Fermented composition with improved flavor and method for producing same

Abstract

To provide a fermentation composition which is reduced in acid taste by post acid formation during storage, and a method for producing the same; and to provide a fermentation composition which is simply reduced in amino acid odor generated when a milk raw material is fermented using viable bacteria of bacteria belonging to Lactococcus and bacteria belonging to Leuconostoc that is lactic acid bacteria together with viable bacterial of lactic acid bacteria and bifidobacteria in production of a fermentation composition without blending flavor and a masking material, and a method for producing the same.SOLUTION: A method for producing a fermentation composition that is reduced in acid taste by post acid formation during storage includes the steps of: fermenting a milk raw material by viable bacteria of one or more kinds of bacteria selected from the group consisting of lactic acid bacteria and bacteria belonging to Bifidobacterium; and adding killed bacteria of the lactic acid bacteria. A method for producing a fermentation composition that is reduced in amino acid odor includes the steps of: fermenting a milk raw material by viable bacteria of one or more bacteria selected from the group consisting of lactic acid bacterial other than bacteria belonging to Lactococcus and bacteria belonging to Leuconostoc, and bacteria belonging to Bifidobacterium; and adding killed bacteria of one or more lactic acid bacteria selected from the group consisting of bacteria belonging to Lactococcus and bacteria belonging to Leuconostoc without using flavor.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The first invention relates to a fermented composition produced by fermenting a milk raw material using live lactic acid bacteria or Bifidobacterium bacteria (hereinafter also referred to as "bifidobacteria"; hereinafter, lactic acid bacteria and bifidobacteria will also be collectively referred to as "lactic acid bacteria, etc."), in which sourness due to post-acid production that occurs during storage, etc. is suppressed, and a method for producing the same. The second invention relates to a fermented composition that reduces the amino acid odor that occurs when milk raw materials are fermented using live lactic acid bacteria such as Lactococcus and Leuconostoc bacteria, together with live lactic acid bacteria such as lactic acid bacteria and bifidobacteria, and a method for producing the same. [Background technology]

[0002] Fermented compositions such as fermented milk obtained by fermenting dairy ingredients with lactic acid bacteria and the like are not only nutritional foods rich in protein and calcium, but also have been attracting increasing attention in recent years because they are expected to have various physiological effects due to the inclusion of lactic acid bacteria and their metabolites. Such physiological effects are known to include improved immunity, amelioration of allergic diseases, improvement of autonomic nervous function, and prevention and amelioration of lifestyle-related diseases. Furthermore, lactic acid bacteria with specific functional effects have been widely studied, and in recent years, consumers have increasingly sought to actively ingest such excellent lactic acid bacteria in food and beverages.

[0003] Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus are known to be suitable for lactic acid fermentation in the production of fermented compositions, and these lactic acid bacteria are currently the predominant lactic acid bacteria used in the production of fermented compositions such as fermented milk. Among lactic acid bacteria, Lactobacillus delbrueckii and Streptococcus thermophilus have relatively high optimum growth temperatures of approximately 37-45°C and are known as thermophiles. Among lactic acid bacteria, there are also lactic acid bacteria with optimum growth temperatures of approximately 25-30°C, such as Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, and Leuconostoc mesentroides subsp. cremoris, and these lactic acid bacteria are known as mesophiles.

[0004] Mesophilic lactic acid bacteria, such as Lactococcus and Leuconostoc bacteria, tend to produce a strong cheese flavor and are often used in fermented butter and cheese. For example, Patent Document 1 discloses a method of using Lactococcus lactic acid bacteria, such as Lactococcus lactis subsp. lactis JCM5805, as lactic acid bacteria for cheese. Thermophilic bacteria generally grow faster at their optimum growth temperature than mesophilic bacteria and have a higher acid-producing capacity, which contributes to the efficient production of fermented milk, such as yogurt. As mentioned above, thermophilic bacteria, such as Lactobacillus bulgaricus and Lactobacillus thermophilus, are primarily used in the production of commercially available fermented milk. However, in order to obtain a flavor and taste different from that of fermented milk produced using only thermophilic bacteria, thermophilic lactic acid bacteria and mesophilic lactic acid bacteria, such as Lactococcus and Leuconostoc bacteria, are sometimes used in combination in the production of commercially available fermented milk. However, when fermenting raw milk materials using live lactic acid bacteria such as Lactococcus or Leuconostoc bacteria in combination with live lactic acid bacteria such as Lactococcus or Leuconostoc bacteria in the production of fermented compositions such as fermented milk, depending on the combination of lactic acid bacteria and the fermentation temperature, a relatively strong amino acid odor originating from the Lactococcus or Leuconostoc bacteria may be generated, resulting in the product being unable to be shipped (see Patent Document 2). Patent Document 2 discloses a method for masking this amino acid odor by adjusting the viscosity of yogurt to 750 to 1250 mPa·s and adding a yogurt flavor. While adding flavorings or masking materials can reduce the amino acid odor, given the recent growing consumer trend of avoiding food additives as much as possible, the use of flavorings or masking materials poses challenges.

[0005] Another problem with fermented compositions such as fermented milk is that, in the case of fermented milk such as yogurt, the sourness is not very strong immediately after the production of the product (for example, immediately after cooling after fermenting the milk raw material), but during low-temperature storage after production (for example, refrigerated storage during distribution), live lactic acid bacteria further produce lactic acid, gradually increasing the sourness, and this sourness becomes excessive at the end of the storage period (the so-called ``post-acidification problem during low-temperature storage'') (see Patent Documents 3 and 4). In the production of fermented milk products such as yogurt, when raw milk ingredients are fermented with lactic acid bacteria, the lactic acid bacteria assimilate lactose and other sugars in the raw milk ingredients to produce lactic acid, which lowers the pH of the fermented liquid. Typically, the fermentation liquid is cooled to stop the fermentation once it reaches a pH of approximately 4.8 to 4.5. However, because lactose and other sugars typically remain in the fermented composition, fermentation by lactic acid bacteria does not completely stop upon cooling. For example, even if the fermented composition is kept at 4°C, fermentation continues gradually over time, gradually lowering the pH by the time the fermented composition is consumed by the consumer. This problem of post-acid production is a common issue regardless of the type of lactic acid bacteria used for fermentation, whether it is thermophilic bacteria such as Lactobacillus bulgaricus or Lactobacillus thermophilus, or mesophilic bacteria such as Lactococcus spp. While keeping the refrigerated storage temperature as low as possible after product production is effective, there is a problem in that the desired refrigeration temperature cannot be maintained depending on the storage location and equipment. Patent Document 3 discloses a method for suppressing or reducing the subsequent acid production that occurs in the yogurt production process by performing aging in an ice-temperature zone after the end of fermentation, and Patent Document 4 discloses a method for suppressing the subsequent acidification of fermented milk products by using milk with reduced lactose as a raw material, etc. However, these methods also have problems such as simplicity. Attempts have also been made to mask the excessive sourness, etc., of fermented milk products using a masking agent. For example, Patent Document 5 discloses a method of masking the sourness, etc., that occurs during storage of fermented milk products with a compound selected from the group consisting of 1,3-octanediol, 5-octene-1,3-diol, and dimethylmethoxyfuranone. Although there are cases where the sourness of fermented dairy products is masked by masking agents, the number of consumers who prefer natural product compositions has increased in recent years, and there are also increasing cases where the use of masking agents does not fit the product concept.

[0006] Incidentally, it is known that the above-mentioned physiological activity of lactic acid bacteria and the like is generally not limited to live bacteria such as lactic acid bacteria, but is also exhibited by dead bacteria (see, for example, Patent Document 6). Furthermore, as a technique using killed cells of lactic acid bacteria and the like, Patent Document 7 discloses a method for promoting the growth of the target lactic acid bacteria and improving the survival rate of the lactic acid bacteria in a product by adding killed cells of lactic acid bacteria or a culture containing killed cells of lactic acid bacteria during the cultivation of the target lactic acid bacteria, and Patent Document 8 discloses a method for improving the body (fullness) of coffee by blending killed cells of lactic acid bacteria and the like into a packaged coffee beverage.

[0007] However, it has not been previously known that the amino acid odor that occurs when milk raw materials are fermented using live lactic acid bacteria such as Lactococcus or Leuconostoc bacteria in addition to live bacteria such as lactic acid bacteria can be reduced by using a predetermined amount of killed cells of one or more types of lactic acid bacteria selected from the group consisting of Lactococcus and Leuconostoc bacteria, or that post-acid production during storage of fermented milk, etc. can be suppressed by using a predetermined amount of killed cells of lactic acid bacteria. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-296972 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-233097 [Patent Document 3] Japanese Patent Application Laid-Open No. 2003-259802 [Patent Document 4] Special Publication No. 2017-522012 [Patent Document 5] Japanese Patent Application Laid-Open No. 2010-200636 [Patent Document 6] Japanese Patent Application Publication No. 2019-216712 [Patent Document 7] Japanese Patent Application Laid-Open No. 2008-5811 [Patent Document 8] Japanese Patent Application Publication No. 2019-122316 Summary of the Invention [Problem to be solved by the invention]

[0009] A first object of the present invention is to provide a fermented composition that suppresses sourness due to post-acid production during storage, and a method for producing the same.

