JP2016189709A - Method for producing fermented milk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing fermented milk suppressing pH decrease in fermented milk containing probiotics, in particular bifidobacterial, during storage, and having good flavor and high survivability of the bifidobacterial for improvement in health function.SOLUTION: A method for producing fermented milk comprises reducing the content of lactose in fermented mix containing milk material to have a concentration equal to or less than 45 mM after completion of fermentation by fermenting the mix so as to prevent pH decrease in fermented milk containing at least Streptococcus thermophiles, Lactobacillus gasseri, Bifidobacterium longum and Lactobacillus burugaricus during storage, flavor deterioration and reduction in the number of viable cells of bifidobacterial with time.SELECTED DRAWING: None

Description

  The present invention includes at least Streptococcus thermophilus, Lactobacillus gasseri, Bifidobacterium longum and Lactobacillus delbrueckii subspices bulgaricus (Lactobacillus delbrueckii). subsp. bulgaricus), and more particularly, to a method for producing the fermented milk with less flavor deterioration over time.

Since Metnikov, a Russian immunologist who won the Nobel Prize in Physiology or Medicine, claims that Bulgarian yogurt (fermented milk) has a health promoting effect, fermented milk from people all over the world who promote health Became a subject of attention. For the same reason, the consumption of fermented milk is increasing year by year in Japan.
In recent years, a lot of beverages and foods containing probiotics have been manufactured and sold due to the growing awareness of health. Probiotics are living microorganisms that have beneficial effects on the host by improving the balance of the intestinal flora of the host, and have a wide range of effects such as intestinal regulation, immunostimulation, and metabolic syndrome. The effect has come to be expected.

Among probiotics, bifidobacteria are applied to fermented milk, lactic acid bacteria beverages, intestinal preparations, and the like as beneficial microorganisms, and various functions are known with a focus on intestinal effect. However, in order for probiotic bacteria to exert their functions, it is often necessary to ingest live bacteria, and ensuring survival of probiotic bacteria in food is an important issue. .
A method for improving the viability of bifidobacteria has been made by many researchers. A method using a hot water extract of the liver (Patent Document 1) and a method using co-culture with Geotrichum candy dam (Patent Document 2). And a method by removing acid (Patent Document 3).

  On the other hand, since fermented milk is a food, not only the above-mentioned health promotion effect but also a good flavor is required. There are various types of fermented milk on the market. In addition to the plain type, which is prepared by fermenting only dairy products such as milk, skim milk powder, cream, and milk protein, the pre-fermented yogurt is finely crushed with a homogenizer, etc. Various types have been put on the market depending on the needs of consumers, such as drinks made in the above-mentioned types, and types in which the above-mentioned fermented milk is mixed with fruit pulp and the like. In addition, fermented milk that combines a plurality of lactic acid bacteria to produce a unique flavor has also been released. In any type of product, a product whose flavor does not deteriorate during storage is preferred. However, in fermented milk having a plurality of living lactic acid bacteria, it is not known to decompose lactose for the purpose of preventing the deterioration of flavor over time and improving the viability of bifidobacteria.

  In addition, since many Japanese do not have lactose-degrading enzymes, ingesting dairy products containing lactose has a high percentage of lactose intolerance that causes symptoms such as diarrhea. Since lactose is also contained in fermented milk, fermented milk in which lactose has been decomposed or removed in advance is also sold so that lactose intolerant can easily take it. For example, there is an example in which lactose is decomposed with lactase (Patent Document 4).

