Agent for enhancing butyric acid or lactic acid production

Abstract

An agent for enhancing butyric acid or lactic acid production that contains soy milk.

Description

Butyric acid or lactic acid production enhancer

[0001] The present invention relates to an agent for enhancing the production of butyric acid or lactic acid, and also to a method for promoting the growth of butyric acid bacteria.

[0002] Short-chain fatty acids such as butyric acid, acetic acid, and propionic acid are known to have various benefits for the intestines. For example, Non-Patent Document 1 discloses that they maintain the intestinal barrier function, suppress the growth of pathogenic bacteria by lowering the pH in the intestines, have anti-inflammatory effects, have immunoregulatory functions, and have the effect of suppressing obesity by increasing insulin sensitivity and improving the maintenance of a feeling of fullness.

[0003] Among the benefits of short-chain fatty acids to the intestine, maintaining intestinal barrier function is extremely important. The intestine functions to absorb substances necessary for the maintenance of the body, such as water and nutrients, while also properly eliminating unnecessary substances, such as harmful substances and pathogenic cells, and plays a crucial role as a barrier that restricts the entry of foreign substances. When this intestinal barrier function is disrupted and the intestinal tract is damaged, foreign substances penetrate the mucosa, triggering an excessive immune response and causing inflammation. Furthermore, if the foreign substances enter the bloodstream, they can lead to a systemic inflammatory state. Non-Patent Document 2 discloses that intestines in a state in which holes develop and leak into the bloodstream are called leaky gut, and that leaky gut is considered a problem because it causes chronic inflammation. Therefore, intestinal barrier function is essential for maintaining the health of animals.

[0004] Here, Non-Patent Documents 1 and 2 disclose that butyric acid, among short-chain fatty acids, in particular, enhances tight junctions and produces mucin and antimicrobial peptides, thereby enhancing intestinal barrier function. Therefore, butyric acid is expected to restrict the passage of microorganisms and foreign substances into the lamina propria mucosa and prevent leaky gut. Furthermore, Non-Patent Document 3 discloses that butyric acid is essential for the differentiation of regulatory T cells (Tregs), which are effective in suppressing allergies and inflammatory bowel disease (IBD). Non-Patent Document 4 discloses that butyric acid increases intestinal oxygen consumption when metabolized by intestinal epithelial cells. Therefore, in addition to suppressing IBD and enhancing intestinal barrier function, butyric acid is also expected to maintain intestinal immune responses and, by maintaining an anaerobic intestinal environment, increase beneficial bacteria such as bifidobacteria and improve intestinal flora. From the above, butyric acid plays various important roles in the intestine, including strengthening intestinal barrier function.

[0005] Here, butyric acid is produced when dietary fiber is assimilated by intestinal bacteria, or when fructose, oligofructose, or inulin is assimilated by butyric acid bacteria such as Eubacterium rectale (now called Agathobacter rectalis) (see Non-Patent Document 5).

[0006] Among butyric acid bacteria, Agathobacter rectalis colonizes the mucus layer that covers the intestinal epithelium, producing butyric acid near intestinal epithelial cells and efficiently exerting physiological effects such as strengthening the intestinal barrier function (see Non-Patent Document 6). In addition, a decrease in microbial communities including Agathobacter rectalis has been confirmed in IBD patients, suggesting that Agathobacter rectalis is involved in suppressing IBD (see Non-Patent Document 7).

[0007] It has been disclosed that an agent containing soy isoflavone as an active ingredient that increases the proportion of lactic acid bacteria in intestinal bacteria and the diversity of intestinal flora increases butyric acid-producing bacteria (Patent Document 1), and that a composition containing soybean pulp increases butyric acid bacteria (Patent Document 2).

