can be used as the incubator. Culture tanks that can also be used for equol production are commercially available. An anaerobic atmosphere can be created by replacing the oxygen that enters the culture tank with an inert gas such as nitrogen.

[0035] Depending on the shape of the culture tank, an agitator or other device can be used to thoroughly agitate the medium. By agitating the culture in the culture tank, the opportunities for the medium components and substrate gas to come into contact with the anaerobic microorganisms can be increased, optimizing the efficiency of equol production. The substrate gas can also be supplied as nanobubbles.

[0036] In the present invention, equol production may be carried out in a sealed system such as a bottle or test tube sealed with a rubber stopper without ventilation, or may be carried out in a gas phase containing one or more gases including hydrogen. When carried out in a gas phase, the hydrogen concentration is not particularly limited.

[0037] When the method of the present invention is carried out in the gas phase, the combination of gases constituting the gas phase is not particularly limited, and in addition to hydrogen, one or more gases selected from carbon dioxide, nitrogen, etc. may be used as constituent components. Furthermore, in order to efficiently recover equol, the aeration rate of the mixed gas constituting the gas phase into the culture tank is preferably 0.01 to 2.0 V / V / M gas volume / liquid volume / min.

[0038] In the present invention, anaerobic microorganisms can be cultured under normal pressure, but when pressurized, the pressurization conditions are not particularly limited as long as they allow the microorganisms to grow. Preferred pressurization conditions include, but are not limited to, a range of 0.02 to 0.2 MPa.

[0039] To increase the amount of equol recovered, the temperature of the culture tank is not particularly limited, but is preferably 30°C to 40°C, and more preferably 33°C to 38°C. The fermentation time can be set appropriately depending on the amount of equol produced, the amount of remaining isoflavones, etc. Examples of the fermentation time include, but are not limited to, 8 to 120 hours, preferably 12 to 72 hours, and particularly preferably 16 to 60 hours.

[0040] An organic acid can be added to the culture solution at the end of the culture step to improve flavor. There are no limitations on the amount added as long as the flavor improvement effect is achieved, but it can be added, for example, using the pH as an indicator. When adding the organic acid, it is recommended to adjust the pH of the culture solution at the end of the culture step to 3.0 to 5.5, preferably 3.5 to 5.0, and more preferably 4.0 to 5.0 with the organic acid.

[0041] The fermentation culture obtained by the culture step of the present invention can be used in a solid form by heat-drying, spray-drying, or freeze-drying, as needed. Heat-drying or spray-drying can be performed using, for example, a spray dryer. Freeze-drying can be performed using a freeze-dryer. The fermentation culture that has been heat-dried, spray-dried, or freeze-dried can be subjected to powdering, as needed.

[0042] The food composition containing equol obtained by the culturing process of the present invention can be provided as an ingredient for foods and drinks (including supplements).

[0043] When the equol-containing food composition of the present invention is provided as a food or drink, it can be used as a general food, a food for specified health uses, a nutritional supplement, a functional food, a food for the sick, a food additive, etc. Examples of food forms that may contain the equol-containing food composition of the present invention include soft drinks, milk, pudding, jelly, candy, gum, gummy candy, yogurt, chocolate, soup, cookies, snacks, ice cream, popsicles, bread, cake, cream puffs, ham, meat sauce, curry, stew, cheese, butter, dressing, supplements, beverages with specified health benefits, and nutritional drinks.

[0044] The equol-containing food composition of the present invention can be prepared by using water, protein, carbohydrates, lipids, vitamins, minerals, organic acids, organic bases, fruit juice, flavors, etc. as main ingredients. Proteins include, for example, animal and vegetable proteins such as whole milk powder, skim milk powder, partially skim milk powder, casein, soy protein, egg protein, and meat protein, as well as their hydrolysates and butter. Carbohydrates include sugars, modified starches (textlin, soluble starch, British starch, oxidized starch, starch esters, starch ethers, etc.), and dietary fiber. Lipids include, for example, animal fats and oils such as lard, fish oil, and their fractionated, hydrogenated, and interesterified oils; and vegetable fats and oils such as palm oil, safflower oil, corn oil, rapeseed oil, coconut oil, and their fractionated, hydrogenated, and interesterified oils. Examples of vitamins include vitamin A, carotenes, B vitamins, vitamin C, D vitamins, vitamin E, K vitamins, vitamin P, vitamin Q, niacin, nicotinic acid, pantothenic acid, biotin, inositol, choline, folic acid, etc. Examples of minerals include calcium, potassium, magnesium, sodium, copper, iron, manganese, zinc, selenium, whey minerals, etc. Two or more of these components can be used in combination, and synthetic products and / or foods containing large amounts of these components can also be used.

