JPH02154638A - Production of fermented milk with lactobacillus bifidus - Google Patents

Abstract

PURPOSE:To industrially and advantageously produce a fermented milk with Lactobacillus bifidus, having good flavor and excellent in survival properties of the Lactobacillus bifidus by filling a milk in a state of no head space using a container having high gas barrier properties. CONSTITUTION:A fermented milk containing Streptococcus.diacetilactis coexisting with Lactobacillus bifidus is produced. In the process, a container having high gas barrier properties, e.g. a container consisting of glass or PET, is used to fill milk therein so as to provide a state of no head space therein. The resultant container is then sealed with a sealing material similarly using a material having high gas barrier properties.

Description

DETAILED DESCRIPTION OF THE INVENTION A) Industrial Application Field The present invention relates to a method for producing Hifidobacterium fermented milk. Bifidobacterium is a microorganism that always resides in the human intestine, and it is known that its status in the intestine is closely related to human health. It is believed that improving the bifidobacterium flora is useful for preventing and treating various diseases, and a market has been formed for products containing various bifidobacteria. The preventive and therapeutic effects of bifidobacteria have been reported to include elimination of harmful intestinal bacteria, immune activation, infection prevention, suppression of carcinogenesis, and other intestinal regulation effects.

By using containers with high gas barrier properties during manufacturing and filling and sealing without head space,
The purpose of the present invention is to industrially advantageously obtain superior bifidobacterium-fermented milk, which is characterized by good flavor and good survival of bifidobacteria.

B) Conventional techniques and their problems In general, bifidobacteria have the following properties, and therefore a rapid decrease in the number of viable bacteria in fermented milk is observed.

The reason for this is that it is an obligate anaerobic bacterium, so it easily dies in the presence of oxygen. Bifidobacteria have significantly weaker acid resistance than normal dairy lactic acid bacteria, and are rapidly killed by lactic acid produced in fermented milk.

In order to prevent such a decrease in the number of bifidobacteria in fermented milk, the following treatment method is adopted for boat fishing. ■A method of obtaining a mutant strain of Bifidobacterium that has resistance to acid and oxygen, and using this to produce Bifidobacterium-fermented milk. ■A method in which a microorganism that produces catalase, such as yeast or Bacillus subtilis, or a cell-free extract thereof is added to remove H and O□ produced within the system. ■Method using Streftococcus and Thermophilus, which have high oxygen absorption capacity. Alternatively, (2) A method of reducing dissolved oxygen in the preservation system, such as adding L-ascorbic acid and Lactobacillus or Acidophilus. ■Streptococcus and Diacetylactis coexist. Alternatively, ■ use lactate monooxygenase. etc. Produces carbon dioxide gas within the system. Other methods have been adopted.

However, the use of mutant strains of Bifidobacterium involves the problem that they are not Bifidobacteria in their natural state, and adding a reducing agent to the fermentation pores requires the use of additives. Not suitable for bacterially fermented milk. On the other hand, when adding yeast, it is necessary to provide pressure resistance to the container because of the carbon dioxide gas produced, and it is extremely difficult to control the amount of produced gas. Furthermore, when Streptoconcus and diacetylactitis coexist, excessively produced diacetyl and acetoin are not favorable in terms of flavor.

(1) Means for Solving the Problems The inventor has conducted extensive research to solve the above-mentioned problems, and as a result, he has completed the present invention. That is, when producing a fermentation hole in which Streb I. coccus diacetylactis and Hyphidobacterium coexist, a container with high gas barrier properties is used and the container is filled and sealed without head space. It has been discovered that while the survival of bifidobacteria in fermented milk is maintained well, the generation of diacetyl and acetoin flavors is slightly suppressed, and fermentation holes with good flavor can be obtained.