[0008] JP 2020-158439 A JP 2020-156420 A

[0009] Riviere et al. Bifidobacteria and Butyrate-Producing Colon Bacteria: Importance and Strategies for Their Stimulation in the Human Gut. Frontiers in Microbiology. 2016, 7, Article 979. Kobayashi, K. and Asami, Y. Effect of Yogurt on Intestinal Barrier Function. Jpn. J. Food Microbiol. 2019, 36(1), 32-35. Furusawa et al. Commensal microbe-derived butyrate induces the differentiation of colonic regulatory T cells. Nature. 2013, 504, 446-450. Takuya Suzuki. The importance of the intestinal tight junction barrier and its regulation by food components. Milk Science. 2020, 69(3), 180-186. F. Moens & De Vuyst. Inulin-type fructan degradation capacity of Clostridium cluster IV and XIVa butyrate-producing colon bacteria and their associated metabolic outcomes. Beneficial Microbes. 2017, 8(3), 473-490. P Van den Abbeele et al. Butyrate-producing Clostridium cluster XIVa species specifically colonize mucins in an in vitro gut model. The ISME Journal. 2013, 7,949-961. Heinken et al. Systematic assessment of secondary bile acid metabolism in gut microbes reveals distinct metabolic capabilities in infrastructure bowl disease. Microbiome. 2019, 7, Article 75. ,

[0010] The problem to be solved by the present invention is to provide a novel component capable of enhancing the production of butyric acid or lactic acid.

[0011] As a result of extensive research to solve the above problems, the present inventors discovered that soy milk enhances the production of butyric acid and lactic acid, leading to the completion of the present invention.

[0012] That is, the present invention is as follows: (1) An agent for enhancing the production of butyric acid or lactic acid, comprising soy milk. (2) The agent for enhancing the production of butyric acid or lactic acid according to (1), comprising polysaccharides derived from soy milk. (3) A food composition comprising the agent for enhancing the production of butyric acid or lactic acid according to (1) or (2). (4) A food composition for enhancing the production of butyric acid or lactic acid, comprising soy milk. (5) A method for enhancing the production of butyric acid or lactic acid using soy milk. (6) A growth promoter for butyric acid bacteria, comprising soy milk. (7) The growth promoter for butyric acid bacteria according to (6), comprising polysaccharides derived from soy milk. (8) A food composition comprising the growth promoter for butyric acid bacteria according to (6) or (7). (9) A food composition for promoting the growth of butyric acid bacteria, comprising soy milk. (10) A method for promoting the growth of butyric acid bacteria using soy milk. In each of the above aspects, the butyric acid bacterium may be Agathobacter rectalis.

[0013] The present invention may be as follows: (11) Soy milk for use in enhancing butyric acid or lactic acid production. (12) A food composition comprising soy milk for use in enhancing butyric acid or lactic acid production. (13) Use of soy milk for enhancing butyric acid or lactic acid production. (14) Use of a food composition comprising soy milk for enhancing butyric acid or lactic acid production. (15) Use of soy milk in producing an enhancer for butyric acid or lactic acid production. (16) Use of soy milk in producing a food composition for enhancing butyric acid or lactic acid production. In the above (11) to (16), polysaccharides derived from soy milk may be contained, and / or the butyric acid bacterium may be Agathobacter rectalis.

[0014] The present invention may be as follows: (21) Soy milk for use in promoting the growth of butyric acid bacteria. (22) A food composition containing soy milk for use in promoting the growth of butyric acid bacteria. (23) Use of soy milk for promoting the growth of butyric acid bacteria. (24) Use of a food composition containing soy milk for promoting the growth of butyric acid bacteria. (25) Use of soy milk in producing a growth promoter for butyric acid bacteria. (26) Use of soy milk in producing a food composition for promoting the growth of butyric acid bacteria. In the above (21) to (26), it is preferable that soy milk is used, and the soy milk may contain polysaccharides derived from soy milk, and / or the butyric acid bacteria may be Agathobacter rectalis.

