Method for producing fermented foods and fermented foods

Abstract

The present invention aims to provide a fermented food in which hardness is imparted and the survival rate of bifidobacteria is improved by fermenting with lactic acid bacteria and bifidobacteria, as well as a method for producing the same. [Solution] A method for producing a fermented food containing lactic acid bacteria and bifidobacteria is provided, characterized by comprising the steps of: adding a carbonate to a raw material mix; and adding lactic acid bacteria and bifidobacteria to the raw material mix and fermenting. The method for producing the fermented food is also provided, wherein the carbonate is one or more selected from sodium bicarbonate and potassium carbonate.

Description

[[Technical Field]]

[0001] The present invention relates to a method for producing a fermented food using lactic acid bacteria and bifidobacteria, and to a fermented food produced by said production method. [[Background Art]]

[0002] Ever since Ilya Mechnikov, a Russian immunologist and Nobel laureate in Physiology or Medicine, claimed that Bulgarian yogurt (fermented milk), a type of fermented milk, has health-promoting effects, fermented milk has attracted attention from people all over the world who pursue health. For the same reason, consumption of fermented milk has been increasing year by year in Japan. In recent years, in particular, due to growing health awareness, a large number of probiotic-containing beverages and foods have been manufactured and sold. Probiotics are live microorganisms that exert beneficial effects on a host by improving the balance of the host's intestinal flora, and the intake of probiotics has come to be expected to provide a wide range of effects such as intestinal regulation, immunostimulation, and improvement of metabolic syndrome.

[0003] Among probiotics, bifidobacteria have been applied as beneficial microorganisms to fermented milk, lactic acid bacteria beverages, intestinal regulators and the like, and various functions centering on intestinal regulation effects are known. However, in order for probiotic bacteria to exert their functions, it is often essential to ingest the bacteria as live cells, and ensuring the survivability of probiotic bacteria in food products is an important issue. Many researchers have developed methods for improving the survivability of bifidobacteria, including a method of adding a hot water extract of liver from fresh pigs or the like to fermented milk containing bifidobacteria (Patent Document 1), a method by removing acid (Patent Document 2), and a method of decomposing lactose in fermented milk containing a plurality of live lactic acid bacteria strains (Patent Document 3). [[Prior Art Documents]] [[Patent Documents]]

[0004] [[Patent Document 1]] Japanese Patent Application Laid-Open No. 62-11053 [Patent Document 2] Japanese Patent Application Publication No. 11-32724 [Patent Document 3] Japanese Patent Publication No. 2016-189709 [Overview of the project] [Problems that the invention aims to solve]

[0005] Incidentally, in fermented foods, insufficient hardness can cause tissue breakdown and increased syneresis during transport. Therefore, a certain degree of hardness is required, especially in static fermented milk, to prevent tissue breakdown. However, there is no known method to improve the hardness of fermented foods using lactic acid bacteria and bifidobacteria while simultaneously improving the viability of bifidobacteria. In particular, when plant-based proteins such as pea protein were used instead of milk protein for fermentation with lactic acid bacteria and bifidobacteria, the resulting fermented food had a low number of viable bifidobacteria, making it difficult to maintain the number of bifidobacteria by the expiration date, and also suffered from insufficient hardness. Based on the above, the present invention aims to provide a method for producing fermented foods using lactic acid bacteria and bifidobacteria, which improves the survival rate of bifidobacteria during storage and provides fermented foods with a certain degree of hardness. [Means for solving the problem]

