Method for producing soybean lactic fermentation food product and soybean lactic fermentation food product

Abstract

To provide a method for producing a soybean lactic fermentation food product, which can decompose fibers derived from soybeans contained in a soybean raw material to use them as a food product and producing a smooth and flavored soybean lactic fermentation food product.SOLUTION: A method for producing a soybean lactic fermentation food product comprises: a step 1 of adjusting a soybean raw material solution using a soybean raw material; a step 2 of adding a lactobacillus starter containing at least one elected from Lactiplantbklacillusplantarum SKA 0024, Leuconostoc mesenteroides SKA 0020, and Leuconostoc mesenteroides SKA 0021 to lactic-fermenting the soybean raw material solution, and then dehydrate it to adjust a dehydrated lactic fermentation card; and a step 3 of adding a mushroom crude enzyme of edible Basidiomycetes to the dehydrated lactic fermentation card to mix them.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a lactic acid fermented soybean food by lactic acid fermentation of soybean raw material, and to a lactic acid fermented soybean food obtained by using said method. [Background technology]

[0002] In recent years, the health consciousness has increased, and soybean processed foods using soybeans with excellent nutritional value and functional ingredients have been attracting attention. Soybeans contain many nutrients such as protein, lipids, carbohydrates, dietary fiber (okara fiber), potassium, calcium, magnesium, iron, zinc, copper, vitamin E, vitamin B1, and folic acid. For example, because soybeans are rich in protein, soybean processed foods are used as a source of protein supplementation and as a substitute food for people with milk, egg, and wheat allergies. Soybeans are also used as a health food that can be expected to have various effects such as lowering blood cholesterol and improving obesity. Also, instead of milk, soybeans have been ground up, water is added to the solution, and the solution is filtered, and the soybean pulp is separated from the soybean pulp, and the soybean lactic acid fermentation food is produced using the soy milk as a raw material.

[0003] However, simply using soy milk as an alternative raw material to cow's milk and carrying out lactic acid fermentation has problems such as poor fermentation, insufficient hardness even when coagulated by lactic acid fermentation, and poor flavor.

[0004] Therefore, Patent Document 1 discloses a method for producing a lactic acid fermented soybean food in which lactic acid fermentation is performed using lactic acid bacteria collected from the epidermis of a cucumber or from the skin of an apple, instead of using lactic acid bacteria commonly used to make cheese from milk, when lactic acid fermenting soybean raw materials. Patent Document 2 discloses a method for producing a lactic acid fermented soybean food in which lactic acid fermentation is performed using lactic acid bacteria used to produce fermented foods made from milk by using an acidic soybean material containing a soybean emulsion composition. Patent Document 3 discloses a method for producing a lactic acid fermented soybean food in which lactic acid fermentation is performed using lactic acid bacteria used to produce fermented foods made from milk by using soy milk from which 60% or more of the soluble sugar fraction in the raw soybeans has been removed. Furthermore, Patent Document 4 discloses a method for producing a lactic acid fermented soybean food by carrying out lactic acid fermentation using a mixture of five lactic acid bacteria strains, namely, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis biovar diacetylactis, Lactobacillus casei subsp. casei, and Lactobacillus plantarum, in soymilk. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-136158 A [Patent Document 2] Patent Publication No. 2013-013396 [Patent Document 3] Japanese Patent Application Publication No. 7-236417 [Patent Document 4] Patent Publication No. 2005-218390 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in Patent Document 1, it is necessary to use a raw material from which insoluble fiber (okara) from soybeans has been removed, or, when using soybean slurry containing insoluble fiber, to use a raw material from which the insoluble fiber has been refined by high pressure treatment, pectinase treatment, or the like. In the case of the former raw material, a process for removing the insoluble fiber is required, and furthermore, unnecessary insoluble fiber is generated as waste. In addition, in the case of the latter raw material, a process for refining the unnecessary fiber is required.

[0007] Furthermore, in Patent Document 2, it is necessary to use an acidic soybean material containing a separately produced soybean emulsion composition as a raw material. And the method for producing this soybean emulsion composition requires complicated steps, such as adding water to fat-containing soybeans to prepare a suspension, subjecting the suspension to solid-liquid separation, transferring neutral lipids and polar lipids to an insoluble fraction, removing the water-soluble fraction containing proteins and carbohydrates, and recovering the insoluble fraction.

[0008] Furthermore, Patent Document 3 uses soymilk from which 60% or more of the soluble sugar fraction in the raw soybeans has been removed, because rennet, a coagulating enzyme used in cow's milk, does not cause coagulation when normal soymilk is used as the raw material. As a method for obtaining a raw material from which 60% or more of the soluble sugar fraction in the raw soybeans has been removed, for example, the method disclosed involves soaking whole soybeans at 50-55°C for 6-10 hours to elute 60% or more of the soluble sugar fraction, followed by grinding and filtering to separate into soybean pulp and soymilk. However, it is necessary to prevent quality deterioration due to enzymes such as lipoxidase, and unnecessary soybean pulp is generated as waste.

[0009] In addition, in Patent Document 4, it is necessary to prepare a lactic acid bacteria starter using the above-mentioned five types of lactic acid bacteria. Since the raw material is soy milk, unnecessary soybean lees are generated as waste when producing soy milk.