JP 62-11053 A JP 2001-029064 Japanese Patent Laid-Open No. 11-32724 JP 09-084520 A

As mentioned above, consumers are demanding not only a good flavor for fermented milk but also a healthy function at the same time.In order to improve the flavor, while using multiple bacterial species, probiotic bacteria It also requires that Bifidobacteria survive.
However, the conventional method for improving the viability of bifidobacteria requires a significant change in the process and the addition of auxiliary materials. In addition, when multiple bacterial species are used, it is difficult to suppress the change in flavor over time.
Therefore, in the present invention, at least Streptococcus thermophilus, Lactobacillus gasseri, Bifidobacterium longum, and Lactobacillus delbruecki subspecies bulgaricus ( Lactobacillus delbrueckii subsp. Bulgaricus) (hereinafter simply referred to as Lactobacillus delbrueckii subsp. Bulgaricus), which suppresses pH reduction during storage of fermented milk, has a good flavor, and has bifidobacteria An object of the present invention is to provide a method for producing fermented milk having a high survival rate.

The present inventors have reduced the content of lactose in a fermentation mix containing milk raw materials to a predetermined concentration in advance, so that at least Streptococcus thermophilus and Lactobacillus gasseri , Preventing deterioration of pH during storage of fermented milk containing Bifidobacterium longum and Lactobacillus delbrueckii subsp. Bulgaricus, and deterioration of flavor over time The present inventors have found that the decrease in the number can be prevented and have completed the present invention.
That is, the present invention has the following configuration.
(1) Fermentation containing at least Streptococcus thermophilus, Lactobacillus gasseri, Bifidobacterium longum and Lactobacillus delbrueckii subsp. Bulgaricus A method for producing milk,
The method for producing fermented milk, comprising a step of adding the lactic acid bacteria to a fermentation mix for fermentation, and fermenting the lactose content after the fermentation to 45 mM or less.
(2) The method for producing fermented milk according to (1), wherein the lactose content of the fermentation mix is adjusted by lactose decomposition.
(3) Fermented milk after storage at 10 ° C for 19 days after completion of fermentation
The viable count of Streptococcus thermophilus in the fermented milk is 1 × 10 ⁸ CFU / mL or more, the viable count of Lactobacillus gasseri is 1 × 10 ⁷ CFU / mL, The viable count of Bifidobacterium longum is 1 × 10 ⁶ CFU / mL or more,
The viable count of Lactobacillus delbrueckii subsp. Bulgaricus is 1 × 10 ⁵ CFU / mL or less, and the pH of the fermented milk is in the range of 4.3 to 4.6.
(1) The manufacturing method of fermented milk as described in (2).

  According to the present invention, at least Streptococcus thermophilus, Lactobacillus gasseri, Bifidobacterium longum and Lactobacillus delbrueckii subsp. Bulgaricus In the fermented milk containing the fermented milk, it is possible to produce fermented milk with little deterioration in flavor over time and good survival of Bifidobacteria.

The change of lactose content with time of the control product and the example product is shown. It shows changes in Streptococcus thermophilus (in the figure, thermophilus bacteria) over time in the control product and the example product. The change of the Lactobacillus gasseri (Gasseri bacterium in the figure) with time of the control product and the example product is shown. It shows changes in Bifidobacterium longum (in the figure, bifidobacteria) over time of the control product and the example product. It shows changes in Lactobacillus bulgaricus (Bulgaricus bacterium in the figure) over time in the control product and the example product. The change of pH over time of the control product and the example product is shown.

  In the present invention, “fermented milk” refers to animal milk such as cow milk or milk containing non-fat milk solids equivalent to or higher than any one of lactic acid bacteria, bifidobacteria, and yeast, or a combination thereof. It has been fermented. When fermented milk is classified according to properties and production methods, it can be divided into 1) stationary fermented milk, 2) agitated fermented milk, and 3) liquid fermented milk. This 1) stationary type fermented milk is called hard type fermented milk, has a purine-like structure filled in a retail container and fermented, and is produced, for example, as follows. First, after homogenizing, sterilizing and cooling the fermentation mix prepared by mixing and dissolving raw materials such as milk, dairy products, sucrose and stabilizers, inoculate a lactic acid bacteria starter, fill the container and seal it Fermentation is carried out in a culture room or a fermentation tunnel, and when the acidity reaches an appropriate level, it is immediately cooled to 5 ° C. to complete the fermentation, and the final product is obtained. 2) Stirring type fermented milk is also referred to as soft type fermented milk. A lactic acid bacteria starter is added to a fermented mix, fermented in a tank, and then the card is crushed and filled into a container to obtain a final product. 3) The liquid fermented milk is obtained by fermenting the fermented mix in the same manner as the stirred type fermented milk, and homogenizing the curd after pulverizing the curd to make it liquid. In this invention, said thing is named generically and fermented milk.