[0006] The inventors of the present invention conducted diligent research to solve the above problems and discovered that by adding carbonate to the raw material mix and fermenting it, it is possible to increase the number of bifidobacteria, maintain the number of viable bacteria at the expiration date (improve viability), and improve the lack of hardness in fermented foods, thus completing the present invention. In other words, the present invention has the following configuration. <1> A method for producing fermented foods containing lactic acid bacteria and bifidobacteria, The process involves adding carbonate to the raw material mix, A step of adding lactic acid bacteria and bifidobacteria to the aforementioned raw material mix and fermenting it, A method for producing the fermented food, characterized by including the above. <2> The carbonate is one or more selected from the group consisting of sodium bicarbonate and potassium carbonate. <1> A method for producing fermented foods as described above. <3> The step of adding carbonate to the raw material mix is ​​a step of adding carbonate in an amount of 0.01 to 1.0% by mass relative to the raw material mix. <1> or <2> A method for producing fermented foods as described above. <4> The aforementioned raw material mix contains plant protein <1> or <2> A method for producing fermented foods as described above. <5> The lactic acid bacteria mentioned above are Streptococcus thermophilus and Lactobacillus bulgaricus. <1> or <2> A method for producing fermented foods as described above. <6> The aforementioned bifidobacteria is Bifidobacterium longum. <1> or <2> A method for producing fermented foods as described above. <7> A fermented food containing lactic acid bacteria, bifidobacteria, and carbonates, with a pH of 5 or less. <8> The hardness after refrigeration for one day following manufacture is 50 gf or higher. <7> Fermented foods as described above. <9> Contains plant protein <7> or <8> Fermented foods as described above. <10> Contains 2-8% by mass of the aforementioned plant protein <9> Fermented foods as described above. <11> The lactic acid bacteria mentioned above are Streptococcus thermophilus and Lactobacillus bulgaricus. <7> or <8> Fermented foods as described above. <12> The fermented food according to <7> or <8>, wherein the bifidobacteria is *Bifidobacterium longum*. <13> a step of adding a carbonate to a raw material mix for a fermented food containing vegetable protein, and a step of adding lactic acid bacteria and bifidobacteria to the raw material mix and performing fermentation, A method for imparting hardness to said fermented food, comprising the above steps. <14> a step of adding a carbonate to a fermentation target, and a step of adding lactic acid bacteria and bifidobacteria to the fermentation target and performing fermentation, A method for improving the survival of bifidobacteria in said fermented food, comprising the above steps. <15> a step of adding a carbonate to a fermentation target, and a step of adding lactic acid bacteria and bifidobacteria to the fermentation target and performing fermentation, A method for promoting the growth of bifidobacteria, comprising the above steps. <16> The method for promoting the growth of bifidobacteria according to <14> or <15>, wherein the fermentation target is a raw material mix for a fermented food. <17> The method according to any one of <13> to <15>, wherein the lactic acid bacteria are *Streptococcus thermophilus* and *Lactobacillus bulgaricus*. <18> The method according to any one of <13> to <15>, wherein the bifidobacteria is *Bifidobacterium longum*. Effects of the Invention

[0007] According to the method for producing a fermented food of the present invention, addition of a carbonate to the raw material mix makes it possible to provide a fermented food with improved survival of bifidobacteria. Furthermore, it is also possible to provide a fermented food to which hardness is additionally imparted. [Modes for carrying out the invention]

[0008] (Fermented foods) In the present invention, "fermented food" refers to a food product obtained by fermenting a raw material mix containing dairy products and plant-based proteins with lactic acid bacteria and bifidobacteria, characterized by containing carbonates and having a certain level of hardness. The fermented foods of the present invention can be any fermented foods made with lactic acid bacteria and bifidobacteria, and can be classified into three types based on their properties and manufacturing method: 1) static type, 2) stirred type, and 3) liquid type. 1) The static type is referred to as a hard-type fermented food, and has a pudding-like texture that is filled into retail containers and fermented. For example, it is manufactured as follows: First, raw material mix prepared by mixing and dissolving raw materials such as dairy products, plant protein, sugars such as sucrose, and stabilizers is homogenized, sterilized under the sterilization conditions of the present invention, cooled, inoculated with lactic acid bacteria and bifidobacteria, filled into containers and sealed, and fermented in a culture room or fermentation tunnel. When the acidity reaches an appropriate level, it is immediately cooled to end the fermentation and become the final product. 2) The stirred type, also called the soft type, involves adding lactic acid bacteria and bifidobacteria to a sterilized raw material mix, similar to 1), and fermenting it in a tank to create a fermentation base. After fermentation, the curd is crushed and filled into containers, and fruit sauce or other ingredients are mixed in as needed to create the final product. 3) For the liquid type, the raw material mix is ​​fermented in the same way as the stirred type, the curd is crushed and homogenized to create a liquid fermented food, which is then mixed with fruit sauce or other ingredients as needed to produce the final product. When the purpose of the present invention is to improve the survival rate of bifidobacteria or to promote their growth, any of the above-mentioned fermented foods can be used to enjoy the effects of the present invention. Furthermore, when the purpose is to impart firmness, static fermented milk is preferred, as it allows for the full enjoyment of the effects of the present invention.

