Food containing viable lactic acid bacteria, method for producing same, and method for suppressing increase in acidity and / or decrease in viable count

Abstract

The invention provides a food containing viable lactic acid bacteria, and aims to solve the problems of acidity increase and viable count reduction in the preservation process of foods with low lactic acid bacteria nutrient source (non-fat milk solid content and protein) content, such as lactic acid bacteria beverages and dairy product lactic acid bacteria beverages. The food contains a milk component and viable lactic acid bacteria, has a non-fat milk solid content of less than 8.0% by weight, a protein content of less than 2.7% by weight, and a pH of 4.6 or less, and contains an emulsifier and a water activity lowering agent.

Description

TECHNICAL FIELD

[0001] The present application relates to a food product containing viable lactic acid bacteria and a method for producing the same, and a method for inhibiting an increase in acidity and / or a decrease in the number of viable bacteria. More specifically, the present application relates to a food product containing viable lactic acid bacteria having a low non-fat milk solid content or a low protein content, a food product in which an increase in acidity and a decrease in the number of viable bacteria during storage are inhibited, and the like. BACKGROUND

[0002] A food product containing viable lactic acid bacteria has a problem in that an increase in acidity due to acid produced by metabolism of lactic acid bacteria and a decrease in the number of viable lactic acid bacteria and deterioration of flavor occur during storage from the time of production until consumption by a consumer through distribution.

[0003] Various techniques have been proposed in order to inhibit an increase in acidity and a decrease in the number of viable bacteria during storage in fermented milk (yogurt). For example, Patent Literature 1 discloses a low-fat fermented food production technique in which a high number of viable bacteria is maintained after storage, and is suitable for a low-fat fermented food obtained by culturing Bifidobacterium bacteria in a low-fat medium. Specifically, "a method for producing a low-fat fermented food, characterized by inoculating Bifidobacterium bacteria into a medium having a fat content of 2.5% by mass or less, and mixing a saturated fatty acid or a salt or an ester thereof into a fermentation broth obtained by culturing the bacteria" (see claim 9). In Patent Literature 2, as a technique for improving the flavor or mouthfeel of fermented milk in which an increase in acidity during storage is inhibited, it is described that a raw material composition is fermented to obtain fermented milk, and a fatty acid ester is added as a food emulsifier. In addition, in Patent Literatures 1 and 2, the use of an emulsifier in combination with a water activity reducing agent is not described.

[0004] Lactic acid bacteria beverages and dairy lactic acid bacteria beverages are preferably low in non-fat milk solid content in order to have a more refreshing flavor compared to fermented milk and to more easily ingest lactic acid bacteria. It is known that it is more difficult to maintain the number of viable lactic acid bacteria in lactic acid bacteria beverages and dairy lactic acid bacteria beverages (Non-Patent Literature 1). This is because, in lactic acid bacteria beverages and dairy lactic acid bacteria beverages, water or the like is added for the purpose of ensuring fluidity, and thus the non-fat milk solid content is low, resulting in a poor nutrient environment compared to fermented milk containing a large amount of non-fat milk solids, i.e., proteins and carbohydrates, which are nutrient sources for lactic acid bacteria. Therefore, in order to inhibit an increase in acidity and a decrease in the number of viable bacteria during storage of beverages, different technical ideas are proposed for lactic acid bacteria beverages and dairy lactic acid bacteria beverages from those for fermented milk. For example, as a technique for maintaining the number of viable bacteria of a lactic acid bacteria beverage, in Patent Literature 3, a scheme for optimizing the Brix of a supplementary material when the supplementary material is mixed with lactic acid bacteria is proposed. This technique alleviates the stress on lactic acid bacteria by controlling the Brix (sugar content) of the supplementary material to be mixed with a sugar solution to be 28% or less when lactic acid bacteria in a fermented product are mixed with the sugar solution, and thereby maintains the viability of lactic acid bacteria in subsequent processes and storage at a higher level. Prior Art Documents Patent Literature

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2020-162478 Patent Literature 2: International Publication No. 2021 / 215530 Patent Literature 3: Japanese Patent Application Laid-Open No. 2022-143723 Non-Patent Literature

[0006] Non-Patent Literature 1: Effect of Milk Solid Concentration on Growth of Lactic Acid Bacteria, Yano et al., Bulletin of the Japanese Society of Animal Science, 31(4), 204-208, 1960 SUMMARY PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The main object of the present application is to provide a technique for inhibiting an increase in acidity and a decrease in the number of viable bacteria during storage in a food product containing viable lactic acid bacteria, i.e., a food product having a non-fat milk solid content of less than 8.0% by weight, a protein content of less than 2.7% by weight, and a pH of 4.6 or less, as a lactic acid bacteria nutrient source, such as a lactic acid bacteria beverage and a dairy lactic acid bacteria beverage. MEANS FOR SOLVING THE PROBLEMS

[0008] To solve the above problems, the present application provides the following [1] to

[44] . [1] A food product containing a milk component and viable lactic acid bacteria, having a non-fat milk solid content of less than 8.0% by weight, a protein content of less than 2.7% by weight, and a pH of 4.6 or less, and containing an emulsifier and a water activity reducing agent. [1-2] The food product according to [1], wherein the oil content is less than 10% by weight. [1-3] The food product according to [1] or [2], wherein the HLB (Hydrophilic-Lipophilic Balance) of the emulsifier is 9 or more. [1-4] The food product according to any one of [1] to [1-3], wherein the content of the water activity reducing agent is 5% by weight or more. [2] The food according to any one of [1] to [1-4], wherein the emulsifier is one or more fatty acid esters selected from the group consisting of sucrose fatty acid ester, monoglyceride, organic acid monoglyceride, polyglycerol fatty acid ester, and stearoyl lactylate, and is preferably sucrose monofatty acid ester and / or stearoyl lactylate. [3] The food according to [2], wherein the emulsifier is sucrose monofatty acid ester and / or stearoyl lactylate, and is contained in an amount of 0.001 to 1.0% by weight. [4] The food according to any one of [1] to [3], wherein the water activity reducing agent is one or more selected from the group consisting of glucose, fructose, sucrose, erythritol, sorbitol, mannitol, isomalto-oligosaccharide, xylo-oligosaccharide, oligotose, maltitol, palatinose, and xylitol, and is preferably glucose, fructose, and / or sucrose. [5] The food according to any one of [1] to [4], wherein the water activity at 25°C is Aw 0.990 or less, and is preferably 0.981 or less. [6] The food according to any one of [1] to [5], wherein the viable cells of the lactic acid bacteria are contained in an amount of 1 x 10 2 cfu / ml or more. [7] The food according to any one of [1] to [6], wherein the value of Y1 / X1 calculated from the acidity increase rate X1 (%) and the survival rate Y1 (%) of the bacteria after storage at 25°C for 21 days after production is 0.012 or more. [8] The food according to any one of [1] to [7], wherein the value of Y2 / X2 calculated from the acidity increase rate X2 (%) and the survival rate Y2 (%) of the bacteria after storage at 30°C for 14 days after production is 0.012 or more. [9] The food according to any one of [1] to [8], wherein the lactic acid bacteria is Lactobacillus (Lactobacillus casei).

[0009]

[10] A method for producing a food product containing a milk component and viable cells of a lactic acid bacterium, the non-fat milk solid content of which is less than 8.0% by weight, the protein content of which is less than 2.7% by weight, and the pH of which is 4.6 or lower; comprising (1) a step of adding a water activity reducing agent to the milk component before fermentation thereof by the lactic acid bacterium, and a step of adding an emulsifier to the milk component after fermentation thereof by the lactic acid bacterium; or, (2) a step of adding a water activity reducing agent to the milk component before fermentation thereof by the lactic acid bacterium, and a step of adding an emulsifier and a water activity reducing agent to the milk component after fermentation thereof by the lactic acid bacterium; or, (3) a step of adding an emulsifier and a water activity reducing agent to the milk component after fermentation thereof by the lactic acid bacterium. [10-2] The method for producing according to

[10] , wherein the oil content of the food product is less than 10% by weight. [10-3] The method for producing according to

[10] or [10-2], wherein the HLB of the emulsifier is 9 or higher. [10-4] The method for producing according to any one of

[10] to [10-3], wherein the content of the water activity reducing agent in the food product is 5% by weight or higher.

[11] The method for producing according to any one of

[10] to [10-4], wherein the emulsifier is one or more fatty acid esters selected from the group consisting of sucrose fatty acid ester, monoglyceride, organic acid monoglyceride, polyglycerol fatty acid ester, and stearoyl lactylate, and is preferably sucrose monofatty acid ester and / or stearoyl lactylate.

[12] The method for producing according to

[11] , wherein sucrose monofatty acid ester and / or stearoyl lactylate is added as the emulsifier at 0.001 to 1.0% by weight.

[13] The method for producing according to any one of

[10] to

[12] , wherein the water activity reducing agent is one or more selected from the group consisting of glucose, fructose, sucrose, erythritol, sorbitol, mannitol, isomaltulose, xylo-oligosaccharide, straight-chain oligosaccharide, maltitol, isomalt, and xylitol, and is preferably glucose, fructose, and / or sucrose.

[14] The method for producing according to any one of

[10] to

[13] , wherein the food product has a water activity of Aw 0.990 or lower, and preferably 0.981 or lower, at 25°C.

[15] The method for producing according to any one of

[10] to

[14] , wherein the food product contains 1 x 10 2 cfu / ml or more of the viable cells of the lactic acid bacterium.

[16] The method for producing according to any one of

[10] to

[15] , wherein the lactic acid bacterium is a Lactobacillus (Lactobacillus casei).

[0010]

[17] A method for inhibiting an increase in acidity and / or a decrease in viable count of a food product after manufacture, the food product containing a milk component and viable lactic acid bacteria, having a non-fat milk solid component content of less than 8.0% by weight, a protein content of less than 2.7% by weight, and a pH of 4.6 or lower; comprising (1) a step of adding a water activity reducing agent to the milk component before fermentation thereof by the lactic acid bacteria, and a step of adding an emulsifier to the milk component after fermentation thereof by the lactic acid bacteria; or, (2) a step of adding a water activity reducing agent to the milk component before fermentation thereof by the lactic acid bacteria, and a step of adding an emulsifier and a water activity reducing agent to the milk component after fermentation thereof by the lactic acid bacteria; or, (3) a step of adding an emulsifier and a water activity reducing agent to the milk component after fermentation thereof by the lactic acid bacteria. [17-2] The method according to

[17] , wherein the food product has a fat content of less than 10% by weight. [17-3] The method according to

[17] or [17-2], wherein the emulsifier has an HLB of 9 or more. [17-4] The method according to any one of

[17] to [17-3], wherein the food product has a water activity reducing agent content of 5% by weight or more.

[18] The method according to any one of

[17] to [17-4], wherein the emulsifier is one or more fatty acid esters selected from the group consisting of sucrose fatty acid ester, monoglyceride, organic acid monoglyceride, polyglycerol fatty acid ester, and stearoyl lactylate, and is preferably sucrose monofatty acid ester and / or stearoyl lactylate.

[19] The method according to

[18] , wherein sucrose monofatty acid ester and / or stearoyl lactylate is added as the emulsifier at 0.001 to 1.0% by weight.

