Fermented soy beverage concentrate and method for producing same

Abstract

The present invention provides a fermented soybean beverage concentrate and a novel method for producing the same. This production method of a fermented soybean beverage concentrate comprises: a fermentation step for adding a microorganism to a soybean beverage and fermenting the soybean beverage; an increment step for mixing the fermented soybean beverage obtained in the fermentation step with the soybean beverage to increase the amount, thereby giving a mixture having a pH value less than 6.0; and a concentration step for concentrating solids from the mixture obtained in the increment step.

Description

[Technical field]

[0001] The present invention relates to a fermented soy beverage concentrate and a method for making the same. [Background technology]

[0002] In recent years, from the perspectives of health and food resources, high-protein plant materials, such as soybeans, peas, and other legumes, as well as various nuts and seeds, have been attracting attention worldwide as non-animal protein sources to replace milk and meat, and demand for them is increasing. These high-protein plant materials are used as substitutes for dairy products such as milk and cheese, and in recent years have also been widely used as substitutes for meat. The global market for artificial meat in 2020 was estimated to be over 250 billion yen, and is estimated to exceed 1.8 trillion yen in 2030.

[0003] Proteins are extracted from soybeans, dried, and powdered, and are used in many ways as ingredients in processed foods. In addition, the consumption of soy milk as a beverage is increasing year by year, and the production volume of soy milk in Japan has doubled in the past 10 years. Extra-thick soy milk with a high protein content has also been developed, and consumption is expanding.

[0004] Meanwhile, fermented foods are widely known as natural and healthy ingredients, and the market for products using lactic acid bacteria and bifidobacteria, especially dairy products, is expanding year by year. In recent years, microorganisms such as lactic acid bacteria have also been used in various foods other than dairy, and various health benefits such as intestinal regulation and immune regulation are expected.

[0005] In light of this, yogurt-like fermented products made by fermenting soy milk with microorganisms such as lactic acid bacteria have been attracting attention as fermented plant materials. However, fermented products derived from soybeans have issues with flavor, such as a bean or grassy smell, and physical properties, such as a brittle texture similar to tofu. For this reason, various efforts have been made to improve flavor, such as by selecting the type of lactic acid bacteria used and searching for additives (Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2018-68267 Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, there is a high demand for fermented soy milk products rich in soy protein as a vegetable protein source, but the variety of such fermented products is still limited. When attempting to concentrate fermented soy milk products to increase the concentration of soy protein, particularly from the perspective of using it as a protein supplying foodstuff, the grassy flavor and brittle physical properties become more pronounced. Many proposals have been made to solve these problems, one of which is to select a specific species of lactic acid bacteria. However, this results in difficulties in utilizing microorganisms such as lactic acid bacteria with specific functionality, or in differentiating products by fermenting with microorganisms such as lactic acid bacteria with unique characteristics.

[0008] In addition, milk and soybeans each contain different allergens and are designated as specific raw materials. Therefore, using dairy production facilities to produce soy products also poses food safety risks, and soy milk fermentation requires the installation of dedicated facilities. Fermentation facilities require temperature control devices and mold prevention, so the capital investment is large, which is a factor preventing the spread of fermented soy milk.

[0009] In light of this background, the present invention aims to provide a new fermented product using soy beverages such as soy milk as a raw material, and a method for producing the same. Another object of the present invention is to provide a fermented soy beverage concentrate containing an amount of soy protein that exceeds the total amount of soy protein contained in the fermented soy beverage obtained in the fermentation process, and a fermented soy beverage concentrate that has undergone fermentation by various types of microorganisms, and a method for producing the same. Furthermore, the present invention aims to provide a fermented soy beverage concentrate that can be produced even in a small-scale fermentation facility relative to the amount of the final product, and a method for producing the same. [Means for solving the problem]

[0010] The present inventors have discovered that the above problems can be solved by a fermented soy beverage concentrate obtained by adding microorganisms such as lactic acid bacteria to a soy beverage to ferment the soy beverage to coagulate the proteins in the soy beverage, mixing the resulting fermented soy beverage with a soy beverage, adjusting the pH to below a specific pH, and concentrating the solids from the mixture, thereby completing the present invention.

[0011] That is, the present invention relates to the following. [1] 1. A method for producing a fermented soy beverage concentrate, comprising: a fermentation step of adding microorganisms to the soy beverage to ferment the soy beverage; a volume increasing step of mixing and increasing the volume of the fermented soy beverage obtained in the fermentation step with the soy beverage to obtain a mixture having a pH of less than 6.0; and A concentration step for concentrating the solid content from the mixture obtained in the weight-increasing step. A manufacturing method comprising: [2] The microorganism is Lactobacillus genus, Lactococcus genus, Leuconostoc genus, Streptococcus genus, Pediococcus Genus and Bifidobacterium The method according to claim 1, wherein the genus of the microorganism is based on an old classification. [3] The method according to [1] or [2], wherein the concentrating step includes a step of separating a solid fraction containing the concentrated solids from the mixture. [4] The method according to any one of [1] to [3], wherein the weight of the soy beverage in the weight increasing step is 20% or more and 500% or less of the weight of the fermented soy beverage. [5] The method according to any one of [1] to [4], wherein the increasing step is carried out at a temperature of 37°C or lower. [6] The method according to any one of [1] to [5], wherein the soy protein content of the soy beverage in the fermentation step and / or the soy beverage in the weight increasing step is 0.5% or more. [7] The method according to any one of [1] to [6], wherein the soybean beverage in the fermentation step contains a buffer. [8] The method according to any one of [1] to [7], wherein the soy beverage in the bulking step contains a pH adjuster. [9] The pH of the fermented soybean beverage after the fermentation step is pH 3.5 or more and pH 5.5 or less; The method according to any one of [1] to [8], wherein the pH of the mixture after the volume increasing step is pH 4.7 or higher and pH 5.9 or lower, provided that the pH of the mixture after the volume increasing step is higher than the pH of the fermented soybean beverage after the fermentation step.

[10] The method according to any one of [1] to [9], wherein the volume increasing step is a step of mixing the fermented soybean beverage obtained in the fermentation step with the soybean beverage so as to obtain a mixture having a pH of 5.7 or less.

[11] The method according to any one of [1] to

[10] , wherein the concentration step is carried out using an apparatus selected from the group consisting of a centrifuge and a membrane separation apparatus.

[12] A fermented soy beverage concentrate produced by the method according to any one of [1] to

[11] .

[13]

[12] A fermented soy beverage concentrate according to claim 12, wherein the protein content per 100 g of water is 8 g or more and / or the relative protein content ratio (weight ratio) when the amount of carbohydrate contained is taken as 1 is 4 or more.

[14] The microorganism is Lactobacillus genus, Amylolactobacillus genus, Holzapfelia genus, Bombilactobacillus genus, Companilactobacillus genus, Lapidilactobacillus genus, Agrilactobacillus genus, Schleiferilactobacillus genus, Lacticaseibacillus genus, Paralactobacillus genus, Latilactobacillus genus, Loigolactobacillus genus, Dellaglioagenus, Liquorilactobacillus genus, Ligilactobacillus genus, Lactiplantibacillus genus, Furfurilactobacillus genus, Paucilactobacillus genus, Limosilactobacillus genus, Secundilactobacillus genus, Levilactobacillus genus, Fructilactobacillus genus, Acetilactobacillus genus, Apilactobacillus genus, Lentilactobacillus genus, Lactococcus genus, Leuconostoc genus, Streptococcus genus, Pediococcus Genus and Bifidobacterium The method according to claim 1, wherein the genus of the microorganism is based on a new classification.

[15] The microorganism is Lactobacillus genus, Lacticaseibacillus genus, Latilactobacillus genus, Lactiplantibacillus genus, Limosilactobacillus genus, Levilactobacillus Genus and Streptococcus The method according to claim 1, wherein the genus of the microorganism is based on a new classification. Effect of the Invention

[0012] According to the present invention, a new fermented soy beverage concentrate and a method for producing the same can be provided, in particular, a fermented soy beverage concentrate containing soy protein in an amount greater than the total amount of soy protein contained in the fermented soy beverage obtained by the fermentation process can be provided. Furthermore, according to the present invention, the physical properties and flavor of the fermented soy beverage concentrate can be changed without relying solely on changing the species or strain of the microorganism used for fermentation. The production method of the present invention also has the advantage that it can be produced even in a small-scale fermentation facility relative to the amount of the final product. [Brief description of the drawings]

[0013]

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[0014] Hereinafter, an embodiment of the present invention (hereinafter also referred to as "the present embodiment") will be described, but the present invention is not limited to the present embodiment. The present embodiments relate to a method for producing a fermented soy beverage concentrate, the method comprising: a fermentation step of adding a microorganism to the soy beverage to ferment the soy beverage; a volume increasing step of mixing and increasing the fermented soy beverage obtained in the fermentation step with the soy beverage to obtain a mixture having a pH of less than 6.0; and The method includes a concentration step of concentrating the solid content from the mixture obtained in the weight increasing step.

[0015] The soy beverage in this specification is not particularly limited as long as it is produced from soybeans and water as raw materials and forms soy protein aggregates by fermentation with microorganisms. Examples include soy milk and prepared soy milk in the soy milk product standard set forth in the Japanese Agricultural Standards, and soy milk beverages in the same standard that form soy protein aggregates by fermentation with microorganisms. The soy beverage in this embodiment also includes so-called "whole soy beverages," which are soy milk-like beverages that contain soy fiber (okara) in a suspended state in the beverage without removing it. In addition, beverages produced by dissolving or suspending soy powder made by finely grinding soybeans or powdered soy milk made by drying soy milk are also included. So long as they do not prevent the aggregation of soy protein, soy beverages may contain other food ingredients or food additives.

