JPWO2006043478A1 - Lactic acid bacteria fermented soymilk and production method thereof - Google Patents

Abstract

Disclosed is a fermented soy milk having a blue odor and egg taste that is difficult to eliminate with conventional fermented lactic acid bacteria soy milk, a good flavor, a smooth texture and a good mouthfeel, and a method for producing the same. The problem could be solved by fermenting lactic acid bacteria using soy milk, which was produced by the action of an enzyme having phytic acid degrading enzyme activity to produce a phytic acid degradation product. That is, a lactic acid bacteria fermented soymilk having a phytic acid content per soy-derived protein of less than 1.5% by weight, preferably a free phosphate content per soy-derived protein of 0.5 to 5% by weight More preferably, a phytic acid decomposition product is contained.

Description

The present invention relates to lactic acid bacteria fermented soymilk and a method for producing the same.

In recent years, vegetable protein foods have been evaluated due to growing interest in health. Especially soy milk made from soybeans contains high-quality protein called “field meat” and does not contain cholesterol. It is attracting attention as a protein health food. However, on the other hand, soy milk made from soybeans has an unpleasant flavor such as blue odor and egg flavor due to minor components such as hexanal and several saponins.
Therefore, various patents have already been proposed for fermenting lactic acid bacteria to improve the flavor of soy milk, and examples thereof include Patent Documents 1-6. However, in these known methods, the odor peculiar to soy milk can be reduced and removed to some extent by fermentation, but the removal effect is not always sufficient, and the texture of the coagulum produced by lactic acid bacteria fermentation is smooth. There are problems such as lack of depth and problems that the rear mouth is not refreshing. In addition, in order to prevent the formation of hexanal, which is said to be the cause of the blue odor of soy milk, soy milk in which soybean lipoxygenase in soybean that promotes its production has been previously inactivated by heating or soybean deficient in lipoxygenase is used in the production of soybean milk. Although it is often used, even if fermented soymilk is produced with such soymilk, there is a problem that unpleasant odor increases after fermentation and during storage.

  As a solution to this problem, the present applicant has applied for a method of using soy milk obtained by homogenizing a soy milk subjected to lactic acid bacteria fermentation by applying a coagulant such as bittern in advance. By adopting this method, we have solved the problems we have had so far and have commercialized lactic acid bacteria fermented soymilk of extremely good quality, but we will make further quality improvements and contribute to the development of the lactic acid bacteria fermented soymilk market in the future. Therefore, technological development from different approaches is also essential.

  On the other hand, soymilk contains about 2% by weight of phytic acid (also referred to as inositol 6-phosphate) per soy-derived protein. Ingestion of a high phytic acid diet is said to inhibit intestinal absorption of minerals. For this reason, technologies such as phytate-degrading enzymes such as phytase and phosphatase are allowed to act on soy milk and soy protein to reduce the amount of phytine, and technologies for adding phytate of neutral salts to precipitate phytic acid are used (patents). Literature 8-10 etc.). However, so far, the technology for reducing soy milk and soy protein has been mainly aimed at improving nutrition such as mineral absorption.

  Therefore, it is not yet known how the enzymatic degradation treatment of phytic acid in soymilk affects the flavor and tissue of lactic acid bacteria fermented soymilk.

JP 61-141840 A JP-A-62-205735 JP-A-63-7743 Japanese Patent Laid-Open No. 2-167044 Japanese Patent Laid-Open No. Hei 6-276979 Japanese Patent Laid-Open No. 8-66161 Japanese Patent No. 3497083 JP 59-166049 A JP 2000-245340 A Japanese Patent Laid-Open No. Sho 63-148953

  An object of the present invention is to provide a fermented soy milk having a blue odor, no taste and good flavor, and a method for producing the same.

  As a result of intensive research on the above problems, the present inventors surprisingly made lactic acid bacteria fermentation using soy milk produced by causing an enzyme having phytate degrading enzyme activity to produce a phytate degradation product as a raw material. The present inventors have found that lactic acid bacteria fermented soy milk having a good flavor free of the blue odor and sour taste peculiar to soy milk and having a smooth texture can be obtained.

