JP7629274B2 - Method for producing cheese-like fermented food - Google Patents

Description

The present invention relates to a technology for producing cheese-like fermented foods from soybean raw materials.

Various studies have been conducted on technologies for producing cheese-like fermented foods from soybean raw materials such as soy milk (see, for example, Patent Documents 1 to 4 and Non-Patent Document 1). Patent Document 1 proposes a method for producing cheese-like foods by fermenting and maturing soy milk, from which 60% or more of the soluble sugar fraction in the raw soybeans has been removed, in a manner similar to that for cheese. Non-Patent Document 1 also discloses the results of component analysis and antioxidant evaluation of soy milk cheese produced by changing the type of lactic acid bacteria used for lactic acid fermentation and the type of cheese mold used for fermentation and maturation.

However, simply replacing cow's milk with soy milk, as in the methods described in Patent Document 1 and Non-Patent Document 1, results in a strong odor and taste specific to soy milk, and it is not possible to obtain a fermented food with a flavor similar to cheese. Therefore, Patent Document 2 proposes a method for producing a cheese-like fermented soy food in which, in order to reduce the taste and odor specific to soybeans, vegetable-derived lactic acid bacteria selected from Lactococcus lactis subsp. lactis Cu-1 strain and/or Lactobacillus plantarum AP-1 strain are added to the soybean raw material, followed by lactic acid fermentation, and the resulting fermented product is solidified and aged.

Patent Document 3 proposes a method for producing a cheese-like food by heating and filtering the curd obtained by fermenting soy milk with lactic acid bacteria having protease activity, in order to obtain a processed cheese-like food without using special soy milk or long-term maturation by mold cultivation. Furthermore, Patent Document 4 proposes a method for obtaining a natural cheese-like fermented food that is highly digestible and has a good flavor and composition, in which curd processed according to a standard cheese manufacturing method is molded and pressed to form into a solid form, and then fermented and maturated in a brewed product made from koji as a substrate while blocking contact with air.

Japanese Patent Application Publication No. 7-236417 JP 2009-136158 A International Publication No. 2009/001443 Japanese Patent Application Laid-Open No. 63-269946

Miki Nishiyama and 5 others, "Preparation of cheese-like food using soy milk and its antioxidant properties and characteristics", Journal of the Japanese Society for Food Science and Technology, Japan Society for Food Science and Technology, September 2013, Vol. 60, No. 9

However, the method described in Patent Document 2 has the problem that, because it uses only lactic acid bacteria, it does not produce aroma components or umami components specific to cheese. In addition, the method described in Patent Document 3 has the problem that, because it only breaks down the proteins in the soy milk using lactic acid bacteria with protease activity and does not carry out fermentation or aging, it does not produce aroma components specific to cheese.

On the other hand, the method described in Patent Document 4 involves fermentation and maturation in a brewed product made from koji as a substrate, and the taste and flavor change significantly depending on the brewed product used, making it difficult to obtain a natural flavor similar to that of cheese. In addition, the method described in Patent Document 4 also has the problem that, when a brewed product made from koji to which yeast has been added is used as a substrate, alcohol is produced and sugar is consumed by the yeast, causing a change in flavor. Thus, using conventional methods, it is difficult to produce a cheese-like fermented food with a flavor and texture similar to that of cheese using soy milk as a raw material.

Therefore, the present invention aims to produce a cheese-like fermented food with a flavor and texture similar to that of cheese from soybean raw materials.

The method for producing a cheese-like fermented food according to the present invention comprises a coagulation step of coagulating a soybean raw material using lactic acid bacteria and/or an acid, a step of separating whey from the coagulated product obtained in the coagulation step to form a curd, and a step of fermenting and maturing the curd with koji mold, in which a liquid containing seed koji is sprayed onto the surface of the curd in the fermentation and maturation step.
In the method for producing a cheese-like fermented food of the present invention, in the fermentation and maturation step, the curd to which the koji mold is attached may be allowed to stand at a temperature of 25 to 35° C. for 1 to 4 days, and then allowed to stand at a temperature of 15 to 25° C. for 10 to 60 days.
In the fermentation and maturation step, the koji mold used can be one for soy sauce and/or one for miso, specifically, one for Aspergillus oryzae and/or Aspergillus soya.
As the soybean raw material, for example, soy milk produced using dehulled soybeans can be used.

The fermented food of the present invention is a cheese-like fermented food obtained by fermenting and maturing a curd formed by coagulating a soybean raw material with lactic acid bacteria and/or an acid, spraying a liquid containing seed koji onto the surface of the curd , and containing 0.70 mg/g or more of isovaleric acid as an aroma component.