[0016] As long as the soy protein aggregates by fermentation with microorganisms, the amount of soy solids and soy protein in the soy beverage is not particularly limited. For example, a soy beverage having a soy solids content of 1% or more (0.5% or more in soy protein equivalent), preferably 4% or more (1.8% or more in soy protein equivalent), more preferably 6% or more (3.0% or more in soy protein equivalent) can be used. According to the Japanese Agricultural Standards, soy milk has a soy solids content of 8% or more (3.8% or more in soy protein equivalent), prepared soy milk has a soy solids content of 6% or more (3.0% or more in soy protein equivalent), and soy milk beverage has a soy solids content of 4% or more (1.8% or more in soy protein equivalent). The upper limit of the soy solids and soy protein content of the soy beverage is not particularly limited, and for example, the soy beverage may have a soy solids content of 20% or less or 15% or less. In this specification, "%" means "% by weight" unless otherwise specified.

[0017] The microorganisms used for fermenting the soy beverage are not particularly limited, so long as they are capable of agglutinating proteins in the soy beverage through fermentation and can be used in foods.

[0018] In this specification, unless otherwise specified, the classification of microorganisms is based on the classification that was publicly known in March 2020 (referred to as the "old classification" in this specification). For example, an example of the old classification is the classification based on the description in Bergey's Manual of Systematic Bacteriology 2nd edition ( Lactobacillus The genus is described in Volume 3 (2009). Lactobacillus The genus was known to consist of 262 species in March 2020 under the old classification, but a reclassification at the genome level (referred to as the "new classification" in this specification) was announced in April 2020 (Zheng J, et al., Int J Syst Evol Microbiol. 2020 Apr; 70(4): 2782-2858. Note that the new classification uses the genome data of the type strain on August 19, 2019). Under the old classification, Lactobacillus Under the new classification, microorganisms that were previously classified into genera are now classified into 25 genera ( Lactobacillus genus, Amylolactobacillus genus,Holzapfelia genus, Bombilactobacillus genus, Companilactobacillus genus, Lapidilactobacillus genus, Agrilactobacillus genus, Schleiferilactobacillus genus, Lacticaseibacillus genus, Paralactobacillus genus, Latilactobacillus genus, Loigolactobacillus genus, Dellaglioa genus, Liquorilactobacillus genus, Ligilactobacillus genus, Lactiplantibacillus genus, Furfurylactobacillus genus, Paucilactobacillus genus, Limosilactobacillus genus, Secundilactobacillus genus, Levilactobacillus genus, Fructilactobacillus genus, Acetylactobacillus genus, Apilactobacillus genus, Lentilactobacillus Although it has been reclassified into the genus Lactobacillus When referring to genera, unless otherwise noted, they are based on the old classification. Lactobacillus Refers to microorganisms that were classified in the genus

[0019] Representative examples of microorganisms used in the fermentation of soy beverages include: Lactobacillus plants (New classification name: Lactiplantibacillus plants )or Lactobacillus short (New classification name: Levilactobacillus short ), Streptococcus thermophilic , Lactococcus milk Microorganisms that are known to be capable of growing in soy beverages and producing acid include, for example, Saccharomyces cerevisiae ... Bifidobacterium Genus and Lactobacillus delbrueckii subsp. Bulgarian For the purpose of improving flavor, etc. Saccharomyces Yeasts of the genus may also be used. Bifidobacterium Genus and Lactobacillus gas stationMicroorganisms known to have health functionality such as the above may also be used.

[0020] In one aspect, the microorganisms used in the soybean fermentation of this embodiment are selected from lactic acid bacteria and bifidobacteria, and lactic acid bacteria and bifidobacteria may be used in combination. Examples of such microorganisms include Lactobacillus genus, Lactococcus genus, Leuconostoc genus, Streptococcus genus, Pediococcus genus, Bifidobacterium Examples of species of these genera include, for example, Lactobacillus casei and Bifidobacterium casei. Lactobacillus acidophilus , Lb. short (New classification name: Levilactobacillus brevis ), Lb. cheese (New classification name: Lactobacillus casei ), Lb. delbrueckii subsp. Bulgarian , Lb. delbrueckii subsp. milk , Lb. leaven (New classification name: Limosilactobacillus leaven ), Lb. gas station , Lb. Swiss , Lb. johnson's , Lb . cheese (New classification name: Lactobacillus cheese ), Lb. plants (New classification name: Lactiplantibacillus plants ), Lb. reuteri (New classification name: Limosilactobacillus reuteri ), Lb. buckthorn (New classification name: Lactobacillus buckthorn ), Lactococcus milk subsp. cream , Luke. milk subsp. milk , Luke milk subsp. milkBiovar. diacetylated , Leuconostoc mesenteroides , Pediococcus acidilactici , P. pentosaceus , Streptococcus thermophiles , Bifidobacterium breve , B. infantis , B. longum In one aspect, the microorganism used in the soybean fermentation of this embodiment is Lactobacillus genus, Lactococcus genus, Leuconostoc Genus and Streptococcus The present invention includes microorganisms of a genera selected from the genera:

[0021] In one aspect, the microorganism used for soybean fermentation of this embodiment is: Lactobacillus genus, Amylolactobacillus genus, Holzapfelia genus, Bombilactobacillus genus, Companilactobacillus genus, Lapidilactobacillus genus, Agrilactobacillus genus, Schleiferilactobacillus genus, Lacticaseibacillus genus, Paralactobacillus genus, Latilactobacillus genus, Loigolactobacillus genus, Dellaglioa genus, Liquorilactobacillus genus, Ligilactobacillus genus, Lactiplantibacillus genus, Furfurilactobacillus genus, Paucilactobacillus genus, Limosilactobacillus genus, Secundilactobacillus genus, Levilactobacillus genus, Fructilactobacillus genus, Acetilactobacillus genus, Apilactobacillus genus, Lentilactobacillus genus, Lactococcus genus, Leuconostoc genus, Streptococcus genus, Pediococcus Genus and Bifidobacterium In one embodiment, the microorganisms used in soybean fermentation of this embodiment are preferably selected from the genus Streptococcus cerevisiae, which is a type of microorganism that is widely used in the food industry, particularly as a fermentation starter or probiotic. Lactobacillus genus, Lacticaseibacillus genus, Latilactobacillus genus, Lactiplantibacillus genus, Limosilactobacillus genus, Levilactobacillus Genus and Streptococcus wherein the genus of the microorganism is based on a new classification.

[0022] In one aspect of this embodiment, the microorganism is a polysaccharide-producing bacterium. By using a polysaccharide-producing strain with excellent polysaccharide production ability, a soft and smooth fermented soy beverage concentrate can be obtained. Polysaccharide production is possible with any lactic acid bacteria and bifidobacteria, and representative species with high production amounts include: Leuconostoc mesenteroides , Lactococcus lactis subsp. cremoris , Streptococcus thermophilus In one embodiment, these can be used alone or in combination with other bacteria.

[0023] For the fermentation of soy beverages, a combination of multiple kinds of microorganisms may be used, or commercially available products may be used. For example, in recent years, starter manufacturers have been selling microorganisms such as lactic acid bacteria for producing yogurt products that claim to be low-fat or fat-free, and such microorganisms can produce soft and smooth fermented products by producing a large amount of polysaccharides even with a low fat content. As long as they can aggregate proteins in soy beverages, they may be used. Furthermore, yogurt starters containing lactic acid bacteria and other microorganisms that have traditionally been sold for dairy use and prepared with milk-free materials are also commercially available so that they can be applied to the fermentation of vegetable matter, and these may be used. For example, various starters are commercially available from CHR HANSEN (YOFLEX series, EXACT series, etc.), DUPONT (YO-MIX series, CHOOZIT series, etc.), SACCO (CRYOFAST series, LYOFAST series, etc.), and DSM (DELVO-YOG series, DELVO-FRESH series, etc.), and these starters can be appropriately selected and used in consideration of the characteristics of the concentrate to be obtained, the presence or absence of milk-derived components, flavor, etc. In one embodiment, starters and microorganisms such as lactic acid bacteria that are known to bring about excellent flavor and physical properties, particularly in the fermentation of soy milk, can be used.

[0024] The fermentation process will now be described. The soy beverage used for fermentation is adjusted to a temperature suitable for the microorganisms used for fermentation (generally in the range of 20°C to 45°C), and then the microorganisms are inoculated. Inoculation of the microorganisms used as starters may be performed using a general inoculation method for starters, as long as it is performed hygienically. Commercially available lactic acid bacteria powder or frozen lactic acid bacteria liquid may be directly added to the soy beverage for inoculation, or a culture of seed bacteria obtained by pre-cultivating the soy beverage in advance using soy milk or the like may be added to the soy beverage. It is preferable that the soy beverage is treated in advance, such as by sterilization, disinfection, or elimination, to prevent contamination by various bacteria, prior to inoculation of the microorganisms. In addition, it is preferable that the soy beverage before or after inoculation is homogenized with a homogenizer before fermentation.