[0015] The present invention may be a therapeutic invention or a non-therapeutic invention, i.e., it may be an invention of a therapeutic or non-therapeutic method, an invention of a therapeutic or non-therapeutic use, or an invention of a therapeutic or non-therapeutic product.

[0016] The present invention makes it possible to provide a novel component capable of enhancing the amount of butyric acid or lactic acid produced.

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. However, the present invention is not limited to the following embodiment.

[0018] The present embodiment provides a butyric acid or lactic acid production enhancer containing soy milk.

[0019] In the present embodiment, "soy milk" refers to a beverage containing a milky soy milk liquid obtained by eluting proteins and other components from soybeans (e.g., whole soybeans, defatted soybeans, powdered soybeans, etc.) with hot water or the like and removing fiber. Examples of 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, are included. The soy milk of the present embodiment may also contain other secondary 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, and flavorings). Furthermore, the soy milk of the present embodiment also includes soy milk preparations prepared by suspending, dissolving, or homogenizing powder of dehulled soybeans or whole soybeans in water, as well as soy beverages made from such preparations. The soy milk may be soy milk that has been pasteurized and sealed in a state of commercial sterility for long-term storage. 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.

[0020] In this embodiment, soy milk may contain polysaccharides. In this case, this embodiment also provides a butyric acid or lactic acid production enhancer containing polysaccharides derived from soy milk. Polysaccharides derived from soy milk can be analyzed by methods known to those skilled in the art, for example, using Fourier transform infrared spectroscopy (FTIR) or HPLC. Polysaccharides are sugars formed by glycosidic bonds between numerous monosaccharide molecules. The polysaccharides in this embodiment may have a molecular weight of greater than 500 Da. The polysaccharides derived from soy milk are not particularly limited, but may be those understood with reference to, for example, JP 2012-036100 A. Furthermore, the polysaccharides derived from soy milk may be those whose main component is polygalacturonic acid. Furthermore, based on the sugar composition of soybean-derived polysaccharides (Akihiro Nakamura, "Development of soybean polysaccharides derived from okara and their use as food functional agents," Journal of the Japanese Society for Food Science and Technology, 2011, 58(11), 559-566, or JP 2012-036100 A, or Tadaaki Kikuchi, "Changes in soybean cell wall polysaccharides during soy sauce brewing," Journal of the Japanese Society for Agricultural Chemical Science, 1976, 50(6), 273-277), the polysaccharides of this embodiment may be polysaccharides containing galacturonic acid, galactose, arabinose, rhamnose, fucose, xylose, glucose, mannose, and ribose. The sugars of arabinogalactan, which are composed of arabinose and galactose, may be partially bound to polygalacturonic acid, which is a polysaccharide included in this embodiment. The polysaccharide derived from soy milk is not particularly limited, but may be one that can be understood by reference to, for example, JP 2012-036100 A.

[0021] In one aspect of this embodiment, in order to increase butyric acid in the intestine, it is important that polysaccharides such as dietary fiber are metabolized by butyric acid bacteria and the like, thereby increasing the number of butyric acid bacteria. As a result of the increase in butyric acid bacteria, an increase in the amount of butyric acid produced can be expected. In other words, the metabolism of polysaccharides such as dietary fiber by butyric acid bacteria and the like promotes the growth of butyric acid bacteria and the like, and an increase in the number of butyric acid bacteria and the like is expected to increase the amount of butyric acid and the like produced. In this embodiment, soy milk may contain polysaccharides, and butyric acid and the like are produced by the metabolism of the polysaccharides by butyric acid bacteria and the like. Furthermore, as a result of the increase in butyric acid bacteria and the like that metabolize polysaccharides and produce butyric acid and the like, an increase in butyric acid in the intestine can be expected, and the physiological functions of butyric acid and the like in the intestine can be expected to be exerted.