[0010] A second object of the present invention is to provide a fermented composition that simply reduces the amino acid odor that occurs when a milk raw material is fermented using live lactic acid bacteria such as Lactococcus or Leuconostoc in addition to live lactic acid bacteria such as lactic acid bacteria or bifidobacteria, without adding any flavorings or masking materials, and a method for producing the same. [Means for solving the problem]

[0011] As a result of intensive research conducted by the present inventors to solve the above-mentioned first problem of the present invention, they found that the above-mentioned problem can be solved by fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, and adding killed cells of the lactic acid bacteria, in a method for producing a fermented composition, and thus completed the first invention.

[0012] As a result of intensive research conducted by the present inventors to solve the above-mentioned second problem of the present invention, they found that the above-mentioned problem can be solved by a method for producing a fermented composition in which a milk raw material is fermented with live bacteria of one or more species selected from the group consisting of lactic acid bacteria other than Lactococcus and Leuconostoc bacteria and Bifidobacterium bacteria, no flavoring is used, and killed cells of one or more species of lactic acid bacteria selected from the group consisting of Lactococcus and Leuconostoc bacteria are added, thereby completing the second present invention.

[0013] That is, the first aspect of the present invention is (1) A fermented composition produced by fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, the fermented composition, wherein killed cells of lactic acid bacteria are added; (2) The fermented composition according to (1) above, wherein the one or more live bacteria selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria are one or more live bacteria selected from the group consisting of Lactobacillus bacteria, Streptococcus bacteria, Lactococcus bacteria, Leuconostoc bacteria, Pediococcus bacteria, Enterococcus bacteria, and Bifidobacterium bacteria; (3) The fermentation composition according to (1) or (2), wherein the dry weight of the killed cells of the lactic acid bacteria added is 0.001% by weight or more based on the total amount of the fermentation composition; (4) A method for producing a fermented composition, A method for producing a fermented composition in which sourness due to post-acid production during storage is suppressed, the method comprising a step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, and adding killed cells of lactic acid bacteria; and (5) In the production of a fermented composition, The method comprises a step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, and is characterized in that killed cells of the lactic acid bacteria are added. A method for suppressing sourness due to post-acid production during storage in a fermented composition; Regarding.

[0014] That is, the second aspect of the present invention is (6) A fermented composition produced by fermenting a milk raw material with one or more live bacteria selected from the group consisting of lactic acid bacteria other than Lactococcus bacteria and Leuconostoc bacteria and Bifidobacterium bacteria, the fermented composition, which does not contain any flavoring agent and to which killed cells of one or more species of lactic acid bacteria selected from the group consisting of bacteria of the genus Lactococcus and bacteria of the genus Leuconostoc have been added; (7) The fermented composition according to (6) above, wherein the one or more live bacteria selected from the group consisting of lactic acid bacteria other than Lactococcus and Leuconostoc bacteria and Bifidobacterium bacteria are one or more live bacteria selected from the group consisting of Lactobacillus, Streptococcus, Pediococcus, Enterococcus, and Bifidobacterium bacteria; (8) The fermentation composition according to (6) or (7) above, wherein the dry weight of the killed cells of the lactic acid bacteria added is 1% by weight or less based on the total amount of the fermentation composition; (9) A method for producing a fermented composition, a method for producing a fermented composition with reduced amino acid odor, comprising a step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria other than Lactococcus and Leuconostoc bacteria and Bifidobacterium bacteria, wherein no flavoring is used and killed cells of one or more species of lactic acid bacteria selected from the group consisting of Lactococcus and Leuconostoc bacteria are added; or (10) In the production of a fermented composition, The method comprises a step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria other than Lactococcus bacteria and Leuconostoc bacteria and Bifidobacterium bacteria, wherein no flavoring agent is used and killed cells of one or more species of lactic acid bacteria selected from the group consisting of Lactococcus bacteria and Leuconostoc bacteria are added. A method for reducing amino acid odor caused by cells of one or more lactic acid bacteria selected from the group consisting of bacteria of the genus Lactococcus and bacteria of the genus Leuconostoc in a fermented composition; Regarding. [Effects of the Invention]

[0015] According to the first aspect of the present invention, it is possible to provide a fermented composition in which the sour taste due to post-acid production during storage is suppressed, and a method for producing the same.

[0016] According to the second invention, it is possible to provide a fermented composition in which the amino acid odor generated when a milk raw material is fermented using live lactic acid bacteria such as Lactococcus or Leuconostoc together with live lactic acid bacteria such as lactic acid bacteria or bifidobacteria is easily reduced without adding any flavorings or masking materials, and a method for producing the same. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 shows the relationship between the Lactococcus lactis subsp. lactis JCM5805 strain and strains equivalent to this strain (strains derived from this strain and strains from which this strain is derived). DETAILED DESCRIPTION OF THE INVENTION

[0018] The first aspect of the present invention is [1] A fermented composition produced by fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, the fermentation composition characterized in that killed cells of lactic acid bacteria are added thereto (hereinafter also referred to as the "fermentation composition of the first invention"); [2] A method for producing a fermented composition, A method for producing a fermented composition in which sourness due to post-acid production during storage is suppressed, the method comprising the step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, and adding killed cells of lactic acid bacteria (hereinafter also referred to as the "production method of the first invention"); [3] In the production of a fermented composition, The method comprises a step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, and is characterized in that killed cells of the lactic acid bacteria are added. A method for suppressing sourness due to post-acid production during storage in a fermented composition (hereinafter also referred to as the "first method for suppressing sourness of the present invention"); The present invention includes embodiments such as:

[0019] The second aspect of the present invention is [1] A fermented composition produced by fermenting a milk raw material with one or more live bacteria selected from the group consisting of lactic acid bacteria other than Lactococcus bacteria and Leuconostoc bacteria, and Bifidobacterium bacteria, The fermentation composition is characterized in that it does not contain any flavoring agent and contains killed cells of one or more species of lactic acid bacteria selected from the group consisting of bacteria of the genus Lactococcus and bacteria of the genus Leuconostoc (hereinafter also referred to as the "second fermentation composition of the present invention"); [2] A method for producing a fermented composition, A method for producing a fermented composition with reduced amino acid odor, comprising a step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria other than Lactococcus and Leuconostoc bacteria and Bifidobacterium bacteria, wherein no flavoring is used and killed cells of one or more species of lactic acid bacteria selected from the group consisting of Lactococcus and Leuconostoc bacteria are added (hereinafter also referred to as the "production method of the second invention"); [3] In the production of a fermented composition, The method comprises a step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria other than Lactococcus bacteria and Leuconostoc bacteria and Bifidobacterium bacteria, wherein no flavoring agent is used and killed cells of one or more species of lactic acid bacteria selected from the group consisting of Lactococcus bacteria and Leuconostoc bacteria are added. A method for reducing amino acid odor caused by cells of one or more lactic acid bacteria selected from the group consisting of bacteria of the genus Lactococcus and bacteria of the genus Leuconostoc in a fermentation composition (hereinafter also referred to as the "second method for reducing amino acid odor of the present invention"); The present invention includes embodiments such as:

[0020] (Milk raw material) "Milk ingredients" in this specification typically include "milk" as defined in the Ministerial Ordinance on Milk, etc., i.e., raw milk, cow's milk, special cow's milk, raw goat's milk, pasteurized goat's milk, raw sheep's milk, composition-adjusted milk, low-fat milk, non-fat milk, and processed milk, or milk containing an equivalent or higher non-fat milk solids content (i.e., 8% or more), but are not particularly limited as long as it is a composition containing a milk component. "Milk components" in this specification include one or more components selected from the group consisting of milk fat derived from "milk" as defined in the Ministerial Ordinance on Milk, etc., and non-fat milk solids derived from said "milk" (for example, proteins derived from said "milk" and / or sugars derived from said "milk").

[0021] The "dairy ingredients" in this specification can be prepared using milk, dairy products, etc. When milk and / or dairy products are used as the "dairy ingredients," more specifically, the ingredients can be prepared using one or more selected from the group consisting of cow's milk, buffalo milk, sheep's milk, goat's milk, horse's milk, concentrated milk, skim milk, concentrated skim milk, skim milk powder, partially skimmed milk powder, whole milk powder, cream, butter, buttermilk, condensed milk, lactose, milk protein concentrate, whey protein concentrate, and water.

[0022] As used herein, "dairy ingredients" include those having a milk component solids concentration of, for example, 1 to 16% by weight, preferably 2 to 14% by weight, and more preferably 4 to 12% by weight, and / or those having a non-fat milk solids concentration of, for example, 1 to 18% by weight, preferably 2 to 16% by weight, more preferably 2 to 14% by weight, and even more preferably 4 to 12% by weight, 6 to 10% by weight, or 7 to 9% by weight, and / or those having a milk fat concentration of, for example, 0 to 8% by weight, preferably 0.1 to 7% by weight, and more preferably 0.5 to 4% by weight or 1 to 3% by weight.