[0010] The present invention has been made in view of the above circumstances, and aims to provide a method for producing a lactic acid fermented soybean food, which can use a soybean raw material containing soybean-derived fiber, can decompose the soybean-derived fiber without going through complicated steps, and can produce a smooth and flavorful lactic acid fermented soybean food, and the lactic acid fermented soybean food. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, as a result of intensive research, the present inventors have come up with the following method for producing a lactic acid fermented soybean food and the following lactic acid fermented soybean food.

[0012] The method for producing a lactic acid fermented soybean food according to the present invention comprises the steps of: step 1 of preparing a soybean raw material solution using a soybean raw material; step 2 of adding a lactic acid bacteria starter containing at least one species selected from Lactiplantibacillus plantarum SKA0024, Leuconostoc mesenteroides SKA0020, and Leuconostoc mesenteroides SKA0021 to the soybean raw material solution, lactic acid fermenting the soybean raw material solution, and dehydrating the solution to prepare a dehydrated lactic acid fermented curd; and step 3 of adding a crude enzyme derived from edible basidiomycete fungus cells to the dehydrated lactic acid fermented curd and kneading the curd.

[0013] In the method for producing a lactic acid fermented soybean food according to the present invention, the soybean raw material is preferably at least one selected from a fiber-containing soybean raw material and a fiber-removed soybean raw material.

[0014] In the method for producing a soybean lactic acid fermented food according to the present invention, it is preferable that the edible basidiomycetes contain at least one species selected from Maitake (Grifola frondosa), Oyster Mushroom (Pleurotus ostreatus), Kōtake (Sarcodon aspratus), Truffle (genus Tuber), and Matsutake (Tricholoma matsutake).

[0015] The method for producing a lactic acid fermented soybean food according to the present invention preferably includes a step 4 of adding an edible mold to the lactic acid fermented soybean food obtained in the step 3, and culturing and maturing the food to impart a cheese flavor.

[0016] In the method for producing a lactic acid fermented soybean food according to the present invention, the edible mold preferably contains at least one species selected from the group consisting of Aspergillus, cheese blue mold, and Penicillium.

[0017] The lactic acid fermented soybean food according to the present invention is a lactic acid fermented soybean food obtained by the above-mentioned method for producing a lactic acid fermented soybean food. Effect of the Invention

[0018] By adopting the method for producing a lactic acid fermented soybean food according to the present invention, it is possible to use soybean raw materials containing soybean-derived fiber, and the soybean-derived fiber can be broken down and used as food without going through complicated processes. In addition, it is possible to produce a smooth and flavorful lactic acid fermented soybean food. [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic flowchart of the production steps of the method for producing a soybean lactic acid fermented food according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, the method for producing a lactic acid fermented soybean food and the lactic acid fermented soybean food according to the present invention will be described. Note that the following description merely shows one embodiment, and should not be construed as being limited to the following description.

[0021] 1. Method for producing soybean lactic acid fermented food The method for producing a lactic acid fermented soybean food according to the present invention uses soybeans as a raw material, can use a soybean raw material containing soybean-derived fiber, and is a method for producing a smooth and flavorful lactic acid fermented soybean food by decomposing the soybean-derived fiber without going through a complicated process. The method for producing a lactic acid fermented soybean food includes the steps of: preparing a soybean raw material solution using the soybean raw material in a step 1; adding a lactic acid bacteria starter containing at least one selected from Lactiplantibacillus plantarum SKA0024, Leuconostoc mesenteroides SKA0020, and Leuconostoc mesenteroides SKA0021 to the soybean raw material solution, lactic acid fermenting the soybean raw material solution, and dehydrating the solution to prepare a dehydrated lactic acid fermented curd; and adding a crude enzyme from edible basidiomycete mushrooms to the dehydrated lactic acid fermented curd and kneading it.

[0022] The mushroom body crude enzymes are a group of enzymes contained in the mushroom body (fruit body and mycelium) tissue. The main enzymes of the mushroom body crude enzymes of edible basidiomycetes in step 3 can decompose the soy protein contained in the dehydrated lactic acid fermented curd in step 2 into peptides and amino acids, and further decompose the soybean-derived fibers such as okara contained in the dehydrated lactic acid fermented curd into oligosaccharides. That is, the method for producing soybean lactic acid fermented food according to the present invention can use soybean raw materials containing soybean-derived fibers, and can decompose the soybean-derived fibers without going through complicated steps and use them as food. In addition, it is possible to produce soybean lactic acid fermented food that is smooth, has no bitterness, and is rich in flavor. The method for producing this soybean lactic acid fermented food is described in detail below.

[0023] 1 shows a schematic flow chart of the production process of the present invention, which includes steps 1 to 3. Note that the production method of the present invention may include steps other than steps 1 to 3.