[0022] The butyric acid or lactic acid production enhancer of this embodiment contains soy milk, thereby enabling the enhancement of butyric acid or lactic acid production. Enhancement of butyric acid or lactic acid production may be evaluated based on the amount of butyric acid or lactic acid produced by butyric acid bacteria. That is, when the amount of butyric acid or lactic acid produced by butyric acid bacteria is greater when soy milk is fed to butyric acid bacteria compared to when soy milk is not fed to butyric acid bacteria, the production can be evaluated as enhanced. For example, when the amount of butyric acid or lactic acid produced per cell of butyric acid bacteria is greater when soy milk is fed to butyric acid bacteria, the production can also be evaluated as enhanced. Furthermore, when the amount of butyric acid or lactic acid produced per cell of butyric acid bacteria is greater when soy milk is fed to butyric acid bacteria, and the number of butyric acid bacteria is also greater, the production can also be evaluated as enhanced. The amount of butyric acid or lactic acid produced can be measured by a method known to those skilled in the art, for example, by HPLC, etc. The butyric acid or lactic acid production enhancer of this embodiment may enhance the amounts of both butyric acid and lactic acid produced.

[0023] Examples of butyric acid bacteria include, but are not limited to, Agathobacter rectalis, Faecalibacterium prausnitzii, Clostridium methylpentosum, Clostridium leptum, Clostridium sporosphaeroides, Clostridium cellulosi, Clostridium viride, Roseburia intestinalis, Roseburia inulinivorans, Roseburia faecis, Roseburia hominis, and Eubacterium. hallii, Anaerostipes caccae, Coprococcus comes, Coprococcus eutactus, Anaerostipes hadrus, Clostridium coccoides, Clostridium celerecrescens, Clostridium voltei, Clostridium oroticum, Clostridium nexile, Clostridium scindens, Clostridium butyricum, Blautia wexlerae, etc., with Agathobacter rectalis being preferred.

[0024] Taking Agathobacter rectalis, a suitable butyric acid bacterium, as an example, Agathobacter rectalis has 52 glycosidases on its genome, including, for example, β-fructofuranosidase, α-arabinofuranosidase, β-xylosidase, exo-oligoxylanase, α-amylase, α- and β-glucosidase, α- and β-galactosidase, and cellulase. Other butyric acid bacteria also contain similar enzyme groups. Because Agathobacter rectalis contains a greater variety of polysaccharide-degrading enzymes than other butyric acid bacteria, it is expected to metabolize polysaccharides and have high butyric acid production ability, making it more suitable for the present invention. Furthermore, in this embodiment, soy milk may contain polysaccharides, and it is believed that such soy milk may enhance the production of butyric acid or lactic acid.

[0025] In this embodiment, butyric acid is a linear saturated carboxylic acid having four carbon atoms, and may be n-butyric acid or isobutyric acid. In this embodiment, lactic acid is an α-hydroxy acid having an asymmetric carbon, and may be D-lactic acid, L-lactic acid, or both.

[0026] The aspect of the butyric acid or lactic acid production enhancer of this embodiment is also applied to other embodiments described below.

[0027] Another embodiment provides a method for enhancing butyric acid or lactic acid production using soy milk. The method for enhancing butyric acid or lactic acid production can be carried out, for example, to increase butyric acid in the body (preferably in the intestine) or when butyric acid is produced by butyric acid bacteria, thereby enhancing the amount of butyric acid produced by butyric acid bacteria. When carrying out a method for enhancing butyric acid or lactic acid production to increase butyric acid in the body, the method may include a step of administering the butyric acid or lactic acid production enhancer of this embodiment to a subject. The subject is preferably a mammal, more preferably a human, monkey, cat, pig, horse, cow, mouse, rat, guinea pig, dog, or rabbit, and even more preferably a human. The dosage and frequency of administration of the butyric acid or lactic acid production enhancer may be appropriately determined depending on various conditions, such as the route of administration and the age, weight, and symptoms of the subject.