That is, the present invention
1. Lactic acid bacteria fermented soymilk, characterized in that the phytic acid content per soy-derived protein is less than 1.5% by weight,
2. The lactic acid bacteria fermented soymilk according to 1 above, wherein the free phosphoric acid content per soybean-derived protein is 0.5 to 5% by weight,
3. 2. Lactobacillus fermented soymilk according to 1 above, comprising a phytic acid degradation product,
4). The lactic acid bacteria fermented soymilk according to 1 above, wherein the product is solid or liquid,
5. 2. Lactobacillus fermented soymilk according to 1 above, wherein the product is a live bacteria type or a bactericidal type
6). A method for producing lactic acid bacteria fermented soymilk, characterized by causing lactic acid bacteria to act on soymilk in which a phytic acid degrading enzyme is acted to produce a phytic acid degradation product;
About.

During soy milk lactic acid bacteria fermentation, phytic acid in soy milk is hydrolyzed to produce a phytic acid degradation product, which suppresses the production of hexanals that cause blue odor and egg flavor during and after fermentation of soy milk. It became possible to reduce these unpleasant tastes.
Furthermore, it became possible to impart a milky taste and richness similar to those of yogurt in milk to lactic acid bacteria fermented soymilk obtained by decomposing phytic acid.
Furthermore, solid fermented soymilk obtained by decomposing phytic acid had a texture with a smooth texture and a good mouth melt.

  The fermented soymilk of lactic acid bacteria of the present invention is characterized in that the phytic acid content per soybean-derived protein is less than 1.5% by weight. The method for producing lactic acid bacteria fermented soymilk of the present invention is characterized in that lactic acid bacteria are allowed to act on soymilk in which a phytic acid-degrading enzyme is allowed to act to produce a phytic acid degradation product. Hereinafter, the present invention will be specifically described.

  Fermented soymilk prepared from soymilk obtained by a normal manufacturing method contains about 2% by weight of phytic acid per soy-derived protein, although there are differences depending on the variety of raw beans. On the other hand, in the lactic acid bacteria fermented soymilk of the present invention (hereinafter simply referred to as fermented soymilk), the phytic acid content is reduced from this range, that is, less than 1.5% by weight, more preferably 1.0% by weight. % Or less, more preferably 0.7% by weight or less, and most preferably 0.5% by weight or less. By reducing the phytic acid content in the fermented soymilk within such a range, a fermented soymilk having a good flavor free of blue odor and taste and a smooth structure can be obtained.

  In addition, fermented soymilk prepared from soymilk obtained by a normal production method contains free phosphoric acid in an amount of less than 0.2% by weight per soy-derived protein, although there are differences depending on the variety of raw beans. I can't. On the other hand, as fermented soymilk of the present invention, it is preferable that the free phosphoric acid content is contained above this value, preferably 0.5% by weight or more, more preferably 1.0% by weight or more, and still more preferably. It is 2.0% by weight or more, most preferably 2.5% by weight or more. By increasing the free phosphoric acid in the fermented soymilk within this range, a fermented soymilk with a better flavor can be obtained. In addition, the upper limit of the free phosphoric acid content is at most not more than the content when about 5 residues of phosphoric acid bound to phytic acid are liberated, and more preferably 5% by weight or less.

The fermented soymilk with reduced phytic acid content of the present invention includes (1) fermented soymilk in which phytic acid itself in soymilk is fractionated and removed, and (2) phytic acid in soymilk has the action of phytate degrading enzyme. There are fermented soy milk received.
(1) The method of fractionating and removing phytic acid is, for example, a method of adjusting soymilk to an alkaline lower pH of 10 or more with an alkaline agent such as sodium hydroxide or potassium hydroxide, and precipitating and removing phytic acid, and chlorinating soymilk. Examples thereof include a method in which neutral salts such as sodium, potassium chloride, sodium sulfate and potassium sulfate are added in an amount of 5% or more, preferably 8% or more, and phytic acid is removed by precipitation.
The fermented soymilk of (2) contains more phytic acid degradation products (inositol, inositol 1-5 phosphate) and free phosphoric acid than usual. In this case, even if the enzyme treatment is followed by dephosphorylation treatment by ultrafiltration or electrodialysis, it corresponds to the fermented soymilk of the present invention. However, when the free phosphoric acid content is out of the above range, the flavor tends to decrease rather than the fermented soymilk without dephosphorylation treatment.
In the present invention, either means (1) or (2) can be employed because it has the effect of smoothing the texture of fermented soymilk. In particular, the fermented soy milk of (2), which can reduce the blue odor, egy taste and the like and can impart a good flavor such as milky taste and richness, is more preferred.