[0023] The "dairy ingredients" in this specification may contain stabilizers, sweeteners, dietary fiber, vitamins, minerals, fermentation-promoting components, etc., within the scope of not impairing the effects of the present invention. The stabilizers are not particularly limited, and examples thereof include agar, gelatin, etc. The sweeteners are also not particularly limited, and examples thereof include sugars, sugar alcohols, and high-intensity sweeteners, and these sweeteners can be used alone or in combination of two or more. Since the fermented composition of the second invention does not contain a flavoring, the dairy raw material used in the second invention does not contain a flavoring, but since the fermented composition of the first invention may contain a flavoring, the dairy raw material used in the first invention may contain a flavoring. However, from the viewpoint of obtaining a fermented composition with a more natural flavor, it is preferable that the dairy raw material used in the first invention and the fermented composition of the first invention do not contain a flavoring.

[0024] (Fermented composition) As used herein, the term "fermented composition" refers to a composition comprising, in any of its manufacturing steps, a step of fermenting a milk raw material with one or more live bacteria selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria. The term "fermented composition" as used herein includes, but is not limited to, "fermented milk," "dairy lactic acid bacteria beverage," "lactic acid bacteria beverage," "milk beverage," "foods made primarily from milk, etc.", and "natural cheese," as defined in the Ministerial Ordinance on Milk and Dairy Products (hereinafter referred to as the "Milk, etc. Ministerial Ordinance"), as long as the composition comprises, in any of its manufacturing steps, a step of fermenting a milk raw material with one or more live bacteria selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria. For example, "fermented milk" as defined in the Ministerial Ordinance on Milk, etc. refers to milk such as raw milk, cow's milk, special milk, raw goat's milk, pasteurized goat's milk, raw sheep's milk, adjusted milk, low-fat milk, non-fat milk, and processed milk; dairy products such as cream, butter, cheese, and condensed milk; and foods that use milk, etc. as a main ingredient; which has been fermented with lactic acid bacteria or yeast and made into a solid (hard type), pasty (soft type), or liquid (drink type), or these are frozen. However, the "fermented composition" in this specification is not limited to fermented milk as defined in the Ministerial Ordinance on Milk, etc. Furthermore, in this specification, "foods made primarily from milk, etc." are not limited to "foods made primarily from milk, etc." as defined in the Ministerial Ordinance on Milk, etc., as long as they involve a process of fermenting a milk raw material with one or more live bacteria selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, but also include foods made primarily from "milk" and / or "dairy products such as cream, butter, cheese, condensed milk, milk powder, and fermented milk." Examples of such "foods made primarily from milk, etc." include sour cream and ricotta.

[0025] The definitions and ingredient standards for fermented milk and other products in the Milk and Dairy Products Ordinance are as follows: The Ministerial Ordinance on Milk, etc. defines fermented milk as "a product made by fermenting milk or milk containing an equivalent or greater amount of non-fat milk solids with lactic acid bacteria or yeast into a paste or liquid state, or a product that has been frozen." Its ingredient specifications are "non-fat milk solids of 8% or more, lactic acid bacteria or yeast count (per ml) of 10 million or more, and coliform negative." In this specification, the unit of lactic acid bacteria or bifidobacteria count is expressed in CFU (colony forming unit). In addition, the Ministerial Ordinance on Milk and Dairy Products defines dairy lactic acid bacteria beverages (live bacteria) as "a beverage (excluding fermented milk) that is processed or whose main ingredient is milk or other products that have been fermented with lactic acid bacteria or yeast." Its ingredient specifications are "non-fat milk solids of 3% or more, lactic acid bacteria or yeast count (per mL) of 10 million or more, and coliform negative." In addition, the Ministerial Ordinance on Milk and Dairy Products defines lactic acid bacteria beverages, which are foods made primarily from milk, as "beverages (excluding fermented milk) that are processed or whose main ingredient is milk or other products fermented with lactic acid bacteria or yeast." The ingredient specifications are "less than 3% non-fat milk solids, 1 million or more lactic acid bacteria or yeast counts (per 1 mL), and negative for coliform bacteria."

[0026] The "fermented composition" in the first invention can be produced by fermenting the "dairy raw material" in this specification with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria. The "fermented composition" in the second invention can be produced by fermenting the "dairy raw material" in this specification with live bacteria of one or more species selected from the group consisting of lactic acid bacteria other than Lactococcus bacteria and Leuconostoc bacteria, and Bifidobacterium bacteria. These production methods can be those commonly used for producing fermented milk, etc. For example, fermented milk may be produced by filling a container with milk ingredients and then fermenting with lactic acid bacteria (a so-called post-fermentation method), or by fermenting a milk ingredient with lactic acid bacteria, crushing the resulting curd, and filling a container (a so-called pre-fermentation method). Those skilled in the art can appropriately determine the fermentation temperature and fermentation time depending on the optimal growth temperature and growth rate of the lactic acid bacteria used, the type of fermented composition, and product design. Fermentation times can be, for example, 1 to 96 hours, preferably 2 to 72 hours, and more preferably 3 to 48 hours. The pH of the fermented composition to which fermentation is performed varies depending on the type of fermented composition and product design, and cannot be generally determined. However, when the fermented composition is fermented milk, fermentation is preferably performed until the pH of the fermented milk reaches, for example, 5 or less, preferably 4.8 to 4.5. The pH of the fermented composition can be measured by a conventional method.

[0027] The "fermented composition" according to the first aspect of the present invention includes, in any of its production steps, a step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, and Killed lactic acid bacteria are added, and Suitable examples include those having a non-fat milk solids concentration of, for example, 1 to 18% by weight, preferably 2 to 16% by weight, more preferably 2 to 14% by weight, and even more preferably 4 to 12% by weight, 6 to 10% by weight, or 7 to 9% by weight, and / or those having a milk fat concentration of, for example, 0 to 8% by weight, preferably 0.1 to 7% by weight, and more preferably 0.5 to 4% by weight, or 1 to 3% by weight.

[0028] The "fermented composition" according to the second aspect of the present invention comprises, in any of its production steps, a step of fermenting a milk raw material with one or more live bacteria selected from the group consisting of lactic acid bacteria other than Lactococcus bacteria and Leuconostoc bacteria, and Bifidobacterium bacteria, and Killed cells of one or more types of lactic acid bacteria selected from the group consisting of Lactococcus bacteria and Leuconostoc bacteria are added, and Suitable examples include those having a non-fat milk solids concentration of, for example, 1 to 18% by weight, preferably 2 to 16% by weight, more preferably 2 to 14% by weight, and even more preferably 4 to 12% by weight, 6 to 10% by weight, or 7 to 9% by weight, and / or those having a milk fat concentration of, for example, 0 to 8% by weight, preferably 0.1 to 7% by weight, and more preferably 0.5 to 4% by weight, or 1 to 3% by weight.

[0029] The fermented composition according to the first invention and the fermented composition according to the second invention are preferably packed in a container. "Packed in a container" means that the product is filled into a container and sealed. Preferred containers include those commonly used in the production of fermented milk and the like, such as plastic, glass, and paper containers.

[0030] (Dead lactic acid bacteria) In the first invention, the species of lactic acid bacteria is not particularly limited, and killed cells of lactic acid bacteria are used, while in the second invention, killed cells of one or more species of lactic acid bacteria selected from the group consisting of Lactococcus bacteria and Leuconostoc bacteria are used.

[0031] "Lactic acid bacteria" is a general term for all those taxonomically recognized as lactic acid bacteria, and is not limited by genus, species, strain, etc. Such "lactic acid bacteria" include bacteria that lactic acid ferment sugar to produce large amounts of lactic acid (preferably 50% or more of the lactic acid consumed), such as bacteria of the genus Lactobacillus, Streptococcus, Lactococcus, Leuconostoc, Pediococcus, and Enterococcus.

[0032] In this specification, the "killed lactic acid bacteria cells" are not particularly limited as long as they are killed lactic acid bacteria cells, and may be dried or non-dried. However, from the viewpoint of storage stability of killed lactic acid bacteria cells, a dried product is preferred, and a suitable example is a dry powder.

[0033] The method for preparing killed lactic acid bacteria cells is not particularly limited, and examples thereof include a method in which a medium in which the lactic acid bacteria have been cultured is sterilized and then the cells are collected by filtration, centrifugation, etc., or a method in which the cells are collected from a medium in which the lactic acid bacteria have been cultured by filtration, centrifugation, etc., and then sterilized, and further drying or crushing treatments can be performed as necessary. The means of sterilization is not particularly limited, and not only heating but also conventional means for killing bacteria, such as ultraviolet light or gamma ray irradiation, can be used.

[0034] In the first and second aspects of the present invention, the killed lactic acid bacteria cells may be added at any step in the production of the fermentation composition, for example, the killed lactic acid bacteria cells may be added to the milk raw material before the fermentation step of the milk raw material, the killed lactic acid bacteria cells may be added to the milk raw material during the fermentation step of the milk raw material, or the killed lactic acid bacteria cells may be added to the fermentation composition after the fermentation step of the milk raw material is completed. Note that it is preferable to mix the killed lactic acid bacteria cells after adding them. In the first and second aspects of the present invention, when killed cells of lactic acid bacteria are added, it is preferable that the milk raw material, the milk raw material during fermentation, or the fermented composition after fermentation to which the killed cells of lactic acid bacteria are added be sterilized in advance.