[0028] In another embodiment, a food composition containing a butyric acid or lactic acid production enhancer is also provided. That is, a food composition containing soy milk that enhances butyric acid or lactic acid production is provided. By including a butyric acid or lactic acid production enhancer in the food composition, the function of enhancing butyric acid or lactic acid production by soy milk is exerted due to the presence of butyric acid bacteria in the food composition, or by the food composition being in an environment where butyric acid bacteria are present. The butyric acid or lactic acid production enhancer may be designed to exert its function directly, or the butyric acid or lactic acid production enhancer may be included in the food composition to exert its function. In this embodiment, the food composition may be a food composition containing butyric acid or lactic acid for enhancing butyric acid or lactic acid production. The food composition containing a butyric acid or lactic acid production enhancer may be a food composition containing a butyric acid or lactic acid production enhancer for enhancing butyric acid or lactic acid production.

[0029] In another embodiment, a growth promoter for butyric acid bacteria containing soy milk is provided. The growth promoter for butyric acid bacteria contains soy milk, which allows it to promote the growth of butyric acid bacteria. The promotion of the growth of butyric acid bacteria may be evaluated based on the proliferation of butyric acid bacteria. That is, if the number of butyric acid bacteria is higher when soy milk is given to butyric acid bacteria compared to when soy milk is not given to butyric acid bacteria, it can be evaluated that the growth of butyric acid bacteria is promoted. The proliferation of butyric acid bacteria can be evaluated by methods known to those skilled in the art, for example, OD ６００ The value of can be measured and evaluated.

[0030] In another embodiment, a method for promoting the growth of butyric acid bacteria using soy milk is also provided. The method for promoting the growth of butyric acid bacteria can be carried out, for example, to increase the number of butyric acid bacteria in the body (preferably in the intestine) or when butyric acid is produced by butyric acid bacteria, thereby promoting the proliferation of butyric acid bacteria and enhancing the amount of butyric acid produced by butyric acid bacteria. When carrying out a method for promoting the growth of butyric acid bacteria in the body to increase the number of butyric acid bacteria in the body, the method may include a step of administering the butyric acid bacteria growth promoter of this embodiment to a subject. The subject is preferably a mammal, more preferably a human, monkey, cat, pig, horse, cow, mouse, rat, guinea pig, dog, or rabbit, and even more preferably a human. The dosage and frequency of administration of the butyric acid bacteria growth promoter may be appropriately determined depending on various conditions, such as the route of administration and the age, weight, and symptoms of the subject.

[0031] As used herein, method includes therapeutic and non-therapeutic methods, and use includes therapeutic and non-therapeutic uses.

[0032] In another embodiment, a food composition containing a butyric acid or lactic acid production enhancer may be understood as a food composition containing a growth promoter for butyric acid bacteria. That is, a food composition containing soy milk may be a food composition containing a butyric acid or lactic acid production enhancer, a food composition containing a butyric acid bacteria growth enhancer, or both. In this embodiment, the food composition may be a food composition for promoting the growth of butyric acid bacteria, containing butyric acid or lactic acid. A food composition containing a butyric acid bacteria growth enhancer may be a food composition for promoting the growth of butyric acid bacteria, containing a butyric acid or lactic acid production enhancer.

[0033] The form of the butyric acid or lactic acid production enhancer or the butyric acid bacteria growth promoter is not particularly limited, and may be in the form of tablets, capsules, granules, fine granules, powders, liquids, syrups, chewable tablets, oral preparations such as troches, ointments, gels, creams, injections, sublingual preparations, inhalants, or suppositories. To obtain these dosage forms, conventionally known additives may be used, and, without particular limitation, industry-known excipients, binders, diluents, disintegrants, buffers, thickeners, stabilizers, emulsifiers, dispersants, suspending agents, and / or preservatives may be used as needed. Furthermore, the butyric acid or lactic acid production enhancer or the butyric acid bacteria growth promoter may be incorporated into foods, feeds, pharmaceuticals, etc.

