JPH06327401A - Fermented milk and production process thereof - Google Patents

Abstract

PURPOSE:To obtain the title fermented milk of high L-lactic acid ratio, high safety and mellowly acidic taste by effecting lactic fermentation of milk using specific bacteria in Lactococcus and Lactobacillus. CONSTITUTION:The lactic fermentation of milk is performed using Lactococcus lactis ssp. lactis (FERM-p-13647) and Lactobacillus confusus (FERM-p-13646) to obtain the objective fermented milk of 0.4 to 1.2 lactic acidity and more than 85% L-lactic acid in total lactic acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new fermented milk having a slightly effervescent, refreshing and mild flavor and a method for producing the same.

[0002]

Fermented milk is obtained by lactic acid-fermenting sugar in raw material milk to convert it into lactic acid. Depending on the type of lactic acid bacterium used in the lactic acid fermentation, the lactic acid produced may be D-lactic acid or L-lactic acid. -There are two types of optical isomers with lactic acid.

However, only L-lactic acid is produced in the human body, which plays an important role in the metabolic function in the body. That is, the L-lactic acid is important as an energy source in the heart, and the L-lactic acid is also used in skeletal muscle, kidney, liver, brain and the like. Thus, humans have the ability to metabolize L-lactic acid, but when D-lactic acid is ingested from the outside, it is hardly metabolized. Therefore, excessive intake of D-lactic acid causes metabolic abnormality. Therefore, in WHO, the intake of D-lactic acid is not preferable for infants less than 3 months old, and the intake of D-lactic acid other than infants is generally preferable to be 100 mg / kg or less. More recently, it has been reported that the upper limit of the intake of D-lactic acid should be within 60 mg / kg. In any case, a large intake of oral D-lactic acid is not preferable.

There are various types of fermented milk. Among them, the one that is generally well known at present is a bacterium producing L-lactic acid, for example, Streptococcus thermophilus.
custhermophilus) and D-lactic acid producing bacteria such as Lactobacillus bulgaric
us, but barge (Bergey's Manual Systematic Bacterio
(L. delbrueckii subsp. bulgaricus)) is a so-called yogurt that is produced in combination with this, for example, a report by Kawanishi et al.
According to (5)), D-lactic acid is 25.
It accounts for 6%, and the ratio of D-lactic acid increases more and more as the aging progresses, and it is said that the ratio will eventually reach about 44%.

Further, as fermented milk other than the above yogurt,
For example, skimmed milk or milk with 1.5-2.0% fat left,
Streptococcus lact
is) and Streptococcus (Streptococ)
Fermented buttermilk obtained by adding cus citrovorus) and fermenting it is also known, and it consists of L-lactic acid only, but it is presently rarely consumed in Japan due to its palatability. Furthermore, Lactobacillus acidophilus (La
It is known that in Acidophilus milk obtained using ctobacillus acidphilus), the bacterium produces D-lactic acid and L-lactic acid at about 50% each. Further, for example, fermented milk can be obtained by using Lactobacillus casei, but the fermented milk thus obtained usually has an unfavorable flavor, and in order to obtain a fermented milk product, flavor and sweetness are required. It is necessary to mask the flavor by adding ingredients or the like.

As described above, all of the currently known fermented milks still have problems to be solved, and especially, the ratio of L-lactic acid is high and it is safe especially for ingestion by infants. In addition, fermented dairy products that meet the tastes of Japanese and have a mellow sourness and a refreshing and mild flavor have not yet been developed.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a new fermented milk product which solves all the above problems of conventional fermented milk.

In particular, the present invention has a high proportion of L-lactic acid, is particularly safe for ingestion by infants, suits Japanese tastes, and has a mellow sourness and a refreshing and mild flavor. The purpose is to provide.

The inventors of the present invention have conducted extensive studies as a result of the above object, and as a result, when using two specific types of lactic acid bacteria, which have never been used for the production of this type of fermented dairy product, the above objects are met. The present invention was completed here by discovering the fact that a new fermented dairy product can be provided.

[0010]

That is, the present invention relates to Lactococcus lactis ssp. Lactis (Lactococus)
lactis ssp. lactis) and Lactobacillus confusus (Lactobacillus confusus) are used to lactic acid-ferment the raw milk, and the lactic acid acidity is 0.4 to 1.2 and L-
A method for producing fermented milk, which comprises fermented milk in which lactic acid is 85% or more of the total lactic acid, the degree of lactic acid obtained by the method is 0.4 to 1.2, and L-lactic acid is the total lactic acid. It relates to fermented milk characterized by being 85% or more.

The fermented milk provided by the present invention is especially
-Because of high lactic acid content and conversely low D-lactic acid content, it is suitable not only for general adults but also especially for infants and children, and it is safe. Further, the fermented milk of the present invention,
It has an appropriate lactic acidity and, on the basis of this, has a slightly effervescent, refreshing and mild flavor. Moreover, the product has characteristics that it is well suited to the tastes of Japanese people and that it does not generate an undesirable flavor or the like.