[20] The method according to any one of

[17] to

[19] , wherein the water activity reducing agent is one or more selected from the group consisting of glucose, fructose, sucrose, erythritol, sorbitol, mannitol, isomaltulose, xylo-oligosaccharide, linear oligosaccharide, maltitol, isomalt, and xylitol, and is preferably glucose, fructose, and / or sucrose.

[21] The method according to any one of

[17] to

[20] , wherein the food product has a water activity of Aw 0.981 or less, preferably 0.981 or less, at 25°C.

[22] The method according to any one of

[17] to

[21] , wherein the food product contains 1 x 10 2 cfu / ml or more of the viable lactic acid bacteria.

[23] The method according to any one of

[17] to

[22] , wherein the value of Y1 / X1 calculated from the acidity increase rate X1 (%) and the bacterial survival rate Y1 (%) after the food is stored at 25°C for 21 days is 0.012 or more.

[24] The method according to any one of

[17] to

[23] , wherein the value of Y2 / X2 calculated from the acidity increase rate X2 (%) and the bacterial survival rate Y2 (%) after the food is stored at 30°C for 14 days is 0.012 or more.

[25] The method according to any one of

[17] to

[24] , wherein the lactic acid bacteria is Lactobacillus (Lactobacillus casei).

[0011]

[26] Use of an emulsifier and a water activity reducing agent in inhibiting an increase in acidity and / or a decrease in viable bacterial count after the manufacture of a food, the food containing a milk component and viable lactic acid bacteria, the non-fat milk solid component being less than 8.0% by weight, the protein being less than 2.7% by weight, and the pH being 4.6 or less. [26-2] The use according to

[26] , wherein the food contains less than 10% by weight of oil and fat. [26-3] The use according to

[26] or [26-2], wherein the HLB of the emulsifier is 9 or more. [26-4] The use according to any one of

[26] to [26-3], wherein the food contains 5% by weight or more of the water activity reducing agent.

[27] The use according to any one of

[26] to [26-4], wherein the emulsifier is one or more fatty acid ester selected from the group consisting of sucrose fatty acid ester, monoglyceride, organic acid monoglyceride, polyglycerol fatty acid ester, and stearoyl lactylate, preferably sucrose monofatty acid ester and / or stearoyl lactylate.

[28] The use according to

[27] , wherein sucrose monofatty acid ester and / or stearoyl lactylate is added to the food as the emulsifier at 0.001 to 1.0% by weight.

[29] The use according to any one of

[26] to

[28] , wherein the water activity reducing agent is one or more selected from the group consisting of glucose, fructose, sucrose, erythritol, sorbitol, mannitol, isomalto-oligosaccharide, xylo-oligosaccharide, straight-chain oligosaccharide, maltitol, isomaltulose, and xylitol, preferably glucose, fructose, and / or sucrose.

[30] The use according to any one of

[26] to

[29] , wherein the food has a water activity of Aw 0.990 or less, preferably 0.981 or less, at 25°C.

[31] The use according to any one of

[26] to

[30] , wherein the food contains 1 x 10 2said lactic acid bacteria live bacteria of 1 x 10

[32] The use according to any one of

[26] to

[31] , wherein the value of Y1 / X1 calculated from the acidity increase rate X1 (%) and the bacteria survival rate Y1 (%) after 21 days of storage at 25°C after the production of the food is 0.012 or more.

[33] The use according to any one of

[26] to

[32] , wherein the value of Y2 / X2 calculated from the acidity increase rate X2 (%) and the bacteria survival rate Y2 (%) after 14 days of storage at 30°C after the production of the food is 0.012 or more.

[34] The use according to any one of

[26] to

[33] , wherein said lactic acid bacteria is Lactobacillus (Lactobacillus casei).

[0012]

[35] A food containing a milk component and lactic acid bacteria live bacteria, the content of non-fat milk solid component being less than 8.0% by weight, the content of protein being less than 2.7% by weight, the content of oil and fat being less than 10% by weight, said food containing an emulsifier having an HLB of 9 or more, said food having a water activity of Aw of 0.990 or less, preferably 0.981 or less, at 25°C.

[36] The food according to

[35] , wherein further containing a water activity reducing agent.

[37] The food according to

[35] or

[36] , wherein the content of the water activity reducing agent is 5% by weight or more.

[38] The food according to any one of

[35] to

[37] , wherein the pH is 4.6 or less.

[39] The food according to any one of

[35] to

[38] , wherein said emulsifier is one or more fatty acid esters selected from the group consisting of sucrose fatty acid ester, monoglyceride, organic acid monoglyceride, polyglycerol fatty acid ester and stearoyl lactylate, preferably sucrose monofatty acid ester and / or stearoyl lactylate.

[40] The food according to

[39] , wherein said emulsifier is sucrose monofatty acid ester and / or stearoyl lactylate, and contains 0.001 to 1.0% by weight.

[41] The food according to any one of

[36] to

[40] , wherein said water activity reducing agent is one or more selected from the group consisting of glucose, fructose, sucrose, erythritol, sorbitol, mannitol, isomaltulose, xylo-oligosaccharide, straight-chain oligosaccharide, maltitol, isomalt and xylitol, preferably glucose, fructose and / or sucrose.

[42] The food according to any one of

[35] to

[41] , wherein 1 x 10 2 cfu / ml or more of said lactic acid bacteria live bacteria.

[43] The food according to any one of

[35] to

[42] , wherein the value of Y1 / X1 calculated from the acidity increase rate X1 (%) and the bacteria survival rate Y1 (%) after storage at 25°C for 21 days after production is 0.012 or greater.

[44] The food according to any one of

[35] to

[43] , wherein the value of Y2 / X2 calculated from the acidity increase rate X2 (%) and the bacteria survival rate Y2 (%) after storage at 30°C for 14 days after production is 0.012 or greater.

[44] The food according to any one of

[35] to

[43] , wherein the lactic acid bacteria is Lactobacillus (Lactobacillus casei). EFFECT OF THE INVENTION

[0013] According to the present application, a technique for inhibiting an increase in acidity and a decrease in the number of viable bacteria during storage is provided in a food containing live lactic acid bacteria, i.e., a food having a low non-fat milk solid content and a low protein content as a nutrient source for lactic acid bacteria, such as a lactic acid bacteria beverage and a dairy lactic acid bacteria beverage. DETAILED DESCRIPTION

[0014] The following describes preferred modes for carrying out the present application. Furthermore, the following described embodiments are one example of showing representative embodiments of the present application, and the scope of the present application cannot be narrowly interpreted from this.

[0015] 1. Food The food to which the present application relates is a food containing a milk component and live lactic acid bacteria, having a non-fat milk solid content of less than 8.0% by weight, a protein content of less than 2.7% by weight, and a pH of 4.6 or less, and containing an emulsifier and a water activity reducing agent. In another embodiment of the food to which the present application relates, a milk component and live lactic acid bacteria are contained, the non-fat milk solid content is less than 8.0% by weight, the protein content is less than 2.7% by weight, the oil content is less than 10% by mass, and an emulsifier having an HLB of 9 or greater and a water activity of Aw0.990 or less at 25°C is contained.

[0016] [Milk component] As the milk component, a conventionally known milk raw material, for example, raw milk or a processed product thereof (for example, cow's milk, component-adjusted cow's milk, processed milk, skim milk, condensed milk, skim condensed milk, whole milk powder, formulated milk powder, skim milk powder, condensed milk, cream, butter, etc.) can be contained. The milk raw material used can be one kind, or a plurality of milk raw materials can be combined.

[0017] From the viewpoint of a refreshing flavor, the non-fat milk solid content is preferably low, and specifically, is preferably less than 8.0% by weight. When the non-fat milk solid content as a nutrient source for lactic acid bacteria is low, it is particularly difficult to maintain the number of viable bacteria, and the effect of the present application becomes significant. The non-fat milk solid content is more preferably 0.1% by weight or more and less than 7% by weight, further preferably 0.5% by weight or more and less than 6.5% by weight, and most preferably 1% by weight or more and less than 4% by weight.

[0018] The protein content is preferably small from the viewpoint of good flowability, and specifically, is preferably less than 2.7% by weight. When the protein content as a nutrient source for lactic acid bacteria is small, it is particularly difficult to maintain the number of viable bacteria, and the effect of the present application becomes significant. The protein content is more preferably 0.01% by weight or more and less than 2.5% by weight, further preferably 0.1% by weight or more and less than 2% by weight, and most preferably 0.5% by weight or more and less than 1.5% by weight.

[0019] The non-fat milk solid content and the protein content can be appropriately set within the above numerical ranges according to the properties, flavor, use, and the like of the target food. The non-fat milk solid content and the protein content can be calculated as theoretical values using the values described in the Japanese Food Standards Ingredients Table 2020 edition (eighth revision). In addition, the non-fat milk solid content and the protein content can be measured by a conventional method, for example, by a method described in the "Ordinance on the Specifications of Ingredients, etc. of Milk and Milk Products" (Ordinance on Milk, etc., Ordinance of the Ministry of Health and Welfare No. 52 of December 27, 1966) based on the Ordinance of the Ministry of Health, Labour and Welfare or the Fermented Milk Standard of the International Standard for Foods (CODEX STANDARD FOR FERMENTED MILKS, CODEX STAN 243-2003).

[0020] For the food related to the present application, the pH value is preferably low at the time point when the storage is started (for example, at the end of the entire manufacturing process of the fermented milk or on the day when the manufacturing is completed), because a lower pH value can bring about a sour taste and a better flavor. In addition, the pH is preferably low from the aspect that the isoelectric point of the milk protein is not exceeded and the possibility that the stability of the food is excellent is high. Specifically, the pH is preferably 4.6 or lower, more preferably 4.5 or lower, further preferably 4.4 or lower, particularly preferably 4.2 or lower, and most preferably 4.0 or lower.

[0021] The food related to the present application is a food containing viable lactic acid bacteria. Specifically, it can be a food using lactic acid bacteria beverages, milk product lactic acid bacteria beverages, or milk and the like as main raw materials. Lactic acid bacteria beverage refers to a food containing milk components, having less than 3% by weight of non-fat milk solids and less than 2.7% by weight of protein content. It includes a food made by a manufacturing method prescribed in any one of the definitions of the Ordinance for the Control of Milk Etc. or the definition based on the regulatory standards for fermented milk beverages (CODEX STANDARD FOR Drinks based on Fermented Milk). Dairy lactic acid bacteria beverage refers to a food containing milk components, having 3% by weight or more of non-fat milk solids and less than 2.7% by weight of protein content. It includes a food made by a manufacturing method prescribed in any one of the definitions of the Ordinance for the Control of Milk Etc. or the definition based on the regulatory standards for fermented milk beverages (CODEX STANDARD FOR Drinks based on Fermented Milk). In addition, fermented milk (yogurt) does not belong to lactic acid bacteria beverage and dairy lactic acid bacteria beverage. Fermented milk refers to a food containing milk components, having 8% by weight or more of non-fat milk solids and 2.7% by weight or more of protein content. It includes a food made by a manufacturing method prescribed in any one of the definitions of the Ordinance for the Control of Milk Etc. or the definition based on the regulatory standards for fermented milk beverages (CODEX STANDARD FOR Drinks based on Fermented Milk). The Ordinance for the Control of Milk Etc. defines fermented milk as "a product made by fermenting milk or milk etc. containing non-fat milk solids components equal to or more than milk with lactic acid bacteria or yeast, into a paste or liquid state or after freezing treatment". Food (except beverages) using milk etc. as a main raw material refers to a food containing milk components, having less than 8% by weight of non-fat milk solids and less than 2.7% by weight of protein content. It includes a food made by a manufacturing method prescribed in any one of the definitions of the Ordinance for the Control of Milk Etc. or the definition based on the regulatory standards for fermented milk beverages (CODEX STANDARD FOR Drinks based on Fermented Milk). The food using milk etc. as a main raw material refers to a food not satisfying the definition of fermented milk prescribed in the Ordinance for the Control of Milk Etc. in terms of non-fat milk solids being less than the reference value.