(Soy milk)
The soy milk used as a raw material for the lactic acid bacteria fermented soy milk of the present invention may be obtained by any method, but soy milk obtained by a conventional method from soybeans or defatted soybeans can be used, for example, whole soybeans and molting It can be obtained by soaking soybeans or the like in water or grinding them in a water-containing state to form “Kure”, and removing the insoluble fraction by filtration or the like. And soymilk can be used combining 1 type, or 2 or more types selected from raw soymilk, unregulated soymilk, prepared soymilk, powdered soymilk, and the like. In addition, soy milk containing insoluble fiber such as okara (also called kure, whole grain soy milk, soybean slurry, soybean milk, etc.) may be used. In this case, the insoluble fiber is further refined by high pressure treatment or pectinase treatment. It can also be used. If necessary, purified soy protein may be added.
Beans used as raw materials are generally yellow soybeans, but black soybeans, green soybeans, kidney beans, broad beans, peas and the like can also be used.
It is preferable to use soy milk that has been moulted and de-embryonic, or heat-treated soy for enzyme deactivation, soy milk with good flavor can be obtained.
Whole soybeans, molted soybeans or molting / dehulled soybeans were brought into contact with hot water or hot water at 50 to 100 ° C. to remove soluble components eluted in the hot water or hot water, and then ground to remove insoluble fractions. Soy milk is preferred.
In addition, soymilk may be obtained by reacting an alkaline earth metal compound in advance as described in Japanese Patent No. 3349803, and various enzymes such as protease and transglutaminase described in Japanese Patent Application Laid-Open No. 2004-261107 are acted on. Things can be used.

(Phytic acid degrading enzyme)
As the enzyme having phytic acid decomposing activity for use in the present invention, phytase and phosphatase are typical, and those of various origins such as those derived from plants, microorganisms, and those produced by gene recombination can be used. The phytate degrading enzyme used in the present invention desirably has no or low protease activity. This is because when the protease activity is high, the protein is hydrolyzed, thereby affecting the physical properties such as gel formability of the protein in the production of solid fermented soymilk. The addition amount of enzyme, treatment temperature, pH, time and the like can be determined as appropriate according to the enzyme used. For example, in a mode in which there is no or low level of protein hydrolysis by protease, the TCA solubilization rate of the protein after the action of phytate degrading enzyme can be defined as 20% or less, preferably 15% or less.
It is appropriate that the enzyme having phytic acid degrading activity is added in an amount of 0.01 to 10% by weight, preferably 0.05 to 2% by weight, more preferably 0.1 to 1% by weight, based on the weight of soy milk. It is.
The treatment time, pH, temperature, etc. vary depending on the enzyme used and the amount of enzyme added, but the treatment temperature is usually 20 to 80 ° C., preferably 30 to 70 ° C., more preferably 35 to 60 ° C. The pH is suitably 4.0 to 8.0, preferably 5.0 to 7.0, and most preferably 5.0 to 6.5. If the pH at the time of action is too low, the fermentation of lactic acid bacteria will be difficult to proceed when lactic acid bacteria are allowed to act thereafter, and if the pH is too high, phytic acid-degrading enzyme will be difficult to act. The treatment time is 10 minutes to 3 hours, preferably 30 to 1 hour.

  In fermented soymilk produced from soymilk in which the enzyme is allowed to act, phytic acid is degraded to a phytic acid content of less than 1.5% by weight per protein derived from soybeans, and phytic acid degradation products are contained and decomposed. Is contained in an amount of 0.5 to 5% by weight per soybean-derived protein. The phytic acid degradation product contains one or more of inositol or inositol 1-5 phosphate.