Bifidobacterium shows a rapid tendency to die in fermented milk, but this was disclosed in Japanese Patent Application Laid-Open No. 63-94938 by the present applicant.
When used together with Streptoconcus and Diacetylarftis, the survivability of the product during storage is significantly improved. Streftococcus and diacetylactis perform a decarboxylation reaction from citric acid in a fermentation substrate made mainly of milk to produce diacetyl and acetoin.

It is known that carbon dioxide generated by this decarboxylation reaction increases the anaerobic degree in fermented milk and is effective in preserving bifidobacteria. It is believed that the growth of anaerobic bacteria stops due to high levels of redox and is killed by the oxidation reaction with oxygen and the hydrogen peroxide produced. This improves the survival of bifidobacteria.

However, when Streftococcus and Diacetylactis are used to improve the survival of Bifidobacteria, diacetyl and acetoin are produced simultaneously with carbon dioxide gas.

Diacetyl and acetoin are important flavor components of yogurt, fermented cream, fermented butter, etc., but when they are produced in excess, a certain fishy odor is felt and the flavor is not necessarily desirable. Therefore, the inventor focused on the fact that the conversion of acetoin to diacetyl occurs under aerobic conditions, and when producing bifidus seedling fermented milk, he used a container with high gas barrier properties and a container with no head space. I tried to keep it sealed. As a result, it was discovered that the fishy odor caused by Streftococcus and Diacetylactis was significantly reduced, resulting in a pleasant flavor with well-balanced taste components. At the same time, the survivability of bifidobacteria was maintained in good condition during the storage period. Based on these findings, we have completed the present invention. The present invention will be explained in detail below.

The process for manufacturing the fermentation hole of the present invention uses raw milk/milk raw materials as the main raw materials, and if necessary, adds sucrose, fruit juice, etc., and homogenizes and sterilizes them in the usual manner as the fermentation substrate. do. 1.0% to 10.0% (v/v) of Bifidobacterium starter, Streftococcus, Diacetylarftis starter, and if necessary, conventional lactic acid bacteria starter for dairy industry.
is added to the substrate. The container is made of a material with high gas barrier properties, such as glass, PET, EVAL, or PVDC. This container is filled so that there is no waste space, and is sealed with a seal material also made of a material with high gas barrier properties. This thing 20~40°
C1 Preferably, fermentation is performed at a temperature range of 30 to 35°C until the lactic acid acidity becomes 0.70 to 1.00% (v/w), and then cooled. Bifidobacterium, Streftococcus, and Diacetylactis do not necessarily have to be used together for fermentation, and Bifidobacterium starter, Streftococcus, and Diacetylactis starter that have been fermented separately can be used in the conventional dairy industry. Even if it is added afterward to the fermentation hole where fermentation was carried out with lactic acid bacteria, the survival of bifidobacteria is maintained well.

At this time, Streptoconcus and Diacetylactis are
It must be cultured with oxygen cut off. In order to keep the amount of dissolved oxygen in the fermentation pores as low as possible before filling, the survivability of bifidobacteria can be further improved by passing through a degassing process during sterilization.

The above is the method for producing bifidobacteria-fermented milk, which is the object of the present invention and has good survival of bifidobacteria and a good flavor. Hereinafter, the effects of the present invention will be explained based on Examples.

Example 1 In this example, a glass container with high barrier properties was used, an aluminum seal was attached as a lid material, there was no head space, and the fermentation hole was 20 m1 in size compared to 80 m1.

We prepared a state with each space and compared the two. In addition, the fermentation hole was adjusted by the following method. That is, raw milk fortified with skim milk powder so that the non-fat milk solids content is 10% (v/w) is homogenized in a conventional manner, heat-treated at 95°C for 30 minutes, and then cooled to 33°C. was used as the fermentation substrate. The starter used is 1O non-fat milk solids.
% (v/v) of skim milk powder was heat sterilized at 95° C. for 30 minutes and used as a common medium. Proceed with lactic acid fermentation,
Streftococcus thermophilus and Lactobacillus bulgaricus were inoculated at a ratio of 1.9:0.1 to produce a good fermentation flavor.
The lactic acid bacteria starter was prepared by culturing at ℃ for 17 hours.