[0022] The food to which the present application relates can also contain oil and fat. The content of oil and fat is less than 10% by weight, more preferably 7% by weight or less, further preferably 4% by weight or less, and most preferably 0.5% by weight or less. When the content of oil and fat is small, it is particularly difficult to maintain the number of viable bacteria, and the effect of the present application becomes significant. In addition, the lower limit of the content of oil and fat is not particularly limited, and it can also be a food containing no oil and fat.

[0023] As the oil and fat, there is no particular limitation, and it can be an animal oil and fat or a vegetable oil and fat. As the animal oil and fat, fish oil, beef tallow, pork tallow, milk fat (butter, anhydrous butter), horse oil, snake oil, egg oil, egg yolk oil, turtle oil, mink oil, and the like can be exemplified. As the vegetable oil and fat, soybean oil, corn oil, cottonseed oil, rapeseed oil, sesame oil, perilla seed oil, rice bran oil, sunflower seed oil, peanut oil, olive oil, palm oil, rice germ oil, wheat germ oil, brown rice germ oil, yam bean oil, garlic oil, macadamia nut oil, avocado oil, evening primrose oil, safflower oil, camellia oil, coconut oil, castor oil, flaxseed oil, cocoa butter, and the like can be exemplified. The oil and fat can also be a product obtained by oil and fat processing (hydrogenation, interesterification, or the like) of these vegetable oil and fats. For example, MCT (medium-chain fatty acid oil), hardened coconut oil, hardened palm kernel oil, or the like, which are hardened oils or processed oil and fats obtained by refining or deodorizing, separation, solidification, interesterification, or the like of liquid or solid materials of vegetable oil and fats, can be exemplified. Further, liquid oil, solid fat, or the like, which are obtained by separating these oil and fats, can be exemplified. Medium-chain fatty acid triglyceride or the like can also be exemplified. From the viewpoint of compatibility with a fermented flavor and product design, the oil and fat is preferably MCT (medium-chain fatty acid oil), milk fat (butter, anhydrous butter), coconut oil, or palm kernel oil.

[0024] [Lactic acid bacteria] The kind of the lactic acid bacteria is not particularly limited, and can be selected from lactic acid bacteria conventionally used as a starter, depending on the properties, flavor, use, or the like of the food as a target. As such lactic acid bacteria, for example, lactic acid bacteria such as Lacticaseibacillus, Lactobacillus, Levilactobacillus, Lentilactobacillus, Limosilactobacillus, Lactiplantibacillus, Ligilactobacillus, Streptococcus, and Bifidobacterium can be exemplified. The lactic acid bacteria can be used alone as any one of them, or two or more of them can be used in combination.

[0025] Further, lactic acid bacteria of the genus Lactobacillus were subdivided in 2020, and some species were changed in genus name (see Zheng et al., “A taxonomic note on the genus Lactobacillus: Description of 23 novel genera, emended description of the genus Lactobacillus Beijerinck 1901, and union of Lactobacillaceae and Leuconostocaceae.” Int. J. Syst. Evol. Microbiol. 2020 Apr;70(4):2782-2858). For example, the genus Lactobacillus was changed to the genus Lactobacillus casei. Hereinafter, the genus name of lactic acid bacteria in the present application is based on the new classification table after the reclassification.

[0026] As specific examples of lactic acid bacteria of the genus Lactobacillus casei, L. casei, L. rhamnosus, L. paracasei subsp. paracasei, and L. zeae can be given.

[0027] As specific examples of lactic acid bacteria of the genus Lactobacillus, Lactobacillus delbrueckii subsp. bulgaricus, L. acidophilus, L. amylovorus, L. crispatus, L. delbrueckii subsp. lactis, L. gallinarum, L. gasseri, L. helveticus, L. helveticus subsp. jugurti, and L. johnsonii can be given.

[0028] As specific examples of lactic acid bacteria of the genus Levilactobacillus, L. brevis can be given.

[0029] Specific examples of Lentilactobacillus-like bacteria include L. buchneri, L. sunkiii, and L. kefir.

[0030] Specific examples of the genus *Limosilactobacillus* include *Lactobacillus fermentum*, *Lactobacillus oris*, and *Lactobacillus reuteri*.

[0031] Specific examples of the genus *Lactiplantibacillus* include *L. paraplantarum*, *L. pentosus*, and *L. plantarum*.

[0032] As a specific example of the genus *Ligilactobacillus*, *L. salivarius* can be cited.

[0033] As a specific example of lactic acid bacteria in the genus Streptococcus, Streptococcus salivarius subsp. thermophilus can be cited.

[0034] Specific examples of lactic acid bacteria in the genus Bifidobacterium include Bifidobacterium adolescentis, Bifidobacterium animalis, Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium catenulatum, Bifidobacterium globosum, Bifidobacterium infantis, Bifidobacterium lactis, Bifidobacterium longum, Bifidobacterium pseudodocatenulatum, and Bifidobacterium suis.

[0035] Lactic acid bacteria are preferably Lactobacillus and Lactobacillus casei, more preferably Lactobacillus bulgaricus and Lactobacillus paracasei subsp. paracasei, and especially preferably Lactobacillus paracasei subsp. paracasei.

[0036] The food product involved in this invention preferably contains 1×10 at the start of storage (e.g., at the end of all manufacturing processes of the fermented milk or on the day of completion). 2 Live lactic acid bacteria with a cfu / ml or higher, preferably containing 1×10⁻⁶ cfu / ml. 3 cfu / ml or higher, more preferably containing 1×104 1 x 10 5 1 x 10 In the Ordinance on Standards for Ingredients, etc. of Milk and Milk Products (Ministry of Health and Welfare Ordinance), it is stipulated that a lactic acid bacteria beverage contains 1 x 10 7 1 x 10 6 1 x 10 6 1 x 10 7 1 x 10

[0037] The number of lactic acid bacteria can be measured according to the method stipulated in the Ordinance on Standards for Ingredients, etc. of Milk and Milk Products (Ministry of Health and Welfare Ordinance No. 52 of Showa 26, published on December 27, 2019 (Ministry of Health, Labour and Welfare Ordinance No. 87 of Reiwa 1) revised).

[0038] [Emulsifier] The emulsifier is preferably one or more kinds of fatty acid esters selected from the group consisting of sucrose fatty acid esters, glycerin fatty acid esters (monoglycerides, organic acid monoglycerides, polyglycerin fatty acid esters, etc.), and stearoyl lactylates (sodium stearoyl lactylate, calcium stearoyl lactylate, etc.), and more preferably sucrose fatty acid esters or stearoyl lactylates. The emulsifier can be used as any one kind, or two or more kinds can be used in combination.

[0039] As specific examples of sucrose fatty acid esters, sucrose laurate (carbon number of fatty acid: 12, the same hereinafter), sucrose myristate (carbon number: 14), sucrose palmitate (carbon number: 16), sucrose stearate (carbon number: 18), sucrose oleate (carbon number: 18, number of double bonds: 1), sucrose behenate (carbon number: 22), sucrose erucate (carbon number: 22, number of double bonds: 1), and sucrose mixed fatty acid ester (for example, mixed fatty acid ester of oleic acid, palmitic acid, and stearic acid) can be listed. Among these, sucrose palmitate is preferred. Such sucrose fatty acid esters can be used as any one kind, or two or more kinds can be used in combination.

[0040] The monoester content of sucrose fatty acid esters is preferably 60% by weight or more, more preferably 70% by weight or more, and further preferably 80% by weight or more.

[0041] The proportions of triesters, monoesters, and diesters in sucrose fatty acid esters can be determined by the method of assay described in "Sucrose Esters of Fatty Acids" (Residue Monograph prepared by the meeting of the Joint FAO / WHO Expert Committee on Food Additives (JECFA), 84th meeting 2017). Specifically, after dissolving a precisely weighed sample in a certain amount of 100% tetrahydrofuran (HPLC grade), the solution after removing insoluble matter with a 0.5-μm membrane filter is set as a sample, and high-performance liquid chromatography under the following conditions is performed, and the peak areas of monoesters, diesters, and triesters are calculated, respectively, and the ratio of the total peak area of all peaks detected in the measurement results for 50 minutes is calculated. The peak area corresponds to the area from the starting point (rising position) to the ending point (falling position) of each peak. If two or more peaks are adjacent and the starting point and the ending point are not clear, the point with the minimum data value between the peaks is taken as the starting point and the ending point, and the area is calculated. <Measurement conditions> Apparatus: Chromaster (manufactured by Hitachi, Ltd.) Detector: Differential refractometer Detecter-5450 (manufactured by Hitachi, Ltd.) Column: TSK gel G2500HXL (manufactured by Tosoh Corporation) Column temperature: 40°C Eluent: Tetrahydrofuran (100%) 0.8 ml / min Injection amount: 10 μl

[0042] Sucrose fatty acid esters can be synthesized by a known method (e.g., transesterification between sucrose and higher alcohol esters of fatty acids), or can be directly selected from commercially available products, for example, as "RYOTO (registered trademark) SUGAR ESTER" manufactured by Mitsubishi Chemical Corporation, various brands (grades) of products having various HLBs are available.

[0043] The HLB (Hydrophilic-Lipophilic Balance) of sucrose fatty acid esters is preferably high in order to have moderate hydrophilicity and to be easily sufficiently incorporated into a raw material composition. Specifically, it is preferably 9 or higher, more preferably 12 or higher, further preferably 13 or higher, and most preferably 15 or higher. The sucrose fatty acid ester is particularly preferably sucrose palmitate having an HLB of 9 or more.

[0044] The HLB can be determined by a known method. Among the methods for calculating the HLB, there are Atlas method, Griffin method, Davies method, Kawakami method, and a method of determining the retention time in high performance liquid chromatography. For example, (i) in the case where the composition of the fatty acid ester in the synthetic mixture is known, the HLB of each fatty acid ester can be calculated using the Griffin method, and then the HLB of the fatty acid ester can be obtained by weighted average; (ii) in the case where the composition of the fatty acid ester is unknown, the HLB of the fatty acid ester can be obtained by comparing the retention time in high performance liquid chromatography (HPLC) with a sample of a fatty acid ester having a known HLB.

[0045] Further, the HLB of "RYOTO (registered trademark) SUGAR ESTER" and "RYOTO (registered trademark) POLY GRY ESTER" is described in the product catalog (refer to the homepage of Mitsubishi Chemical Corporation, http: / / www.mfc.co.jp / product / nyuuka / ryoto_syuga / list.html, https: / / www.mfc.co.jp / product / nyuuka / ryoto_polygry / list.html) with an approximate value (as a value with "about"), but the value can be considered as the HLB of the emulsifier (fatty acid ester). As the sucrose fatty acid ester, when other products are used, the HLB can also be referred to the product catalog value.