According to the present invention, a cheese-like fermented food having a flavor and texture closer to that of cheese than conventional fermented soy milk foods can be obtained using soybean raw materials.

1 is a flowchart showing the steps of producing a cheese-like fermented food according to an embodiment of the present invention.

The following describes in detail the embodiments of the present invention with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below.

Figure 1 is a flow chart showing the steps of producing a cheese-like fermented food according to an embodiment of the present invention. As shown in Figure 1, the method of producing a cheese-like fermented food according to this embodiment includes a coagulation step (step S1), a curd formation step (step S2), and a fermentation and maturation step (step S3).

[Solidification process]
In the coagulation step S1, the soybean raw material is coagulated using at least one of lactic acid bacteria, acid, and a coagulant to obtain a coagulated product. Examples of the soybean raw material used in the method for producing a cheese-like fermented food of this embodiment include soy milk, soy flour, and soy slurry, among which soy milk is particularly preferred. The soy milk is not particularly limited as long as it is obtained by crushing soybeans that have been soaked in water to absorb moisture, and filtering out insoluble components such as okara, but soy milk produced using dehulled soybeans is preferred. By using soy milk produced using dehulled soybeans as the soybean raw material, the grassy odor specific to soybeans is reduced, and a fermented food with a flavor closer to cheese is obtained.

The soybean raw material used as the raw material is not limited to one type, and multiple soybeans with different types and processing methods can be used in combination. The soybean raw material may be sterilized before adding lactic acid bacteria, or soybeans that have already been sterilized may be used. Furthermore, when coagulating by lactic acid fermentation, sugar may be added to the soybean raw material as necessary.

In the case of using lactic acid to solidify the soybean raw material, lactic acid bacteria are added to the soybean raw material to cause lactic acid fermentation. Examples of lactic acid bacteria that can be used in this case include lactic acid bacteria of the genus Streptococcus, such as Streptococcus thermophilus; lactic acid bacteria of the genus Lactobacillus, such as Lactobacillus bulgaricus, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus gasseri, and Lactobacillus delbrueckii; lactic acid bacteria of the genus Lactococcus, such as Lactococcus lactis; lactic acid bacteria of the genus Leuconostoc mesenteroites and Leuconostoc lactis; Examples of lactic acid bacteria include lactic acid bacteria of the genus Enterococcus, such as Enterococcus faecalis and Enterococcus faecium, lactic acid bacteria of the genus Bifidobacterium, such as Bifidobacterium bifidum and Bifidobacterium adolescentis, and lactic acid bacteria of the genus Pediococcus, such as Pediococcus pentosaceus and Pediococcus halophilus, but are not limited to these, and any lactic acid bacteria that can aggregate soybean raw materials may be used.

The conditions for lactic acid fermentation are not particularly limited and can be set appropriately depending on the type of soybean raw material and lactic acid bacteria. For example, when fermenting with the aforementioned lactic acid bacteria, fermentation can be carried out at a temperature of 20 to 43°C for about 4 to 20 hours. This causes the soybean raw material to coagulate, resulting in a coagulated material with a pH of 5 or less. It is preferable to heat and sterilize the coagulated material obtained by lactic acid fermentation for about 1 to 15 minutes at a temperature that results in a central temperature of 85°C or higher in order to kill the lactic acid bacteria and promote the excretion of whey.

On the other hand, when the soybean raw material is coagulated using an acid, an organic acid such as citric acid, lactic acid, acetic acid, ascorbic acid, or gluconic acid, or an inorganic acid such as dilute hydrochloric acid, is added to the soybean raw material to adjust the pH of the soybean raw material to be acidic. When the soybean raw material is coagulated using a coagulant, a divalent metal salt such as magnesium chloride or calcium chloride, which is used as a tofu flocculant, can be added to the soybean raw material.

[Card formation process]
In the curd formation step S2, whey is separated from the coagulated product obtained in the coagulation step S1 to form a curd. The method for separating the whey can be a method used in cheese production. For example, the coagulated product is wrapped in cotton cloth or placed in a mold or hoop, and left to stand overnight under a predetermined pressure. This allows the whey to be discharged, and a curd with an appropriate hardness is obtained.

When salt is to be added to a cheese-like fermented food, for example, the curd obtained by draining the whey is broken down and salt is added, and then the curd is re-wrapped in cotton cloth or placed in a mold or hoop and left to stand for 4 to 12 hours under a certain pressure to reform the curd. Alternatively, salt can be added by, for example, immersing the curd in 20% saline for 10 minutes to overnight.