[0035] (Amount of killed lactic acid bacteria used in the first aspect of the present invention) In the first aspect of the present invention, the amount of killed lactic acid bacteria used is, for example, 0.01% by weight or more of the dry weight of killed lactic acid bacteria relative to the total amount of the fermentation composition, and preferably 0.1% by weight or more from the viewpoint of further suppressing the sourness due to post-acid production during storage. There is no particular upper limit to the amount of killed lactic acid bacteria used in the first invention, but examples include 3% by weight or less, preferably 1% by weight or less, in terms of dry weight of killed lactic acid bacteria based on the total amount of fermentation composition. The genus or species of killed lactic acid bacteria in the first present invention is not limited, but when killed cells of one or more species of lactic acid bacteria selected from the group consisting of Lactococcus and Leuconostoc bacteria are used, the concentration is preferably 1% by weight or less, and more preferably 0.1% by weight or less, from the viewpoint of suppressing the sour taste due to post-acid production during storage and achieving the effect of reducing the amino acid odor.

[0036] (Amount of killed cells of one or more species of lactic acid bacteria selected from the group consisting of Lactococcus bacteria and Leuconostoc bacteria in the second invention) In the second present invention, the amount of killed cells of one or more lactic acid bacteria selected from the group consisting of Lactococcus bacteria and Leuconostoc bacteria is, for example, 1% by weight or less of the dry weight of the killed cells of the lactic acid bacteria relative to the total amount of the fermentation composition, and preferably 0.1% by weight or less from the viewpoint of obtaining a greater effect in reducing the amino acid odor. There is no particular lower limit to the amount of killed lactic acid bacteria used in the second invention, but from the viewpoint of not only obtaining the effect of reducing the amino acid odor but also suppressing the sour taste due to post-acid production during storage, the amount of killed lactic acid bacteria used relative to the total amount of the fermentation composition is preferably 0.01% by weight or more, and more preferably 0.1% by weight or more, in terms of dry weight, relative to the total amount of the fermentation composition. From the viewpoint of the balance between the effect of reducing the amino acid odor and the effect of suppressing the sour taste due to post-acid production during storage, the amount of killed cells of the above-mentioned lactic acid bacteria used in the second invention is preferably 0.01 to 1 wt %, 0.01 to 0.1 wt %, or 0.1 to 1 wt %.

[0037] (Types of killed lactic acid bacteria in the first aspect of the present invention) The genus or species of the killed lactic acid bacteria in the first present invention is not particularly limited, but examples include one or more bacteria selected from the group consisting of Lactobacillus, Streptococcus, Lactococcus, Leuconostoc, Pediococcus, and Enterococcus, preferably one or more bacteria selected from the group consisting of Lactococcus and Leuconostoc, and more preferably one or more bacteria selected from the group consisting of Lactococcus.

[0038] More specific preferred embodiments of the killed bacteria in the first aspect of the present invention include Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. delbrueckii, Lactobacillus delbrueckii subsp. lactis, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus gasseri, Lactobacillus helveticus, and Lactobacillus johnsonii. johnsonii), Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus casei subsp. rhamnosus, Lactobacillus pentosus, Lactobacillus fermentum, Streptococcus salivarius subsp. thermophilus (hereinafter also referred to simply as "Streptococcus thermophilus"), Lactococcus lactis subsp. lactis (hereinafter also referred to simply as "Lactococcus lactis"),Lactococcus lactis subsp. lactis biovar diacetylactis, Lactococcus lactis subsp. cremoris, Lactococcus raffinolactis, Lactococcus piscium, Lactococcus plantarum, Lactococcus garvieae, Lactococcus lactis subsp. hordniae, Leuconostoc mesenteroides subsp. cremoris, Leuconostoc lactis lactis, Pediococcus damnosus, Pediococcus pentosaceus, Pediococcus acidilactici, Enterococcus faecalis, and Enterococcus faecium faecium), and preferably includes killed cells of one or more bacteria selected from the group consisting of Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis, Lactobacillus delbrueckii subsp. delbrueckii, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus gasseri, Lactobacillus helveticus, Lactobacillus johnsonii, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus casei subsp. rhamnosus, Lactobacillus pentosus, Lactobacillus fermentum,Examples include killed cells of one or more bacteria selected from the group consisting of Streptococcus salivarius subsp. thermophilus, Lactococcus lactis subsp. lactis, Lactococcus lactis biovariant diacetylactis, Lactococcus lactis subsp. cremoris, Lactococcus raffinolactis, Lactococcus pythium, Lactococcus plantarum, Lactococcus garvieae, Lactococcus lactis subsp. holdoniae, Leuconostoc mesentroides subsp. cremoris, and Leuconostoc lactis, and more preferably Lactococcus lactis, Lactococcus lactis biovariant diacetylactis, Lactococcus lactis subsp. Examples include killed cells of one or more bacteria selected from the group consisting of Tococcus lactis subsp. cremoris, Lactococcus raffinolactis, Lactococcus pythium, Lactococcus plantarum, Lactococcus garvieae, and Lactococcus lactis subsp. holdoniae, more preferably killed cells of Lactococcus lactis, even more preferably killed cells of one or more bacteria selected from the group consisting of Lactococcus lactis JCM5805, Lactococcus lactis JCM20101, Lactococcus lactis NBRC12007, and Lactococcus lactis NRIC1150, and particularly preferably killed cells of Lactococcus lactis JCM5805.

[0039] (Types of killed lactic acid bacteria according to the second aspect of the present invention) The killed bacteria in the second present invention are killed bacteria of one or more species of lactic acid bacteria selected from the group consisting of Lactococcus bacteria and Leuconostoc bacteria, and preferably killed bacteria of one or more species of bacteria selected from the group consisting of Lactococcus bacteria.

[0040] More specific and preferred embodiments of the killed cells in the second present invention include killed cells of one or more bacteria selected from the group consisting of Lactococcus lactis subsp. lactis, Lactococcus lactis biovariant diacetylactis, Lactococcus lactis subsp. cremoris, Lactococcus raffinolactis, Lactococcus pythium, Lactococcus plantarum, Lactococcus garvieae, Lactococcus lactis subsp. holdoniae, Leuconostoc mesentroides subsp. cremoris, and Leuconostoc lactis, and preferably Lactococcus lactis, Lactococcus lactis biovariant diacetylactis, Lactococcus lactis subsp. cremoris, and Lactococcus lactis. Examples of the bacterial cell extract include killed cells of one or more bacteria selected from the group consisting of Lactococcus lactis subsp. cremoris, Lactococcus raffinolactis, Lactococcus pythium, Lactococcus plantarum, Lactococcus garvieae, and Lactococcus lactis subsp. holdoniae, more preferably killed cells of Lactococcus lactis, even more preferably killed cells of one or more bacteria selected from the group consisting of Lactococcus lactis JCM5805, Lactococcus lactis JCM20101, Lactococcus lactis NBRC12007, and Lactococcus lactis NRIC1150, and particularly preferably killed cells of Lactococcus lactis JCM5805.

[0041] (Living bacteria such as lactic acid bacteria according to the first aspect of the present invention) The fermented composition of the first invention is a fermented composition produced by fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria (lactic acid bacteria, etc.). In the first aspect of the present invention, the one or more live bacteria selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria are not particularly limited as long as they are one or more live bacteria selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, but are preferably one or more live bacteria selected from the group consisting of Lactobacillus bacteria, Streptococcus bacteria, Lactococcus bacteria, Leuconostoc bacteria, Pediococcus bacteria, Enterococcus bacteria, and Bifidobacterium bacteria (preferably Examples of the viable bacteria include one or more (preferably two or more, more preferably three or more) species of live bacteria selected from the group consisting of bacteria of the genus Lactobacillus, bacteria of the genus Streptococcus, bacteria of the genus Lactococcus, bacteria of the genus Leuconostoc, and bacteria of the genus Bifidobacterium, and even more preferably one or two or more (preferably one or two) species of live bacteria of the genus Lactobacillus and one or two or more (preferably one or two) species of live bacteria of the genus Streptococcus; Live bacteria of one or more (preferably one or two) species of Lactobacillus bacteria, one or more (preferably one or two) species of Streptococcus bacteria, and one or more (preferably one or two) species of Bifidobacterium bacteria; or One or more (preferably one or two) live bacteria of the genus Streptococcus and one or more (preferably one or two) live bacteria of the genus Lactococcus; or one or more (preferably one or two) live bacteria of the genus Streptococcus, one or more (preferably one or two) live bacteria of the genus Lactococcus, and one or more (preferably one or two) live bacteria of the genus Bifidobacterium; Examples include:

[0042] More specific preferred embodiments of the probiotic bacteria in the first aspect of the present invention include Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis, Lactobacillus delbrueckii subsp. delbrueckii, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus gasseri, Lactobacillus helveticus, Lactobacillus johnsonii, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus casei subsp. rhamnosus, Lactobacillus pentosus, and Lactobacillus furan. fermentum, Streptococcus salivarius subsp. thermophilus, Lactococcus lactis subsp. lactis, Lactococcus lactis biovariant diacetylactis, Lactococcus lactis subsp. cremoris, Lactococcus raffinolactis, Lactococcus pythium, Lactococcus plantarum, Lactococcus garbieae, Lactococcus lactis subsp. holdoniae, Leuconostoc mesentroides subsp. cremoris, Leuconostoc lactis, Pediococcus damnosus, Pediococcus Pentosaceus, Pediococcus acidilactici, Enterococcus faecalis, Enterococcus faecium, Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium longum subsp. longum, Bifidobacterium longum subsp. infantis, Bifidobacterium animalis subsp. animalis,Bifidobacterium animalis subsp. lactis (hereinafter simply referred to as "Bifidobacterium lactis"), Bifidobacterium adolescentis, Bifidobacterium angulatum, Bifidobacterium catenulatum, and Bifidobacterium pseudocatenulatum. Examples of live bacteria include one or more (preferably two or more, more preferably three or more) species selected from the group consisting of Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis, Lactobacillus delbrueckii subsp. delbrueckii, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus gasseri, Lactobacillus helveticus, Lactobacillus johnsonii, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus casei subsp. rhamnosus, Lactobacillus pentosus, Lactobacillus fermentum, and Streptococcus aureus. Lactococcus salivarius subsp. thermophilus, Lactococcus lactis subsp. lactis, Lactococcus lactis biovariant diacetylactis, Lactococcus lactis subsp. cremoris, Lactococcus raffinolactis, Lactococcus pythium, Lactococcus plantarum, Lactococcus garvieae, Lactococcus lactis subsp. holdoniae, Leuconostoc mesentroides subsp. cremoris, Leuconostoc lactis, Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium longum subsp. longum, Bifidobacterium longum subsp. infantis,Examples include live bacteria of one or more (preferably two or more, more preferably three or more) species selected from the group consisting of Bifidobacterium animalis subsp. animalis, Bifidobacterium animalis subsp. lactis, Bifidobacterium adolescentis, Bifidobacterium anguulatum, Bifidobacterium catenulatum, and Bifidobacterium pseudocatenulatum, and more preferably Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. live bacteria of one to three species selected from the group consisting of Lactobacillus delbrueckii subsp. lactis, Lactobacillus delbrueckii subsp. delbrueckii, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus gasseri, Lactobacillus helveticus, Lactobacillus johnsonii, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus casei subsp. rhamnosus, Lactobacillus pentosus, Lactobacillus fermentum, and Streptococcus salivarius subsp. thermophilus, or Examples include a combination of one to three live bacterial species selected from this group with one or two live bacterial species selected from the group consisting of Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium longum subsp. longum, Bifidobacterium longum subsp. infantis, Bifidobacterium animalis subsp. animalis, and Bifidobacterium animalis subsp. lactis. In the first aspect of the present invention, the type of lactic acid bacteria used for the killed cells and the type of lactic acid bacteria used for the live cells may be the same or different, or some species may overlap.

[0043] Another preferred embodiment of the one or more live bacteria selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria in the first invention includes live bacteria similar to the live bacteria such as lactic acid bacteria in the second invention, i.e., one or more live bacteria selected from the group consisting of lactic acid bacteria other than Lactococcus bacteria and Leuconostoc bacteria and Bifidobacterium bacteria, and preferably one or more (preferably two or more, more preferably three or more) live bacteria selected from the group consisting of Lactobacillus bacteria, Streptococcus bacteria, Pediococcus bacteria, Enterococcus bacteria, and Bifidobacterium bacteria, More preferably, the active ingredient is one or more (preferably two or more, more preferably three or more) live bacteria selected from the group consisting of Lactobacillus bacteria, Streptococcus bacteria, and Bifidobacterium bacteria, More preferred examples include live bacteria of one or more (preferably one or two) species of Lactobacillus bacteria, one or more (preferably one or two) species of Streptococcus bacteria, and one or more (preferably one or two) species of Bifidobacterium bacteria; or live bacteria of one or more (preferably one or two) species of Lactobacillus bacteria and one or more (preferably one or two) species of Streptococcus bacteria. Using such live bacteria as the live bacteria of the first invention is preferable in that it not only suppresses the sourness caused by post-acid production during storage, but also more reliably avoids the amino acid odor that can occur when milk raw materials are fermented using live bacteria of the genus Lactococcus or Leuconostoc.

[0044] (Living bacteria such as lactic acid bacteria according to the second aspect of the present invention) The fermented composition of the second invention is a fermented composition produced by fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria other than Lactococcus bacteria and Leuconostoc bacteria, and Bifidobacterium bacteria. In the second aspect of the present invention, the one or more live bacteria selected from the group consisting of lactic acid bacteria other than Lactococcus and Leuconostoc bacteria, and Bifidobacterium bacteria are not particularly limited as long as they are one or more live bacteria selected from the group consisting of lactic acid bacteria other than Lactococcus and Leuconostoc bacteria, and Bifidobacterium bacteria, but preferably include one or more (preferably two or more, more preferably three or more) live bacteria selected from the group consisting of Lactobacillus, Streptococcus, Pediococcus, Enterococcus, and Bifidobacterium bacteria, More preferably, the active ingredient is one or more (preferably two or more, more preferably three or more) live bacteria selected from the group consisting of Lactobacillus bacteria, Streptococcus bacteria, and Bifidobacterium bacteria, More preferred examples include live bacteria of one or more (preferably one or two) species of Lactobacillus bacteria, one or more (preferably one or two) species of Streptococcus bacteria, and one or more (preferably one or two) species of Bifidobacterium bacteria; or live bacteria of one or more (preferably one or two) species of Lactobacillus bacteria and one or more (preferably one or two) species of Streptococcus bacteria.

[0045] More specific preferred embodiments of the probiotic bacteria in the second aspect of the present invention include Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis, Lactobacillus delbrueckii subsp. delbrueckii, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus gasseri, Lactobacillus helveticus, Lactobacillus johnsonii, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus casei subsp. rhamnosus, Lactobacillus pentosus, Lactobacillus fermentum, Streptococcus salivarius subsp. thermophilus, Pediococcus damnosus, and Pediococcus one or more (preferably two or more, more preferably three or more) types of bacteria selected from the group consisting of Bacillus pentosaceus, Pediococcus acidilactici, Enterococcus faecalis, Enterococcus faecium, Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium longum subsp. longum, Bifidobacterium animalis subsp. animalis, Bifidobacterium animalis subsp. lactis, Bifidobacterium adolescentis, Bifidobacterium angularatum, Bifidobacterium catenulatum, and Bifidobacterium pseudocatenulatum. Probiotic bacteria include, preferably, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis, Lactobacillus delbrueckii subsp. delbrueckii, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus gasseri, Lactobacillus helveticus, Lactobacillus johnsonii, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus casei subsp. rhamnosus, Lactobacillus pentosus, Lactobacillus fermentum, Streptococcus salivarius subsp. thermophilus,One or more species (preferably two or more species, more preferably two or more species) selected from the group consisting of Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium longum subsp. longum, Bifidobacterium animalis subsp. animalis, Bifidobacterium animalis subsp. lactis, Bifidobacterium adolescentis, Bifidobacterium angularatum, Bifidobacterium catenulatum, and Bifidobacterium pseudocatenulatum. Examples of live bacteria include Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis, Lactobacillus delbrueckii subsp. delbrueckii, Lactobacillus gasseri, Lactobacillus helveticus, Lactobacillus johnsonii, Lactobacillus brevis, Lactobacillus casei subsp. rhamnosus, Lactobacillus pentosus, and Lactobacillus fermenta. Bifidobacterium salivarius subsp. thermophilus, Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium longum subsp. longum, Bifidobacterium longum subsp. infantis, Bifidobacterium animalis subsp. animalis, Bifidobacterium animalis subsp. lactis, Bifidobacterium adolescentis, Bifidobacterium angularatum, Bifidobacterium canaliculata Examples of the probiotic include one or more (preferably two or more, more preferably three or more) live bacteria selected from the group consisting of Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis, Lactobacillus delbrueckii subsp. delbrueckii, Lactobacillus gasseri, Lactobacillus helveticus, Lactobacillus johnsonii ... helveticus, Lactobacillus helveticus, Lactobacillus helveticus, Lactobacillus helveticus, Lactobacillus helveticus, Lactobacillus helveticus, Lactobacillus helveticus, Lactobacillus helveticus, Lactobacillus helveticus, Lactobacillus helveticus, Lactobacillus helveticus, Llive bacteria of one to three species selected from the group consisting of Lactobacillus brevis, Lactobacillus casei subsp. rhamnosus, Lactobacillus pentosus, Lactobacillus fermentum, and Streptococcus salivarius subsp. thermophilus; or Examples include a combination of one to three live bacterial species selected from this group with one or two live bacterial species selected from the group consisting of Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium longum subsp. longum, Bifidobacterium longum subsp. infantis, Bifidobacterium animalis subsp. animalis, and Bifidobacterium animalis subsp. lactis.