[0009] (Bifidobacteria) The Bifidobacteria used in this invention are not particularly limited as long as they belong to the genus Bifidobacterium, but examples include Bifidobacterium longum, Bifidobacterium pseudorongum, Bifidobacterium bifidum, Bifidobacterium infantis, Bifidobacterium breve, Bifidobacterium animalis, Bifidobacterium addresscentis, Bifidobacterium lactis, Bifidobacterium catenulatum, Bifidobacterium denthium, and Bifidobacterium globossum. Among these, Bifidobacterium longum is preferred. A higher number of viable Bifidobacteria in fermented foods is preferable; for example, 1.0 × 10⁶ when stored refrigerated at 1-10°C for 18 days. 7 Anything above that is acceptable, preferably 1.5 × 10 7 The above, and more preferably 2.0 × 10 7 The above, and more preferably 2.5 × 10 7 The above is the most preferred, and most preferably 3.0 × 10 7 That's all.

[0010] (lactic acid bacteria) In the present invention, the lactic acid bacteria used for fermentation are not particularly limited as long as they are lactic acid bacteria commonly used in the production of fermented foods. Examples include one or more selected from lactic acid bacilli such as Lactobacillus bulgaricus and Lactobacillus lactis, lactic acid cocci such as Streptococcus thermophilus, and other lactic acid bacteria and yeasts commonly used in the production of fermented milk. Of these, a combination of Lactobacillus bulgaricus and Streptococcus thermophilus is preferred.

[0011] (raw materials) The fermented food of the present invention is essential to include plant protein and / or animal protein and carbonate as raw materials, and is obtained by fermenting a raw material mix containing these raw materials with lactic acid bacteria and bifidobacteria.

[0012] (Carbonate) In this invention, carbonate is a general term for compounds containing carbonate ions, and includes sodium bicarbonate, potassium carbonate, calcium carbonate, sodium carbonate, and magnesium carbonate, among which sodium bicarbonate and potassium carbonate are preferred. In this invention, by adding carbonate to the raw material mix, that is, by fermenting the raw material mix containing carbonate with lactic acid bacteria and bifidobacteria, the number of bifidobacteria in the fermented food can be maintained when stored under refrigeration after production (improved survival). Furthermore, the number of bifidobacteria during fermentation can be increased (promotion of growth). In addition, it is possible to impart hardness to the fermented food. The timing of adding carbonate is flexible; it only needs to be present in the raw material mix during fermentation. This includes adding it to the raw material mix from the beginning, as well as adding it to the raw material mix as soon as fermentation starts. However, it is preferable that the carbonate be added before the lactic acid bacteria and bifidobacteria are added. The amount of carbonate added is preferably 0.01 to 1.0% by mass relative to the raw material mix, more preferably 0.02 to 0.5% by mass, and even more preferably 0.03 to 0.10% by mass.

[0013] (Plant-based protein) One embodiment of the fermented food of the present invention is one that contains plant protein. The inclusion of plant protein does not mean that it does not contain any animal protein such as milk, and includes embodiments in which a portion of the milk protein is replaced with plant protein and fermented, or in which all of the milk protein is replaced and no animal protein is contained at all. Examples of plant-based protein sources include protein sources derived from legumes such as cowpeas, kidney beans, broad beans, peas, chickpeas, lentils, soybeans, and peanuts; protein sources derived from seeds such as sesame, hemp seeds, almonds, peanuts, cashews, hazelnuts, macadamia nuts, pistachios, chestnuts, walnuts, and coconuts; and protein sources derived from algae. Of these, protein sources derived from the genus Pisum of the legume family, such as green peas, yellow peas, red peas, and white peas, are particularly preferred. Furthermore, protein concentrates derived from the genus Pisum of the legume family, such as green peas, yellow peas, red peas, and white peas, are preferred. Commercially available pea-derived protein concentrates can also be used. Examples of such commercially available products include TRUPRO2000 (manufactured by IFF) and NUTARYS S85F (manufactured by Rocket). In embodiments of the present invention that include plant protein in the fermented food, the plant protein content can range from 0.1 to 15% by mass. Of these, 2.0% to 8.0% by mass is preferred, 3.0% to 6.0% by mass is more preferred, and 3.5% to 4.5% by mass is even more preferred. The amount of plant protein in a fermented food using each plant protein material can be determined by multiplying the amount of protein (%) in the material by the proportion of the fermented food in which it is incorporated.