In producing fermented soymilk containing soymilk subjected to the action of phytic acid-degrading enzyme, the timing of the action of the enzyme should be at least until the fermented soymilk is finally made into a product. For example,
(1) The stage of preparing soy milk from beans (when beans are soaked, ground, etc.),
(2) Stage of soy milk after being prepared from beans
(3) A stage in which auxiliary ingredients are added to soy milk,
(4) A stage during fermentation in which lactic acid bacteria are allowed to act on soy milk,
(5) A stage after fermentation in which lactic acid bacteria are allowed to act on soy milk,
Etc.
After the action of phytic acid degrading enzyme, a heat treatment step is required to inactivate the enzyme. Therefore, when producing viable bacterial fermented soymilk, the timing of (1) to (3) is preferable. In the case of the sterilization type, (4) and (5) are also possible.
Moreover, in order to make phytic acid-degrading enzyme act, when the viscosity of soymilk becomes high, an enzyme is fully disperse | distributed, and since strong stirring is required in order to make it react, in the case of fermented soymilk other than a liquid type, (1) The timing of (3) is suitable. In the case of a liquid type, (4) and (5) are also possible.

(Enzyme deactivation)
The soy milk treated with an enzyme having phytic acid decomposing activity is heat-treated to deactivate the enzyme. The heat treatment for enzyme deactivation varies depending on the enzyme used, but it is desirable to heat at a temperature at which phytic acid decomposing activity is deactivated. The method of the heat treatment is not particularly limited, and either direct heating or indirect heating may be used. As the heating device, a direct heating device such as a steam injection type, a plate type or a retort type indirect heating device can be used freely. In particular, direct high temperature instantaneous heating is more preferable. Direct high-temperature instant sterilization mixes soymilk and steam in the steam injection section, and causes protein to undergo denaturation due to high temperature and high pressure, thereby causing a decrease in viscosity and micronization. It is thought that it contributes to fermented soymilk, and further, the deodorizing effect of reduced pressure in the flash pan contributes to the improvement of the flavor of fermented soymilk. The temperature of direct high-temperature instantaneous heating is usually 110 to 150 ° C., and the heating time is usually 1 to 120 seconds, but 2 to 10 seconds is more preferable.

(Auxiliary raw material before fermentation)
The fermented soymilk of the present invention can be mixed with auxiliary materials as needed before lactic acid bacteria fermentation. For example, it is a raw material generally used for fermented milk such as yogurt. Sugar, glucose, maltose, lactose, trehalose, palatinose and other sugars, erythritol, xylitol, maltitol, reduced starch syrup, sugar alcohols such as sorbitol, soy oligosaccharides, oligosaccharides such as dairy oligosaccharides, thaumatin, aspartame, stevia, High-intensity sweeteners such as sucralose and acesulfame potassium, thickeners such as agar, xanthan gum, guar gum, locust bean gum, gellan gum, pectin and carrageenan, and juices such as gelatin, apples and lemons, polydextrose, cellulose, inulin and water Dietary fiber such as basic soybean polysaccharides, minerals such as calcium, magnesium, iron, and zinc, and flavors can be used.

(Lactic acid bacteria fermentation)
When the obtained pre-fermentation preparation is fermented with lactic acid bacteria, it is not always necessary to add lactic acid bacteria-assimilating saccharides such as sugar and oligosaccharides, but by adding lactic acid bacteria fermented fermented soymilk with excellent flavor Can be obtained. About a fermentation method, a bulk starter can be made and added, and freeze-concentrated bacteria and freeze-dried concentrated bacteria can also be added directly to the pre-fermentation preparation. The addition amount can be appropriately determined according to the fermentation temperature and fermentation time. The fermentation temperature is generally 20 to 50 ° C., the fermentation time is 3 to 48 hours, preferably 25 to 45 ° C., and the fermentation time is preferably 4 to 24 hours. The pH of the obtained fermented soymilk is 3.5 to 5.0, preferably 4.0 to 4.8.