[0046] (Classification of lactic acid bacteria and bifidobacteria based on their optimal growth temperatures) Lactic acid bacteria and bifidobacteria used in producing fermented compositions are also classified according to their optimum growth temperatures. Generally, lactic acid bacteria with an optimum growth temperature of approximately 25 to 30°C are called mesophilic bacteria, and lactic acid bacteria with an optimum growth temperature of 37 to 45°C are called thermophilic bacteria. Examples of thermophilic bacteria include Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis, Lactobacillus delbrueckii subsp. delbrueckii, Lactobacillus gasseri, Lactobacillus helveticus, Lactobacillus johnsonii, Lactobacillus brevis, Lactobacillus casei subsp. rhamnosus, Lactobacillus pentosus, and Streptococcus salivarius subsp. thermophilus. Examples of mesophilic bacteria include Lactobacillus casei, Lactobacillus paracasei, Lactobacillus plantarum, Lactococcus lactis subsp. lactis, Lactococcus lactis biovariant diacetylactis, Lactococcus lactis subsp. cremoris, and Leuconostoc mesentroides subsp. cremoris. In the production of packaged yogurt, live thermophilic bacteria are often used, but live mesophilic bacteria may also be used, or a combination of live thermophilic and mesophilic bacteria may also be used. In the production of cheese, mesophilic bacteria are often used. Regarding the relationship between the type of lactic acid bacteria and the type of fermented composition, Lactococcus bacteria are often used in the production of cheese, Streptococcus thermophilus is often used in fermented milk such as yogurt, and Lactobacillus bacteria are used in the production of a wide range of fermented compositions, including fermented milk such as yogurt and cheese.

[0047] (How to obtain lactic acid bacteria, etc.) The live strains of lactic acid bacteria and the like used in the first aspect of the present invention, or the live strains of lactic acid bacteria and the killed strains of lactic acid bacteria used in the second aspect of the present invention, can be obtained from Microbial Materials Development Laboratory, RIKEN BioResource Center (1-1 Takanodai 3-chome, Tsukuba, Ibaraki Prefecture), American Type Culture Collection (USA), National Institute of Technology and Evaluation (5-8 Kazusa Kamatari 2-chome, Kisarazu, Chiba Prefecture), Tokyo University of Agriculture, Culture Collection (1-1-1 Sakuragaoka 1-chome, Setagaya-ku, Tokyo), etc. More specifically, for example, JCM strains can be obtained from the Microbial Materials Development Laboratory of the RIKEN BioResource Center (http: / / jcm.brc.riken.jp / ja / ), NBRC strains can be obtained from the National Institute of Technology and Evaluation, Biotechnology Center (http: / / www.nbrc.nite.go.jp), and NRIC strains can be obtained from the Tokyo University of Agriculture, Culture Collection (http: / / nodaiweb.university.jp / nric / ).

[0048] Regarding the bacterial strains of killed bacteria listed herein, in the first aspect of the present invention, strains equivalent to the strains are included as long as they have the effect of suppressing sourness due to post-acid production during storage. In the second aspect of the present invention, strains equivalent to the strains are included as long as they can produce a fermented composition with a reduced amino acid odor. Here, "equivalent strains" refers to strains derived from the above strains, strains from which the above strains are derived, or descendant strains of such strains. Equivalent strains may also be preserved in other strain collections. Figure 1 shows strains derived from Lactococcus lactis subsp. lactis JCM5805 and the strain from which Lactococcus lactis subsp. lactis JCM5805 is derived. Strains equivalent to Lactococcus lactis subsp. lactis JCM5805 shown in Figure 1 can also be used as the killed cells of the first invention as long as they have the effect of suppressing sourness due to post-acid production during storage, and can also be used as the killed cells of the second invention as long as they can produce a fermented composition with a reduced amino acid odor. In this specification, the term "Lactococcus lactis subsp. lactis JCM5805" includes these equivalent strains.

[0049] (Fermented composition that suppresses sourness due to post-acid production during storage) The fermentation composition of the first invention is a fermentation composition in which sourness due to post-acid production during storage is suppressed. As used herein, a fermentation composition in which sourness due to post-acid production during storage is suppressed refers to a fermentation composition in which sourness due to post-acid production during storage is suppressed compared to a fermentation composition produced using the same type of dairy raw material and the same production method, except that killed lactic acid bacteria cells are not added (hereinafter also referred to as a "control fermentation composition of the first invention"). Preferably, the control fermentation composition and the fermentation composition to be evaluated are fermented until the pH is 0.3 to 1 lower than the normal pH immediately after production of the fermentation composition (e.g., the target pH in the production method for the fermentation composition) (for example, to pH 4.3 or lower, preferably to pH 3.9 to 4.3 in the case of fermented milk) (preferably, after storage for 7 to 10 days at a predetermined storage temperature, such as 2 to 10°C, following production of the fermentation composition).

[0050] A trained panel can easily and clearly determine the degree of suppression of sourness due to post-acid production during storage (hereinafter also simply referred to as "sourness") in a certain fermentation composition, and how such sourness compares with the control fermentation composition of the first invention (e.g., whether or not it is suppressed). The evaluation criteria and the method for summarizing the panel's evaluations can be general methods. The number of panelists evaluating the sourness level of a fermentation composition may be one. However, from the viewpoint of obtaining a more objective evaluation, the lower limit of the number of panelists can be, for example, three or more, preferably four or more. Furthermore, from the viewpoint of more easily conducting the evaluation test, the upper limit of the number of panelists can be, for example, six or less. When the panel consists of two or more panelists, the evaluation of the sourness level of the fermentation composition may be the average of the evaluations of all panelists regarding the sourness level of the fermentation composition. When evaluation points are assigned to each evaluation criterion, the average of the evaluation points of all panelists may be used as the evaluation of the sourness level of the fermentation composition. As described above, when the average evaluation points are used, the average may be rounded to one decimal place. In addition, when there are two or more panels, in order to reduce variation in the evaluations of each panel, it is preferable to standardize the evaluation criteria so that the evaluation criteria of each panel are as consistent as possible before conducting the actual sensory evaluation test. For example, such standardization may involve standardizing the perception of the degree of sourness corresponding to the evaluation score at the highest sourness intensity among the panels before evaluating each sample beverage. Furthermore, by standardizing the evaluation criteria in advance, it is preferable to ensure that the standard deviation of the evaluation of the degree of sourness by each panel is within 0.5, for example, when the evaluation score is on a five-point scale of 0, 1, 2, 3, and 4.

[0051] The level of sourness in a certain fermentation composition can be evaluated by, for example, a method similar to, and preferably the same method as, the sensory evaluation method described in Tests 1 to 5 in the Examples described below. More specifically, the level of sourness in the fermentation composition is evaluated on a five-point scale of "0: mild sourness is noticeable," "1: moderate sourness is noticeable," "2: somewhat strong sourness is noticeable," "3: strong sourness is noticeable but within the acceptable range," and "4: too strong sourness is not within the acceptable range." Fermentation compositions whose sourness is reduced in the above five-point scale compared to the sourness of the control fermentation composition of the first present invention are preferably cited as fermentation compositions that can be evaluated as having reduced sourness.

[0052] (Fermented composition with reduced amino acid odor) The fermentation composition of the second invention is a fermentation composition with reduced amino acid odor. In this specification, a fermentation composition with "reduced amino acid odor" refers to a fermentation composition in which the amino acid odor (hereinafter also referred to simply as "amino acid odor") caused by the cells of one or more lactic acid bacteria selected from the group consisting of Lactococcus bacteria and Leuconostoc bacteria is reduced compared to a fermentation composition (hereinafter also referred to as "control fermentation composition of the second invention") produced by the same production method using the same type of milk raw material, except that in addition to live lactic acid bacteria other than Lactococcus bacteria and Leuconostoc bacteria, live cells of one or more lactic acid bacteria selected from the group consisting of Lactococcus bacteria and Leuconostoc bacteria are used to ferment a milk raw material, and killed cells of one or more lactic acid bacteria selected from the group consisting of Lactococcus bacteria and Leuconostoc bacteria are not added.

[0053] A trained panel can easily and clearly determine the level of amino acid odor in a certain fermentation composition and how the amino acid odor compares with the control fermentation composition of the second invention (e.g., whether it is reduced). The evaluation criteria and the method for summarizing the panel's evaluations can be general methods. The number of panelists evaluating the level of amino acid odor in a fermentation composition may be one. However, to obtain a more objective evaluation, the minimum number of panelists can be, for example, three or more, preferably four or more. Furthermore, to simplify the evaluation test, the maximum number of panelists can be, for example, six or less. When the panel consists of two or more panelists, the evaluation of the level of amino acid odor in the fermentation composition may be the average of the evaluations of all panelists. When evaluation points are assigned to each evaluation criterion, the average of the evaluation points of all panelists may be used as the evaluation of the level of amino acid odor in the fermentation composition. As described above, when using the average evaluation points, the average may be rounded to one decimal place. In addition, when there are two or more panels, in order to reduce the variation in the evaluations of each panel, it is preferable to standardize the evaluation criteria so that the evaluation criteria of each panel are as consistent as possible before the actual sensory evaluation test is conducted. For example, such standardization can be achieved by standardizing the recognition of the degree of amino acid odor corresponding to the evaluation score when the amino acid odor intensity is at its highest among the panels, and then evaluating each sample beverage. Furthermore, by performing such prior standardization of the evaluation criteria, it is preferable to ensure that the standard deviation of the evaluation of the degree of amino acid odor by each panel is within 0.5 when the evaluation score is on a five-point scale of 0, 1, 2, 3, and 4.