[0046] As specific examples of the polyglyceryl fatty acid ester, polyglyceryl caprylate (carbon number 8 of the fatty acid, the same hereinafter), polyglyceryl laurate (carbon number 12), polyglyceryl myristate (carbon number 14), polyglyceryl palmitate (carbon number 16), polyglyceryl stearate (carbon number 18), polyglyceryl oleate (carbon number 18, double bond number 1), and polyglyceryl behenate (carbon number 22) can be listed. Among these, polyglyceryl palmitate is preferred.

[0047] The polyglyceryl fatty acid ester can be synthesized by a known method (for example, transesterification between polyglycerol and higher alcohol ester of fatty acid), or can be directly selected from commercially available products, for example, as "RYOTO (registered trademark) POLY GRY ESTER" manufactured by Mitsubishi Chemical Corporation, various brands (grades) of products having various HLBs are available.

[0048] The polyglyceryl fatty acid ester preferably has an average degree of polymerization of 3. More preferably, the average degree of polymerization is 2.5 or less, and further preferably, 2 or less.

[0049] The average degree of polymerization of the polyglycerin fatty acid ester and the constituent fatty acid bonded to the polyglycerin fatty acid ester can be measured or determined by a conventional method. For example, a method (GC method) in which the polyglycerin is converted into a TMS-derivatized and / or acetylated derivative and then separated and quantified by gas chromatography can be cited. Based on the analysis by the GC method, for example, a fused silica capillary with a low-polarity liquid phase such as a chemically bonded methyl silicone on the inner wall can be used, and the analysis can be performed at a temperature rising of 10°C / min from 100°C to 250°C. Further, the determination of the degree of polymerization corresponding to each peak on the gas chromatogram can be performed, for example, by the following method: the gas chromatograph is coupled with a double-focusing mass spectrometer, ionization is performed by a method such as chemical ionization and measurement is performed, and then the molecular weight of the parent ion is determined to obtain the molecular weight corresponding to each peak on the gas chromatogram, and further the degree of polymerization of glycerin is obtained from the chemical formula.

[0050] As specific examples of the organic acid monoglyceride, diacetyl monoglyceride (DATEM), succinic acid monoglyceride can be cited.

[0051] The content of the emulsifier is preferably 0.001 to 5.0% by weight, more preferably 0.005 to 0.5% by weight. When the emulsifier is a sucrose fatty acid ester, the content thereof is particularly preferably 0.001 to 1.0% by weight, more preferably 0.05 to 0.5% by weight, and further preferably 0.08 to 0.20% by weight. When the emulsifier is a stearoyl lactylate, the content thereof is particularly preferably 0.001 to 1.0% by weight, more preferably 0.01 to 0.5% by weight, and further preferably 0.05 to 0.15% by weight.

[0052] The content of the emulsifier in the food can be measured, for example, by a conventional method such as high-performance liquid chromatography (HPLC).

[0053] [water activity reducing agent] The water activity reducing agent refers to a substance which is dissolved in water and reduces the water activity in the food. The water activity reducing agent is preferably one or more selected from the group consisting of glucose, xylose, fructose, psicose, sucrose, lactose, erythritol, sorbitol, trehalose, mannitol, isomalto-oligosaccharide, xylo-oligosaccharide, oligotose (a straight-chain oligosaccharide whose main component is maltotriose), maltitol, isomaltulose, xylitol, sodium chloride, magnesium chloride, calcium lactate, glycerin, ethanol, and isopropanol. The water activity reducing agent is more preferably glucose, fructose, sucrose, erythritol, and mannitol, and further preferably glucose, fructose, and / or sucrose, from the viewpoint of good flavor.

[0054] From the viewpoint of the assimilability of lactic acid bacteria, the water activity reducing agent is preferably at least one selected from the group consisting of glucose, fructose, sucrose, erythritol, sorbitol, mannitol, isomaltulose, xylooligosaccharide, straight-chain oligosaccharide, maltitol, isomalt, and xylitol.

[0055] The content of the water activity reducing agent is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and further preferably 2 to 35% by weight. The content of the water activity reducing agent is preferably 5% by weight or more, more preferably 10.0% by weight or more, and further preferably 20% by weight or more.

[0056] The content of the water activity reducing agent in the food product can be measured by a conventional method such as high-performance liquid chromatography (HPLC), for example, if the water activity reducing agent is a saccharide such as glucose or fructose.

[0057] The food product according to the present application containing the water activity reducing agent in the above content can have a water activity of Aw 0.990 or less at 25°C. The water activity at 25°C is more preferably 0.985 or less. It is further preferably 0.983 or less, most preferably 0.981 or less, and further 0.979 or less. The water activity Aw can be measured by a water activity measuring device. The "water activity at 25°C" in the present application includes a measurement value at 24.5°C to 25.4°C.

[0058] The food product according to the present application containing the water activity reducing agent and the emulsifier can suppress the increase in acidity and the decrease in the number of viable lactic acid bacteria even when the content of non-fat milk solid components, proteins, and fats, which are the nutrient sources of lactic acid bacteria, is low. It is considered that the lactic acid bacteria are in a state like dormancy by the combined use of the water activity reducing agent and the emulsifier, and thus the number of viable lactic acid bacteria is maintained. In particular, in regions where the cold-chain distribution system is not perfect, or in situations where the cold-chain distribution is difficult to select due to the cost of energy and the influence on the global environment, even if the normal-temperature distribution is adopted, the increase in acidity and the decrease in the number of viable lactic acid bacteria can be suppressed. It is considered that the metabolic inhibition of lactic acid bacteria by the emulsifier and the water activity reducing agent can contribute to the suppression of the increase in acidity and the decrease in the number of viable lactic acid bacteria after a certain period of storage.

[0059] The inhibition of the increase in acidity can be confirmed, for example, by storing the food at a prescribed temperature and for a prescribed period of time, and calculating the increase in acidity from the day of the start of storage to the day of the end of storage. For example, for the food according to the present application and a food serving as a comparative control, each is stored at a prescribed temperature (for example, 4 to 10°C, 11 to 20°C, or 21 to 30°C) for a prescribed period of time (for example, 14 days), and the acidity before and after storage is measured, and it can be judged that the effect of inhibiting the increase in acidity during storage has been exerted, based on the fact that the increase in acidity of the food according to the present application is smaller than that of the control. Further, the inhibition of the decrease in the number of viable lactic acid bacteria can be confirmed, for example, by storing the food at a prescribed temperature and for a prescribed period of time, and calculating the decrease in the number of bacteria from the day of the start of storage to the day of the end of storage. For example, for the food according to the present application and a food serving as a comparative control, each is stored at a prescribed temperature (for example, 4 to 10°C, 11 to 20°C, or 21 to 30°C) for a prescribed period of time (for example, 14 days), and the number of bacteria before and after storage is measured, and it can be judged that the effect of inhibiting the decrease in the survival rate of lactic acid bacteria during storage has been exerted, based on the fact that the decrease in the number of bacteria of the food according to the present application is smaller than that of the control.

[0060] The acidity of the fermented milk can be measured according to the method prescribed in the Ordinance on Standards for Ingredients, etc. of Milk and Milk Products (Showa 26th Ordinance No. 52 of the Ministry of Health and Welfare, published on December 27, 1911 (Ordinance No. 87 of the Ministry of Health, Labour and Welfare, 1911) revised).

[0061] The survival rate (%) of the lactic acid bacteria can be calculated by dividing the number of viable bacteria after storage for a prescribed period of time by the number of viable bacteria at the point of time of the start of storage (for example, at the end of or on the day of the end of the entire manufacturing process of the fermented milk), as the proportion thereof.

[0062] The food according to the present application preferably has a high value of Y / X calculated from the acidity increase rate X (%) and the bacterial survival rate Y (%) after storage at 25 to 30°C for 14 to 21 days after manufacturing. Specifically, it is preferred that the value of Y1 / X1 calculated from the acidity increase rate X1 (%) and the bacterial survival rate Y1 (%) after storage at 25°C for 21 days after manufacturing be 0.012 or greater, more preferably 0.015 or greater, further preferably 0.03 or greater, and most preferably 0.04 or greater. Further, it is preferred that the value of Y1 / X1 calculated from the acidity increase rate X1 (%) and the bacterial survival rate Y1 (%) after storage at 30°C for 14 days after manufacturing be 0.012 or greater, more preferably 0.015 or greater, further preferably 0.03 or greater, and most preferably 0.04 or greater.

[0063] [Other ingredients] As other components which can be arbitrarily contained in the food of the present application, for example, food additives such as colorants, thickeners, stabilizers, gelling agents (gelatin, agar, pectin, carboxymethyl cellulose (CMC), etc.), and flavorings can be mentioned.

[0064] 2. Manufacturing method The manufacturing method of the food of the present application is a manufacturing method of a food containing a milk component and viable lactic acid bacteria, having a non-fat milk solid content of less than 8.0% by weight, a protein content of less than 2.7% by weight, and a pH of 4.6 or lower, which has a step of fermenting the milk component, and a step of adding a water activity reducing agent and an emulsifier to the milk component. The step of fermenting the milk component, and the step of adding the water activity reducing agent and the emulsifier to the milk component can be performed in either order. Furthermore, the addition of the water activity reducing agent and the emulsifier to the milk component can be performed simultaneously, or separately. The addition of the water activity reducing agent and the emulsifier can be performed at once, or can be performed in multiple stages. The manufacturing method of the food of the present application preferably comprises any one of the following (1) to (3). (1) a step of adding a water activity reducing agent to a milk component before fermentation by lactic acid bacteria, and a step of adding an emulsifier to a milk component after fermentation by lactic acid bacteria. (2) a step of adding a water activity reducing agent to a milk component before fermentation by lactic acid bacteria, and a step of adding an emulsifier and a water activity reducing agent to a milk component after fermentation by lactic acid bacteria. (3) a step of adding an emulsifier and a water activity reducing agent to a milk component after fermentation by lactic acid bacteria.

[0065] The manufacturing method of the food of the present application can be manufactured by the same procedures as the manufacturing method of a food containing viable lactic acid bacteria in general, in addition to the above-mentioned steps of adding a water activity reducing agent and an emulsifier. The manufacturing method of a food containing viable lactic acid bacteria generally comprises a step of preparing a raw material composition (preparation step), and a step of adding a lactic acid bacteria starter to the raw material composition and fermenting it (fermentation step). Here, the step (1) of the manufacturing method of the food of the present application can be performed by adding a water activity reducing agent to the raw material composition in the preparation step of the conventional manufacturing method, and fermenting it, and then adding an emulsifier to the fermented milk. The step (2) of the manufacturing method of the food of the present application can be performed by adding a part of the water activity reducing agent to the raw material composition in the preparation step, fermenting it, and then adding an emulsifier and the remaining water activity reducing agent to the fermented milk. The step (3) of the manufacturing method of the food of the present application can be performed by adding an emulsifier and a water activity reducing agent to the obtained fermented milk after the fermentation step.