[0024] [Process 1] Step 1 shown in FIG. 1 is a step of preparing a soybean raw material solution using soybean raw materials. As the soybean raw material used here, fiber-containing soybean raw materials such as fiber-containing soybean flour obtained by finely grinding full-fat soybeans or defatted soybeans, and fiber-containing soybean mash obtained by grinding full-fat soybeans or defatted soybeans soaked in water can be used. In addition, fiber-removed soybean raw materials such as soy milk from which okara fiber has been removed can also be used. That is, it is preferable to use at least one type of soybean raw material selected from fiber-containing soybean raw materials and fiber-removed soybean raw materials as the soybean raw material used in step 1. Here, the average particle size of the fiber-containing soybean flour or fiber-containing soybean mash is preferably fine in order to obtain a smooth taste, and is preferably 20 μm or less. The average particle size here means the particle size at 50% of the integrated value in the volume-based particle size distribution measured by a laser diffraction scattering method. The method of producing fiber-containing soy flour by finely grinding full-fat soybeans or defatted soybeans, and the method of producing fiber-containing soybean paste by grinding full-fat soybeans or defatted soybeans are not particularly limited as long as they can produce a soybean raw material that can be used in step 1. In addition, the method of producing soy milk from which soybean pulp fiber has been removed is also not particularly limited as long as they can produce a soybean raw material that can be used in step 1.

[0025] When the above-mentioned fiber-containing soy flour or fiber-containing soy bean paste is used as the soybean raw material, the fiber-containing soy flour or fiber-containing soy bean paste is placed in boiling water, vigorously stirred to disperse and dissolve, and then cooled to obtain a soybean raw material solution. The method of vigorously stirring is not particularly limited as long as it can disperse and dissolve the fiber-containing soy flour or fiber-containing soy bean paste in boiling water. When soy milk is used, it may be used as is, or the water content of soy milk may be adjusted to an appropriate level to form the soybean raw material solution. The fiber-containing soy flour, fiber-containing soy bean paste, soy milk, etc. may be used alone or in combination.

[0026] Raw materials other than soybean raw materials may be added to the soybean raw material solution. For example, vegetable oils such as coconut oil, palm oil, and cacao oil, which have melting points close to those of butter, are added to the soybean raw material solution and emulsified to adjust the fat content of the soybean raw material solution to 3.5% or more, which is close to the fat content of milk, to add a richness, flavor, and thickness like cheese.

[0027] The weight proportion of the soybean raw material in the soybean raw material solution is not particularly limited, but is preferably a weight proportion that allows soy protein to be aggregated in at least step 2 to obtain lactic acid fermented curd, and is preferably a weight proportion of the soybean raw material that results in a soybean solids content of 7% by weight or more and 15% by weight or less.

[0028] [Process 2] Step 2 shown in Fig. 1 is a step of adding a lactic acid bacteria starter containing at least one species selected from Lactiplantibacillus plantarum SKA0024, Leuconostoc mesenteroides SKA0020, and Leuconostoc mesenteroides SKA0021 to the soybean raw material solution prepared in step 1, lactic acid fermenting the soybean raw material solution, and then dehydrating it to prepare dehydrated lactic acid-fermented curd. Lactic acid bacteria decompose oligosaccharide components of the soybean raw material to produce lactic acid, acidifying the soybean raw material solution to prevent the proliferation of other harmful bacteria, aid the action of coagulating enzymes, strengthen the adhesion of curd grains to facilitate the discharge of moisture, and mainly decompose proteins in the soybean raw material to create flavor and aroma.

[0029] The lactic acid bacteria starter used in step 2 contains at least one species selected from plant-derived (citrus) Lactiplantibacillus plantarum SKA0024, Leuconostoc mesenteroides SKA0020, and Leuconostoc mesenteroides SKA0021. By using this lactic acid bacteria strain as the lactic acid bacteria starter, the soybean raw material solution prepared in step 1 can be fully assimilated, and a lactic acid fermented curd with a refreshing, sweet, and yummy yogurt flavor can be obtained through lactic acid fermentation.

[0030] The lactic acid bacteria starter may be a mixture of the above-mentioned lactic acid bacteria strains with other lactic acid bacteria strains, because by mixing the above-mentioned lactic acid bacteria strains with other lactic acid bacteria strains and using them as a mixed lactic acid bacteria starter, fermentation can be carried out under conditions other than those suitable for the above-mentioned lactic acid bacteria strains, and lactic acid fermented curd with a different flavor can be obtained.

[0031] The lactic acid bacteria strains that can be mixed include known lactic acid bacteria strains such as Lactobacillus, Streptococcus, Lactococcus, Leuconostoc, and Bifidobacterium. Examples of the Lactobacillus include L. casei, L. plantarum, L. bulgaricus, L. gasseri, L. acidophilus, L. lactis, L. brevis brevis, L. fermentum, L. mali, L. delbrueckii, L. buchneri, and L. cellobiosus. Examples of the Streptococcus include S. thermophilus, S. lactis, and S. diacetyllactis. Examples of the Lactococcus include L. lactis lactis and L. lactis cremoris. Examples of the Leuconostoc include L. mesenteroides cremoris and L. lactis. In addition, the genus Bifidobacterium includes B. bifidum, B. longum, B. infantis, B. breve, B. angularum, B. pseudocatenulatum, B. pseudolongum, B. thermophilum, B. boeum, B. magnum, B. asteroides, B. indicum, B. lactis, B. gallinarum, B. circulare, and B. coryneforme.