[0054] The level of amino acid odor in a certain fermentation composition can be evaluated by, for example, a method similar to, and preferably the same method as, the sensory evaluation method described in Tests 6 to 8 in the Examples below. More specifically, the level of amino acid odor in the fermentation composition is evaluated on a five-point scale: "0: not detectable," "1: slightly detectable," "2: detectable," "3: detectable, but within the acceptable range for product flavor," and "4: outside the acceptable range for product flavor." Fermentation compositions that have a reduced amino acid odor in the above five-point scale compared to the amino acid odor of the control fermentation composition of the second present invention are preferred as fermentation compositions that can be evaluated as having a reduced amino acid odor.

[0055] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Tests 1 to 5 below relate to the first invention, and Tests 6 to 8 relate to the second invention. [Example]

[0056] [Test 1] Reduction of excessive sourness occurring during storage of fermented composition by killed Lactococcus bacteria Evaluation 1 The following test was carried out to investigate how the addition of killed cells of Lactococcus bacteria in the production of a fermented composition affects the excessive sourness that occurs during storage of the fermented composition.

[0057] 1) A fermented composition sample prepared by over-fermenting non-fat milk (without added flavoring) at 42°C using live Lactobacillus acidophilus, Streptococcus thermophilus, and Bifidobacterium lactis bacteria to a pH of 3.9 was used as a control sample. 2) Fermentation composition samples were prepared by mixing the control sample with 0.001 wt%, 0.01 wt%, 0.1 wt%, and 1 wt% dried killed cell powder of Lactococcus lactis JCM5805, and these were designated as samples A, B, C, and D, respectively. These samples in Test 1 fall under the category of "fermented milk" as defined in the "Ministry Ordinance on the Compositional Standards of Milk and Dairy Products." 3) Five trained sensory evaluators evaluated the acidity intensity of the control sample and each of Samples A to D based on the following acidity intensity index. The evaluation results (average values) of the five sensory evaluators are shown in Table 1.

[0058] <Acidity intensity index> 0: Mild acidity can be felt 1: Moderate acidity can be felt 2: A slightly strong sour taste is felt 3: Strong acidity is felt, but within acceptable limits 4: Too sour and unacceptable

[0059] [Table 1]

[0060] The results in Table 1 show that when 0.01 wt % or more of dried killed cells of Lactococcus bacteria are added in the production of a fermentation composition, the intensity of the sourness can be reduced compared to the control sample.

[0061] [Test 2] Reduction of excessive sourness occurring during storage of fermented composition by killed Lactococcus bacteria Evaluation 2 The following test was conducted to investigate whether the addition of killed Lactococcus bacteria during the production of a fermented composition can reduce the excessive sourness that occurs during storage of the fermented composition, even when different types of lactic acid bacteria and milk ingredients are used than those used in Test 1.

[0062] 1) A fermented composition sample was prepared as a control sample by over-fermenting a liquid milk material (without added flavoring) containing 12% by weight of non-fat milk solids at 30°C using live Streptococcus thermophilus and Lactococcus lactis bacteria to a pH of 4.3. 2) Fermentation composition samples were prepared by mixing the control sample with 0.001 wt%, 0.01 wt%, 0.1 wt%, and 1 wt% dried killed cell powder of Lactococcus lactis JCM5805, and these were designated as samples A, B, C, and D, respectively. These samples in Test 2 fall under the category of "fermented milk" as defined in the "Ministry Ordinance on the Compositional Standards of Milk and Dairy Products." 3) Five trained sensory evaluators evaluated the acidity intensity of the control sample and each of Samples A to D based on the following acidity intensity index. The evaluation results (average values) of the five sensory evaluators are shown in Table 2.

[0063] <Acidity intensity index> 0: Mild acidity can be felt 1: Moderate acidity can be felt 2: A slightly strong sour taste is felt 3: Strong acidity is felt, but within acceptable limits 4: Too sour and unacceptable

[0064] [Table 2]

[0065] The results in Table 2 show that even when different types of lactic acid bacteria and milk ingredients are used than those used in Test 1, adding 0.001% by weight or more of dried killed Lactococcus bacteria in the production of a fermented composition can reduce the intensity of the sourness compared to the control sample.

[0066] [Test 3] Reduction of excessive sourness occurring during storage of fermented composition by killed Lactococcus bacteria Evaluation 3 The following test was conducted to investigate whether the addition of killed Lactococcus bacteria during the production of a fermented composition can reduce the excessive sourness that occurs during storage of the fermented composition, even when different types of lactic acid bacteria and milk ingredients are used than those used in Tests 1 and 2.

[0067] 1) A fermented composition sample prepared by over-fermenting milk at 42°C with live Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus bacteria to a pH of 4.2 was used as a control sample. 2) Fermentation composition samples were prepared by mixing the control sample with 0.001 wt%, 0.01 wt%, 0.1 wt%, and 1 wt% dried killed cell powder of Lactococcus lactis JCM5805, and these were designated as samples A, B, C, and D, respectively. These samples in Test 3 fall under the category of "fermented milk" as defined in the "Ministry Ordinance on the Compositional Standards of Milk and Dairy Products." 3) Five trained sensory evaluators evaluated the acidity intensity of the control sample and each of Samples A to D based on the following acidity intensity index. The evaluation results (average values) of the five sensory evaluators are shown in Table 3.

[0068] <Acidity intensity index> 0: Mild acidity can be felt 1: Moderate acidity can be felt 2: A slightly strong sour taste is felt 3: Strong acidity is felt, but within acceptable limits 4: Too sour and unacceptable

[0069] [Table 3]

[0070] The results in Table 3 show that even when different types of lactic acid bacteria and milk ingredients are used than those used in Tests 1 and 2, adding 0.01% by weight or more of dried killed Lactococcus bacteria in the production of a fermented composition can reduce the intensity of the sourness compared to the control sample.

[0071] [Test 4] Reduction of excessive sourness occurring during storage of fermented composition by killed Lactococcus bacteria Evaluation 4 The following test was conducted to investigate whether the addition of killed Lactococcus bacteria during the production of a fermented composition can reduce the excessive sourness that occurs during storage of the fermented composition, even when a different type of dairy ingredient is used than the dairy ingredient used in Test 1.

[0072] 1) A fermented composition sample was prepared as a control sample by over-fermenting a liquid milk raw material (without added flavoring) containing 7% by weight of non-fat milk solids at 42°C using live bacteria Lactobacillus acidophilus, Streptococcus thermophilus, and Bifidobacterium lactis to a pH of 4.1. 2) Fermentation composition samples were prepared by mixing the control sample with 0.001 wt%, 0.01 wt%, 0.1 wt%, and 1 wt% dried killed cell powder of Lactococcus lactis JCM5805, and these were designated as samples A, B, C, and D, respectively. These samples in Test 4 do not fall under the category of "fermented milk" as defined in the "Ministerial Ordinance on the Compositional Standards of Milk and Dairy Products," but are classified as "foods whose main ingredient is milk, etc." This is because the liquid milk ingredients used to prepare the fermented composition samples in Test 4 did not contain more than 8% by weight of non-fat milk solids. 3) Five trained sensory evaluators evaluated the acidity intensity of the control sample and each of Samples A to D based on the following acidity intensity index. The evaluation results (average values) of the five sensory evaluators are shown in Table 4.

[0073] <Acidity intensity index> 0: Mild acidity can be felt 1: Moderate acidity can be felt 2: A slightly strong sour taste is felt 3: Strong acidity is felt, but within acceptable limits 4: Too sour and unacceptable

[0074] [Table 4]

[0075] The results in Table 4 show that even when a different type of milk raw material is used than the milk raw material used in Test 1, adding 0.01% by weight or more of dried killed Lactococcus bacteria in the production of a fermented composition can reduce the intensity of the sourness compared to the control sample.

[0076] [Test 5] Reduction of excessive sourness that occurs during storage of fermented milk by killed Lactococcus bacteria Evaluation 5 The following test was carried out to investigate whether excessive sourness can be reduced even when killed cells of Lactococcus bacteria are added to commercially available fermented milk that has been re-fermented and over-fermented.

[0077] 1) A commercially available fermented milk (flavored product) fermented with Lactobacillus delbrueckii subsp. bulgaricus was re-fermented to a pH of 4.1 and used as a control sample. 2) Fermented milk samples were prepared by mixing the control sample with 0.001 wt%, 0.01 wt%, 0.1 wt%, and 1 wt% dried killed cell powder of Lactococcus lactis JCM5805, and these were designated as samples A, B, C, and D, respectively. 3) Five trained sensory evaluators evaluated the acidity intensity of the control sample and each of Samples A to D based on the following acidity intensity index. The evaluation results (average values) of the five sensory evaluators are shown in Table 5.

[0078] <Acidity intensity index> 0: Mild acidity can be felt 1: Moderate acidity can be felt 2: A slightly strong sour taste is felt 3: Strong acidity is felt, but within acceptable limits 4: Too sour and unacceptable

[0079] [Table 5]

[0080] The results in Table 5 show that whether commercially available fermented milk is used or killed Lactococcus bacteria are added, adding 0.001% by weight or more of dried killed Lactococcus bacteria can reduce the sourness intensity compared to the control sample.

[0081] [Test 6] Evaluation of amino acid odor reduction by killed Lactococcus bacteria 1 In the production of a fermented composition, fermentation was carried out using lactic acid bacteria other than Lactococcus and Leuconostoc bacteria, and the following test was conducted to investigate the effect that adding killed Lactococcus bacteria has on the amino acid odor of the fermented composition.