[0025] After inoculation, it is desirable to carry out stirring for a certain period of time so that the microorganisms are uniformly dispersed in the fermentation vessel. The inoculation ratio of the starter to the soybean beverage can be appropriately set according to the bacterial concentration and vitality of the microorganisms contained in the starter, and is usually in the range of 0.0001% to 10%. The inoculation ratio is preferably 0.001% to 0.1% in the case of a concentrated starter, and preferably 0.1% to 5% in the case of a cultured culture as the starter. When using a commercially available microorganism, the microorganism can be inoculated in the recommended amount. The fermentation time can also be appropriately set depending on the microorganism used. Some microorganisms complete fermentation in a few hours, while others take several days. It is desirable to carry out the fermentation process at a temperature close to the optimum temperature of the microorganism. Microorganisms that perform high-temperature short-time fermentation can be cultured, for example, in the range of 35°C to 45°C for 2 to 20 hours, preferably 2 to 10 hours. Microorganisms that perform low-temperature long-time fermentation can be cultured, for example, in the range of 20°C to 35°C for 10 to 240 hours, preferably 10 to 72 hours.

[0026] The isoelectric point of protein in soybeans is around pH 4.5, but in soy beverages, solids gradually begin to aggregate when the pH falls below 5.9. The pH at which aggregation begins varies somewhat depending on the type of soy beverage, the manufacturing method, and the lot. In particular, in soy beverages that contain ingredients other than soybeans, such as emulsifiers and antifoaming agents, such as prepared soy milk, the pH at which aggregation begins may vary due to the influence of ingredients other than soybeans. The fermentation process is carried out until the pH of the soy beverage falls below the pH at which aggregation occurs. The lower the pH at the end of fermentation, the more soy beverage can be added in the subsequent volume increase process, and the final amount of fermented soy beverage concentrate can be increased. On the other hand, if a large amount of soy beverage is added in the volume increase process, the various ingredients and the number of microorganisms generated in the fermentation process will be diluted. Therefore, it is advisable to determine the pH at the end of fermentation taking into account the factors required for the product. For example, the pH of the fermented soybean beverage obtained in the fermentation process can be pH 3.5 or more and pH 5.5 or less, pH 3.5 or more and pH 4.7 or less, pH 3.8 or more and pH 5.5 or less, or pH 3.8 or more and pH 4.7 or less, preferably in the range of pH 3.5 or more and pH 5.5 or less (including cases where the value rounded to one decimal place falls within these ranges; the same applies to pH below), and more preferably in the range of pH 3.8 or more and pH 4.7 or less.

[0027] The soy beverage in the fermentation step may contain a buffering agent. The buffering agent is not particularly limited as long as it is acceptable for addition to food, and examples thereof include organic acids and salts thereof, such as malic acid and its salts (e.g., sodium malate), citric acid and its salts (e.g., sodium citrate), and succinic acid and its salts (e.g., sodium succinate). By adding a buffering agent, the acidity of the fermented soy beverage becomes higher (more lactic acid can be contained) due to the buffering action, even if the pH at the end of the fermentation step is about the same, compared to when no buffering agent is added. This allows more soy beverage to be added to the fermented soy beverage in the subsequent weight-increasing step. The buffering agent in this specification may have a pH adjusting action, and may be the same as the pH adjusting agent in the weight-increasing step described below, so long as it has the desired buffering action. In one embodiment, the soy beverage may preferably contain a buffering agent having an acid dissociation constant (pKa) between 3.8 and 6, for example, 3.8 to 5.9. The amount of addition is not particularly limited as long as it exhibits buffering ability.

[0028] The increasing process will be described. The fermented soy beverage is mixed with the soy beverage after the fermentation process to increase the volume. In order to facilitate mixing, it is preferable to crush the curd formed by acid coagulation. The curd may be crushed immediately after the end of fermentation, or after cooling the fermented product. Crushing the curd after cooling often results in a smoother texture of the fermented soy beverage, which is preferable. The method of crushing the curd is not limited. When the curd is hard, it is crushed by mechanical equipment such as an agitator or a curd breaker. When the curd is soft, it may be crushed by the pump used for liquid transfer without stirring. The curd can also be crushed through a mixer provided in the liquid transfer pipe.

[0029] The soy beverage mixed in the volume increase step may be the same as or different from the soy beverage used in fermentation in terms of type and composition. The mixing procedure may involve gradually adding the soy beverage to a fixed amount of fermented soy beverage, or gradually adding the fermented soy beverage to a fixed amount of soy beverage. A method in which the fermented soy beverage and the soy beverage are simultaneously pumped in a fixed ratio using a metering pump or the like while being mixed using an in-line mixer or the like may also be used. In either case, it is desirable to mix the fermented soy beverage and the soy beverage by stirring them in a container so that the mixture is as homogenous as possible.

[0030] The mixing ratio of the fermented soy beverage and the soy beverage is arbitrary as long as the pH of the resulting mixture is in the range of less than pH 6.0, and can be freely determined according to the design of the product, for example, the soy beverage to be used, the physical properties to be obtained, etc. The pH of the mixture is preferably in the range of pH 4.7 to pH 5.9. As a pH that can be adapted to various product designs, the lower limit is preferably pH 4.8, more preferably pH 5.0, and the upper limit is preferably pH 5.8, more preferably pH 5.7, and particularly preferably pH 5.6. For example, the pH of the mixture obtained in the weight-increasing step can be pH 4.8 to pH 5.8, pH 4.8 to pH 5.7, pH 4.8 to pH 5.6, pH 5.0 to pH 5.8, pH 5.0 to pH 5.7, or pH 5.0 to pH 5.6. Since the pH, which has been changed to acidic in the above-mentioned fermentation process, changes to the neutral side in the volume-increasing process, the pH of the mixture obtained in the volume-increasing process becomes higher than the pH of the fermented product (fermented soybean beverage) obtained in the fermentation process. For example, in one embodiment, the pH of the fermented product at the end of fermentation is preferably in the range of pH 3.5 to pH 5.5, and the pH of the mixture obtained in the volume-increasing process is in the range of pH 4.8 to pH 5.6, but the pH of the mixture is higher than the pH of the fermented product.

[0031] In the bulking step, the soy beverage to be mixed with the fermented soy beverage may contain a pH adjuster. The type and amount of the pH adjuster is not particularly limited as long as the pH of the soy beverage is maintained higher than the pH of the mixture obtained in the bulking step, and any pH adjuster that is acceptable for addition to foods can be used. In the range in which the pH of the soy beverage is maintained higher than the pH of the mixture obtained in the bulking step, the lower the pH, the more desirable it is because the amount of the adjuster added to the fermented soy beverage can be increased. As the pH adjuster, those mentioned above as buffers can be used, and for example, organic acids such as citric acid, malic acid, and succinic acid can be used as pH adjusters.

[0032] The pH of the soy protein in the soy beverage added in the bulking step is lowered by mixing with the fermented soy beverage, and the soy protein aggregates in a short time. If the pH at the end of mixing is low, the fermented soy beverage concentrate finally obtained is relatively hard, and if the pH at the end of mixing is high, the fermented soy beverage concentrate finally obtained is relatively soft. On the other hand, if the pH at the end of mixing is low, separation is facilitated when whey is separated in the subsequent concentration step, and the solid fraction is easily recovered. If the pH at the end of mixing is too high, some of the solids may flow out or remain in the whey, or more advanced separation conditions may be required to recover the solid fraction. Furthermore, the higher the pH, the less likely the sourness is to be felt. Taking these factors into consideration according to the purpose, the pH of the mixture of the fermented soy beverage and the soy beverage can be determined. Even if the type of soy beverage or the type of lactic acid bacteria is changed, there will be no significant difference in the pH value at which aggregation is formed in the soy beverage, but some variation may occur. Therefore, it is desirable to set the pH of the mixture at the end of the bulking step based on a preliminary test.

[0033] The amount of soy beverage mixed in the volume-increasing step can be appropriately determined according to the pH of the mixture. For example, the lower limit of the amount of soy beverage can be 0.1 times (10%) or more of the fermented soy beverage, preferably 0.2 times (20%) or more, more preferably 0.3 times (30%) or more, even more preferably 0.5 times (50%) or more, even more preferably 1 time (100%) or more, for example 1.5 times (150%) or more. The upper limit of the amount of soy beverage can be mixed as long as the pH after the volume-increasing step is within the desired range. For example, when the pH of the soy beverage to be mixed is low, for example, about 20 times (2000%) of the fermented soy beverage may be mixed. In one embodiment, the amount of soy beverage can be added in an amount of preferably 15 times (1500%) or less, more preferably 10 times (1000%) or less, for example 5 times (500%) or less of the fermented soy beverage. For example, in the volume increasing process, the soy beverage can be mixed in an amount that is 0.1 to 15 times, 0.1 to 10 times, 0.1 to 5 times, 0.2 to 15 times, 0.2 to 10 times, 0.2 to 5 times, 0.3 to 15 times, 0.3 to 10 times, 0.3 to 5 times, 0.5 to 15 times, 0.5 to 10 times, or 0.5 to 5 times the amount of the fermented soy beverage.

[0034] In one aspect, as described above, the soy beverage in the fermentation step contains a buffering agent, which can increase the acidity after fermentation. As a result, a larger amount of soy beverage can be added during the bulking step, and the amount of solids recovered can be increased. In addition, the soy beverage in the bulking step can contain a pH adjuster. As a result, a larger amount of soy beverage can be added during the bulking step, and the amount of solids recovered can be increased. According to the production method of this embodiment, a fermented soy beverage concentrate with a high solid content can be obtained even when a large amount of soy beverage is added during the bulking step. Therefore, a fermented soy beverage concentrate can be produced even with a small fermentation facility relative to the amount of the final product.