[0045] The proportion of the equol-containing food composition in these foods can be appropriately determined depending on the type of food, the equol content, the age and sex of the person taking it, the expected effect, etc. An example is, but is not limited to, a proportion of 0.01 to 100 g, preferably 0.1 to 10 g, and more preferably 0.5 to 5 g per 100 g of food. The daily intake of foods containing equol-containing food compositions varies depending on the equol content in the composition, the age and weight of the person taking them, and the frequency of intake, but can be, for example, an amount equivalent to 0.01 to 10 g of composition per adult per day. The present invention will be described based on examples, but the scope of the present invention is not limited to the following examples. [Example]

[0046] Example 1 (Preparation of pre-culture medium) 1 L of Anaerobe Basal Broth (ABB) medium (Thermo Scientific) was dispensed into a 2 L fermenter, which was then sterilized by replacing the gas with nitrogen gas. (Preparation of main culture medium) Daidzein was added to the ABB medium to a concentration of 600 mg / L, and 1 L of the mixture was dispensed into a 2 L fermenter. The mixture was then sterilized by replacing the gas with nitrogen gas. (preculture) After inoculating the pre-culture medium with Asaccharobacter celatus DSM 18785 strain, the atmosphere was replaced with nitrogen gas and the medium was cultured at 37°C for 1 day.

[0047] (main culture) Each of the pre-cultured strains was inoculated into the main culture medium, and the gas was replaced with a hydrogen / nitrogen mixed gas, followed by culturing at 37°C for 5 days. (acidification process) The pH of the liquid obtained after the completion of the main culture was lowered to 5.0 by adding citric acid, lactic acid, phosphoric acid, gluconic acid, acetic acid, malic acid, and orotic acid, and then sterilized by heating. (Lyophilization) After the completion of the main culture, the liquid was sterilized using a filter with a pore size of 0.2 μm and then freeze-dried to obtain powder 1.

[0048] Example 2 Powder 2 was obtained in the same manner as in Example 1, except that Adlercreutzia equolifaciens DSM 19450 strain was used instead of Asaccharobacter celatus DSM 18785 strain.

[0049] Comparative Example 1 Powder C1 was obtained in the same manner as in Example 1, except that 10% hydrochloric acid was used instead of the various organic acids. Comparative Example 2 Powder C2 was obtained in the same manner as in Example 2, except that 10% hydrochloric acid was used instead of the various organic acids.

[0050] (Fragrance evaluation) The resulting powders 1, 2, C1, and C2 were evaluated for fragrance. Four men and women in their 30s to 50s were selected to evaluate the fragrance through a sensory test, and the results were rated AAA to A according to the following criteria.

[0051] AAA: Good fragrance; AA: There is a scent derived from the culture medium, but it is not bothersome; A: It has a scent derived from the culture medium.

[0052] The results of the sensory test are shown in Tables 1 and 2. In the tables, "AC" represents the Asaccharobacter celatus DSM 18785 strain, and "AE" represents the Adlercreutzia equolifaciens DSM 19450 strain. As is clear from Tables 1 and 2, it was confirmed that powders 1 and 2 of Examples 1 and 2, i.e., powders obtained using an organic acid as a pH adjuster, had a reduced characteristic aroma derived from the medium components compared to powders C1 and C2 of Comparative Examples 1 and 2, i.e., powders obtained using hydrochloric acid as a pH adjuster. The content of each organic acid in the powder is shown in Table 3.

[0053] [Table 1]

[0054] [Table 2]

[0055] [Table 3]

[0056] Table 4

[0057] Table 5

Claims

1. A food composition comprising equol and an organic acid.

2. The food composition has an organic acid content of 1.5 to 29% by weight, when the food composition is taken as 100% by weight.

3. 3. The food composition according to claim 1, wherein the organic acid is at least one selected from the group consisting of carbonic acid, bicarbonate, citric acid, lactic acid, phosphoric acid, gluconic acid, acetic acid, malic acid, and orotic acid, as well as their ammonium salts, alkali metal salts, alkaline earth metal salts, and chelates thereof.

4. A method for obtaining an equol-containing food composition, comprising the step of culturing at least one equol raw material selected from the group consisting of daidzein glycoside, daidzein, and dihydrodaidzein with an anaerobic microorganism, A method for producing an equol-containing food composition, characterized in that during the culture process, at least one organic acid selected from the group consisting of carbonic acid, bicarbonate, citric acid, lactic acid, phosphoric acid, gluconic acid, acetic acid, malic acid, and orotic acid, as well as their ammonium salts, alkali metal salts, alkaline earth metal salts, and chelates thereof, is added.

5. The method according to claim 4, wherein the content of the organic acid is 1.5 to 29% by weight when the equol-containing food composition is taken as 100% by weight.

6. 6. The method according to claim 4 or 5, wherein the anaerobic microorganism is a microorganism belonging to the genus Asaccharobacter or Adlercreutzia.

7. The method according to any one of claims 4 to 6, wherein the pH of the culture solution at the end of the culture step is adjusted to 3.0 to 5.5 with the organic acid.

Images