[0032] Lactic acid fermentation can be carried out as follows: Lactic acid bacteria containing at least one species selected from Lactiplantibacillus plantarum SKA0024, Leuconostoc mesenteroides SKA0020, and Leuconostoc mesenteroides SKA0021 are inoculated individually or in equal amounts into an appropriate amount of the soybean raw material solution obtained in step 1, and cultured for about 3 to 8 hours in an environment of 40°C until the viable cell count reaches 10 7 The lactic acid bacteria starter is added to the soybean raw material solution, and lactic acid fermentation is carried out for 3 to 24 hours, preferably 5 to 20 hours, in an environment of 10°C to 45°C, preferably 20°C to 40°C. The pH of the soybean raw material solution after fermentation is not particularly limited as long as the soybean protein in the soybean raw material solution can be coagulated, but is preferably 4.0 to 5.5, more preferably 4.5 to 5.0. The lactic acidity of the soybean raw material solution after fermentation is preferably 0.1% to 1.5%, more preferably 0.3% to 1.0%.

[0033] Next, the soybean raw material solution after lactic acid fermentation is dehydrated to solidify the curd (coagulated product) to obtain a dehydrated lactic acid fermented curd. The dehydration method is not particularly limited, but for example, a filtration method using a filter cloth or a filter or a centrifugation method can be used. The moisture content of the dehydrated lactic acid fermented curd is not particularly limited, but for example, based on the moisture content of milk-derived cheese products listed in the 2020 edition (8th edition) of the Standard Tables of Food Composition in Japan, fresh cheese is 79.0%, semi-hard Gouda cheese is 40.5%, hard Cheddar cheese is 35.5%, and extra-hard Parmesan cheese is 15.0%, a suitable value for the soybean lactic acid fermented food to be produced can be selected based on the values. The dehydrated lactic acid fermented curd obtained in this way has a refreshing sour taste and a mild fermented flavor without any peculiar taste.

[0034] [Step 3] Step 3 shown in Fig. 1 is a step in which a mushroom cell crude enzyme such as a paste or extract of edible basidiomycete mushroom cell (fruit body and mycelium) tissue is added to the dehydrated lactic acid fermented curd prepared in step 2 and kneaded. The main enzymes contained in the edible basidiomycete mushroom cell crude enzymes break down the soy protein contained in the dehydrated lactic acid fermented curd from step 2 into peptides and amino acids, and further break down soy-derived fiber such as okara contained in the dehydrated lactic acid fermented curd into oligosaccharides and the like. This eliminates the gritty texture of the dehydrated lactic acid fermented curd and allows for the production of a smooth soy lactic acid fermented food (fresh mushroom paste).

[0035] The edible basidiomycetes according to the present invention are edible basidiomycetes classified as white-rot fungi. White-rot fungi contain cellulase and have a strong decomposition ability to decompose cellulose, hemicellulose, and lignin. Therefore, by adding the edible basidiomycete mushroom cellulase according to the present invention to the dehydrated lactic acid fermented curd and kneading it, the soybean-derived fibers such as soybean pulp contained in the dehydrated lactic acid fermented curd can be decomposed into the oligosaccharide cellobiose, thereby achieving smoothness. In addition, the edible basidiomycetes contain a protein-decomposing enzyme (protease). This protein-decomposing enzyme is an exopeptidase that hydrolyzes peptide bonds at the amino or carboxyl terminals of peptide chains, and therefore sequentially releases amino acids from the terminals of the peptide chains in the protein of the soybean raw material. This decomposes bitter peptides produced by proteases contained in lactic acid bacteria, mold, and fruit juice, and suppresses bitterness during aging. Furthermore, the free amino acids can express umami.

[0036] The so-called "mushrooms" that can be used as the edible basidiomycete fungi of the present invention include cultivated species such as shiitake, maitake, tsukuritake, enokitake, bunashimeji, nameko, eringi, oyster mushroom, kikurage, yukitake, mukitake, yamabushitake, abalone mushroom, willow matsutake, tamogitake, kuritake, and hatakeshimeji, while wild species include matsutake, yamadoritake, koutake, truffle, hanaiguchi, shimofuritake, amitake, honshimeji, and kurokawa. Among these, it is preferable that the edible basidiomycete used in step 3 contains at least one species selected from Maitake (Grifola frondosa), Oyster Mushroom (Pleurotus ostreatus), Kohtake (Sarcodon aspratus), Truffle (genus Tuber), and Matsutake (Tricholoma matsutake), because they have a strong flavor and high enzyme activity.

[0037] In step 3, other substances can be added to the dehydrated lactic acid fermented curd in addition to the crude enzyme of edible basidiomycete fungi according to the present invention. For example, raw extracts or raw pastes of fruits such as pineapple, pear, fig, papaya, kiwi fruit, etc., which contain proteolytic enzymes, or root vegetables such as ginger can be added. This is because they can assist in the decomposition of proteins and add aroma.

[0038] In this specification, the mushroom body crude enzyme contains enzymes such as protease and cellulase contained in pastes and extracts of edible basidiomycete mushroom body (fruit body and mycelium) tissues. The mushroom body crude enzyme is not particularly limited, but may be a mushroom body crude enzyme extract obtained by cutting and squeezing the mushroom body of the edible basidiomycete according to the present invention, or a mushroom body crude enzyme paste obtained by grinding the mushroom body of the edible basidiomycete according to the present invention. In addition, when two or more kinds of basidiomycetes are used, the type, part, and form (dried powder, extract, paste, etc.) of the mushroom body crude enzyme to be combined, and the weight ratio of each of them to be mixed are not particularly limited, and may be adjusted according to the degree of decomposition of soybean-derived fiber, the flavor to be added, etc.