(Lactic acid bacteria)
The lactic acid bacteria used for lactic acid bacteria fermentation will not be specifically limited if it is used for normal yogurt. For example, Lactobacillus casei, Lactobacillus blantarum, Lactobacillus helveticus, Lactobacillus bulgaricus, Lactobacillus gasseri, Lactobacillus acidophilus, Lactobacillus salivaius sarivarius, Lactobacillus gallinarum, Lactobacillus amylobolus, lacto Bacillus brevis brevis, Lactobacillus fermentum, Lactobacillus mali, Lactobacillus genus such as Lactobacillus delbrukki, Streptococcus thermophilus, Streptococcus lactis genus Streptococcus, Lactococcus lactis lactis, Lactococcus lactis Lactococcus genus such as Lactis cremoris, Leuconostoc mesenteroides cremoris, Leuconos Click lactis Leuconostoc genus, etc., it can be used Bifidobacterium breve, Bifidobacterium bifidum, a well-known strains of lactic acid bacteria of the genus Bifidobacterium such as Bifidobacterium longum. In addition, these lactic acid bacteria can be used alone or in combination of two or more. In addition to the above lactic acid bacteria, other useful bacteria (acetic acid bacteria, yeast, etc.) can be used in combination as appropriate.

(Post-fermentation treatment)
After fermentation with lactic acid bacteria, when fermentation is performed in a product container, it can be cooled as it is to obtain a hard type solid product. On the other hand, when fermentation is carried out in the production tank, the fermented soymilk can be cooled after stirring and filled into a product container to obtain a soft-type solid product.
In addition, the fermented soymilk is stirred and then subjected to a liquid treatment such as homogenization, and if necessary, heat-sterilized and cooled, it can be made into a liquid product of a viable bacterial type or a sterile type. Further, if necessary, a fruit type product can be prepared by adding fats and oils, fragrances, pigments, stabilizers, acidulants, sweeteners, etc., or adding fruit preparations.

  Examples will be described below, but the technical idea of the present invention is not limited to these examples. In the following Examples and Comparative Examples, “parts” and “%” are parts by weight and% by weight.

(Example 1)
10 parts of water is added to 1 part of molting and dehiking shaft soybeans, and 1 part of molting and dehiking shaft soybeans (water content 40 to 55%) is sufficiently absorbed by immersion at 30 to 50 ° C. for 60 minutes or more. 85 parts) was added and treated with a grinder (manufactured by Masuko Sangyo Co., Ltd.), and sodium hydroxide was added thereto to adjust the pH to 7.4 to 8.0. This was supplied to a homogenizer (manufactured by APV) and homogenized at 15 MPa. The homogenized grinding liquid was treated with a centrifugal separator at 3000 G for 5 minutes to obtain soy milk and okara. This soymilk had a solid content of 9.0%, a protein of 4.5%, and a pH of 7.5.
After adjusting this soy milk to pH 6.0 with 1N hydrochloric acid, 5 g of phytase (trade name “Sumiteam PHY”, manufactured by Shin Nippon Chemical Co., Ltd.) is added to 1 kg of soy milk, and the mixture is reacted at 35 ° C. for 30 minutes with stirring. A phytase-treated soymilk was obtained.
Various commercial products of Lactobacillus bulgaricus, Streptococcus thermophilus, and Bifidobacterium longum are added to phytase-treated soymilk that has been inactivated by heating at 140 ° C for 4 seconds using a direct high temperature instantaneous heating system. 1% of each culture solution of lactic acid bacteria (lyophilized product) was added as a starter and fermented at 40 ° C. for 7 hours. The mixture was stirred and cooled to 7 ° C., filled into a product container, and allowed to stand still under refrigeration to form a solid, and a soft fermented soymilk like yoghurt was prepared. The obtained fermented soymilk had a pH of 4.3, and had a milky taste and richness. On the contrary, there was no blue odor and taste, and the fermented soymilk had a smooth mouthfeel and a smooth mouthfeel. Further, even after 14 days of storage in the refrigerator, the fermented soymilk had a uniform tissue with little protein aggregation, and the flavor was good and unchanged.