[0066] In the preparation step of the conventional manufacturing method, the above-mentioned milk component is mixed with other components to obtain a raw material composition. In the manufacturing method of the food product according to the present application, it is preferable to adjust the raw material composition at this time so that the non-fat milk solid component and the protein content are within the above-mentioned numerical ranges. In the fermentation step, fermentation is usually performed at 30 to 50°C, preferably 40 to 45°C, for usually 1 to 24 hours, preferably 3 to 24 hours. In the manufacturing method of the food product according to the present application, it is preferable to adjust the lactic acid bacteria starter, the fermentation temperature and the fermentation time at this time so that the lactic acid bacteria number and the pH are within the above-mentioned numerical ranges. In addition, the raw material composition can also be sterilized by a conventional method before starting the fermentation.

[0067] According to the manufacturing method of the food product according to the present application, by compounding an emulsifier and a water activity reducing agent, a food product containing lactic acid bacteria viable cells which suppresses the increase in acidity and the decrease in lactic acid bacteria viable cell number after a certain period of storage can be obtained.

[0068] 3. A method for suppressing the increase in acidity and / or the decrease in viable cell number The method for suppressing the increase in acidity and / or the decrease in viable cell number of a food product after manufacturing according to the present application is a method for suppressing the increase in acidity and / or the decrease in viable cell number of a food product containing a milk component and lactic acid bacteria viable cells, the content of non-fat milk solid component being less than 8.0% by weight, the content of protein being less than 2.7% by weight, and the pH being 4.6 or less, which has a step of fermenting the above-mentioned milk component, and a step of adding a water activity reducing agent and an emulsifier to the milk component. The step of fermenting the milk component, and the step of adding a water activity reducing agent and an emulsifier to the milk component can be performed in either order. In addition, the addition of the water activity reducing agent and the emulsifier to the milk component can be performed simultaneously, or separately. The addition of the water activity reducing agent and the emulsifier can be performed at once, or can be performed in multiple stages. The manufacturing method of the food product according to the present application preferably includes any of the above-mentioned (1) to (3).

[0069] The method for suppressing the increase in acidity and / or the decrease in viable cell number of a food product after manufacturing according to the present application can be appropriately applied to the technical matters related to the above-mentioned manufacturing method of the food product according to the present application.

[0070] 4. Use of an emulsifier and a water activity reducing agent As described above, the food of the present application contains the emulsifier and the water activity reducing agent in the above-mentioned range, and even after a certain period of storage, the increase in acidity and the decrease in the number of viable lactic acid bacteria can be suppressed. That is, the use of the emulsifier and the water activity reducing agent of the present application is to suppress the increase in acidity and / or the decrease in the number of viable bacteria after manufacture in a food containing milk components and viable lactic acid bacteria, having a non-fat milk solid content of less than 8.0% by weight, a protein content of less than 2.7% by weight, and a pH of 4.6 or less, and the use of the emulsifier and the water activity reducing agent. Examples

[0071] Except for the cases specifically mentioned, the products and the measuring methods used in the following examples are as described below. Emulsifier: Sucrose fatty acid ester "RYOTOSUGAR ESTER P-1670" (Mitsubishi Chemical Corporation, sucrose palmitate, HLB = 16, monoester content 80% by weight) New Yakult (Japan Yakult Honsha Co., Ltd.) Lactic acid bacteria FD-DVS L. casei-01 (Danisco) Granulated sugar (Granulated sugar, Nisshin Sugar Co., Ltd.) Fujifruct F-100 (Nippon Shokuhin Kako Co., Ltd.) Skim milk powder (Morinaga Milk Industry Co., Ltd.) Anhydrous crystalline glucose (Showa Denko K.K.)

[0072] (1) Calculation of the content of non-fat milk solids and protein Using the values described in the Japanese Food Standards Table 2020 Edition (Eighth Revision), the theoretical values in each component were calculated. (2) Measurement of the number of lactic acid bacteria, and calculation of the survival rate The measurement of the number of lactic acid bacteria was performed in accordance with the Ordinance on Standards for Ingredients, etc. of Milk and Milk Products ((Showa 26, Ministry of Health and Welfare Ordinance No. 52) published on December 27, Heisei (Ministry of Health, Labour and Welfare Ordinance No. 87, Heisei) revised), and appropriate conditions were set and measured. The survival rate (%) is the number of viable bacteria after a certain period of storage divided by the number of viable bacteria immediately after preparation (stored for 0 days), and the proportion is calculated. (3) Measurement of acidity The lactic acid acidity (%) was calculated by measuring it according to the method described in the Ordinance on Ingredients of Milk and Milk Products (Showa 26th Ordinance No. 52 of the Ministry of Health and Welfare, revised and promulgated on December 27, 2019 (Ordinance No. 87 of 2019 of the Ministry of Health, Labour and Welfare)). The acidity increase rate (%) was calculated by dividing the acidity after the prescribed period of storage by the acidity immediately after preparation (0 days of storage). (4) Measurement of Water Activity Aw The water activity Aw was measured using an AquaLab Series 4TDL (manufactured by METER Corporation).

[0073] [Example 1] (1) Preparation of mother starter 15% by weight of skim milk powder, 8% by weight of fructose-glucose syrup, and 74% by weight of water were mixed and dissolved. After sterilizing the mixed solution at 100°C for 1 hour, it was cooled to 37°C. To the mixed solution, 3% by weight of New Yakult was added, and after mixing, it was fermented at 37°C for 48 hours to obtain a mother starter. The mother starter was frozen with liquid nitrogen and stored frozen.

[0074] (2) Preparation of lactic acid bacteria beverage The skim milk powder, water activity reducing agent (fructose-glucose syrup) were dissolved in water, and the mother starter, which was returned to room temperature, was added to be fermented at 35°C to obtain a fermented milk base. According to the final formulation shown in Table 1, emulsifier (sucrose palmitate) and water activity reducing agent (sugar, i.e., granulated sugar and fructose-glucose syrup) were added to the obtained fermented milk base and mixed. The mixed solution was filled in a plastic container and cooled overnight to obtain a lactic acid bacteria beverage (Example 1). The obtained lactic acid bacteria beverage had a non-fat milk solid content of 3.43% by weight, a protein content of 1.2% by weight, and a pH of 3.66.

[0075] [Comparative Example 1] In Example 1, a lactic acid bacteria beverage was obtained in the same manner as in Example 1, except that no sucrose palmitate was added in the preparation of the lactic acid bacteria beverage. The obtained lactic acid bacteria beverage had a pH of 3.65.

[0076] [Table 1] Comparative Example 1 Example 1 Skim milk powder 3.60 wt% 3.60 wt% White sugar 3.04 wt% 3.04 wt% High fructose corn syrup 17.60 wt% 17.60 wt% Sucrose fatty acid ester (no) 0.114 wt%

[0077] After the lactic acid bacteria beverages of Example 1 and Comparative Example 1 were stored at 25°C for 21 days or at 30°C for 14 days, the acidity was measured and the survival rate was calculated, and the results are shown in Tables 2 and 3.

[0078] [Table 2] Comparative Example 1 Example 1 Viable cell count after 0 days of storage (cfu / ml) 4.7E+08 3.1E+08 Viable cell count after 21 days of storage at 25°C (cfu / ml) 6.50E+06 1.50E+07 Survival rate (after 21 days of storage / after 0 days of storage) 1.38％ 4.84％ Acidity after 0 days of storage 0.62％ 0.61％ Acidity after 21 days of storage at 25°C 0.80％ 0.74％ Acidity increase rate (after 21 days of storage / after 0 days of storage) 129％ 121％ Bacterial survival rate / acidity increase rate 0.011 0.040

[0079] [Table 3] Comparative Example 1 Example 1 Viable cell count after 0 days of storage (cfu / ml) 4.7E+08 3.1E+08 Viable cell count after 14 days of storage at 30°C (cfu / ml) 4.1E+06 1.8E+07 Survival rate (after 14 days of storage / after 0 days of storage) 0.87％ 5.8％ Acidity after 0 days of storage 0.62％ 0.61％ Acidity after 14 days of storage at 30°C 0.80％ 0.77％ Acidity increase rate (after 14 days of storage / after 0 days of storage) 129％ 126％ Bacterial survival rate / acidity increase rate 0.0067 0.046

[0080] Under the storage conditions of 25°C for 21 days and 30°C for 14 days, the increase in acidity was inhibited and the survival rate was significantly improved in the lactic acid bacteria beverage of Example 1 compared to the lactic acid bacteria beverage of Comparative Example 1. That is, it was demonstrated that the food according to the present application can inhibit the increase in acidity and the decrease in viable bacteria count during storage, although the non-fat milk solid content and the protein content are low.

[0081] [Example 2] The same test was performed by changing the strain of lactic acid bacteria in Example 1.

[0082] (1) Preparation of lactic acid bacteria beverage Skim milk powder, a water activity reducing agent (fructose-glucose syrup) were dissolved in water, and powdered lactic acid bacteria (FD-DVSL. casei-01) as a fermenting agent was added, and the mixture was fermented at 37°C to obtain a fermented milk base. According to the final formulation shown in Table 4, emulsifier (sucrose palmitate), water activity reducing agent (sucrose, fructose-glucose syrup), and stabilizer (pectin) were added to the obtained fermented milk base and mixed. The mixture was filled in a plastic container, cooled overnight, and a lactic acid bacteria beverage (Example 2) was obtained. The obtained lactic acid bacteria beverage had a non-fat milk solid content of 3.43% by weight, a protein content of 1.2% by weight, and a pH of 3.81.

[0083] [Comparative Example 2] In Example 2, a lactic acid bacteria beverage was obtained in the same manner as in Example 2, except that sucrose palmitate was not added in the preparation of the lactic acid bacteria beverage. The obtained lactic acid bacteria beverage had a pH of 3.79.

[0084] [Table 4] Comparative Example 2 Example 2 Skim milk powder 3.60 wt% 3.60 wt% White sugar 3.04 wt% 3.04 wt% High fructose corn syrup 17.60 wt% 17.60 wt% Pectin 0.25 wt% 0.25 wt% Sucrose palmitate (no) 0.15 wt%

[0085] Each lactic acid bacteria beverage was stored at 10°C, 25°C, or 30°C for 20 days, and then the acidity was measured, and the results are shown in Tables 5-7.

[0086] [Table 5] Comparative Example 2 Example 2 Acidity after 0 days of storage 0.49％ 0.48％ Acidity after 20 days of storage at 10°C 0.67％ 0.51％ Acidity increase rate (after 20 days of storage / after 0 days of storage) 137％ 106％

[0087] [Table 6] Comparative Example 2 Example 2 Acidity after 0 days of storage 0.49％ 0.48％ Acidity after 20 days of storage at 25°C 0.99％ 0.79％ Acidity increase rate (after 20 days of storage / after 0 days of storage) 202％ 165％

[0088] [Table 7] Comparative Example 2 Example 2 Acidity after 0 days of storage 0.49％ 0.48％ Acidity after 20 days of storage at 30°C 1.11％ 0.86％ Acidity increase rate (after 20 days of storage / after 0 days of storage) 227％ 179％

[0089] The increase in acidity was inhibited in the lactic acid bacteria beverage of Example 2 compared to the lactic acid bacteria beverage of Comparative Example 2 under the storage conditions at 10°C, 25°C and 30°C for 20 days. That is, it was demonstrated that the food according to the present application, which has a small amount of non-fat milk solid component and protein, can inhibit the increase in acidity during storage.