[0039] The method of adding and kneading the dehydrated lactic acid fermented curd with the mushroom cell crude enzyme of edible basidiomycetes is to add salt in an amount of 1% by weight to 2% by weight based on the weight of the dehydrated lactic acid fermented curd and the mushroom cell crude enzyme in an amount of 0.1% by weight to 5% by weight based on the weight of the dehydrated lactic acid fermented curd to the dehydrated lactic acid fermented curd, and knead for 5 to 30 minutes. Kneading means mixing and kneading, and the kneading means is not particularly limited as long as it is a means that can promote protein decomposition of the dehydrated lactic acid fermented curd and obtain a smooth texture by mixing the mushroom cell crude enzyme with the dehydrated lactic acid fermented curd and kneading it. The amount of salt and the mushroom cell crude enzyme added to the dehydrated lactic acid fermented curd is not limited to the above, and an appropriate amount can be selected depending on the raw material and water content used to prepare the dehydrated lactic acid fermented curd. The kneading time is also not limited to the above time, as long as the mushroom cell crude enzyme decomposes soybean-derived fibers such as soybean pulp contained in the dehydrated lactic acid fermented curd.

[0040] The lactic acid fermented soybean food obtained by kneading can be shaped and refrigerated for 3 to 15 days to increase its smoothness and flavor. The lactic acid fermented soybean food obtained in this way is similar to cream cheese, has a fragrance derived from the edible basidiomycetes added, and has a creamy, mild, and mellow flavor without bitterness.

[0041] [Step 4] Although not shown in FIG. 1, the method for producing a lactic acid fermented soybean food according to the present invention can also include step 4, after step 3, in which edible mold is transplanted into the lactic acid fermented soybean food (fresh mushroom paste) obtained in step 3, and cultured and aged to impart a cheese flavor. The edible mold assimilates lactic acid and other substances produced by lactic acid fermentation contained in the fresh mushroom paste, raising the pH and softening the sourness. The edible mold imparts a desirable mold flavor to the fresh mushroom paste, and can also produce the umami taste of amino acids. Through this step 4, a lactic acid fermented soybean food is prepared as a nutritious food with a creamy cheese-like texture and excellent fermented flavor.

[0042] The edible mold to be added to the fresh mushroom paste preferably contains at least one selected from the Aspergillus genus, blue mold for cheese, and Penicillium genus. As for the Aspergillus genus, the Aspergillus mold used in brewing miso, soy sauce, sake, etc. can be used, and the white Aspergillus luchuensis mut.Kawachi is preferred. As for the blue mold and white mold genera, Penicillium camamberti, Penicillium dolce, and Penicillium piccante are preferred.

[0043] The method of transplanting edible mold is to first prepare a mold starter. For the Aspergillus genus, dried rice koji or the like can be used as the mold starter as is. For Penicillium genus and Penicillium genus, Penicillium genus and Penicillium genus can be cultured in a soybean whey starch medium, and the isolated Penicillium genus and Penicillium genus colonies can be harvested to prepare the mold starter. Next, the shaped mushroom fresh paste is thinly coated with salt, and the above-mentioned mold starter is transplanted.

[0044] The mushroom fresh paste transplanted with the edible mold is cultured for about 7 to 14 days at, but not limited to, about 15° C. Then, it is aged for, but not limited to, about 7 to 20 days at, but not limited to, 5 to 15° C., more preferably 5 to 10° C., for about 7 to 14 days. In this way, a white soybean lactic acid fermented food with widespread mycelium can be obtained without long-term aging like milk-derived cheese.

[0045] Steps 3 and 4 may be carried out simultaneously. That is, a crude enzyme derived from edible basidiomycete fungus is added to the dehydrated lactic acid fermented curd prepared in step 2, and then kneaded, after which an edible mold is transplanted and cultured, to obtain a lactic acid fermented soybean food with an excellent cheese flavor.

[0046] 2. Embodiments of soy lactic acid fermented food The lactic acid fermented soybean food of the present invention employs a lactic acid fermented soybean food obtained by the method for producing a lactic acid fermented soybean food of the present invention. Because the lactic acid fermented soybean food of the present invention is obtained by the method for producing a lactic acid fermented soybean food of the present invention, even if a soybean raw material containing soybean-derived fiber is used, the soybean-derived fiber is decomposed into oligosaccharides and the like, resulting in a smooth, mellow flavor without bitterness.

[0047] The embodiment of the present invention described above is one aspect of the present invention, and can be modified as appropriate without departing from the spirit of the present invention. The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. EXAMPLES

[0048] In Example 1, a soybean lactic acid fermented food was produced by carrying out steps 1, 2, and 3 described below. First, step 1 was carried out. As the soybean raw material, "Miracle Kinakko" (manufactured by Yamato Material Co., Ltd.), a fine soybean flour containing dietary fiber derived from soybeans such as okara, was used. The average particle size of this "Miracle Kinakko" is approximately 20 μm or less. Then, 1 part by weight of "Miracle Kinakko" was added to 10 parts by weight of boiling water, and the mixture was dispersed and dissolved by vigorously stirring with a mixer, and cooled to prepare a soybean raw material solution. This soybean raw material solution had a soybean solid content of 8.6% by weight, a protein content of 3.3% by weight, and a pH of 6.6.