[0035] The aggregation of proteins in the soy beverage added in the weight-increasing step occurs due to a chemical reaction that does not rely on fermentation by microorganisms, and therefore, unlike the fermentation step, there is no need to maintain the optimum temperature for the fermenting microorganisms in the weight-increasing step. Rather, a final product with a finer texture can be obtained by performing the weight-increasing step while maintaining a low temperature. Without being bound by theory, the reason for this is thought to be as follows: By slowly proceeding at a low temperature the chemical reaction in which lactic acid in the fermented soy beverage mixes with the proteins in the soy beverage to cause protein aggregation, the occurrence of localized protein aggregation can be prevented. Therefore, in one embodiment, it is more preferable to cool the fermented soy beverage obtained in the fermentation step and mix it with a soy beverage that has been cooled in advance than to mix the two without cooling them. Also, if the fermented soy beverage and the soy beverage are mixed at a temperature at which the metabolism of the microorganisms used for fermentation is active, secondary fermentation occurs, further decreasing the pH, and therefore it may be difficult to maintain the pH of the mixture at a constant value. From this viewpoint as well, it is preferable to perform the weight-increasing step at a low temperature.

[0036] For example, the weight-increasing step can be carried out at a temperature below 45°C, for example 43°C or lower, preferably 37°C or lower, more preferably 30°C or lower. In one aspect, the weight-increasing step can be carried out at a temperature range of 0 to 20°C. However, pre-cooling before the weight-increasing step is not essential in this embodiment. Mixing and cooling can also be carried out instantly and simultaneously, which can be achieved, for example, by simultaneously feeding the fermented soy beverage and the soy beverage in small amounts into a device with strong mixing power such as an in-line mixer, and immediately cooling them on a cooling plate while mixing them instantly.

[0037] The concentration step will now be described. In the mixture of the fermented soy beverage and the soy beverage obtained in the weight-increasing step, not only the soy protein derived from the fermented soy beverage is aggregated by the acid, but also the soy protein in the soy beverage added later is aggregated by the acid in the fermented soy beverage. Therefore, by concentrating the aggregated solids from the mixture, the protein in the soy beverage added in the weight-increasing step can be simultaneously concentrated in addition to the protein in the soy beverage fermented in the fermentation step. Therefore, compared to the case where the mixture is directly concentrated after the fermentation step, a large amount of fermented soy beverage concentrate can be obtained relative to the size of the fermentation tank. The concentration step preferably includes a step of separating a solid fraction containing the solids concentrated from the mixture from whey, which is a liquid fraction. In this embodiment, concentrating the solids refers to a reduction in moisture from the solid fraction, which is a fraction containing solids, compared to before the concentration, and the solid fraction after the concentration step may contain moisture. Preferably, in the concentration step, the solids are concentrated from the mixture to obtain a separable solid fraction.

[0038] The solid content can be concentrated by a method generally used in food processing or food production, for example, by a centrifugal separator (separator), a membrane separator, or a combination thereof. Fine filtration equipment such as a filter press or a dehydrator that can industrially separate solids and liquids can be used for the concentration operation without any particular limitation. When concentration is performed by centrifugation, a centrifuge for food processing such as a quark separator used in the production of quark cheese can be used. The rotation speed during centrifugation is not particularly limited as long as the desired concentrate can be obtained, and is, for example, 15,000×g or less, preferably 1,500×g to 10,000×g, and more preferably 3,000×g to 8,000×g. The rotation speed and processing time can be appropriately set according to the physical properties of the concentrate to be obtained. For membrane separation, a microfiltration membrane (MF membrane) or an ultrafiltration membrane (UF membrane) used in food processing can be used.

[0039] By the concentration operation using such a centrifuge or membrane separator, low molecular odorous substances derived from soybeans and microorganisms, organic acids including lactic acid produced by fermentation, sugars in the soy beverage, etc. are separated from the solids together with whey. Although a certain amount of whey remains in the solid fraction obtained by concentration, the above-mentioned concentration operation can significantly reduce the concentrations of organic acids, odorous substances, sugars, etc., compared to the fermented soy beverage before the volume increase step or the concentrate obtained by concentrating the fermented soy beverage without the volume increase step. In addition, because the concentration operation recovers soy protein in the solid fraction, it is possible to obtain a fermented soy beverage containing an amount of soy protein that exceeds the total amount of soy protein contained in the fermented soy beverage obtained in the fermentation step.

[0040] When a centrifuge is used, the ratio of the solid fraction to the separated liquid after concentration can be adjusted by the centrifugal speed, separation plate area, liquid feed amount, etc., and when a membrane separation device is used, the ratio can be adjusted by the membrane area, liquid feed amount, liquid feed pressure, etc. By this adjustment, the hardness, fluidity, etc. of the obtained solid fraction can be adjusted.

[0041] The fermented soy beverage concentrate thus obtained has physical properties and flavor similar to Greek yogurt with a high solid content, and can be eaten as is or used as a cooking ingredient. According to the manufacturing method of this embodiment, it is easy to impart flavor and physical properties according to the purpose. For example, by adjusting the pH of the mixture to a high value close to pH 6 in the weight-increasing step to suppress sourness, a concentrate that can be used as a food ingredient produced from soybeans and has a rich creamy mouthfeel can be obtained. In addition, since such a fermented soy beverage concentrate is less likely to have a sour taste, it is easy to add flavor to the fermented soy beverage concentrate with ingredients or flavors that are difficult to combine with sourness, such as black tea, cocoa, and chocolate. In addition, by increasing the solid content in the concentration step, a fermented soy beverage concentrate can be obtained that has a texture similar to quark cheese, which is even richer than Greek yogurt, and such a fermented soy beverage concentrate can also be used as a substitute for fresh cheese produced from soybeans. By adding seasoning ingredients such as vinegar, salt, spices, etc. to the fermented soy beverage concentrate, the resulting seasoned concentrate can be used as a seasoning sauce such as a salad dip, salad dressing, mayonnaise, etc. The fermented soy beverage concentrate may also be used as an ice dessert by freezing it.

[0042] The obtained fermented soy beverage concentrate may be used as is, but its shelf life can be extended by suppressing microbial fermentation through sterilization. The sterilization temperature and time vary depending on the strain of bacteria used. Since sterilization at high temperatures denatures soy protein and reduces physical properties, it is desirable to sterilize the fermented soy beverage concentrate at a temperature of 55°C to 63°C for 30 seconds to 10 minutes. In addition, when sterilization after concentration is to be avoided from the viewpoint of flavor and physical properties, fermentation tanks and separation equipment can be made steam sterilizable and sealed, thereby preventing microbial contamination during the production process and obtaining a hygienic product. In this case, since the microorganisms used in fermentation survive, it is desirable to use microorganisms with weak post-fermentation properties.

[0043] In this embodiment, the fermented soy beverage concentrate is not particularly limited as long as it includes a fermented soy beverage concentrate obtained by fermenting a soy beverage, and may include a non-fermented soy beverage concentrate and other ingredients. Preferably, the fermented soy beverage concentrate in this embodiment includes a non-fermented soy beverage concentrate in addition to the fermented soy beverage concentrate.

[0044] The fermented soy beverage concentrate produced by the above process has at least one of the following characteristics: 1) The fermented soy beverage concentrate has a high soy protein content because the soy protein in the soy beverage is acid coagulated and then the whey fraction is removed. 2) In addition to soy protein, fermented soy beverage concentrates contain polysaccharides produced by microorganisms such as lactic acid bacteria and the bacterial cells themselves. Therefore, fermented soy beverage concentrates are softer, maintain fluidity, and have smoother physical properties than concentrates obtained by adding lactic acid to a soy beverage to precipitate soy protein. In particular, when microorganisms that produce a large amount of polysaccharides are used for fermentation, the fermented soy beverage concentrates have soft and smooth physical properties. 3) As long as the proteins in soy beverages can be aggregated by fermentation, a wide range of microorganisms that can be used in food products can be used. Since the physical properties and flavor can be subtly changed depending on the type of microorganism, it is possible to design products that take advantage of the characteristics of the strain. Health benefits derived from microbial fermentation can also be expected. 4) After fermentation and coagulation, soy beverage is added to raise the pH before concentrating, so the pH of the fermented soy beverage concentrate is also higher than that immediately after fermentation, and it is less likely to taste sour when consumed. 5) The only essential ingredients are soy beverage and fermentation microorganisms; basically no other additives are required.

[0045] In addition to the above features, the manufacturing method of this embodiment has the following advantages. 1) The fermentation equipment can be made smaller. The fermentation equipment is equipped with a heat sterilization equipment, a heat retention device, and a cooling device, and is required to be airtight. Therefore, the fermentation equipment is larger and more expensive than a normal tank. As a manufacturing method for solidifying liquid protein by lactic acid fermentation, total fermentation is generally used, such as in the manufacturing method of yogurt and cheese. However, in the total fermentation, the fermented liquid needs to be left stationary in the fermentation tank for a long fermentation time, so the capacity and space required for the fermentation tank are large, and it is necessary to make a large investment in expensive fermentation equipment and to secure space for installing the manufacturing facility. In contrast, in the manufacturing method of this embodiment, only a portion of the soybean beverage used is fermented, and the remainder is simply mixed after fermentation. Therefore, in the manufacturing method of this embodiment, the equipment and space required for fermentation can be made smaller.