[Fermentation and maturation process]
In the fermentation and maturation step S3, koji mold is attached to the curd formed in the whey separation step, and the curd is fermented and maturated by the koji mold. The type of koji mold is not particularly limited, but soy sauce koji mold and miso koji mold are preferred, and it is more preferred to use Aspergillus oryzae or Aspergillus soya, or both. This results in a cheese-like fermented food that has a flavor similar to cheese, a smooth texture, and good taste. The koji mold may be used alone or in combination of multiple types.

The method of attaching the koji mold is not particularly limited, and for example, a method of spraying a liquid containing the above-mentioned koji mold seed koji onto the card so that the koji mold adheres to the entire surface of the card, or a method of mixing the above-mentioned koji mold seed koji, soybean koji, or rice koji into the card can be applied.

The maturation period can be set appropriately depending on the type of cheese-like fermented food to be produced and the maturation temperature. For example, when producing a fermented food with a fresh aroma and a light, sour flavor, such as cream cheese or cottage cheese, it is preferable to shorten the maturation period. On the other hand, when producing a fermented food with a strong umami taste and a mellow flavor, such as Parmigiano Reggiano, it is preferable to maturate for one month or more. The cheese-like fermented food of this embodiment is maturated at a constant temperature and humidity (mainly at low temperatures of 7 to 16°C) to develop a cheese-like flavor and texture.

Industrially, the curd with the koji mold attached is left to stand for 1 to 4 days at a temperature of, for example, 25 to 35°C to allow the koji mold to grow, and then left to stand for 10 to 60 days at a temperature of, for example, 15 to 25°C to mature, to obtain a cheese-like fermented food. In this case, the curd with the koji mold grown may be sealed in a film bag containing an oxygen scavenger or wrapped in paraffin paper and matured in this state. This stops the growth of the koji mold, prevents the generation of unpleasant odors caused by vigorous growth of the koji mold, and allows the product to be fermented and matured using the enzymes produced by the koji mold while preventing the contamination and proliferation of harmful microorganisms.

The cheese-like fermented food produced by the above-mentioned method contains 0.70 mg/g or more of isovaleric acid as an aroma component, and has a flavor and texture closer to that of cheese than conventional products produced using soybean raw materials. If the amount of isovaleric acid in the fermented food is less than 0.70 mg/g, a flavor closer to that of cheese cannot be obtained. The isovaleric acid content referred to here is a value measured using gas chromatography.

As described above in detail, the method for producing a cheese-like fermented food of this embodiment involves fermenting and maturing curds formed from soybean raw materials using koji mold, so compared to conventional fermented soy milk foods produced using cheese mold, the grassy smell peculiar to soy milk is suppressed and a fermented food with a flavor closer to cheese is obtained. The cheese-like fermented food produced by the method of this embodiment has a smooth texture and is also delicious.

The effects of the present invention will be specifically explained below with examples and comparative examples.

(First embodiment)
In this example, cheese-like fermented foods were produced by varying only the maturation period according to the method described below, and the taste, flavor and texture were evaluated, and the aroma components were analyzed.

The soybean raw material used was unsweetened soy milk manufactured by Kikkoman Beverage Co., Ltd., which had been heat-sterilized for 15 minutes at a core temperature of 85°C or higher. The sterilized soybean raw material was mixed with lactic acid bacteria (Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus,
Lactobacillus helveticus) was added, and lactic acid fermentation was carried out for 4.5 to 7 hours at a fermentation temperature of 43° C. The fermented soy milk obtained by this lactic acid fermentation was heat sterilized at a center temperature of 85° C. or higher for 1 minute, then wrapped in cotton cloth and a mold and left to stand overnight under pressure, and the whey was drained to form curds.

Next, the formed curd was broken down once, and 4% by weight of salt was added to the total weight of the curd. The curd was then wrapped in cotton cloth and mohair and left to stand for 5 hours under pressure to reform the curd. Then, the entire surface of the resulting curd was sprayed with koji mold (Aspergillus oryzae: Bioc, for good koji seed soy sauce). A suspension of 0.103 g of koji seed in 10 ml of 0.9% by weight saline was used.

The cards with the koji mold attached were left to stand at 25°C for 2 or 3 days, and the koji mold was allowed to grow until the surface turned yellow with a slight green color. Each sample was then placed in a film bag containing an oxygen absorber, sealed, and left to stand for a specified period of time at 15°C to mature.