(Comparative Example 1)
Solid fermented soymilk was prepared in the same manner as in Example 1 except that soymilk without phytase was used in Example 1. The pH of the obtained fermented soymilk was 4.3, the milky taste and richness were inferior to those of Example 1, the blue odor and the taste remained, and the heavy and heavy texture was not smooth, It was fermented soy milk with a clean mouth.

(Example 2)
The phytase-treated soy milk of Example 1 was passed through an anion exchange resin column “Duolite A-375” (manufactured by Sumitomo Chemical Co., Ltd.), and the free phosphoric acid low-content raw material soy milk from which free phosphoric acid was adsorbed and removed was used. A solid fermented soymilk was prepared in the same manner as in Example 1. The pH of the obtained fermented soymilk was 4.3, and it did not have a blue odor or taste, and had a clean and smooth mouthfeel. Further, even after 14 days of storage in the refrigerator, the fermented soymilk had a uniform tissue with little protein aggregation, and the flavor was good and unchanged. However, the milky taste and richness were inferior to the fermented soy milk of Example 1, and it was fermented soy milk that was too refreshed and had no umami.

(Example 3)
To soy milk obtained in the same manner as in Example 1 (phytase untreated), 10% potassium chloride was added, and the resulting precipitate containing phytic acid was removed by a centrifuge. The supernatant was diluted 3 times and concentrated to 3 times using a ceramic filter (pore size 500 mm) manufactured by Toshiba Ceramics to obtain phytic acid fraction-removed soy milk.
Next, solid fermented soymilk was prepared in the same process as in Example 1. The obtained fermented soymilk had a pH of 4.3, a refreshing and smooth mouthfeel, and a good flavor immediately after production. However, when it was stored for 14 days in the refrigerator, the flavor tended to generate a blue odor and an egg flavor.

  Examples 1 to 3 and Comparative Example 1 The evaluation results of each sample are summarized in Table 1. The flavor of each sample was evaluated in 4 stages using 5 panelists. The free phosphoric acid content was measured using a method in which a sample was directly colored with ammonium molybdate. The odor component recovered from the fermented soymilk was analyzed by gas chromatography, and the detected amount of hexanal in the total amount of the detected substance was measured as the content. The phytic acid content and the free phosphoric acid content are shown by weight% per soybean-derived protein.

(Table 1)

As shown in Table 1, when fermenting lactic acid bacteria with phytase-treated soymilk that has produced a phytic acid degradation product, there is a milky taste and richness, on the contrary, there is no blue odor or taste, and the back mouth is clean and smooth. A fermented soy milk per mouth was obtained (Example 1). Such sensory evaluation is supported by the fact that the content of hexanal is significantly lower than that of Comparative Example 1.
However, even when the phytase treatment was performed, when the dephosphorization treatment was further performed, the milky taste and the rich taste were reduced (Example 2).
In addition, when phytic acid itself was precipitated and removed by adding a neutral salt without enzymatic degradation of phytic acid, the same texture improvement effect as in Examples 1 and 2 was observed. However, as for the flavor, the same blue odor as in Comparative Example 1 was felt.

According to the present invention, conventional soymilk that has been lactic acid fermented cannot be excluded, the blue odor and egg taste are reduced, the milky taste and richness are obtained, and a smooth fermented fermented soymilk is obtained. Compared with fermented milk, it is possible to eat without any sense of incongruity, and it is possible to further increase the utility value of soy milk that has been spreading recently.

Claims (6)

A lactic acid bacteria fermented soymilk, wherein the phytic acid content per soybean-derived protein is less than 1.5% by weight. The lactic acid bacteria fermented soymilk according to claim 1, wherein the free phosphoric acid content per soybean-derived protein is 0.5 to 5% by weight. The fermented soymilk of lactic acid bacteria according to claim 1, wherein a phytic acid decomposition product is contained. The lactic acid bacteria fermented soymilk according to claim 1, wherein the product is solid or liquid. 2. The lactic acid bacteria fermented soymilk according to claim 1, wherein the product is a live bacteria type or a bactericidal type. A method for producing lactic acid bacteria fermented soymilk, characterized in that lactic acid bacteria are allowed to act on soymilk in which a phytic acid-degrading enzyme is allowed to act to produce a phytic acid degradation product.