[0046] 2) Strict fermentation control is not required. In the case of total fermentation as mentioned in 1) above, the acidity and pH at the end of fermentation determine the quality of the product. Therefore, fermentation must be controlled by paying close attention to the timing of stopping fermentation by cooling, temperature control of the cooling water for the fermentation tank, differences in the progress of fermentation due to temperature unevenness in the fermentation equipment, etc. On the other hand, in the production method of this embodiment, the acidity and pH of the final product can be adjusted in the volume increase process in which the fermented soy beverage and the unfermented soy beverage are mixed, and strict fermentation control is not required.

[0047] 3) A fermented soy beverage concentrate can be produced regardless of the type of soy beverage or microorganism used for fermentation. As the soy beverage, various soy protein-containing beverages can be used, such as unsweetened soy milk, prepared soy milk, and whole soy beverages. In addition, the microorganisms used for fermentation are not limited as long as they can ferment the soy beverage to produce acid and cause protein coagulation, so there is a high degree of freedom in the selection of bacterial species and strains.

[0048] The present embodiment also relates to a fermented soy beverage concentrate. In one aspect, the fermented soy beverage concentrate of the present embodiment contains 8 g or more, preferably 10 g or more, of protein per 100 g of water. In one aspect, the fermented soy beverage concentrate of the present embodiment has a ratio (weight ratio) of protein to carbohydrate in its composition of 4 or more, preferably 5 or more, for every 1 carbohydrate. In one aspect, the fermented soy beverage concentrate of this embodiment (for example, the fermented soy beverage concentrate obtained in the examples described below) has a particle size peak of 20 μm or less, preferably 15 μm or less, in the particle size distribution measured by a particle size distribution meter (laser diffraction / scattering type) after homogenizing the structure of the fermented soy beverage concentrate by aspirating and discharging with a 30 ml capacity thermo syringe (without needle). In one aspect, the fermented soy beverage concentrate of this embodiment has a particle size distribution measured by the above method, in which the ratio of particles having a size of 50 μm or more to the total particles is 20% or less, preferably 10% or less, more preferably 5% or less, even more preferably 2% or less, and particularly preferably 1% or less. In one aspect, the fermented soy beverage concentrate of this embodiment has thixotropy. In one aspect, the fermented soy beverage concentrate of this embodiment has a shear stress (τ; Pa) of 70 or more and 150 or less when the shear rate (γ·; 1 / s) is changed from 20 to 100 with a rheometer. EXAMPLES

[0049] The following examples relate to a method for producing a fermented soy beverage concentrate, comprising at least the following steps (1) to (3). (1) A fermentation process, in which a microorganism is added to a soybean beverage to ferment the soybean beverage to obtain a fermented soybean beverage. (2) A volume increasing step of mixing the fermented soy beverage with the soy beverage to increase the volume. (3) A concentrating step for concentrating the mixture obtained in the increasing step.

[0050] [Example 1] This test shows the relationship between the pH after mixing with soy beverage in the bulking process and the solid fraction after the concentration process when different types and brands of soy beverage are used as raw materials. Six types of commercially available soy beverages were inoculated with a lactic acid bacteria starter (Sacco SY42) at the manufacturer's recommended inoculation rate and fermented (43°C, 10 hours). After cooling to below 15°C in a refrigerator, the curd formed by lactic acid fermentation was crushed using a spatula. The same soy beverage used for fermentation was gradually added to each fermented soy beverage to increase the volume and mix by stirring. The resulting mixture was centrifuged (7,000×g, 10 min) using a Koki Holdings Himac CR-N22 high-speed refrigerated centrifuge and an R12A6 rotor to separate the supernatant and precipitate, after which the supernatant was discarded and the solid fraction was collected.

[0051] The pH after mixing was adjusted by changing the amount of soy beverage added to the fermented soy beverage. The relationship between the adjusted pH and the solid fraction of the fermented soy beverage concentrate recovered by centrifugation is shown in Figure 1. The solid fraction is the ratio of the weight of the solid fraction obtained by discarding the supernatant after centrifugation to the total weight of the mixture of the fermented soy beverage and the soy beverage before centrifugation (weight of solid fraction / total weight of the mixture of the fermented soy beverage and the soy beverage before centrifugation). From this result, it can be seen that although the solid fraction obtained differs depending on the soy beverage used, in the case of each soy beverage, the solid fraction after the concentration process changes significantly when the pH after mixing with the soy beverage in the weight-increasing process is between 5.6 and 6.0. In the case of each soy beverage, the solid fraction was high when the pH after mixing with the soy beverage in the weight-increasing process was 5.7 or less, especially 5.6 or less, and low when it was 6.0 or more.

[0052] The soybean beverages used here are the following six types: Soy drink A: Kikkoman Beverages Corporation Delicious unsweetened soy milk 1000ml (soybean solids 8% or more) Soy drink B: Kikkoman Beverages Corporation, prepared soy milk, 1000ml (soybean solids 7%) Soy drink C: Marusanai Co., Ltd. Daily delicious unsweetened soy milk 1000ml (soybean solids 9%) Soy drink D: Marusanai Co., Ltd. Prepared soy milk 1000ml (soybean solids 7%) Soy drink E: Otsuka Foods Co., Ltd. Domestic soy milk-like soy 950ml (whole soy drink. Soybean solids 7% or more) Soy drink F: Kikkoman Beverage Corporation Soy milk drink banana 200ml (soybean solids 4% or more)

[0053] [Example 2] In this test, the pH reached when lactic acid bacteria were added to soy beverages diluted with water to change the amount of ingredients contained therein and fermented was examined. The soy beverage A of Example 1 was diluted 1.3 times, 2 times, 2.7 times, 4 times, and 8 times with ion-exchanged water, and the diluted soy beverage A was fermented (43°C, 12 hours) using the lactic acid bacteria of Example 1, and the pH at the completion of fermentation was examined. The composition of soy beverage A is shown in Table 1. The composition in Table 1 is as indicated by the nutritional components based on measurements by the manufacturer. Table 2 shows the dilution rate of each sample, the amount of protein contained calculated based on the dilution rate, and the pH after fermentation. At any dilution rate, the pH reached was equal to or lower than that without dilution, and it was confirmed that fermentation is possible even when the soy beverage is diluted to 0.5% soy protein, using the protein in the soy beverage as an indicator. [Table 1] [Table 2]

[0054] [Example 3] In this test, the solid fraction ratio obtained in the concentration process was investigated when soy beverages diluted with water to change the amount of ingredients and fermented soy beverages were used as raw materials. The soy beverage A of Example 1 was diluted 2 times, 4 times, and 8 times with ion-exchanged water, and the diluted soy beverage A was fermented (37°C, 16 hours) using the lactic acid bacteria of Example 1, and the pH was adjusted to 5.4 and pH 6.2 by adding the soy beverage A diluted in the same manner. As a control, the same procedure was performed using undiluted soy beverage A. Each sample was centrifuged (7,000 x g, 10 min) using a Koki Holdings Himac CR-N22 high-speed refrigerated centrifuge and an R18A rotor, and the supernatant was discarded to recover the solid fraction. Table 3 shows the solid fraction ratio obtained for each pH adjusted in the volume increase process at the dilution ratio of the soy beverage used as the raw material. The solid fraction obtained decreases depending on the dilution ratio of the soy beverage, but when comparing the values ​​obtained by multiplying the solid fraction by the dilution ratio, the values ​​were almost the same for all dilution ratio samples. It was confirmed that for soy beverages with a soy protein concentration of at least 0.5%, there is almost no difference in the efficiency of solid recovery during the concentration process. [Table 3]

[0055] [Comparative Example 1] This test shows the relationship between the pH after the bulking process and the solid fraction after the concentration process when a curd prepared by adding lactic acid to a soy beverage to lower the pH was used instead of the fermented soy beverage of Example 4. Lactic acid (food additive) was added to the soy beverage A of Example 1 to lower the pH to 4.5 to prepare curd. The same soy beverage was added to this curd to adjust the pH, and the resulting mixture was centrifuged (7,000×g, 10 min) using a Koki Holdings Himac CR-N22 high-speed refrigerated centrifuge and an R12A6 rotor, and the supernatant was discarded to recover the solid fraction. The relationship between the pH after adjustment by adding the soy beverage and the solid fraction rate obtained after centrifugation is shown in FIG. 2. The solid fraction rate is the ratio of the weight of the solid fraction obtained by discarding the supernatant after centrifugation to the total weight of the mixture of the curd and the soy beverage before centrifugation (weight of solid fraction / total weight of the mixture of the curd and the soy beverage before centrifugation). When the pH after adjustment by adding the soy beverage was in the range of pH 4.5 to pH 5.6, the solid fraction rate increased slightly from 0.37 to 0.47, but at pH 5.7, the solid fraction rate dropped sharply to 0.07. At pH 5.8 and above, the solid fraction was 0.03.

[0056] [Example 4] This study showed the relationship between the pH after mixing with the soy beverage in the subsequent volume increase process and the solid fraction after the concentration process when soy beverages were fermented using lactic acid bacteria starters of different species and strains. Four different types of commercially available lactic acid bacteria starters were inoculated into the soy beverage A of Example 1 in appropriate amounts (manufacturer's recommended amounts) and fermented (43°C, 10 hours; Lactic acid bacteria D only, 30°C, 24 hours). The same soy beverage used for fermentation was added in different ratios to the fermented soy beverages prepared with each lactic acid bacteria, and the volume was increased by stirring and mixing. The pH of the resulting mixture was measured, and then the mixture was concentrated by centrifugation (7,000×g, 10 min) using a Koki Holdings Himac CR-N22 high-speed refrigerated centrifuge and an R12A6 rotor. The supernatant was discarded, and the solid fraction was collected.