<Sensory evaluation>
After aging, each sample was taken out of the bag, and two panelists performed a sensory evaluation of the umami, texture (smoothness), and flavor. As a result, for taste, if both panelists felt the umami, it was marked as ○, if one panelist felt the umami, it was marked as △, and if neither panelist felt the umami, it was marked as ×. For flavor, if both panelists felt the flavor was similar to cheese, it was marked as ○, if one panelist felt the flavor was similar to cheese, it was marked as △, and if neither panelist felt the flavor was similar to cheese, it was marked as ×. For texture, if both panelists felt it was smooth (not rough), it was marked as ○, if only one panelist felt it was smooth, it was marked as △, and if both panelists felt it was rough, it was marked as ×.

<Aroma component analysis>
The analysis of aroma components was performed by gas chromatography (HERACLES II manufactured by Alpha Moss Japan Co., Ltd.), and the concentration of isovaleric acid, an aroma component specific to cheese, was calculated. At that time, 2 g of the sample was sealed in a 20 ml vial, and the components inside the vial were concentrated and extracted by SPME (solid phase microextraction method), the trap temperature was set to 40 ° C./240 ° C. (desorption temperature), and hydrogen was used as the carrier gas. The column used was a metal capillary column (MXT-5 MXT-WAX), and the column heating conditions were an initial temperature of 40 ° C., an initial constant temperature time of 10 seconds, and a heating rate of 1.5 ° C./second from 40 ° C. to 250 ° C., and detection was performed at an FID temperature of 260 ° C.

The above results are shown in Table 1 below.

As shown in Table 1 above, it was confirmed that the fermented food produced under the conditions of this example had a high isovaleric acid concentration and a good taste, texture, and flavor when aged for 15 days or more. Therefore, in the examples shown below, the aging period was set to 30 days.

Second Example
Next, cheese-like fermented foods of the examples and comparative examples were produced by the methods described below, and the taste, flavor and texture were evaluated by the same methods as in the first example.

The soybean raw material used was unsweetened soy milk manufactured by Kikkoman Beverages Corporation, which had been heat-sterilized for 15 minutes at a core temperature of 85°C or higher. Lactic acid bacteria were added to the sterilized soybean raw material, and lactic acid fermentation was carried out under the conditions shown in Table 2 below. The fermented soy milk obtained by this lactic acid fermentation was heat-sterilized for 1 minute at a core temperature of 85°C or higher, then wrapped in cotton cloth and a mold and left to stand overnight under pressure, allowing the whey to be drained off and forming curds.

Next, the formed curd was broken once, and 4% by mass of salt based on the total mass of the curd was added, and then the curd was reformed by wrapping it in cotton cloth and molle and leaving it to stand for 5 hours under pressure. Then, for samples No. 1 to 3, the koji mold seed koji shown in Table 3 below was sprayed onto the entire surface of the obtained curd. At that time, a liquid in which 0.103 g of seed koji was suspended in 10 ml of 0.9% by mass saline was used. Note that no koji mold was attached to sample No. 4.

The cards with the koji mold attached were left to stand at 25° C. for 2 or 3 days to allow the koji mold to grow until the surface turned yellow with a slight green color. Each sample was then placed in a film bag containing an oxygen scavenger, sealed, and left to stand at 15° C. for 30 days to mature. The results are shown in Table 4 below.

As shown in Table 4 above, samples No. 1 to 3 produced by the production method of the present invention were excellent in taste, texture, and flavor. On the other hand, sample No. 4, which was not fermented and aged with koji mold, did not have a cheese-like flavor and was not smooth.

These results confirm that the present invention makes it possible to produce a cheese-like fermented food with a flavor and texture similar to that of cheese from soybean raw materials.

Claims (6)

A coagulation step of coagulating the soybean raw material using lactic acid bacteria and/or acid;
A step of separating whey from the coagulated product obtained by the coagulation step to form a curd;
and fermenting and maturing the curd with koji mold.
In the fermenting and maturing step, a liquid containing seed koji is sprayed onto the surface of the curd. The method for producing a cheese-like fermented food according to claim 1, wherein in the fermentation and maturation step, the curd to which the koji mold is attached is left to stand at a temperature of 25 to 35°C for 1 to 4 days, and then left to stand at a temperature of 15 to 25°C for 10 to 60 days. The method for producing a cheese-like fermented food according to claim 1 or 2, wherein the koji mold used in the fermentation and maturation process is a koji mold for soy sauce and/or a koji mold for miso. The method for producing a cheese-like fermented food according to claim 3, wherein Aspergillus oryzae and/or Aspergillus soya are used in the fermentation and maturation process. The method for producing a cheese-like fermented food according to any one of claims 1 to 4, wherein the soybean raw material includes soy milk produced using dehulled soybeans. The method for producing a cheese-like fermented food according to any one of claims 1 to 5, which obtains a cheese-like fermented food containing 0.70 mg/g or more of isovaleric acid as an aroma component.

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