On the other hand, Bifidobacterium starter was prepared by inoculating Bifidobacterium and longum and culturing it under anaerobic conditions at 34°C for 17 hours. Streftococcus, diacetylactis starter contains Bifidobacterium longum and Streftococcus, diacetylactis 5:
The cells were inoculated at a ratio of 2:2 and cultured at 34°C for 17 hours for adjustment.

Fermentation substrates include 3.0% (V/V) lactic acid bacteria starter, 5.0% (V/S) Bifidobacterium starter, 1.0% C Streztococcus, and Diacetylactis starter.
After adding v/li to each, stirring and homogenizing, the above-mentioned containers were respectively filled in the above-mentioned state and fermented at 33°C. A panel of 20 experts evaluated the changes in flavor of both products over time after fermentation. The results are shown in Table-1.

(Note) Diacetyl and acetomono odor reviews gB + + + + + + + + + ++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ In Example 1, which is normally a little tasteless and tasteless, as shown, cetyl and acetoin, which have gas barrier properties, did not generate odor and had a good flavor.

Example-2 Raw milk enriched with skim milk powder so that the non-fat milk solids content was 9.Sjf (w/w) was homogenized in a conventional manner and heated to 95°C.
The number of Bifidobacteria when the Bifidobacterium starter was filled in a 5° container and stored in aluminum at 10°C without head space.
number/ml) and Table 2.

(Note) ■Lactic acid acidity (titration method) ■Bifidobacteria count (anaerobic culture method using BL blood plate) ■Streptococcus Selective counting was performed using a medium with the following composition.

Composition Whey 1000 m Trypticase Peptone Glucose 5.0 g Agar
15.0gPl-I
6.6 Add 1% (v/v) of each of liquid A and liquid B to autoclay 7.
Use after adding to the above sterilized medium.

Solution A: 10% Potassium ferricyanide Solution B: 2.
5% ferric citrate 2, 5% sodium citrate Solutions A and B are each sterilized by filter before use.

ReferencesG. M. Kempler and L. L. M
ckeyJ, Dairy Sci. , 64.
1527-ls39, 1981 ■ Lactic acid bacteria count (conventional method using BCP medium) As shown in Example 2, when Bifidobacterium, Streftococcus, and Diacetylactis coexist, it is packed in a state with no hent spaces. In this case, the survival of bifidobacteria was almost the same as when the fermentation hole had a head space of 20 ml with respect to 80 ml. In terms of flavor, it was delicious with little diacetyl and acetoin odor.

Effects of the invention In order to improve the survival of Bifidobacterium in fermented milk, Streftococcus. coexist with diacetylactis,
When carbon dioxide gas is generated in the system to increase the anaerobic degree and protect bifidobacteria, diacetyl and acetoin, which are simultaneously generated, impair flavor. The present invention focuses on the fact that the conversion of acetoin to diacetyl proceeds under aerobic conditions, attempts to block the fermentation pores from air, that is, oxygen, and uses containers and equipment with high gas barrier properties. The mixture was filled and sealed in the absence of head space and fermented. As a result, it was possible to successfully obtain fermentation pores in which diacetyl and acetoin odors were not produced and Bifidobacterium had good survival. It is assumed that this is due to the fact that the conversion of acetoin to diacetyl is suppressed by fermentation under anaerobic conditions without headspace, but the details are not known.

The phenomenon is that there is no fishy odor associated with diacetyl and acetoin odor, and the survival of bifidobacteria is high.
It was an extremely commercially valuable invention that was expected to have preventive and therapeutic effects.

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Claims (1)

[Claims] Bifidobacterium-fermented milk containing Streftococcus and Diacetylactis is filled into a container with high gas barrier properties and sealed without head space. A method for producing good bifidobacteria-fermented milk.