[0090] [Example 3] In Example 2, the lactic acid bacteria beverage was prepared in the same manner except that the fructose-glucose syrup as the water activity reducing agent added when preparing the fermented milk base was replaced with glucose, and the white sugar (i.e., granulated sugar) and the fructose-glucose syrup as the water activity reducing agent added to the prepared fermented milk base were replaced with only white sugar (i.e., granulated sugar). (1) Preparation of lactic acid bacteria beverage The skim milk powder, the water activity reducing agent (glucose) and the powder lactic acid bacteria (FD-DVSL. casei-01) as the fermenting agent were dissolved in water, and the mixture was fermented at 37°C to obtain a fermented milk base. The emulsifier (sucrose palmitate), the water activity reducing agent (white sugar, i.e., granulated sugar) and the stabilizer (pectin) were added to the obtained fermented milk base in accordance with the final formulation shown in Table 8, and mixed. The mixture was filled in a plastic container, and cooled overnight to obtain a lactic acid bacteria beverage (Example 3). The content of the non-fat milk solid component of the lactic acid bacteria beverage was 3.43% by weight, the content of the protein was 1.2% by weight, and the pH was 3.81.

[0091] [Comparative Example 3] In Example 3, the lactic acid bacteria beverage was obtained in the same manner as in Example 3 except that the sucrose palmitate was not added in the preparation of the lactic acid bacteria beverage. The pH of the obtained lactic acid bacteria beverage was 3.81.

[0092] [Table 8] Comparative Example 3 Example 3 Skim milk powder 3.6 wt% 3.6 wt% White sugar 13.68 wt% 13.68 wt% Glucose 1.70 wt% 1.70 wt% Pectin 0.25 wt% 0.25 wt% Sucrose palmitate (no) 0.15 wt%

[0093] After each of the lactic acid bacteria beverages was stored at 10°C for 20 days, the acidity was measured, and the results are shown in Table 9.

[0094] [Table 9] Comparative Example 3 Example 3 Acidity after 0 days of storage 0.48％ 0.49％ Acidity after 21 days of storage at 10°C 0.66％ 0.58％ Acidity increase rate (after 21 days of storage / after 0 days of storage) 138％ 118％

[0095] The increase in acidity was inhibited in the lactic acid bacteria beverage of Example 3 compared to the lactic acid bacteria beverage of Comparative Example 3.

[0096] After each of the lactic acid bacteria beverages was stored at 25°C for 20 days, the acidity was measured and the survival rate was calculated, and the results are shown in Table 10.

[0097] [Table 10] Comparative Example 3 Example 3 Viable cell count after 0 days of storage (cfu / ml) 1.1E+09 7.6E+08 Viable cell count after 20 days of storage at 25°C (cfu / ml) 2.2E+07 2.6E+07 Survival rate (after 20 days of storage / after 0 days of storage) 2％ 3.4％ Acidity after 0 days of storage 0.48％ 0.49％ Acidity after 20 days of storage at 25°C 0.89％ 0.85％ Acidity increase rate (after 20 days of storage / after 0 days of storage) 185％ 173％ Bacterial survival rate / acidity increase rate 0.011 0.020

[0098] In the lactic acid bacteria beverage of Example 3, the increase in acidity was inhibited, and the survival rate was significantly improved, as compared with the lactic acid bacteria beverage of Comparative Example 3. That is, it was demonstrated that the food according to the present application, which has a small amount of non-fat milk solid component and protein, can inhibit the increase in acidity and the decrease in viable count during storage.

[0099] [Experimental Example 1: Study of the type and concentration of emulsifier] 1. Study of sucrose fatty acid ester The type of emulsifier (sucrose fatty acid ester) in Example 2 was changed, and the same test was performed.

[0100] Skim milk powder and a water activity reducing agent (fructose-glucose syrup) were dissolved in water, and powdered lactic acid bacteria (FD-DVSL. casei-01) was added as a fermenting agent, and the mixture was fermented at 37°C to obtain a fermented milk base. According to the final formulation shown in Table 11, various emulsifiers, water activity reducing agents (sucrose (white sugar) and fructose-glucose syrup), and stabilizers (pectin) were added to the obtained fermented milk base and mixed. The mixture was filled in plastic containers, and cooled overnight to obtain a lactic acid bacteria beverage. The content of non-fat milk solid component in the obtained lactic acid bacteria beverage was 3.43% by weight, and the content of protein was 1.2% by weight. The pH of the obtained lactic acid bacteria beverage is shown in Table 11.

[0101] The following substances were used as emulsifiers. "RYOTOSUGAR ESTER S-1170" (Mitsubishi Chemical Corporation, sucrose stearate, HLB = 11) "RYOTOSUGAR ESTER S-1670" (Mitsubishi Chemical Corporation, sucrose stearate, HLB = 16) "RYOTOSUGAR ESTER L-1695" (Mitsubishi Chemical Corporation, sucrose laurate, HLB = 16) "RYOTOSUGAR ESTER M-1695" (Mitsubishi Chemical Corporation, sucrose myristate, HLB = 16) "RYOTOSUGAR ESTER O-1570" (Mitsubishi Chemical Corporation, sucrose oleate, HLB = 15) "RYOTOSUGAR ESTER P-1670" (Mitsubishi Chemical Corporation, sucrose palmitate, HLB = 16)

[0102] [Table 11]

[0103] The survival rate (the ratio of the number of viable bacteria after 35 days of storage to the number of viable bacteria at 0 days of storage) was calculated after the lactic acid bacteria beverage was stored at 25°C for 35 days, and the results are shown in Table 11. The results for Comparative Example 2 (in which no emulsifier was added) are also shown in the table. Compared with Comparative Example 2, the survival rate was improved in Examples 4 to 9, and the improvement in the survival rate was remarkable in Example 7 and Example 9, in which sucrose myristate (HLB = 16) and sucrose palmitate (HLB = 16) were used.

[0104] Further, the compounding amount of sucrose palmitate (HLB = 16) in Example 9 was changed, and the same test was performed. The formulation and the pH of the resulting lactic acid bacteria beverage are shown in Table 12.

[0105] [Table 12] Overall composition Comparative Example 2 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Skim milk powder 3.60％ 3.60％ 3.60％ 3.60％ 3.60％ 3.60％ 3.60％ 3.60％ White sugar 3.04％ 3.04％ 3.04％ 3.04％ 3.04％ 3.04％ 3.04％ 3.04％ High fructose corn syrup 17.60％ 17.60％ 17.60％ 17.60％ 17.60％ 17.60％ 17.60％ 17.60％ Sucrose palmitate (P-1670) 0％ 0.08％ 0.10％ 0.12％ 0.14％ 0.16％ 0.18％ 0.20％ Pectin 0.25％ 0.25％ 0.25％ 0.25％ 0.25％ 0.25％ 0.25％ 0.25％ Water 75.51％ 75.43％ 75.41％ 75.39％ 75.37％ 75.35％ 75.33％ 75.31％ Total 100％ 100％ 100％ 100％ 100％ 100％ 100％ 100％ pH at manufacture 3.61 3.6 3.6 3.6 3.6 3.6 3.6 3.6 Survival rate 1.51％ 9.33％ 10.83％ 13.64％ 25.00％ 36.84％ 34.21％ 39.47％ Acidity increase 134％ 123％ 122％ 123％ 121％ 119％ 119％ 119％

[0106] The acidity increase rate (the ratio of the acidity after 29 days of storage to the acidity at 0 days of storage) and the survival rate (the ratio of the number of viable bacteria after 29 days of storage to the number of viable bacteria at 0 days of storage) were calculated after the lactic acid bacteria beverage was stored at 25°C for 29 days, and the results are shown in Table 12. The results for Comparative Example 2 (in which no emulsifier was added) are also shown in the table. The effect of inhibiting the increase in acidity and the effect of improving the survival rate were observed in any of the compounding amounts of Examples 10 to 16.

[0107] 2. Study of emulsifiers other than sucrose fatty acid esters The same test was performed by replacing the emulsifier in Example 2 with the following emulsifiers that are not sucrose fatty acid esters. The formulation and the pH of the resulting lactic acid bacteria beverage are shown in Table 13. "DATEM 517K" (Danisco, diacetyl tartaric acid ester of monoglyceride, shown as "DATEM" in the table) "GRINSTED SSL FP55" (Danisco, sodium stearoyl lactylate, shown as "SSL" in the table) "RYOTOPOLY GRY ESTER M-7D" (Mitsubishi Chemical, polyglycerol myristate, shown as "M-7D" in the table) "POEM B-30" (Riken Vitamin, glyceryl succinyl stearate, shown as "succinic acid MG" in the table) "TRP-97RF" (Riken Vitamin, glyceryl tripalmitate, shown as "TP" in the table)

[0108] [Table 13]

[0109] The survival rate (ratio of the number of viable bacteria after 28 days of storage to the number of viable bacteria at 0 days of storage) was calculated after the lactic acid bacteria beverage was stored at 25°C for 28 days, and the results are shown in Table 13. The results of Example 9 are also shown in the table. Examples 17 to 21 all showed good survival rates (see Table 12, data for 29 days of storage of Comparative Example 2), with Example 18, which used sodium stearoyl lactylate (SSL), significantly improving the survival rate as much as Example 9, which used sucrose palmitate (HLB = 16).

[0110] Further, the same test was performed using "DP-95RF" (Riken Vitamin Co., Ltd., glycerol dipalmitate, shown as "DP" in the table) as the emulsifier, and in addition, the compounding amounts of TP and SSL used in the above were changed. The formulations and the pH of the resulting lactic acid bacteria beverages are shown in Table 14.

[0111] [Table 14]

[0112] The survival rate (ratio of the number of viable bacteria after 28 days of storage to the number of viable bacteria at 0 days of storage) was calculated after the lactic acid bacteria beverage was stored at 25°C for 28 days, and the results are shown in Table 14. Examples 22 to 26 showed good survival rates (see Table 12, data for 29 days of storage of Comparative Example 2). The survival rate was significantly improved in any of the compounding amounts of sodium stearoyl lactylate (SSL) in Examples 24 to 26.

[0113] [Experimental Example 2: Study of the type and concentration of the water activity reducing agent] The same test was performed by changing the type of the water activity reducing agent in Example 2.

[0114] Skim milk powder, a water activity reducing agent (fructose syrup), and a lactic acid bacteria powder (FD-DVSL. casei-01) as a starter culture were dissolved in water, and the mixture was fermented at 37°C to obtain a fermented milk base. An emulsifier (sucrose palmitate), various water activity reducing agents, and a stabilizer (pectin) were added to the obtained fermented milk base in the final formulation shown in Table 15, and the mixture was mixed. A sample in which no water activity reducing agent was added was also prepared. The mixture was filled into plastic containers, and the containers were cooled overnight to obtain a lactic acid bacteria beverage. The content of non-fat milk solids in the obtained lactic acid bacteria beverage was 3.43% by weight, and the content of protein was 1.2% by weight. The pH of the obtained lactic acid bacteria beverage is shown in Table 15, and the water activity value is shown in Table 16.