[0049] Next, step 2 was carried out. Lactiplantibacillus plantarum SKA0024 was used as the lactic acid bacteria starter. Then, 1 part by weight of the lactic acid bacteria starter was added to 10 parts by weight of the soybean raw material solution obtained in step 1, and the mixture was stirred and subjected to lactic acid fermentation for 5 hours in an environment of 40°C. Thereafter, the soybean raw material solution after lactic acid fermentation was placed in a dehydration bag and centrifuged to prepare a dehydrated lactic acid fermented curd. This dehydrated lactic acid fermented curd had a soybean solid content of 42% by weight, a protein content of 18.3% by weight, and a pH of 4.89.

[0050] Next, step 3 was carried out. Maitake mushroom (Grifola frondosa) was used as the edible basidiomycete. The mushroom fungus of the edible basidiomycete was ground and then squeezed to prepare a mushroom fungus crude enzyme (mushroom fungus crude enzyme extract). The above-mentioned mushroom fungus crude enzyme was added at a ratio of 0.3% by weight to 10 parts by weight of dehydrated lactic acid fermented curd, and salt was further added to make the amount 1.5% by weight, and then kneaded for 30 minutes to obtain a soybean lactic acid fermented food. This soybean lactic acid fermented food had a soybean solid content of 42% by weight, a protein content of 18.6% by weight, and a pH of 4.96. EXAMPLES

[0051] In Example 2, a soybean lactic acid fermented food was produced by carrying out the following step 3 on the dehydrated lactic acid fermented curd prepared in the same manner as in Example 1. Truffles (genus Tuber) and oyster mushrooms (Pleurotus ostreatus) were used as edible basidiomycetes. Equal amounts of the mushroom fungi of the edible basidiomycetes were mixed, ground, and squeezed to prepare a mushroom fungal crude enzyme (mushroom fungal crude enzyme extract). To 10 parts by weight of dehydrated lactic acid fermented curd prepared in the same manner as in Example 1, an equal amount of the above-mentioned mushroom fungal crude enzyme mixture was added at a ratio of 0.3% by weight, and further, salt was added to make the amount 1.5% by weight, and then kneaded for 30 minutes to obtain a soybean lactic acid fermented food. This soybean lactic acid fermented food had a soybean solid content of 42% by weight, a protein content of 18.6% by weight, and a pH of 4.96. EXAMPLES

[0052] In Example 3, the same step 1 as in Example 1 was carried out, and then steps 2 and 3 described below were carried out to produce a soybean lactic acid fermented food. In step 2, an equal mixture of Lactiplantibacillus plantarum SKA0024, Leuconostoc mesenteroides SKA0020, and Leuconostoc mesenteroides SKA0021 was used as the lactic acid bacteria starter. Then, 1 part by weight of the lactic acid bacteria starter was added to 10 parts by weight of the soybean raw material solution obtained in step 1, and the mixture was stirred and subjected to lactic acid fermentation for 5 hours in an environment of 40°C. After that, the soybean raw material solution after lactic acid fermentation was put into a dehydration bag and centrifuged to prepare a dehydrated lactic acid fermented curd. This dehydrated lactic acid fermented curd had a soybean solid content of 41.5% by weight, a protein content of 18.5% by weight, and a pH of 4.85.

[0053] Next, step 3 was carried out. Matsutake (Tricholoma matsutake) and Oyster mushroom (Pleurotus ostreatus) were used as edible basidiomycetes. Equal amounts of mushroom fungi of the edible basidiomycetes were mixed, ground, and then squeezed to prepare a mushroom fungal crude enzyme (mushroom fungal crude enzyme extract). The above-mentioned mushroom fungal crude enzyme mixture was added in an amount of 0.3% by weight to 10 parts by weight of dehydrated lactic acid fermented curd, and salt was added to make the amount 1.5% by weight. The mixture was then kneaded for 30 minutes to obtain a soybean lactic acid fermented food. This soybean lactic acid fermented food had a soybean solid content of 42% by weight, a protein content of 18.6% by weight, and a pH of 4.92. EXAMPLES

[0054] In Example 4, a soybean lactic acid fermented food was produced by carrying out the following step 3 on the dehydrated lactic acid fermented curd prepared in the same manner as in Example 1. Sarcodon aspratus was used as the edible basidiomycete. Each mushroom body was ground and then squeezed to prepare a mushroom body crude enzyme (mushroom body crude enzyme extract). The above-mentioned mushroom body crude enzyme was added at a ratio of 0.3% by weight to 10 parts by weight of the dehydrated lactic acid fermented curd prepared in the same manner as in Example 1, and salt was further added to make a concentration of 1.5% by weight. The mixture was then kneaded for 30 minutes to obtain a soybean lactic acid fermented food. This soybean lactic acid fermented food had a soybean solid content of 42% by weight, a protein content of 18.6% by weight, and a pH of 5.06. EXAMPLES

[0055] In Example 5, a lactic acid fermented soybean food was produced by carrying out steps 1 to 4 shown below. First, step 1 was carried out. The soybean raw material used was the same "Miracle Kinakko" as in Example 1. Then, 1 part by weight of "Miracle Kinakko" was added to 10 parts by weight of boiling water, and dispersed and dissolved by vigorously stirring with a mixer. Then, 0.2 parts by weight of coconut oil was added, and emulsified by vigorously stirring with a mixer, and cooled to prepare a soybean raw material solution. This soybean raw material solution had a soybean solid content of 10.2% by weight, a protein content of 3.4% by weight, and a pH of 6.7.