[0057] The relationship between the pH and the solid fraction rate after mixing the fermented soy beverage and the soy beverage is shown in FIG. 2. The solid fraction rate is the ratio of the weight of the solid fraction obtained by discarding the supernatant after centrifugation to the total weight of the mixture of the fermented product and the soy beverage before centrifugation (weight of the solid fraction / total weight of the mixture of the fermented product and the soy beverage before centrifugation). As can be seen from this result, regardless of which lactic acid bacteria starter was used, the solid fraction rate after the concentration process changed significantly when the pH after mixing with the soy beverage in the volume increase process was in the range of 5.6 to 6.0. Specifically, the solid fraction rate was high at pH 5.6 or less and low at pH 6.0 or more. Even at pH 5.7, where the solid fraction rate was significantly low when the same soy beverage A was used in Comparative Example 1, a high solid fraction rate was obtained when fermented with any lactic acid bacteria, similar to the case of pH 5.6. When the pH after mixing with the soy beverage in the volume increase process was pH 5.8 or more, the solid fraction rate decreased, but the decrease was not as extreme as in Comparative Example 1 when any lactic acid bacteria was used. Furthermore, at a pH lower than 5.7, a higher solid fraction rate was obtained than in Comparative Example 1, regardless of which lactic acid bacteria was used for cultivation. The following differences were observed between Comparative Example 1 and Example 4: in Comparative Example 1, the lower the pH, with a peak at pH 5.6, the smaller the volume that could be recovered as a solid fraction, whereas in Example 4, the lower the pH, the greater the volume that could be recovered as a solid fraction. Furthermore, the fermented soybean beverage concentrate obtained in Example 4 had a softer and smoother texture than that obtained in Comparative Example 1 at any pH. Furthermore, the fermented soybean beverage concentrate obtained in Example 4 had differences in flavor and physical properties depending on the lactic acid bacteria used, and were accompanied by the fermentation characteristics of each lactic acid bacteria.

[0058] Without being bound by theory, in the case of Example 4, in which fermentation was performed with lactic acid bacteria, the lactic acid bacteria bodies and polysaccharides produced by the lactic acid bacteria were included, and it is believed that these were intertwined, and the higher the ratio of the fermented product, the greater the volume recovered as a solid fraction. Although the characteristics of the fermented product of each lactic acid bacteria were somewhat reflected, the relationship between the pH value after the volume increase step and the solid fraction rate after concentration showed a similar tendency regardless of which lactic acid bacteria was used. On the other hand, in the curd coagulated with lactic acid, it is believed that the lower the pH after the volume increase step, the stronger the aggregation of soybean protein, and as a result, the smaller the volume recovered as a solid fraction.

[0059] Each lactic acid bacteria starter has different properties and is made up of different species of lactic acid bacteria, as follows: Lactic acid bacteria D can ferment at low temperatures for a long time, while the others can ferment at high temperatures for a short time. Lactic acid bacteria A: YO-MIX883 (DUPONT) Streptococcus thermophiles and Lactobacillus delbrueckii subsp. bulgaricus )Milk-free. High polysaccharide production. Relatively soft fermented products are obtained. Lactic acid bacteria B: CRYOFAST SY42 (SACCO) Streptococcus thermophiles and Lactobacillus delbrueckii subsp. bulgaricus )Milk-free. Produces a relatively firm fermented product. Lactic acid bacteria C: CRYOFAST SY1 (SACCO Streptococcus thermophiles and Lactobacillus delbrueckii subsp. bulgaricus ) The resulting fermented product has a strong sour taste. Lactic acid bacteria D: CRYOFAST MW031N (SACCO) Lactococcuslactis subsp. lactis , Lactococcus lactis subsp. cremoris , Lactococcus lactis subsp. lactis Biovar. diacetylactis and Leuconostoc mesenteroides ) The resulting fermented product has a sweet aroma and a flavor similar to Emmental cheese.

[0060] [Example 5] In this test, the ratio of the amount of soy beverage that can be added to a fixed amount of fermented soy beverage in the volume increasing step of one aspect of this embodiment was confirmed. The soybean beverage A of Example 1 was inoculated with an appropriate amount (the amount recommended by the manufacturer) of the lactic acid bacteria B of Example 4, and fermented (43°C, 10 hours). The same soybean beverage as that used for fermentation was added in different amounts to the obtained fermented soybean beverage, and mixed by stirring. The pH of the obtained mixture was measured.

[0061] FIG. 3 shows the relationship between the ratio of the amount of soy beverage added to the amount of fermented soy beverage and the pH after mixing. From the results of Example 1, it has been confirmed that the soy beverage A used in this test provides a high solid fraction rate at a pH of 5.7 or less. The addition rate of the soy beverage resulting in a pH of 5.7 in this test was 360%. In other words, it was confirmed that a sufficient amount of solids can be recovered even if 3.6 times the amount of the fermented soy beverage is added in the volume-increasing step. As shown in FIG. 1, depending on the type of soy beverage, the pH value after the volume-increasing step at which a high solid fraction rate is obtained varies to some extent. Here, if the pH of the soy beverage is low, a mixture with a low pH can be obtained even if a large amount of soy beverage is added. Therefore, depending on the type and pH of the soy beverage, it is considered that a sufficient amount of solids can be recovered even if a very large amount (about 20 times, for example about 10 times) of soy beverage is added in the volume-increasing step. The lower limit of the amount of soy beverage added in the volume increase process is not particularly limited as long as the pH after mixing is within the desired range, and for example, the amount of the soy beverage may be 10%, 20%, or 30% of the amount of the fermented soy beverage.

[0062] [Reference example] Soybean beverage A of Example 1 was fermented with the same lactic acid bacteria as in Example 1, and the relationship between the lactic acid acidity and pH in the fermented product was measured over time. The lactic acid acidity (sometimes simply referred to as acidity) of the fermented product was measured using a Hiranuma automatic titrator COM-1700A (Hiranuma Sangyo Co., Ltd.). The results are shown in Figure 4. Based on the graph shown in Figure 4, an approximation formula showing the relationship between pH and lactic acid acidity was derived, and is also shown in Figure 4. A correspondence table between pH and lactic acid acidity calculated based on this approximation formula is shown in Table 4 below. [Table 4]

[0063] Based on the correspondence table in Table 4 above, the amount of soy beverage (by weight) per part of fermented soy beverage required to adjust the mixture to pH 5.7 or pH 5.8 was calculated. The results are shown in Tables 5 and 6 below. As is clear from the calculation results, when unadjusted soy milk is added to a sufficiently fermented product with a pH of 3.9 to adjust the pH to 5.8, about 15 times the amount of soy milk can be added. Considering that the relationship between pH and acidity may vary slightly depending on the soy beverage, these results also suggest that about 20 times the amount of soy beverage can be added as compared to the fermented soy beverage, depending on the pH of the fermented soy beverage, the pH of the soy beverage, and the pH of the desired mixture. [Table 5] [Table 6]

[0064] [Example 6] The higher the buffering capacity of the fermented soy beverage to which the soy beverage is added, the less likely the pH will change, and the more soy beverage can be added. In this test, therefore, salts of organic acids were added to the soy beverage, fermentation was carried out, and in the volume increase process, soy beverages that did not contain organic acid salts were added, and the relationship between the amount of soy beverage added and the pH was examined.

[0065] Sodium malate was added to soybean beverage A of Example 1 at concentrations from 0% to 0.8%, and fermentation (43°C, 12 hours) was carried out using the lactic acid bacteria of Example 1. The pH before and after fermentation and the acidity after fermentation are shown in Table 7. The lactic acid acidity of the fermented product was measured using a Hiranuma automatic titrator COM-1700A (Hiranuma Sangyo Co., Ltd.). As shown in Table 7, the pH before and after fermentation did not change significantly even when the amount of sodium malate added was changed. On the other hand, the acidity of the fermented product increased as the amount of sodium malate added increased. [Table 7]

[0066] Next, the relationship between the amount of soy beverage added (amount added relative to the fermented soy beverage (%)) and pH when a soy beverage without sodium malate was added to a fermented soy beverage without sodium malate or a fermented soy beverage containing 0.8% sodium malate is shown in FIG. 5. As shown in FIG. 5, the amount of soy beverage added to the fermented soy beverage containing sodium malate was greater than that of the fermented soy beverage without sodium malate to adjust the pH to the same level. For example, when adjusting the pH to 5.7, about 3.5 times the amount of soy beverage was added to the fermented soy beverage without sodium malate, while 5 times or more the amount of soy beverage was added to the fermented soy beverage containing 0.8% sodium malate. When the buffer capacity of the fermented soy beverage is high, the amount of soy beverage added to the fermented product in the volume increase step can be increased, and therefore, it is considered that a larger solid content can be obtained from the same amount of fermented soy beverage in the next concentration step.

[0067] After examining several buffering agents, the following became clear: in the preparation of a fermented soy beverage, if a salt of an organic acid with a pKa between 3.8 and 6, for example 3.8 to 5.9 (between the pH of the fermented product and the pH after bulking), such as sodium citrate or sodium succinate, is added instead of or in addition to sodium malate, the buffering power of the fermented soy beverage becomes particularly high, and more lactic acid can be produced during fermentation at the same pH (higher acidity). As a result, more soy beverage can be added during the bulking process, which is thought to increase the recovery of the solid fraction. In addition, the soy beverage added to the fermented soy beverage must have a higher pH than the target pH in the volume increase step, and the lower the pH within that range, the greater the amount that can be added. Therefore, by adding a pH adjuster to the soy beverage to adjust the pH, the amount of addition can be further increased.