[0014] (Animal protein) The animal protein used as a raw material for the fermented food of the present invention is mainly milk protein, and the raw materials include raw milk such as cow's milk, whole milk, skim milk, whey, and processed products thereof (for example, whole milk powder, whole milk concentrate, skim milk powder, desalted skim milk powder, skim milk concentrate, condensed milk, whey powder, whey concentrate, cream, butter, cheese, etc.). In embodiments of the fermented food of the present invention that include animal protein, the content of animal protein is preferably 2.0% by mass or more and 8.0% by mass or less, more preferably 3.0% by mass or more and 6.0% by mass or less, and even more preferably 3.5% by mass or more and 4.5% by mass or less. Furthermore, if the fermented food of the present invention contains both animal protein and plant protein, the total amount of protein is preferably 2.0% by mass or more and 8.0% by mass or less, more preferably 3.0% by mass or more and 6.0% by mass or less, and even more preferably 3.5% by mass or more and 4.5% by mass or less.

[0015] (Other ingredients) In one embodiment of the fermented food of the present invention, in addition to plant proteins and / or animal proteins and carbonates, it may contain sugars, flavoring agents, and colorants. Examples of flavoring agents include sweeteners such as sugars, flavorings, fruit juice, fruit pulp, vitamins, minerals, vegetable oils and fats, emulsifiers, and other foods or food components and food additives.

[0016] A more specific embodiment of the method for producing the fermented food of the present invention is described below. It is obtained by weighing dairy products, plant protein raw materials, carbonates, and other raw materials commonly used in the production of fermented foods (also called raw material mix) and dissolving and mixing them in water, then homogenizing or micronizing and sterilizing them, and finally fermenting them with lactic acid bacteria and bifidobacteria.

[0017] (Homogenization process or particle formation process) The conditions for homogenizing the raw material mix in the method for producing fermented food according to the present invention are not particularly limited. Preferred conditions include, for example, a temperature of 50°C to 70°C and a pressure of 15 MPa or higher. More preferably, the pressure is 15 MPa to 50 MPa, and even more preferably, 18 MPa to 30 MPa. The homogenization treatment may be carried out using a known homogenization apparatus such as a homogenizer. By micronizing the raw material mix before fermentation, it is possible to suppress the sedimentation of raw materials during the fermentation process and to create a more uniform texture in the fermented food.

[0018] (sterilization process) The sterilization conditions for the raw material mix are not particularly limited. Preferred conditions include a temperature of 80°C to 95°C for a holding time of 2 seconds to 10 minutes. Sterilization methods include the HTST method, UHT method, tubular method, and batch method, but among these, the HTST method and UHT method are preferred. The equipment used for heating and sterilization in the homogenization or micronization process described above may be a plate heat exchanger, a tube sterilizer, a thermo-cylinder, a Joule heating device, a batch sterilization system using tanks, or any combination thereof, but is not limited to these; any equipment that can be used in the production of fermented foods is acceptable.

[0019] (Fermentation process) Lactic acid bacteria and bifidobacteria are added to the sterilized and cooled raw material mix, and then the mixture is filled into containers. When adding lactic acid bacteria and bifidobacteria, fermentation conditions are preferably 2 to 20 hours at a temperature of 30°C to 45°C, and the endpoint of fermentation can be exemplified as the point when the pH of the raw material mix reaches 5 or below. The timing of adding lactic acid bacteria and bifidobacteria can be simultaneous or sequential. If added sequentially, the order in which they are added does not matter. As mentioned above, examples of lactic acid bacteria and bifidobacteria used in fermentation include Lactobacillus bulgaricus, Streptococcus thermophilus, and Bifidobacterium longum, but there are no particular restrictions. After fermentation is complete, a static fermented food can be obtained by cooling the container to, for example, 10°C or below. Alternatively, a stirred-type fermented food can be obtained by adding lactic acid bacteria to the raw material mix, fermenting it in a tank, crushing the curd, filling it into containers, and mixing in fruit sauce or other ingredients as needed. Furthermore, a liquid fermented food can be obtained by fermenting the raw material mix in the same way as the stirring type, crushing the curd, homogenizing it, and mixing the resulting fermented food with fruit sauce or other ingredients as needed.