[0056] Next, step 2 was carried out. Lactiplantibacillus plantarum SKA0024 was used as the lactic acid bacteria starter. Then, 1 part by weight of the lactic acid bacteria starter was added to 10 parts by weight of the soybean raw material solution obtained in step 1, and the mixture was stirred and subjected to lactic acid fermentation for 5 hours in an environment of 40°C. Thereafter, the soybean raw material solution after lactic acid fermentation was placed in a dehydration bag and centrifuged to prepare a dehydrated lactic acid fermented curd. This dehydrated lactic acid fermented curd had a soybean solid content of 43% by weight, a protein content of 17.8% by weight, and a pH of 4.93.

[0057] Next, step 3 was carried out. Maitake mushroom (Grifola frondosa) was used as the edible basidiomycete. The mushroom fungus of the edible basidiomycete was ground and then squeezed to prepare a mushroom fungus crude enzyme (mushroom fungus crude enzyme extract). The above-mentioned mushroom fungus crude enzyme was added at a ratio of 0.3% by weight to 10 parts by weight of the dehydrated lactic acid fermented curd obtained in step 2, and salt was further added to make the amount 1.5% by weight. The mixture was then kneaded for 30 minutes to prepare a mushroom fresh paste.

[0058] Next, step 4 was carried out. For 10 parts by weight of the mushroom fresh paste obtained in step 3, 0.1 parts by weight of white Aspergillus luchuensis mut. Kawachi (manufactured by Nihon Jozo Kogyo Co., Ltd.) of koji mold was transplanted as edible mold. After that, it was cultured at 15°C for 14 days to allow mycelium to spread in the mushroom fresh paste, and then aged at 5°C for 14 days to produce a soybean lactic acid fermented food with a characteristic mold flavor added to the mushroom fresh paste. This soybean lactic acid fermented food had a soybean solid content of 43% by weight, protein of 18.0% by weight, and a pH of 5.6. Comparative Example

[0059] In the comparative example, a process was carried out in which pineapple pulp juice containing a protease not used in the process 3 of the present invention was used in addition to the dehydrated lactic acid fermented curd obtained through the same processes 1 and 2 as in Example 1. Specifically, 0.5% by weight of the above-mentioned pineapple juice was added to 10 parts by weight of the dehydrated lactic acid fermented curd obtained through the same processes 1 and 2 as in Example 1, and salt was further added to give a concentration of 1.5% by weight, and then kneaded for 30 minutes to obtain a comparative lactic acid fermented soybean food in which the soybean protein in the dehydrated lactic acid fermented curd was hydrolyzed. This comparative lactic acid fermented soybean food had a soybean solid content of 41% by weight, a protein content of 18.0% by weight, and a pH of 4.90.

[0060] 〔evaluation〕 The raw materials used in each step in Examples 1-5 and the Comparative Example are shown in Table 1. Note that in Examples 1-4 and the Comparative Example, step 4 was not performed, and therefore it is indicated in Table 1 as "not performed."

[0061] [Table 1]

[0062] In the manufacturing method of the lactic acid fermented soybean food of Example 1, lactic acid fermentation proceeded well, and a good quality dehydrated lactic acid fermented curd was obtained. The edible basidiomycetes used contained a protein-degrading enzyme (protease) that decomposed the proteins in the soybean raw material, and further decomposed soybean-derived fibers such as okara into the oligosaccharide cellobiose, resulting in a smooth soybean lactic acid fermented food. The bitter peptides contained in the dehydrated lactic acid fermented curd were decomposed in the obtained soybean lactic acid fermented food, and it had a mellow cream cheese-like flavor with a Maitake mushroom aroma without bitterness.

[0063] In the method for producing the lactic acid fermented soybean food of Example 2, lactic acid fermentation proceeded well, and a good quality dehydrated lactic acid fermented curd was obtained. The edible basidiomycetes used contained a protein-degrading enzyme (protease), which quickly decomposed the protein of the soybean raw material, and further decomposed soybean-derived fiber such as okara into the oligosaccharide cellobiose, thereby obtaining a lactic acid fermented soybean food that was smooth on the palate. The bitter peptides contained in the dehydrated lactic acid fermented curd were decomposed in the obtained lactic acid fermented soybean food, and the food exhibited a mellow cream cheese-like truffle flavor with little bitterness. From this, it was understood that a more preferable flavor can be obtained by adjusting the type of edible basidiomycetes used and the weight ratio of the respective squeezed juices and pastes mixed when preparing the mushroom fungal crude enzyme (mushroom fungal crude enzyme extract).