[0034] The soy milk content in the butyric acid or lactic acid production enhancer or the butyric acid bacteria growth promoter may be any content as long as it can exert its function, but it is preferably 0.1 mass% or more relative to the total amount of the butyric acid or lactic acid production enhancer or the butyric acid bacteria growth promoter, and may be, for example, 0.1 mass%, 0.2 mass%, 0.5 mass%, 1.0 mass%, 2.0 mass%, 3.0 mass%, 4.0 mass%, 5.0 mass%, or 10 mass% or more.

[0035] The food composition may be in a form suitable for the intended use, including, but not limited to, oral preparations such as tablets, capsules, granules, fine granules, powders, liquids, syrups, chewable tablets, and lozenges, as well as ointments, gels, creams, injections, sublingual preparations, inhalants, and suppositories. The food composition may be in an edible form, including, but not limited to, solids, liquids, granules, powders, capsules, creams, pastes, or jellies. For example, capsules may be coated with one or more membranes as needed. These dosage forms and shapes can be prepared using conventionally known additives, including, but not limited to, excipients, binders, diluents, disintegrants, buffers, thickeners, stabilizers, emulsifiers, dispersants, suspending agents, and / or preservatives known in the food industry.

[0036] Food compositions include, but are not limited to, foods and beverages, health foods, functional foods, foods for specified health uses, nutrient-functional foods, health supplements, and supplements. Food and beverage products include, for example, beverages, foods, seasonings, and food additives. Specific examples of beverages include soft drinks, fruit juices, carbonated drinks, dairy drinks, alcoholic drinks, sports drinks, and energy drinks. Specific examples of foods include breads, noodles, rice, soups, prepared dishes, tofu, dairy products, and confectioneries. Specific examples of seasonings include those used in miso paste, soy sauce, and dressings.

[0037] If necessary, coloring agents, flavoring agents, sweeteners, bittering agents, acidulants, preservatives, antioxidants, pH adjusters, and / or thickening stabilizers may be added to the food composition.

[0038] The food composition may be provided after heat sterilization, or may be provided in a sealed form in a bag or container. When provided, the food composition may be labeled with the following: "Enhances intestinal barrier function," "Increases intestinal butyric acid," "Nurtures intestinal butyric acid bacteria," or "For those concerned about intestinal health."

[0039] The food composition may preferably contain any amount of an agent for enhancing the production of butyric acid or lactic acid, or an agent for promoting the growth of butyric acid bacteria, as long as the agent can exert its function.

[0040] The present invention will be described in more detail below with reference to specific examples, although the present invention is not limited thereto.

[0041] Example 1 Evaluation of the Effect of Soy Milk on the Growth of Butyric Acid Bacteria and the Amounts of n-Butyric Acid and Lactic Acid Produced (1) Preparation of Modified YCFA Medium YCFA medium for culturing butyric acid bacteria was prepared according to Tables 1-1 to 1-6 below. The pH of the prepared YCFA medium was adjusted to 7.45 using 10 N NaOH, and then autoclaved at 121°C for 20 minutes. The autoclaved medium was then returned to room temperature, and 0.5 mL of Vitamin Solution II (Table 1-7) was added.

[0042] Next, Agathobacter rectalis JCM 17463, a butyric acid bacterium purchased from the RIKEN BioResource Research Center, was used. Ｔ A preculture of A. rectalis (hereafter referred to as A. rectalis) was inoculated into YCFA medium at 2% (v / v) and subjected to static culture for 16 hours at 37°C in an anaerobic chamber (manufactured by COY) under conditions of constant hydrogen concentration. The culture was centrifuged at 7,500 rpm (5,100 x g) for 10 minutes, and the supernatant was sterilized by filtration twice using a 0.20 μm Minisart® Syringe Filter (manufactured by Sartorius) to prepare modified YCFA medium.