  In the present invention, milk and dairy products used as raw materials for fermented milk are designated as “milk” and “dairy products” in the Ministerial Ordinance (December 27, 1951, Ministry of Health and Welfare Ordinance No. 52) on the component standards of milk and dairy products. Applicable. That is, `` milk '' refers to raw milk, cow milk, special milk, raw goat milk, pasteurized goat milk, raw noodle milk, ingredient adjusted milk, low fat milk, non-fat milk and processed milk, and `` dairy products '' , Cream, butter, butter oil, cheese, concentrated whey, ice cream, concentrated milk, defatted concentrated milk, sugar-free condensed milk, sugar-free defatted condensed milk, sweetened condensed milk, sweetened defatted condensed milk, whole powdered milk, defatted powdered milk, cream powder, whey It refers to powder, protein-enriched whey powder, buttermilk powder, sweetened powdered milk, prepared powdered milk, fermented milk, lactic acid bacteria beverages (limited to those containing non-fat milk solids of 3.0% or more) and milk beverages.

  The fermentation mix of the present invention means a raw material mixture containing milk components for adding and fermenting lactic acid bacteria, and can be prepared by any conventionally known method. For example, non-fat milk solids (SNF) and It is preferable to prepare the milk prepared by adjusting the milk fat content (Fat) by cooling, homogenizing by heating with lactose-degrading enzyme, sterilizing, inactivating the enzyme and cooling. Or, using milk raw materials with reduced lactose such as lactose-decomposed powdered milk or lactose-removed powdered milk, the prepared milk prepared with non-fat milk solids (SNF) and milk fat (Fat) is cooled, heat homogenized, and sterilized -It can also be prepared by cooling. As described above, in the present invention, lactose that has been degraded to some extent by lactose-degrading enzyme has been obtained by sufficiently degrading lactose in advance so as to be 20 mM or less after completion of fermentation, which is a feature of the present invention, In some cases, the term “fermentation mix” may be used for those from which lactose has been removed.

In the production method of the present invention, it is necessary that the lactose content after completion of fermentation by adding four types of lactic acid bacteria to the fermentation mix is 20 mM or less. By setting the lactose content after the completion of fermentation to 20 mM or less, even in the state in which the four types of lactic acid bacteria coexist in the process of distribution and storage thereafter, a decrease in pH during storage of the fermented milk is prevented, It is possible to prevent flavor deterioration with time and decrease in the number of viable Bifidobacterium.
In order to set the lactose content after the completion of fermentation to 20 mM or less, the lactose content at the start of fermentation is desirably 20 to 30 mM.
In order to set the lactose content after fermentation to 20 mM or less, a method using a fermentation mix containing a milk raw material with a low lactose content as a raw material in advance, or a fermentation containing a milk raw material that does not particularly reduce the lactose content. There is a method in which lactose-degrading enzyme is added to the mix, decomposed to 20-30 mM, and subjected to fermentation through a step of inactivating the enzyme.

  As the lactose-degrading enzyme used in the fermentation mix of the present invention, any commercially available one can be used. For example, GODO-YNL (manufactured by Godo Shusei Co., Ltd.), lactase F “Amano”, lactoles L3 (Amano Enzyme) Sumilacto L (manufactured by Shin Nippon Chemical Industry Co., Ltd.), lactase Y-AO (manufactured by Yakult Pharmaceutical Co., Ltd.), lactozyme (manufactured by Novozymes Japan Co., Ltd.) and the like can be used.