[0068] [Example 7] In this test, in one aspect of this embodiment, the compositions of a fermented soy beverage, a concentrate obtained by concentrating the fermented soy beverage directly without going through a volume increase process, and a fermented soy beverage concentrate obtained by performing a volume increase process in which a soy beverage is added to the fermented soy beverage and then concentrating the fermented soy beverage were analyzed and compared. An appropriate amount (amount recommended by the manufacturer) of lactic acid bacteria B of Example 4 was inoculated into the soybean drink A of Example 1, and fermentation was carried out (43° C., 10 hours). Samples 1 to 5 were prepared as follows. Sample 1: The fermented soybean beverage itself Sample 2: The concentrate obtained by centrifuging the fermented soybean beverage (7,000×g, 10 min) Sample 3: Supernatant (whey) obtained by centrifugation to obtain Sample 2 Sample 4: A fermented soy beverage concentrate obtained by adding the same soy beverage used for fermentation to the fermented soy beverage to increase the volume, mixing and adjusting the pH to 5.5, and then centrifuging the mixture (7,000×g, 10 min). Sample 5: Supernatant (whey) obtained by centrifugation to obtain Sample 4 Samples 1-5 were sent to the Japan Food Research Center (General Incorporated Foundation) for nutritional analysis.

[0069] The results are shown in Table 8. The protein content in the soy beverage after fermentation did not change from the protein content before fermentation shown in Table 1. Compared with the protein content in Sample 1, which was obtained by simply fermenting the soy beverage, the protein content in Sample 2, which was obtained by directly concentrating the fermented soy beverage, was 1.6 times higher. The protein content in Sample 4, which was a fermented soy beverage concentrate obtained by adding a soy beverage to the fermented soy beverage, mixing the mixture, and then concentrating the mixture, was even higher at 2.2 times higher than the protein content in Sample 1. There was no significant difference in the amount of carbohydrates among Samples 1, 2, and 4. Next, we focus on the total amount of protein obtained when the same amount of each sample, specifically 100 g of fermented soy beverage, is processed. The protein content of sample 1, obtained by only fermenting the soy beverage, was 4.1 g. In contrast, in sample 2, which was obtained by directly concentrating the fermented soy beverage, calculations showed that 4.0 g of protein (a value obtained by multiplying the protein content of the concentrate, 6.6 g / 100 g, by a recovery rate of 60%) was recovered in the sample, which is almost the same as sample 1. On the other hand, in the concentrate (sample 4) obtained by adding the soy beverage to the fermented soy beverage and then concentrating the mixture, calculations showed that 12.6 g of protein (a value obtained by multiplying the protein content, 9.0 g / 100 g, by the volume ratio increased by adding the soy beverage, 3.33, and then multiplying by a recovery rate of 42%) was recovered in the sample, and it was confirmed that the protein yield of sample 4 was more than three times that of sample 2. In addition, whey obtained by concentrating the fermented soy beverage directly (Sample 3) and whey obtained by adding a soy beverage to the fermented soy beverage, mixing them, and then concentrating the mixture (Sample 5) had a low protein content, confirming that the soy protein in the fermented soy beverage and the added soy beverage was efficiently recovered in the concentrate. [Table 8]

[0070] The protein amount per 100g of water and the ratio of the protein amount to the carbohydrate amount in the sample are shown below for Samples 1, 2, and 4 in Table 8 above. Also, soybean drink A before fermentation is designated as Sample 0. The protein amount per 100g of water was less than 8g in Samples 0 to 2, whereas it was 10g or more in Sample 4. Also, the ratio of the protein amount to the carbohydrate amount was less than 4 in Samples 0 to 2, whereas it was 5 or more in Sample 4. [Table 9]

[0071] [Example 8] In this study, the differences in physical properties between a product obtained by simply fermenting a soy beverage and a product obtained by mixing the fermented soy beverage with a soy beverage in a volume increase step followed by concentrating the mixture were identified. The soybean beverage A of Example 1 was inoculated with an appropriate amount (the amount recommended by the manufacturer) of the lactic acid bacteria B of Example 4, and fermentation (43°C, 10 hours) was performed. The obtained fermented soybean beverage was increased in volume by adding the same unfermented soybean beverage, stirred and mixed, and the pH was adjusted to 5.6. The mixture was then centrifuged (7,000 x g, 10 min) using a Koki Holdings Himac CR-N22 high-speed refrigerated centrifuge and an R12A6 rotor. The supernatant was discarded, and the solid fraction was collected. The shear rate was continuously changed using a rheometer (HAAKE Viscotester iQ) to measure the hysteresis curves of the samples obtained by only fermentation and the samples obtained by increasing the volume by adding the soybean beverage after fermentation and concentrating by centrifugation.

[0072] The results are shown in Figure 6. It was confirmed that the sample obtained by concentration had a higher viscosity in the entire shear rate range measured compared to the sample obtained by fermentation alone. Accordingly, the sample obtained by concentration also had a higher shear stress, and the area enclosed by the curves at the time of increasing and decreasing the shear rate was large, and thixotropy was confirmed. From the above, it was confirmed that the physical properties of the product obtained when only fermenting a soy beverage and when mixing a soy beverage after fermentation and concentrating are clearly different, and that a product with physical properties that cannot be obtained by fermentation alone can be obtained by this manufacturing method. In addition, when mixing a soy beverage after fermentation and concentrating, the thixotropy is higher than when only fermentation is performed, so there is a large difference in texture between the two. Specifically, the product obtained by mixing a soy beverage after fermentation and concentrating it felt viscous and thick when scooped with a spoon or immediately after putting it in the mouth, but when stirred or chewed, it was a product with physical properties that were smooth and easy to swallow.

[0073] [Example 9] In this test, it was confirmed that when the amount of soy beverage added to the fermented soy beverage in the volume increase process was changed to change the pH during volume increase mixing, the physical properties of the fermented soy beverage concentrate obtained after concentration also differed. The soybean beverage A of Example 1 was inoculated with an appropriate amount (the amount recommended by the manufacturer) of the lactic acid bacteria B of Example 4, and fermented (43°C, 10 hours). The resulting fermented soybean products were increased in volume by adding various amounts of the same unfermented soybean beverage, and the pH was adjusted to 5.0, 5.5, 5.6, and 5.7 by stirring and mixing. Then, each mixture was centrifuged (7,000 x g, 10 min) using a Koki Holdings Himac CR-N22 high-speed refrigerated centrifuge and an R12A6 rotor. The supernatant was discarded, and the solid fraction was collected. The linear elastic modulus of the four solid fractions obtained was measured by strain change using a rheometer (HAAKE Viscotester iQ).

[0074] The results are shown in Figure 7. It was confirmed that both G' (storage elasticity) and G" (loss elasticity) showed lower values ​​as the pH increased, in other words, the tissue softened as the pH increased. In addition, the intersection point of the G' and G" curves, which indicates the transition point between elasticity and plasticity (the point where the phase difference δ° = 45), was also different between pH 5.0 and pH 5.5 or higher. From the above, it was confirmed that by changing the pH after adding a soy beverage to the fermented soy beverage in the volume increase process, it is possible to produce fermented soy beverage concentrates with different physical properties.

[0075] [Comparative Example 2] This test was a control for Example 10. Specifically, in this test, the physical properties of the product were examined when a soy beverage obtained by adding lactic acid to the soy beverage and coagulating it with acid was used instead of a fermented soy beverage obtained by fermentation with lactic acid bacteria. Lactic acid (food additive) was added to the soy beverage A of Example 1 to lower the pH to 4.5 to prepare a curd. The same soy beverage was added to this curd to adjust the pH to 5.6. The mixture was then centrifuged (7,000×g, 10 min) using a Koki Holdings Himac CR-N22 high-speed refrigerated centrifuge and an R12A6 rotor, and the supernatant was discarded to recover the solid fraction. The hysteresis curve of the obtained solid fraction was measured by continuously changing the shear rate using a rheometer (HAAKE Viscotester iQ). The linear elastic modulus of the solid fraction was also measured by changing the strain using the same device. The results will be described in Example 10.

[0076] [Example 10] In this study, the physical properties of fermented soy beverage concentrates obtained under different conditions, only the strain of lactic acid bacteria used for fermentation, were compared. The soybean beverage A of Example 1 was mixed with three different commercially available lactic acid bacteria starters (Lactic Acid Bacteria A or B of Example 4) or Lactic Acid Bacteria E (ST386 (SACCO Co., Ltd.) Streptococcus thermophiles)) was inoculated in an appropriate amount (the amount recommended by the manufacturer) and fermented (43°C, 10 hours). The obtained fermented soybean beverage was increased in volume by adding the same unfermented soybean beverage, and the mixture was stirred and mixed to adjust the pH to 5.6. Then, each mixture was centrifuged (7,000 x g, 10 min) using a Koki Holdings Himac CR-N22 high-speed refrigerated centrifuge and an R12A6 rotor, and the supernatant was discarded to recover the solid fraction. The hysteresis curves of the obtained three solid fractions were measured by continuously changing the shear rate using a rheometer (HAAKE Viscotester iQ). In addition, the linear elastic modulus of these three solid fractions was measured by changing the strain using a rheometer (HAAKE Viscotester iQ).