[0115] The water activity reducing agent used the following substances. Xylitol (Xylitol, Mitsuwa Food Science Co., Ltd.) Fructose (Crystalline Fructose M, A&M JAPAN Co., Ltd.) Xylooligosaccharide (Xylooligosaccharide 95PN, Suntory Food Industries, Ltd.) Maltitol (MALBIT, Suntory Food Industries, Ltd.)

[0116] [Table 15]

[0117] [Table 16] Temperature (°C) Aw Example 27 24.83 0.9959 Example 28 24.94 0.9789 Example 29 24.77 0.9789 Example 30 24.8 0.9765 Example 31 24.82 0.9787 Example 2 24.85 0.9803

[0118] The survival rate (ratio of the number of viable bacteria after 34 days of storage to the number of viable bacteria at 0 days of storage) was calculated after the lactic acid bacteria beverage was stored at 25°C for 34 days, and the results are shown in Table 15. The results of Example 2 (sucrose, i.e., table sugar, high-fructose corn syrup) are also described in the table. An increase in the survival rate was confirmed in Examples 27 to 31. The increase in the survival rate was more remarkable in Examples 28 to 31 and Example 2, in which the Aw was 0.990 or less.

[0119] Further, the same test was performed using the following water activity reducing agents. The formulations and the pH of the resulting lactic acid bacteria beverages are shown in Table 17, and the water activity values are shown in Table 18. Sucrose (GRANEW Sugar, Nisshin Sugar Co., Ltd.) Isomaltulose (PUREPARA, DM Morita Sugar Co., Ltd.) Isomalto-oligosaccharide (Oligo Time, Showa Sangyo Co., Ltd.) Linear oligosaccharide (Oligotose, Mitsubishi Chemical Corporation)

[0120] [Table 17]

[0121] [Table 18] Temperature (°C) Aw Example 32 24.82 0.9818 Example 33 24.81 0.9804 Example 34 24.79 0.9825 Example 35 24.92 0.9781

[0122] The survival rate (ratio of the number of viable bacteria after 28 days of storage to the number of viable bacteria at 0 days of storage) was calculated after the lactic acid bacteria beverage was stored at 25°C for 28 days, and the results are shown in Table 17. An increase in the survival rate was confirmed in Examples 32 to 35, and the effect of sucrose (Example 32) was particularly remarkable.

[0123] Further, a lactic acid bacteria beverage was prepared in the same manner as in Example 3, except that the white sugar, i.e., table sugar, of the water activity reducing agent added to the fermented milk base after preparation in Example 3 was replaced with glucose.

[0124] Skim milk powder, a water activity reducing agent (glucose) were dissolved in water, and a powder lactic acid bacteria (FD-DVSL. casei-01) was added as a fermenting agent, and allowed to ferment at 37°C to obtain a fermented milk base. To the obtained fermented milk base, an emulsifier (sucrose palmitate), a water activity reducing agent (glucose), and a stabilizer (pectin) were added in accordance with the final formulation shown in Table 19, and mixed. The mixture was filled in a plastic container, and allowed to cool overnight to obtain a lactic acid bacteria beverage. The content of non-fat milk solid in the lactic acid bacteria beverage was 3.43% by weight, and the content of protein was 1.2% by weight. The pH of the obtained lactic acid bacteria beverage is shown in Table 20, and in addition, the water activity value is shown in Table 19.

[0125] [Table 19] Overall composition Example 36 Example 37 Example 38 Example 39 Skim milk powder 3.60％ 3.60％ 3.60％ 3.60％ Glucose 1.69％ 8.08％ 13.08％ 18.08％ Sucrose palmitate (P-1670) 0.15％ 0.15％ 0.15％ 0.15％ Pectin 0.25％ 0.25％ 0.25％ 0.25％ Water 94.31％ 87.92％ 82.92％ 77.92％ Total 100％ 100％ 100％ 100％ pH at manufacture 3.67 3.65 3.63 3.61 Survival rate 1.34％ 2.04％ 4.86％ 18.82％

[0126] [Table 20] Temperature (°C) Aw Example 36 24.78 0.9943 Example 37 24.85 0.9858 Example 38 24.85 0.9806 Example 39 24.83 0.9733

[0127] After the lactic acid bacteria beverage was stored at 25°C for 35 days, the survival rate (the ratio of the number of viable bacteria after 35 days of storage to the number of viable bacteria at 0 days of storage) was calculated, and the results are shown in Table 19. The increase in survival was confirmed in Examples 36 to 39. In particular, in Examples 37 to 39 in which 2% or more of the water activity reducing agent was added, the increase in survival was remarkable.

[0128] [Experiment Example 3: Verification of the effect of the combination of an emulsifier and a water activity reducing agent] A lactic acid bacteria beverage was obtained (Example 40) in the same manner and composition as in Example 2. In addition, in the preparation of the fermented milk base of Example 2, a water activity reducing agent (high fructose syrup) was still used, and no water activity reducing agent (sucrose, i.e., granulated sugar, high fructose syrup) was added to the fermented milk base to obtain a lactic acid bacteria beverage (Example 41). Skim milk powder, a water activity reducing agent (high fructose syrup) were dissolved in water, and a powder lactic acid bacteria (FD-DVSL. casei-01) was added as a fermenting agent, and allowed to ferment at 37°C to obtain a fermented milk base. To the obtained fermented milk base, an emulsifier, a water activity reducing agent (sucrose, i.e., granulated sugar, high fructose syrup), and a stabilizer (pectin) were added in accordance with the final formulation shown in Table 21, and mixed. The mixture was filled in a plastic container, and allowed to cool overnight to obtain a lactic acid bacteria beverage. The content of non-fat milk solid in the lactic acid bacteria beverage was 3.43% by weight, and the content of protein was 1.2% by weight. The pH of the obtained lactic acid bacteria beverage is shown in Table 21.

[0129] [Comparative Example 3] A lactic acid bacterium beverage was obtained in the same manner as in Example 40, except that sucrose palmitate was not added in the preparation of the lactic acid bacterium beverage in Example 40. The pH of the obtained lactic acid bacterium beverage is shown in Table 21.

[0130] [Comparative Example 4] A lactic acid bacterium beverage was obtained in the same manner as in Example 41, except that sucrose palmitate was not added in the preparation of the lactic acid bacterium beverage in Example 41. The pH of the obtained lactic acid bacterium beverage is shown in Table 21, and the water activity value is shown in Table 22.

[0131] The acidity increase rate (the ratio of the acidity after 29 days of storage to the acidity after 0 days of storage) was calculated after the lactic acid bacterium beverage was stored at 25°C for 29 days, and the result is shown in Table 21.

[0132] [Table 21] Overall composition Comparative Example 3 Example 40 Comparative Example 4 Example 41 Skim milk powder 3.60％ 3.60％ 3.60％ 3.60％ Sucrose 3.04％ 3.04％ 0％ 0％ High fructose syrup 17.60％ 17.60％ 2.40％ 2.40％ Sucrose fatty acid ester (P-1670) 0％ 0.15％ 0％ 0.15％ Pectin 0.25％ 0.25％ 0.25％ 0.25％ Water 75.51％ 75.36％ 93.75％ 93.60％ Total 100％ 100％ 100％ 100％ pH at manufacture 3.63 3.64 3.68 3.68 Acidity rise 170.1％ 146.6％ 167.0％ 166.4％

[0133] [Table 22] Temperature (°C) Aw Comparative Example 3 24.93 0.9787 Example 40 24.90 0.9793 Comparative Example 4 24.92 0.9957 Example 41 24.96 0.9919

[0134] In Comparative Example 4 in which no water activity reducing agent and emulsifier were used in the preparation of the lactic acid bacterium beverage, the acidity increase rate was 167.0%. In Example 41 in which an emulsifier was used in the preparation of the lactic acid bacterium beverage, the acidity increase rate was 166.4%. In Comparative Example 3 in which a water activity reducing agent was used in the preparation of the lactic acid bacterium beverage, the acidity increase rate was substantially the same as in Comparative Example 4, and was 170.1%. In contrast, in Example 40 in which both a water activity reducing agent and an emulsifier were used in the preparation of the lactic acid bacterium beverage, the acidity increase rate was greatly suppressed to 146.6%. From this result, it was found that the acidity increase can be suppressed by containing an emulsifier and a water activity reducing agent.

[0135] [Experimental Example 4: Study of HLB of Emulsifier] The HLB of the emulsifier (sucrose fatty acid ester) used in Example 2 was changed, and the same test was performed.

[0136] Skim milk powder, a water activity reducing agent (fructose syrup), and water were dissolved, and powdered lactic acid bacteria (FD-DVSL. casei-01) were added as a fermenting agent, and the mixture was fermented at 37°C to obtain a fermented milk base. To the obtained fermented milk base, various emulsifiers, water activity reducing agents (sugar, i.e., granulated sugar, fructose syrup) and stabilizers (pectin) were added in accordance with the final formulation shown in Table 23 and mixed. The mixed solution was filled in plastic containers, cooled overnight, and a lactic acid bacteria beverage was obtained. The content of non-fat milk solid component of the obtained lactic acid bacteria beverage was 3.43% by weight, and the content of protein was 1.2% by weight. The pH of the obtained lactic acid bacteria beverage is shown in Table 23.

[0137] The emulsifiers used were the following substances "RYOTOSUGAR ESTER S-570" (Mitsubishi Chemical Corporation, sucrose stearate, HLB = 5) "RYOTOSUGAR ESTER S-770" (Mitsubishi Chemical Corporation, sucrose stearate, HLB = 7) "RYOTOSUGAR ESTER S-970" (Mitsubishi Chemical Corporation, sucrose stearate, HLB = 9) "RYOTOSUGAR ESTER P-1570" (Mitsubishi Chemical Corporation, sucrose palmitate, HLB = 15) "RYOTOSUGAR ESTER P-1670" (Mitsubishi Chemical Corporation, sucrose palmitate, HLB = 16)

[0138] [Comparative Example 5] A lactic acid bacteria beverage was obtained in the same manner as in Example 2 except that no emulsifier (sucrose fatty acid ester) was added in the preparation of the lactic acid bacteria beverage. The pH of the obtained lactic acid bacteria beverage is shown in Table 23.

[0139] After the lactic acid bacteria beverage was stored at 30°C for 29 days, the survival rate (the ratio of the number of viable bacteria after 35 days of storage to the number of viable bacteria at 0 days of storage) was calculated, and the results are shown in Table 23.

[0140] [Table 23] Overall composition Comparative Example 5 Example 42 Example 43 Example 44 Example 45 Example 46 Skim milk powder 3.60％ 3.60％ 3.60％ 3.60％ 3.60％ 3.60％ Sucrose 3.04％ 3.04％ 3.04％ 3.04％ 3.04％ 3.04％ High fructose syrup 17.60％ 17.60％ 17.60％ 17.60％ 17.60％ 17.60％ Sucrose fatty acid ester (S-570) 0％ 0.15％ 0％ 0％ 0％ 0％ Sucrose fatty acid ester (S-770) 0％ 0％ 0.15％ 0％ 0％ 0％ Sucrose fatty acid ester (S-970) 0％ 0％ 0％ 0.15％ 0％ 0％ Sucrose fatty acid ester (P-1570) 0％ 0％ 0％ 0％ 0.15％ 0％ Sucrose fatty acid ester (P-1670) 0％ 0％ 0％ 0％ 0％ 0.15％ Pectin 0.25％ 0.25％ 0.25％ 0.25％ 0.25％ 0.25％ Water 75.51％ 75.36％ 75.36％ 75.36％ 75.36％ 75.36％ Total 100％ 100％ 100％ 100％ 100％ 100％ pH at manufacture 3.63 3.65 3.65 3.65 3.64 3.64 Survival rate 0.40％ 0.75％ 0.71％ 1.20％ 1.51％ 3.08％

[0141] Compared with Comparative Example 5, the survival rate was improved in Examples 42 to 46, and the survival rate was significantly improved in Examples 44 to 46 in which sucrose fatty acid ester having an HLB of 9 or more was used.