In the present invention, the process after preparation of the fermentation mix conforms to a general method for producing fermented milk. That is, fermented milk is produced by the following method. The fermentation mix is appropriately mixed with a homomixer or the like, and then homogenized at a homogeneous pressure of 0 to 500 kg / cm ² . The homogenized fermentation mix is then sterilized. Sterilization can be performed using a plate heat exchanger, a tubular sterilizer, a jacketed tank, or the like, and may be performed at 70 to 140 ° C. for 1 second to 30 minutes, preferably 90 to 95 ° C. for 1 minute to 10 minutes. It should be done for a minute. Then, it cools to 40-50 degreeC using a plate type heat exchanger, a tubular type cooler, a jacket type tank, etc. At least Lactobacillus delbrueckii subsp. Bulgaricus and Streptococcus thermophilus and Bifidobacterium longum and Lactobacillus gasseri in the cooled fermentation mix 1 to 8% by weight of a lactic acid bacteria starter is added, held at a temperature suitable for the growth of the lactic acid bacteria used (around 32 to 43 ° C.), fermented for about 1 to 24 hours, preferably about 2 to 5 hours. Let it be stationary type fermented milk.
As Lactobacillus gasseri, SBT-2055 (Accession Number FERM BP-10953) is particularly preferable, and as Bifidobacterium longum, SBT-2928 (Accession Number FERM P) is particularly preferable. -10657) is preferred. Other lactic acid bacteria starters include Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus casei, Lactococcus lactis, etc. The starter is not particularly limited as long as it is a lactic acid bacterium starter that is commonly used in the field.
In addition to mixing and fermenting all lactic acid bacteria as described above, the lactic acid bacteria may be mixed after being fermented by one or more kinds. After the fermentation is completed, the obtained stationary fermented milk is crushed and filled into a container as necessary to obtain a stirred fermented milk. As a crushing method, a method of refining the tissue using a homogenizer, stirring, a dish, or the like can be used.

  Hereinafter, the present invention will be described in more detail with reference to examples of the present invention, but the present invention is not limited thereto.

Lactobacillus delbrueckii subsp. Bulgaricus SBT-0164, Streptococcus thermophilus SBT-10137 (Accession Number FERM P-19531), Bifidobacterium longum SBT- Method for producing fermented milk using 2928 (Accession No. FERM P-10657) and Lactobacillus gasseri SBT-2055 (Accession No. FERM BP-10953) Preparation method of fermentation mix After mixing the raw material of A division of Table 1, it heated to 65 degreeC and applied to the homogenizer. Subsequently, after cooling to 5 ° C., lactose-degrading enzyme (Lactores L3, Amano Enzyme) was added at 0.3 wt%, and the enzyme reaction was performed at 5 ° C. for 16 hours to adjust the lactose content to 27 mM or less. . This was heated up to 90 degreeC, the enzyme was deactivated, it cooled to 39 degreeC, and the fermentation mix was obtained.

2. Method for preparing fermented milk The lactic acid bacteria starter of the ratio of the division | segmentation B of Table 1 was added to the fermentation mix obtained by. Fermentation was performed at around 39 ° C., and the fermentation mixture was adjusted to pH 4.85, and the fermentation was completed. The lactose content was 19.5 mM.