[0077] The results of the hysteresis curve are shown in FIG. 8. The samples of this embodiment obtained by fermentation with lactic acid bacteria had significantly lower values ​​of both shear stress and viscosity over the entire range of shear rates examined, compared to the samples obtained using the acid coagulated product of Comparative Example 2. It was also confirmed that the values ​​of viscosity and shear stress at the same shear rate differ depending on the lactic acid bacteria used, in other words, by changing the microorganisms used, it is possible to produce fermented soybean beverage concentrates with somewhat different physical properties. The samples obtained using lactic acid bacteria A and B, which are commercially available as strains with high polysaccharide-producing ability and suitable for fermenting low-fat milk and vegetable matter, had soft physical properties and had lower values ​​of both shear stress and viscosity compared to the samples obtained using the acid coagulated product of Comparative Example 2 and the samples obtained using lactic acid bacteria E.

[0078] The results of the linear elastic modulus measurement are shown in Figure 9. The samples of this example obtained by fermentation with lactic acid bacteria had significantly lower values ​​for both G' (storage elasticity) and G" (loss elasticity) compared to the samples obtained from the acid coagulated product of Comparative Example 2, and the samples obtained using lactic acid bacteria A and B, which have high polysaccharide production ability, had particularly low values. These results confirmed that, compared to the samples obtained from the acid coagulated product obtained by adding lactic acid to a soy beverage, the fermented soy beverage concentrate had soft and smooth physical properties after the concentration process, and in particular, the soy beverage concentrate using the strain with high polysaccharide production was even softer and smoother. Note that the slight difference in the measurement results of Figures 7 and 9 is due to the degree of tissue destruction when the sample scooped with a spoon from the fermentation vessel was transferred to the measurement site of the measurement device, but it was confirmed that the behavior of the G' and G" values ​​was similar in both measurements. The shear stress (τ; Pa) of the fermented soy beverage concentrate was 70 to 150 when the shear rate (γ·; 1 / s) was changed from 20 to 100 with a rheometer.

[0079] The above results of the rheometer measurements were also supported by the texture. The samples obtained using the fermentation product with lactic acid bacteria had a softer and smoother texture than the samples obtained using the acid coagulated product, and those using lactic acid bacteria A and B were particularly smooth. On the other hand, the sample obtained using lactic acid bacteria E had a relatively firm texture and a strong feeling of richness.

[0080] [Example 11] In this test, the effect of the temperature at which the fermented soy beverage and the soy beverage are mixed in the volume increasing step on the physical properties of the fermented soy beverage concentrate obtained through the concentration step was investigated. The soybean beverage A of Example 1 was inoculated with an appropriate amount (amount recommended by the manufacturer) of the lactic acid bacteria A of Example 4, and fermented (43°C, 10 hours). The fermented soybean beverage after fermentation was cooled to 4°C and then used for testing. The fermented soybean beverage after cooling and the same soybean beverage used for fermentation were placed in thermostatic chambers adjusted to the respective temperatures of 0°C, 20°C, 30°C, 37°C, and 43°C for conditioning. Thereafter, the fermented soybean beverage and the soybean beverage were mixed and increased in volume while maintaining each temperature so that the pH was 5.5. The mixtures maintained at each temperature were centrifuged (7,000×g, 10 min) using a Koki Holdings Himac CR-N22 high-speed refrigerated centrifuge and an R12A6 rotor. The supernatant was discarded and the solid fraction was collected. For each sample obtained, the tissue was homogenized by aspirating and dispensing with a 30 ml capacity Thermo syringe (without needle), and then the particle size distribution was measured using a particle size distribution analyzer (LA-960 laser diffraction / scattering particle size distribution analyzer, manufactured by Horiba, Ltd.).

[0081] The results are shown in FIG. 10. As the temperature during the bulking process increased from 0°C, 20°C, 30°C, 37°C, and 43°C, the particle size distribution showed a clear tendency for larger particles to increase. In particular, as the temperature increased, the number of particles with a particle size of 5 μm to 20 μm decreased, and the number of particles with a particle size of 50 μm to 100 μm increased significantly. Accordingly, the texture also changed, specifically, the lower the temperature during the bulking process, the smoother the texture, and the higher the temperature, the rougher the tongue felt. In addition, the cumulative frequency (integral distribution) from the smallest particle size in each particle size distribution measurement is also shown in FIG. 10. As the temperature during the bulking process decreased, the ratio of particles with a size of 50 μm or more to the total particles decreased to 20% or less, 10% or less, and 5% or less, improving the mouthfeel. It is considered desirable to keep the ratio of particles with a size of 50 μm or more to the total particles to 5% or less, more preferably 2% or less, and particularly preferably 1% or less, in order to maintain a smooth texture.

[0082] [Example 12] In this test, the relationship between centrifugal force and the resulting solid fraction was investigated in a case where solid-liquid separation in the concentration process was performed using a centrifuge. The soybean beverage A of Example 1 was inoculated with an appropriate amount (the amount recommended by the manufacturer) of the lactic acid bacteria C of Example 4, and fermentation (43°C, 10 hours) was performed. The same soybean beverage as that used for fermentation was added to the obtained fermented soybean beverage to increase the volume, and the mixture was stirred and mixed to adjust the pH to 5.5. The obtained mixture was centrifuged with a centrifuge (Koki Holdings Himac CR-N22 high-speed refrigerated centrifuge and R18A rotor) to separate solid and liquid. Most centrifuges for the food industry are of the separation plate type, and their centrifugal force is generally about 5,000 x g to 10,000 x g. In the separation plate type centrifuge, the separation plate interval is narrow at 1 mm or less, allowing instantaneous sedimentation. However, since this test uses a 50 ml centrifuge tube with a long sedimentation distance, the centrifugation time was set to 10 minutes. The rotor speed was adjusted to give a centrifugal force between 3,000×g and 10,000×g, and the ratio of the solid fraction obtained at each centrifugal force was compared. The ratio of the solid fraction was calculated by dividing the weight of the solid fraction obtained by discarding the supernatant after centrifugation by the weight of the sample subjected to centrifugation.

[0083] The results are shown in FIG. 11. At all centrifugal forces tested, from 3,000×g to 10,000×g, the solid fraction was neatly separated from the supernatant, and no turbidity was observed in the supernatant. The ratio of the solid fraction was in the range of 0.43 to 0.64, and the ratio of the solid fraction decreased as the centrifugal force increased. This is thought to be because the stronger the centrifugal force, the more the solid fraction was compressed and the whey contained therein oozed out from the solid fraction. From these results, it was confirmed that the concentration step in the present invention can be easily carried out by using a general centrifugal separator used in the food industry. It was also confirmed that a product with the desired hardness can be obtained by adjusting the centrifugation conditions.

[0084] This application claims priority to Japanese Patent Application No. 2020-45455, filed on March 16, 2020, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0085] According to the production method of the present invention, a fermented soy beverage concentrate having a high soy protein content can be efficiently produced even in a small fermentation facility. Furthermore, the production method of the present invention allows for a wide range of freedom in the selection of soy beverages and fermentation microorganisms to be used, making it possible to produce a fermented soy beverage concentrate that makes the most of the characteristics of each ingredient. Furthermore, according to the production method of the present invention, a fermented soy beverage concentrate having smooth physical properties can be produced. The produced fermented soy beverage concentrate can be widely used as a food product or as a raw material for food production.

Claims

1. 1. A method for producing a fermented soy beverage concentrate, comprising: a fermentation step of adding microorganisms to the soy beverage to ferment the soy beverage; a volume increasing step of mixing and increasing the volume of the fermented soy beverage obtained in the fermentation step with the soy beverage to obtain a mixture having a pH of less than 6.0; and A concentration step for concentrating the solid content from the mixture obtained in the weight-increasing step. A manufacturing method comprising:

2. 2. The method of claim 1, wherein the microorganism comprises a microorganism of a genus selected from the genera Lactobacillus, Lactococcus, Leuconostoc, Streptococcus, Pediococcus and Bifidobacterium, wherein the genus of the microorganism is based on an older classification.

3. 3. The method of claim 1 or 2, wherein the concentrating step comprises separating a solid fraction comprising the concentrated solids from the mixture.

4. The method according to any one of claims 1 to 3, wherein the weight of the soy beverage in the weight increasing step is 20% or more and 500% or less of the weight of the fermented soy beverage.

5. The method according to any one of claims 1 to 4, wherein the volume increasing step is carried out at a temperature below 37°C.

6. The method according to any one of claims 1 to 5, wherein the soy protein content of the soy beverage in the fermentation step and / or the soy beverage in the weight-increasing step is 0.5% or more.

7. The method according to any one of claims 1 to 6, wherein the soy beverage in the fermentation step comprises a buffering agent.

8. The method of any one of claims 1 to 7, wherein the soy beverage in the bulking step comprises a pH adjuster.

9. The pH of the fermented soybean beverage after the fermentation step is pH 3.5 or more and pH 5.5 or less; The method according to any one of claims 1 to 8, wherein the pH of the mixture after the bulking step is from pH 4.7 to pH 5.9, provided that the pH of the mixture after the bulking step is higher than the pH of the fermented soy beverage after the fermentation step.

10. The method according to any one of claims 1 to 9, wherein the volume increasing step is a step of mixing the fermented soy beverage obtained in the fermentation step with the soy beverage so as to obtain a mixture having a pH of 5.7 or less.

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