[0020] (Number of viable Bifidobacteria) In this invention, the number of Bifidobacteria is 1.5 × 10⁶ on the first day of storage after the production of the fermented food. 8 The above is preferable, 1.7 × 10 8 The above is even more preferable. The effect of improving viability can be evaluated by the degree of decrease in the number of viable bacteria after refrigeration for a certain period. Specifically, after refrigeration for a certain period, if the number of viable bacteria is higher when carbonate is added compared to when it is not (control), then the effect of improving viability due to the addition of carbonate can be evaluated. The method for measuring the number of viable bifidobacteria after fermentation with lactic acid bacteria and bifidobacteria is as follows. For the measurement, bacterial solutions serially diluted with dilution water (shown below) were mixed onto TOS mupirocin medium and incubated anaerobically at 37°C for 72 hours using an anaerobic culture system (product name: Aneropack, manufactured by Mitsubishi Gas Chemical Company, Inc.). After incubation, the number of viable Bifidobacteria was measured by plate counting. Dilution water: 0.6% NaHPO4, 0.45% KH2PO4, 0.05% L-cysteineHCl-H2O, and 0.05% agar dissolved in water, then sterilized at 121°C for 15 minutes.

[0021] (hardness) The hardness of the fermented food in this invention is preferably such that the structure does not break down during transport, for example, 50 gf or more is preferred, and 60 gf or more is even more preferred. Hardness can be measured using compression testing machines such as a texture analyzer (Stable Micro Systems), a Rheonar (Yamaden Co., Ltd.), or a rheometer (Rheotec). In the test examples described later, the hardness (gf) was defined as the maximum load when a 16 mm diameter plunger was inserted into a sample adjusted to 10°C at a speed of 1 mm / second.

[0022] (pH) The pH of the fermented food in this invention is preferably 5 or less, more preferably 4.9 to 3.5, and even more preferably 4.8 to 4.0.

[0023] (Methods for improving the survival rate of Bifidobacterium, etc.) Another aspect of the present invention is a method for improving the viability of bifidobacteria in fermented foods, comprising the steps of adding a carbonate to a fermentation target and adding lactic acid bacteria and bifidobacteria to the fermentation target and fermenting. Another embodiment is a method for promoting the growth of bifidobacteria by including the steps of adding carbonate to the fermentation target and adding lactic acid bacteria and bifidobacteria to the fermentation target and fermenting. In this case, if the fermentation target is a raw material mix for fermented foods, it is possible to promote the growth of bifidobacteria during the production of fermented foods and to increase the survival rate of bifidobacteria during storage of the produced fermented foods. Another embodiment is a method for imparting hardness to a fermented food by including the steps of adding carbonate to a raw material mix for a fermented food and adding lactic acid bacteria and bifidobacteria to the raw material mix and fermenting it. [Examples]

[0024] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. [Example 1] 1. Method for producing fermented foods The ingredients shown in Table 1 were mixed and homogenized at a homogenization pressure of 18 MPa and 85°C. Then, carbonates were added to the homogenized raw material mix at the levels shown in Table 2, and heat sterilization was performed at 90°C for 10 minutes. After cooling, 0.01% by mass of lactic acid bacteria (S. thermophilus, L. bulgaricus) and bifidobacteria (B. longum) were added to each raw material mix, 400g were filled into containers, sealed, and fermented at 40°C. When the pH reached 4.8, it was cooled to below 10°C to produce a static fermented food. The static fermented food was stored refrigerated at 10°C, and the hardness and number of bifidobacteria were measured on day 1 and day 18 after production.

[0025] [Table 1]

[0026] 2. Test Method 2-1. Method for measuring hardness The measurement was performed using a rheometer (Rheotec), a compression testing machine. The hardness (gf) was defined as the maximum load when a 16 mm diameter plunger was inserted at a speed of 1 mm / second into a container of statically fermented milk prepared as described above and stored at 10°C.