[0064] In the manufacturing method of the lactic acid fermented soybean food of Example 3, lactic acid fermentation proceeded well, and a dehydrated lactic acid fermented curd with a rich flavor was obtained. The edible basidiomycetes used contained proteolytic enzymes (proteases, etc.) that decomposed the proteins in the soybean raw material, and the fiber-decomposing enzymes contained in the fungus pulp (cellulases, etc.) decomposed the fibers derived from soybeans such as okara into the oligosaccharide cellobiose, resulting in a lactic acid fermented soybean food that was smooth on the palate. The bitter peptides contained in the dehydrated lactic acid fermented curd were decomposed in the obtained lactic acid fermented soybean food, and the food exhibited a mellow cream cheese-like flavor with a Matsutake aroma without bitterness. This shows that a more preferable flavor can be obtained by adjusting the type of edible basidiomycetes used and the weight ratio of the respective squeezed juices and pastes mixed when preparing the mushroom fungus crude enzyme (mushroom fungus crude enzyme extract).

[0065] In the manufacturing method of the lactic acid fermented soybean food of Example 4, lactic acid fermentation proceeded well, and a good quality dehydrated lactic acid fermented curd was obtained. The edible basidiomycetes used contained proteolytic enzymes (proteases, etc.) that decomposed the proteins in the soybean raw material, and further contained fibrous enzymes (cellulases, etc.) that decomposed soybean-derived fibers such as okara into oligosaccharides such as cellobiose, resulting in a smooth soybean lactic acid fermented food. The bitter peptides contained in the dehydrated lactic acid fermented curd were decomposed in the obtained soybean lactic acid fermented food, which had a mellow cream cheese-like taste without bitterness, and showed a strong aroma due to the koutake mushrooms and a rich flavor of lactic acid bacteria.

[0066] In the manufacturing method of the lactic acid fermented soybean food of Example 5, lactic acid fermentation proceeded well, and a good quality dehydrated lactic acid fermented curd was obtained. By adding coconut oil to the raw material, a dehydrated lactic acid fermented curd with increased richness, umami, and cheese-like flavor was obtained in addition to the characteristics of the dehydrated lactic acid fermented curd of Examples 1-3. The edible basidiomycetes used contained a protein-degrading enzyme (protease) and thus decomposed the protein in the soybean raw material. Furthermore, the fiber-degrading enzymes contained therein (cellulase, etc.) decomposed soybean-derived fibers such as okara into the oligosaccharide cellobiose, and a lactic acid fermented soybean food with a smooth texture was obtained. The bitter peptides contained in the dehydrated lactic acid fermented curd were decomposed in the obtained lactic acid fermented soybean food, and the food exhibited a flavor with a sweet coconut aroma and a Maitake mushroom aroma without bitterness. Furthermore, the sweet Kyoto miso aroma was also exhibited by culturing and maturing koji mold.

[0067] In the comparative example, the lactic acid fermented soybean food was made by decomposing the protein of the soybean raw material with the protease bromelain contained in pineapple juice, and turning the dehydrated lactic acid fermented curd into a paste. However, the fiber derived from soybeans such as soybean pulp was not decomposed, and a smooth texture was not obtained. Furthermore, when aged, it became bitter, making it unsuitable for consumption. [Industrial Applicability]

[0068] The method for producing a lactic acid fermented soybean food according to the present invention can use a soybean raw material containing soybean-derived fiber, and can decompose the soybean-derived fiber without complicated processes to use it as a food. Since the method can produce a smooth and flavorful lactic acid fermented soybean food without bitterness, it can be suitably used for producing a lactic acid fermented soybean food using soybeans as a raw material.

Claims

1. A step 1 of preparing a soybean raw material solution using a soybean raw material; a step 2 of adding a lactic acid bacteria starter containing at least one selected from Lactiplantibacillus plantarum SKA0024, Leuconostoc mesenteroides SKA0020, and Leuconostoc mesenteroides SKA0021 to the soybean raw material solution, fermenting the soybean raw material solution with lactic acid, and then dehydrating the soybean raw material solution to prepare a dehydrated lactic acid fermented curd; A step 3 of adding a crude enzyme from edible basidiomycete fungus to the dehydrated lactic acid fermented curd and kneading it; A method for producing a soybean lactic acid fermented food, comprising the steps of:

2. 2. The method for producing a lactic acid fermented soybean food according to claim 1, wherein the soybean raw material is at least one selected from the group consisting of a fiber-containing soybean raw material and a fiber-removed soybean raw material.

3. 2. The method for producing a soybean lactic acid fermented food according to claim 1, wherein the edible basidiomycetes include at least one selected from the group consisting of Maitake (Grifola frondosa), Oyster Mushroom (Pleurotus ostreatus), Koutake (Sarcodon aspratus), Truffle (genus Tuber), and Matsutake (Tricholoma matsutake).

4. 2. A method for producing a soybean lactic acid fermented food according to claim 1, further comprising, after step 3, a step 4 of adding an edible mold to the soybean lactic acid fermented food obtained in step 3, culturing and maturing the food to impart a cheese flavor.

5. 5. The method for producing a soybean lactic acid fermented food according to claim 4, wherein the edible mold comprises at least one selected from the group consisting of Aspergillus, cheese blue mold, and Penicillium.

6. A lactic acid fermented soybean food, characterized in that it is obtained by using the method for producing a lactic acid fermented soybean food according to any one of claims 1 to 5.

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