[0142] [Reference Test Example 1: Verification of the Effect of the Combined Use of an Emulsifier and a Water Activity Reducing Agent in a Low Non-Fat Milk Solid Component Food] Milk (protein 3.4 g / 100 ml, lipid 3.9 g / 100 ml), skim milk powder (protein 34 g / 100 g, lipid 0.13 g / 100 g), raw cream (protein 1.7 g / 100 ml, lipid 47 g / 100 ml), and water were mixed in accordance with the formulation shown in Table 24, 2% by weight of Meiji Bulgaria Yogurt Plain (Meiji Co., Ltd.) was added to the whole fermented milk, and it was allowed to ferment at 42°C for 3.5 hours to obtain three kinds of fermented milk bases. The fermented milk base of Composition 1 had a large amount of non-fat milk solid component, the fermented milk base of Composition 2 had a small amount of non-fat milk solid component. The fermented milk base of Composition 3 had a large amount of lipid (oil and fat).

[0143] [Table 24] Overall composition Composition 1 Composition 2 Composition 3 Milk 36.2％ 37.0％ 0.0％ Cream 0.0％ 0.0％ 32.6％ Skim milk powder 6.0％ 0.0％ 2.1％ Water 55.7％ 60.9％ 63.2％ Fermenting agent (yogurt) 2.2％ 2.2％ 2.2％ Total 100.0％ 100.0％ 100.0％

[0144] In accordance with the final formulation shown in Table 25, sucrose palmitate and water were added to 92 parts by weight of the fermented milk base (Composition 1 to 3) and mixed. The mixture was filled in a plastic container and allowed to cool overnight to obtain the fermented milk of Reference Example 47 and the lactic acid bacteria beverages of Reference Examples 48 and 49. The pH and viable cell count of the obtained fermented milk and lactic acid bacteria beverages are shown in Table 25.

[0145] The fermented milk and lactic acid bacteria beverages were obtained in the same manner as in Reference Examples 47 to 49 except that no emulsifier (sucrose fatty acid ester) was added in the preparation of the fermented milk in Reference Examples 47 to 49. The obtained fermented milk and lactic acid bacteria beverages were set as Reference Comparative Examples 6 to 8, respectively, and the pH and viable cell count thereof are shown in Table 25.

[0146] After the fermented milk and lactic acid bacteria beverages were stored at 25°C for 14 days, the lactic acid bacteria count was measured and the acidity increase rate (the ratio of the acidity after storage for 14 days to the acidity after storage for 0 day) was calculated. The results are shown in Table 25.

[0147] [Table 25] Overall composition Reference Comparative Example 6 Reference Example 47 Reference Comparative Example 7 Reference Example 48 Reference Comparative Example 8 Reference Example 49 Composition 1 92.00％ 92.00％ 0％ 0％ 0％ 0％ Composition 2 0％ 0％ 92.00％ 92.00％ 0％ 0％ Composition 3 0％ 0％ 0％ 0％ 92.00％ 92.00％ Sucrose palmitate (post- addition) 0％ 0.15％ 0％ 0.15％ 0％ 0.15％ Water (post-addition) 8.00％ 7.85％ 8.00％ 7.85％ 8.00％ 7.85％ Total 100.0％ 100.0％ 100.0％ 100.0％ 100.0％ 100.0％ Protein 3.07％ 3.07％ 1.22％ 1.22％ 1.22％ 1.22％ Lipid 1.39％ 1.39％ 1.36％ 1.36％ 14.19％ 14.19％ Carbohydrate 6.33％ 6.33％ 3.47％ 3.47％ 1.96％ 1.96％ pH at manufacture 4.45 4.49 4.19 4.31 4.16 4.21 Viable count preservation 0 days (cfu / ml) 8.1E+08 7.7E+08 2.8E+08 2.8E+07 3.2E+08 3.4E+08 Acidity rise 213.50％ 169.30％ - - 206.10％ 193.00％

[0148] In Reference Example 47 (fermented milk), the viable cell count immediately after preparation (storage for 0 day) was the same as that of Reference Comparative Example 6 in which no emulsifier was added, and the increase in acidity after storage for 14 days was also inhibited. It was found that when the non-fat milk solid component (protein, etc.) was large, a high viable cell count could be obtained immediately after preparation even without using a water activity reducing agent, and the increase in acidity during storage was also inhibited. On the other hand, in Reference Example 48 (lactic acid bacteria beverage) compared with Reference Comparative Example 7 in which no emulsifier was added, the number of viable bacteria immediately after preparation (0 days of storage) was reduced to 1 / 10, and thus it was not possible to evaluate the effectiveness of the lactic acid bacteria beverage sample in inhibiting post-fermentation during storage (rise in acidity). This result indicates that in the case of a small amount of non-fat milk solid component (protein, etc.), the number of viable bacteria immediately after preparation is reduced even when only an emulsifier is added, and more careful control of the fermentation process is required.

[0149] Further, in Reference Example 49 (lactic acid bacteria beverage) compared with Reference Comparative Example 8 in which no emulsifier was added, the number of viable bacteria immediately after preparation (0 days of storage) was the same, and the rise in acidity after 14 days of storage was also inhibited to a slight extent. It was found that even in the case of a small amount of non-fat milk solid component (protein, etc.), if the lipid (oil) content is high, then by using only an emulsifier without using a water activity reducing agent, a certain degree of effect on the number of viable bacteria immediately after preparation and the rise in acidity during storage can be obtained. That is, this result indicates that in the case of a small amount of non-fat milk solid component (protein, etc.) and a small amount of lipid (oil), in order to maintain the number of viable bacteria, more careful control of the fermentation process is required.

Claims

1. A food product, characterized by, A food product containing a milk component and viable lactic acid bacteria, having a non-fat milk solid content of less than 8.0% by weight, a protein content of less than 2.7% by weight, a pH of 4.6 or less, and containing an emulsifier and a water activity reducing agent.

2. The food product of claim 1, wherein, The oil content is less than 10% by weight.

3. The food product of claim 2, wherein, The HLB of the emulsifier is 9 or more, and the HLB is a hydrophilic-lipophilic balance.

4. The food product of claim 3, wherein, The water activity reducing agent content is 5% by weight or more.

5. The food product of claim 1, wherein, The emulsifier is one or more fatty acid esters selected from the group consisting of sucrose fatty acid esters, monoglycerides, organic acid monoglycerides, polyglycerol fatty acid esters, and stearoyl lactylates.

6. The food product of claim 5, wherein, The emulsifier is a sucrose monofatty acid ester and / or a stearoyl lactylate, and contains 0.001 to 1.0% by weight.

7. The food product of claim 1, wherein, The water activity reducing agent is one or more selected from the group consisting of glucose, fructose, sucrose, erythritol, sorbitol, mannitol, isomalto-oligosaccharides, xylo-oligosaccharides, straight-chain oligosaccharides, maltitol, isomaltulose, and xylitol.

8. The food product of claim 7, wherein, The water activity at 25°C is Aw 0.990 or less.

9. The food product of claim 8, wherein, The water activity at 25°C is Aw 0.981 or less.

10. The food product of claim 1, wherein, containing the live lactic acid bacteria 1 x 10 2 cfu / ml or more.

11. The food product of claim 10, wherein, The Y1 / X1 value calculated from the acidity increase rate X1 and the bacterial survival rate Y1 after storage at 25°C for 21 days after manufacture is 0.012 or more, and the units of X1 and Y1 are both %.

12. The food product of claim 11, wherein, The Y2 / X2 value calculated from the acidity increase rate X2 and the bacterial survival rate Y2 after storage at 30°C for 14 days after manufacture is 0.012 or more, and the units of X2 and Y2 are both %.

13. The food product of claim 1, wherein, The lactic acid bacteria is Lactobacillus (Lactobacillus casei).

14. A method of manufacturing a food product, characterized by, It is a method for producing a food product containing a milk component and viable lactic acid bacteria, having a non-fat milk solid content of less than 8.0% by weight, a protein content of less than 2.7% by weight, and a pH of 4.6 or less; the method includes any one of the following processes: (1) a process of adding a water activity reducing agent to the milk component before fermentation by the lactic acid bacteria, and a process of adding an emulsifier to the milk component after fermentation by the lactic acid bacteria; (2) a process of adding a water activity reducing agent to the milk component before fermentation by the lactic acid bacteria, and a process of adding an emulsifier and a water activity reducing agent to the milk component after fermentation by the lactic acid bacteria; (3) a process of adding an emulsifier and a water activity reducing agent to the milk component after fermentation by the lactic acid bacteria.

15. A method for inhibiting the increase in acidity and / or the decrease in viable count of a food product after manufacture, characterized in that, The food product contains a milk component and viable lactic acid bacteria, has a non-fat milk solid content of less than 8.0% by weight, a protein content of less than 2.7% by weight, and a pH of 4.6 or less; the method includes any one of the following processes: (1) a process of adding a water activity reducing agent to the milk component before fermentation by the lactic acid bacteria, and a process of adding an emulsifier to the milk component after fermentation by the lactic acid bacteria; (2) a process of adding a water activity reducing agent to the milk component before fermentation by the lactic acid bacteria, and a process of adding an emulsifier and a water activity reducing agent to the milk component after fermentation by the lactic acid bacteria; (3) a step of adding an emulsifier and a water activity reducing agent to the milk component after the fermentation thereof by the lactic acid bacteria.

16. Use of an emulsifier and a water activity reducing agent for inhibiting the increase in acidity and / or the decrease in viable counts after manufacture of a food product, characterised in that, The food product contains a milk component and viable lactic acid bacteria, has a non-fat milk solid content of less than 8.0% by weight, a protein content of less than 2.7% by weight, and a pH of 4.6 or lower.

17. A food product, characterized by, The food product contains a milk component and viable lactic acid bacteria, has a non-fat milk solid content of less than 8.0% by weight, a protein content of less than 2.7% by weight, and a fat content of less than 10% by weight, The food product contains an emulsifier having an HLB of 9 or higher, The food product has a water activity of Aw 0.990 or lower at 25°C.

18. The food product of claim 17, wherein, The food product has a water activity of Aw 0.981 or lower at 25°C.

19. The food product of claim 17, wherein, The emulsifier is one or more fatty acid esters selected from the group consisting of sucrose fatty acid ester, monoglyceride, organic acid monoglyceride, polyglycerin fatty acid ester, and stearoyl lactylate.

20. The food product of claim 17, wherein, Further, one or more of glucose, fructose, sucrose, erythritol, sorbitol, mannitol, isomalto-oligosaccharide, xylo-oligosaccharide, straight-chain oligosaccharide, maltitol, isomaltulose, and xylitol is further contained as a water activity reducing agent.

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