[0027] 2-2. Method for measuring the number of viable Bifidobacteria The measurement of the number of viable bifidobacteria after fermentation with lactic acid bacteria and bifidobacteria is as follows: For the measurement, static fermented milk was serially diluted with dilution water (shown below), and this was mixed with TOS mupirocin medium as a bacterial suspension. The mixture was then cultured anaerobically at 37°C for 72 hours using an anaerobic culture system (product name: Aneropack, manufactured by Mitsubishi Gas Chemical Company, Inc.). After the culture was completed, the number of viable Bifidobacteria was measured by plate counting. Dilution water: 0.6% NaHPO4, 0.45% KH2PO4, 0.05% L-cysteineHCl-H2O, and 0.05% agar dissolved in water, then sterilized at 121°C for 15 minutes.

[0028] 3. Evaluation Results and Discussion The results are shown in Table 2. The control level is the level without carbonate addition. Samples No. 2 to No. 4, to which sodium bicarbonate was added, showed a high number of viable Bifidobacteria, and no decrease in the number of viable bacteria was observed even after 18 days of storage, indicating that high survival rates were maintained. Samples No. 5 to No. 7, to which potassium carbonate was added, showed a high number of viable Bifidobacteria, and no decrease in the number of viable bacteria was observed even after 18 days of storage, indicating that high survival rates were maintained. From the above, it was found that adding carbonate to the mix and fermenting it improves the survival rate of bifidobacteria. Furthermore, it was found that the carbonate added should preferably be at least 0.03% by mass. Furthermore, it was found that samples NO.2-NO.4, which had sodium bicarbonate added, and NO.5-NO.7, which had potassium carbonate added, had higher hardness compared to the control. From this, it was found that hardness can be imparted to fermented foods by adding carbonates during fermentation. Furthermore, on day 1, the number of Bifidobacteria increased more in the mixture fermented with added carbonate than in the control, indicating that adding carbonate to the raw material mix during fermentation can promote the growth of Bifidobacteria. It was also found that a carbonate concentration of 0.03% by mass or higher is preferable.

[0029] [Table 2]

[0030] [Example 2] Method for producing fermented food (comparison of carbonate and other salts) 1. Method for producing fermented foods The ingredients shown in Table 3 were mixed and homogenized at a homogenization pressure of 18 MPa and 85°C. The homogenized raw material mixes were then heat-sterilized at 90°C for 10 minutes. After cooling, 0.01% by mass of lactic acid bacteria (S. thermophilus, L. bulgaricus) was added to each raw material mix. 400g of each mixture was then filled into containers, sealed, and fermented at 40°C. When the pH reached 4.8, the mixture was cooled to below 10°C to produce a static fermented food. The static fermented food was stored refrigerated at 10°C, and its hardness and the number of bifidobacteria were measured on day 1 and day 18 after production.

[0031] [Table 3]

[0032] 2. Test Method Same as Example 2.

[0033] 3. Evaluation Results and Discussion The results are shown in Table 4. Note that the control level does not contain potassium carbonate or sodium citrate. Samples NO.2 and NO.3, to which potassium carbonate was added, showed a high number of Bifidobacterium bacteria, and no decrease in bacterial count was observed even after 18 days of storage, indicating that high survival rates were maintained. It was found that adding sodium citrate to samples No. 4 and No. 5 did not increase the number of bifidobacteria compared to the control, and did not affect their survival rate. Furthermore, it was found that the hardness and the number of bifidobacteria on the first day after production were higher when potassium carbonate was added compared to when sodium citrate was added. From the above, it was found that carbonates are preferable for improving the survival rate of bifidobacteria, imparting hardness, and promoting the growth of bifidobacteria.

[0034] [Table 4]

[0035] [Example 3] Method for producing fermented food 1. Method for producing fermented foods The ingredients shown in Table 5 were mixed and homogenized at a homogenization pressure of 18 MPa and 85°C. The homogenized raw material mixes were then heat-sterilized at 90°C for 10 minutes. After cooling, 0.01% by mass of lactic acid bacteria (S. thermophilus, L. bulgaricus) was added to each raw material mix. 400g of each mixture was then filled into containers, sealed, and fermented at 40°C. When the pH reached 4.8, the mixture was cooled to below 10°C to produce a static fermented food. The static fermented food was stored refrigerated at 10°C, and its hardness and the number of bifidobacteria were measured on day 1 and day 18 after production.