[0082] 1) Fermented composition sample M1 was prepared by fermenting milk at 42°C using live bacteria Lactobacillus acidophilus, Streptococcus thermophilus, and Bifidobacterium lactis. 2) Fermented composition sample Y1 was prepared by fermenting milk at 30°C using live Lactococcus lactis bacteria. A fermented composition sample prepared by mixing fermented composition sample M1 and fermented composition sample Y in a 1:1 weight ratio was used as a control sample. 3) A fermented composition sample was prepared by adding 0.1% by weight of a flavoring for fermented milk to the control sample, and this was designated as Sample A. 4) Fermentation composition samples prepared by mixing 0.01 wt%, 0.1 wt%, 1 wt%, and 5 wt% of dried killed cell powder of Lactococcus lactis JCM5805 with fermentation composition sample M1 were designated samples B, C, D, and E, respectively. These samples in Test 6 fall under the category of "fermented milk" as defined in the "Ministry Ordinance on the Compositional Standards of Milk and Dairy Products." 5) Five trained sensory evaluators evaluated the flavor of the control sample and samples A to E based on the amino acid odor intensity index below. The evaluation results (average values) of the five sensory evaluators are shown in Table 6.

[0083] <Amino acid odor intensity index> 0: Not felt 1: Slightly noticeable 2: I can feel it 3: Perceivable, but within the acceptable range for product flavor 4: Product flavor is outside the acceptable range

[0084] [Table 6]

[0085] The results in Table 6 show that when live Lactococcus bacteria are not used and 1 wt% or less of dried killed Lactococcus bacteria is added, a fermented composition with reduced amino acid odor compared to the control sample is obtained.

[0086] [Test 7] Evaluation of amino acid odor reduction by killed Lactococcus bacteria 2 The following test was conducted to confirm whether a fermented composition with reduced amino acid odor could be obtained by adding killed Lactococcus bacteria instead of live Lactococcus bacteria, even when using a different type of lactic acid bacteria than the lactic acid bacteria used in Test 6.

[0087] 1) Fermented composition sample M2 was prepared by fermenting milk at 42°C using live bacteria Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. 2) Fermented composition sample Y1 was prepared by fermenting milk at 30°C using live Lactococcus lactis bacteria. A fermented composition sample prepared by mixing fermented composition sample M2 and fermented composition sample Y1 in a 1:1 weight ratio was used as a control sample. 3) A fermented composition sample was prepared by adding 0.1% by weight of a flavoring for fermented milk to the control sample, and this was designated as Sample A. 4) Fermentation composition samples prepared by mixing fermentation composition sample M2 with dried killed cell powder of Lactococcus lactis JCM5805 at 0.01 wt%, 0.1 wt%, 1 wt%, and 5 wt% were designated as samples B, C, D, and E, respectively. These samples in Test 7 fall under the category of "fermented milk" as defined in the "Ministry Ordinance on the Compositional Standards of Milk and Dairy Products." 5) Five trained sensory evaluators evaluated the flavor of the control sample and samples A to E based on the amino acid odor intensity index below. The evaluation results (average values) of the five sensory evaluators are shown in Table 7.

[0088] <Amino acid odor intensity index> 0: Not felt 1: Slightly noticeable 2: I can feel it 3: Perceivable, but within the acceptable range for product flavor 4: Product flavor is outside the acceptable range

[0089] [Table 7]

[0090] The results in Table 7 show that even when a different type of lactic acid bacteria than that used in Test 6 is used, if live Lactococcus bacteria are not used and 1 wt% or less of dried killed Lactococcus bacteria is added, a fermented composition with reduced amino acid odor compared to the control sample can be obtained.

[0091] [Test 8] Evaluation of amino acid odor reduction by killed Lactococcus bacteria 3 In Tests 6 and 7, milk was fermented with lactic acid bacteria, etc. However, even when a dairy product such as milk that does not fall under the category of "milk" as defined in the "Ministry Ordinance on the Compositional Standards of Milk and Dairy Products" is fermented with lactic acid bacteria, the following test was conducted to confirm whether a fermented composition with reduced amino acid odor can be obtained by adding killed Lactococcus bacteria instead of using live Lactococcus bacteria.

[0092] 1) Fermented composition sample M3 was prepared by fermenting a liquid milk raw material with a non-fat milk solids content of 7% by weight at 42°C using live bacteria Lactobacillus acidophilus, Streptococcus thermophilus, and Bifidobacterium lactis. 2) Fermented composition sample Y2 was prepared by fermenting a liquid milk raw material with 8% by weight of non-fat milk solids at 30°C using live Lactococcus lactis bacteria. A fermented composition sample prepared by mixing fermented composition sample M3 and fermented composition sample Y2 in a 1:1 weight ratio was used as a control sample. 3) A fermented composition sample was prepared by adding 0.1% by weight of a flavoring for fermented milk to the control sample, and this was designated as Sample A. 4) Fermentation composition samples prepared by mixing 0.01 wt%, 0.1 wt%, 1 wt%, and 5 wt% of dried killed cell powder of Lactococcus lactis JCM5805 with fermentation composition sample M3 were designated samples B, C, D, and E, respectively. These samples in Test 8 do not fall under the category of "fermented milk" as defined in the "Ministerial Ordinance on the Compositional Standards of Milk and Dairy Products," but are classified as "foods whose main ingredient is milk, etc." This is because the liquid milk ingredients used to prepare the fermented composition samples in Test 8 did not contain more than 8% by weight of non-fat milk solids. 5) Five trained sensory evaluators evaluated the flavor of the control sample and samples A to E based on the amino acid odor intensity index below. The evaluation results (average values) of the five sensory evaluators are shown in Table 8.

[0093] <Amino acid odor intensity index> 0: Not felt 1: Slightly noticeable 2: I can feel it 3: Perceivable, but within the acceptable range for product flavor 4: Product flavor is outside the acceptable range

[0094] [Table 8]

[0095] The results in Table 8 show that even when dairy products such as milk, which do not fall under the category of "milk" as defined in the "Ministry Ordinance on the Compositional Standards of Milk and Dairy Products," are fermented with lactic acid bacteria, a fermented composition with reduced amino acid odor can be obtained by adding 1% by weight or less of dried killed Lactococcus bacteria instead of using live Lactococcus bacteria.

Claims

1. A fermented composition produced by fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, The fermented composition, wherein killed cells of Lactococcus lactis JCM5805 are added after the completion of fermentation.

2. The fermentation composition according to claim 1, wherein the one or more live bacteria selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria are one or more live bacteria selected from the group consisting of Lactobacillus bacteria, Streptococcus bacteria, Lactococcus bacteria, Leuconostoc bacteria, Pediococcus bacteria, Enterococcus bacteria, and Bifidobacterium bacteria.

3. 3. The fermentation composition according to claim 1, wherein the dry weight of the killed cells of Lactococcus lactis JCM5805 added is 0.001% by weight or more based on the total amount of the fermentation composition.

4. In a method for producing a fermented composition, A method for producing a fermented composition in which sourness due to post-acid production during storage is suppressed, the method comprising the step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, and the step of adding killed cells of Lactococcus lactis JCM5805 after the fermentation step.

5. In the production of the fermented composition, The method comprises a step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria, and further comprising adding killed cells of Lactococcus lactis JCM5805 after the fermentation step. A method for suppressing sourness due to post-acid production during storage in a fermented composition.

6. A fermented composition according to claim 1 or 2, wherein the one or more live bacteria selected from the group consisting of lactic acid bacteria and Bifidobacterium bacteria are one or more live bacteria selected from the group consisting of lactic acid bacteria other than Lactococcus bacteria and Leuconostoc bacteria and Bifidobacterium bacteria, and wherein the fermented composition does not contain any flavoring agent.

7. The fermentation composition according to claim 6, wherein the one or more live bacteria selected from the group consisting of lactic acid bacteria other than Lactococcus and Leuconostoc bacteria and Bifidobacterium bacteria are one or more live bacteria selected from the group consisting of Lactobacillus, Streptococcus, Pediococcus, Enterococcus, and Bifidobacterium bacteria.

8. 8. The fermentation composition according to claim 6, wherein the dry weight of the killed cells of Lactococcus lactis JCM5805 added is 1% by weight or less based on the total amount of the fermentation composition.

9. In a method for producing a fermented composition, A method for producing a fermented composition with reduced amino acid odor, comprising a step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria other than Lactococcus and Leuconostoc bacteria and Bifidobacterium bacteria, no flavoring is used, and killed cells of Lactococcus lactis JCM5805 are added after the fermentation step.

10. In the production of the fermented composition, The method comprises a step of fermenting a milk raw material with live bacteria of one or more species selected from the group consisting of lactic acid bacteria other than Lactococcus and Leuconostoc bacteria and Bifidobacterium bacteria, wherein no flavoring agent is used, and killed cells of Lactococcus lactis JCM5805 are added after the fermentation step. A method for reducing the amino acid odor caused by the cells of one or more lactic acid bacteria selected from the group consisting of Lactococcus bacteria and Leuconostoc bacteria in a fermented composition.

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