[0043] Table 1-1 YCFA medium 500 mL

[0044] Table 1-2 Mineral solution I

[0045] Table 1-3 Mineral solution II

[0046] Table 1-4 VFA (volatile fat acid) mix

[0047] Table 1-5 Hemin solution

[0048] Table 1-6 Vitamin Solution I

[0049] Table 1-7 Vitamin Solution II

[0050] (2) Evaluation of the effect of soy milk on the growth of A. rectalis and the production of n-butyric acid and lactic acid A. rectalis stored as a glycerol stock at -80°C was thawed in an anaerobic chamber (manufactured by COY), diluted 5-fold with YCFA medium, and restored by static culture overnight at 37°C under conditions where the hydrogen concentration was kept constant. The restored culture was diluted 10-fold with YCFA medium and subcultured, and the culture was measured at an OD ６００The culture medium was diluted with modified YCFA medium so that the pH was within the range of 0.15-0.25 to prepare a subculture solution.

[0051] 50 μL of the above subculture solution was inoculated into 950 μL of modified YCFA medium containing 5% (v / v) of filtered unadjusted soy milk (Kikkoman Corporation) or into a control modified YCFA medium without unadjusted soy milk, and static culture was performed at 37°C for 15 hours under conditions where the hydrogen concentration was kept constant. After static culture, the OD ６００ was measured.

[0052] The supernatant of the statically cultured culture was centrifuged at 15,000 rpm (204 × 100 g) at 4°C for 10 minutes. The supernatant was sterilized by filtration using a 0.22 μm Millex®-GV PVDF filter (Merck). The supernatant was then added to 500 μL of Amicon® Ultra Ultracel-10K-0.5 mL (Merck) and ultrafiltered at 12,900 rpm (150 × 100 g) at 4°C for 10 minutes. The flow-through solution was collected and the amounts of n-butyric acid and lactic acid were measured using a Nexera Organic Acid Analysis System (Shimadzu Corporation) with pH buffering and electrical conductivity detection (Shimadzu High-Performance Liquid Chromatography Organic Acid Analysis System, Application Data Collection). For separation of n-butyric acid and lactic acid, three Shim-pack SCR-102H (300 mm × 8 mm, ID 7 μm) columns were connected in series (temperature 50°C) and a 2.5 mmol / L aqueous p-toluenesulfonic acid solution (flow rate 0.8 mL / min) was used as the eluent. For detection, the eluate from the column was mixed with 2.5 mmol / L p-toluenesulfonic acid, 10 mmol / L Bis-Tris, and 0.05 mmol / L EDTA-4H buffer (flow rate 0.8 mL / min), and an electric conductivity meter (polatity: +) was used.

[0053] The OD of the culture medium statically cultured as described above using Modified YCFA medium containing 5% (v / v) unadjusted soy milk was ６００ The value of OD of the culture solution (control) statically cultured as described above using Modified YCFA medium without modified soy milk was ６００The effect of unadjusted soy milk on the growth of A. rectalis was evaluated using the value obtained by dividing the amount of n-butyric acid and lactic acid measured by the HPLC method by the value for the control (growth activity) as an index. The effect of unadjusted soy milk on the production of n-butyric acid and lactic acid was also evaluated in the same manner as above, using the value obtained by dividing the amount of n-butyric acid and lactic acid measured by the HPLC method by the value for the control (n-butyric acid and lactic acid production ratio) as an index. The results of the above evaluation are shown in Table 2.

[0054] Table 2. Results of proliferation activity and n-butyric acid and lactic acid production ratio in 5% (v / v) unadjusted soy milk

Claims

1. An agent for enhancing the production of butyric acid or lactic acid, including soy milk.

2. A food composition comprising the butyric acid or lactic acid production enhancer according to claim 1.

3. A method of promoting the growth of butyric acid bacteria using soy milk.