[0036] [Table 5]

[0037] 2. Test Method Same as Example 2.

[0038] 3. Evaluation Results and Discussion The results are shown in Table 6. The control level is the level without carbonate addition. Samples NO.2 and NO.3, to which sodium bicarbonate was added, showed a high number of viable Bifidobacteria, and no decrease in the number of viable bacteria was observed even after 18 days of storage, indicating that high survival rates were maintained. Samples No. 4 and No. 5, to which potassium carbonate was added, showed a high number of viable Bifidobacteria, and no decrease in the number of viable bacteria was observed even after 18 days of storage, indicating that high survival rates were maintained. From the above, it was found that adding carbonate to the mix and fermenting it improves the survival rate of bifidobacteria. Furthermore, it was found that the carbonate added should preferably be at least 0.03% by mass. Furthermore, on day 1, the number of Bifidobacteria increased more in the mixture fermented with added carbonate than in the control, indicating that adding carbonate to the raw material mix during fermentation can promote the growth of Bifidobacteria. It was also found that a carbonate concentration of 0.03% by mass or higher is preferable. Therefore, it was found that the effects of adding carbonates on improving the survival rate and promoting the growth of Bifidobacterium are similar even when milk proteins such as skim milk powder are included. Furthermore, since no difference in hardness was observed at any level, the hardening effect of carbonate addition can be considered a unique effect specific to the presence of plant-based proteins.

[0039] [Table 6]

Claims

1. A method for producing fermented foods containing lactic acid bacteria and bifidobacteria, The process involves adding carbonate to the raw material mix, A step of adding lactic acid bacteria and bifidobacteria to the aforementioned raw material mix and fermenting it, A method for producing the fermented food, characterized by including the above.

2. The method for producing a fermented food according to claim 1, wherein the carbonate is one or more selected from the group consisting of sodium bicarbonate and potassium carbonate.

3. The method for producing a fermented food according to claim 1 or 2, wherein the step of adding carbonate to the raw material mix is ​​a step of adding carbonate in an amount of 0.01 to 1.0% by mass relative to the raw material mix.

4. A method for producing a fermented food according to claim 1 or claim 2, wherein the raw material mix contains plant protein.

5. A method for producing a fermented food according to claim 1 or 2, wherein the lactic acid bacteria are Streptococcus thermophilus and Lactobacillus bulgaricus.

6. A method for producing a fermented food according to claim 1 or 2, wherein the Bifidobacterium is Bifidobacterium longum.

7. A fermented food containing lactic acid bacteria, bifidobacteria, and carbonates, with a pH of 5 or less.

8. The fermented food according to claim 7, wherein the hardness on the first day of refrigerated storage after manufacturing is 50 gf or more.

9. A fermented food according to claim 7 or 8, comprising plant protein.

10. The fermented food according to claim 9, comprising 2 to 8% by mass of the aforementioned plant protein.

11. The fermented food according to claim 7 or 8, wherein the lactic acid bacteria are Streptococcus thermophilus and Lactobacillus bulgaricus.

12. The fermented food according to claim 7 or 8, wherein the Bifidobacterium is Bifidobacterium longum.

13. The process of adding carbonate to a raw material mix for fermented foods containing plant protein and A step of adding lactic acid bacteria and bifidobacteria to the aforementioned raw material mix and fermenting it, A method for imparting hardness to a fermented food, characterized by containing the following.

14. The process of adding carbonate to the substance to be fermented and A step of adding lactic acid bacteria and bifidobacteria to the fermentation target and fermenting it, A method for improving the survival rate of bifidobacteria in the fermented food, characterized by including the following.

15. The process of adding carbonate to the substance to be fermented and A step of adding lactic acid bacteria and bifidobacteria to the fermentation target and fermenting it, A method for promoting the growth of Bifidobacterium, characterized by including [a specific ingredient / method].

16. The method for promoting the growth of Bifidobacterium according to claim 14 or 15, wherein the substance to be fermented is a raw material mix for fermented foods.

17. The method according to any one of claims 13 to 15, wherein the lactic acid bacteria are Streptococcus thermophilus and Lactobacillus bulgaricus.

18. The method according to any one of claims 13 to 15, wherein the Bifidobacterium is Bifidobacterium longum.

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