[Test Example 1]
The control was prepared using a fermentation mix that had not undergone lactose degradation. Other procedures were performed in the same manner as in Example 1. The control and Example product 1 were stored at 10 ° C. for 19 days.
1. Measurement of Lactose Content For Example Product 1 and the control, the lactose content at the start of storage (Day 0) and Storage 7 and 19 was measured by ion chromatography (ICS-5000: Thermo Scientific Co., Ltd.). did. The measurement result of lactose content is shown in FIG.
From the results shown in FIG. 1, the lactose content of the example products was 1/10 or less compared to the control in any storage days.
2. Measurement of the number of viable bacteria With respect to Example Product 1 and the control, the number of lactic acid bacteria was measured at the start of storage (Day 0) and on Days 7 and 19. All the bacteria were anaerobically cultured at 37 ° C. for 3 days, and the number of grown colonies was counted. There was no difference in the numbers of Streptococcus thermophilus and Lactobacillus gasseri between the control and the examples (FIGS. 2 and 3). The number of bacteria of Lactobacillus delbrueckii subsp. Bulgaricus was slightly lower in Example product 1 than in the control (FIG. 5). The number of Bifidobacterium longum was higher in Example Product 1 than in the control on the 17th day of storage, and the survival rate was high (FIG. 4).
From the above results, it can be seen that the product of Example 1 has improved survival of Bifidobacterium longum compared to the control.
3. Measurement of pH With respect to Example Product 1, the pH was measured at the start of storage (day 0) and on days 7 and 19 of storage. The results are shown in FIG.
From FIG. 6, the pH of the control and Example product 1 was the same at the start of storage, but the pH of the control decreased significantly according to the number of storage days. On the other hand, in Example Product 1, the pH drop accompanying storage was gradual compared to the control.
4). Sensory evaluation Sensory evaluation was performed on Example Product 1 at the start of storage (day 0) and on the 7th and 19th days of storage. It was judged comprehensively whether it was fermented milk with little sourness and excellent balance between sourness and sweetness, and evaluated as good: ○, slightly good: Δ, bad: ×. The evaluation was conducted by 5 trained specialized panels. The results of sensory evaluation are shown in Table 2.
From the results shown in Table 2, compared with the control, the product of Example 1 was good in evaluation on the 0th, 7th and 19th days of storage.

  After performing the fermentation in the same procedure as in Example 1, the curd was crushed by stirring and cooled to 5 ° C. to obtain stirred fermented milk (Example Product 2). Control and Example product 2 were stored at 10 ° C. for 19 days. Compared to the control, the product of Example 2 was good in the evaluation on the 19th day after storage.

After performing to fermentation in the same procedure as Example 1, the curd was crushed by stirring and cooled to 5 ° C. A sugar solution prepared by mixing isomerized sugar and warm water and a fermentation mix were mixed at a ratio of 1: 2, and homogenized at 150 kg / cm ² to obtain liquid fermented milk (Example Product 3). The control and Example product 3 were stored at 10 ° C. for 19 days. Compared to the control, the product of Example 3 was good in evaluation on the 19th day after storage.

  According to the present invention, at least Streptococcus thermophilus, Lactobacillus gasseri, Bifidobacterium longum and Lactobacillus delbrueckii subsp. bulgaricus) Even if it contains multiple bacterial species, it does not involve a large-scale facility change, suppresses the pH drop during storage of fermented milk, has a good flavor, and has good survival of Bifidobacterium It is possible to provide a method for producing milk.

Claims (3)

Production of fermented milk containing at least Streptococcus thermophilus, Lactobacillus gasseri, Bifidobacterium longum and Lactobacillus delbrueckii subsp. Bulgaricus A method,
The method for producing fermented milk, comprising a step of adding the lactic acid bacteria to a fermentation mix for fermentation, and fermenting the lactose content after the fermentation to 45 mM or less. The method for producing fermented milk according to claim 1, wherein the lactose content of the fermentation mix is adjusted by lactose decomposition. Fermented milk after storage at 10 ° C. for 19 days after completion of fermentation
The viable count of Streptococcus thermophilus in fermented milk is 1 × 10 ⁸ CFU / mL or more, and the viable count of Lactobacillus gasseri is 1 × 10 ⁷ CFU / mL, The viable count of Bifidobacterium longum is 1 × 10 ⁶ CFU / mL or more,
The number of viable bacteria of Lactobacillus delbrueckii subsp. Bulgaricus is 1 × 10 ⁵ CFU / mL or less, and the pH of fermented milk is in the range of 4.3 to 4.6. ,
The manufacturing method of fermented milk of Claim 1 or 2.