The production of the fermented milk of the present invention will be described in detail below. In order to produce the fermented milk of the present invention, it is essential to use the above-mentioned specific two kinds of lactic acid bacteria in combination. Each bacterium used here is known per se and is easily available to those skilled in the art. For example, one of the above bacteria, Lactococcus lactis
sp. As lactis, typically, the present inventors have newly identified and isolated MOS-11 from raw milk (deposited as MOS-11 at the Institute of Life Science and Technology (FERM), Institute of Industrial Science and Technology, FERM P-13647) and ATCC (American Type Culture Collection) 19435,
ATCC11454, ATCC29146, JCM (RIKEN Institute for Microbial System Preservation Facility) 1158, IFO (Institute for Research Institute 12007, etc.) can be used.
It is also possible to use strains from various places separated from the natural world, raw milk and the like.

The other bacterium, Lactobacillus confusus, is typically NGB-82 (FERM P-1) newly separated and identified from raw milk by the present inventors.
3646), JCM1093, JCM1160, ATC
In addition to C10881 and the like, various strains isolated from the natural world, raw milk and the like can be used.

The above-mentioned bacteria can be used in the present invention as they are obtained, or after culturing in an appropriate medium such as a general lactic acid storage detection medium or a general lactic acid inoculation medium in advance,
It is also possible to act on the raw material milk in the state of the culture solution or in the state of cells collected from the culture solution by centrifugation or the like.

The combination ratio of the above two kinds of bacteria in the method of the present invention is not particularly limited as long as both can act on the raw material milk to carry out lactic acid fermentation, but usually the latter is 1/20 compared to the former.
〜20 times (bacteria number), more preferably 1 /
It is suitable to be used together in the range of about 10 to 5 times.

In the method of the present invention, the raw material milk may be any of various kinds known to be applicable to this type of lactic acid fermentation, and specific examples thereof include milk which is usually commercially available, and particularly It is not limited. Besides, skim milk and the like can be similarly used as the raw material milk. The ratio of the above-mentioned specific two kinds of lactic acid bacteria to the raw material milk can be appropriately determined and is not particularly limited, but in general, the viable cell count of the added lactic acid bacteria is about 10 ⁴ to 10 ⁹ / ml at the final concentration, preferably 10 ⁵ to 10 ⁷
It is preferable to be selected from the range of about / ml.

The lactic acid fermentation according to the method of the present invention can be carried out under suitable conditions under which each of the above-mentioned bacteria can act, and the conditions themselves are not particularly limited. Usually, for example, the above Lactococcus lactis ssp. The optimum pH for growth of lactis and Lactobacillus confusus is around neutral, and the pH of ordinary milk, skim milk, etc. is around 6.5, and therefore, it is not necessary to adjust the pH. When the pH is acidic due to the addition of fruit juice or the like, this is adjusted to 5.5 to 7.
It is preferable to adjust to around 5. The growth temperature is Lactococcus lactis ssp. Ractis is in the range of about 5-40 ℃, Lactobacillus confusus is about 15-45
Considering that the temperature is in the range of 0 ° C, it is suitable that the temperature is in the range of approximately 15 to 40 ° C, preferably approximately 20 to 35 ° C. The fermentation time varies depending on the above temperature conditions and can be appropriately determined according to the acidity of the fermented milk of interest, but is generally about 6 to 16 hours.

By the above lactic acid fermentation, desired fermented milk satisfying the desired lactic acidity and L-lactic acid content of the present invention can be obtained. The lactic acid content and L-lactic acid content of the fermented milk obtained are
It can be appropriately changed within the scope of the present invention by appropriately adjusting the conditions of the lactic acid fermentation, such as the concentration of bacteria to be used, pH, temperature conditions, and action time. Further, the L-lactic acid content can be appropriately adjusted by the combined use ratio of the bacteria to be used in combination.

The fermented milk thus obtained may be used as it is as a plain type or as a drink type fermented milk after the usual post-treatment such as homogenization, pectin, sugar and the like, and agar or gelatin and sugar are added. As hard type fermented milk, fruit juice, pulp, flavors, etc. are added as soft type fermented milk, or frozen to freeze type, and diluted or sterilized to produce lactic acid bacteria beverages. can do.

[0020]

EXAMPLES Examples will be given below to explain the present invention in more detail, but the present invention is not limited to these.

[0021]

Example 1 Lactococcus lactis ssp. Was subcultured in a general lactic acid storage detection medium (Nissui Pharmaceutical). Lactis MOS-11 (FERM P-13647) and Lactobacillus confusus NGB-82 (FERM
P-13646) in milk sterilized at 30 ° C
Preculture was carried out for 8 hours. 10 ml each (6.8 × 10 ⁸ / ml and 1.6 × 10 ⁸ / ml, respectively) as a starter were collected and added to 1 liter of commercially available milk that had been sterilized for 40 minutes at 100 ° C. Lactic acid fermentation was performed by static culture for a period of time.

As a result, a fermented milk having an acidity of 0.73% (calculated as lactic acid, the same applies hereinafter) having a refreshing and mellow flavor was obtained.

The amount of L- and D-lactic acid in this fermented milk was measured by using F kit D-lactic acid / L-lactic acid manufactured by Boehringer Mannheim, and as a result, D-lactic acid was 9.8% and L-lactic acid was 90%. It was 0.2%. After the fermented milk was stored in the refrigerator for 2 days and 6 days, the L-lactic acid and D-lactic acid contents were measured in the same manner, and there was no change in the amount.

[0024]

Example 2 Lactococcus lactis ssp. Lactic acid fermentation was carried out in the same manner as in Example 1 using Lactis ATCC19435 and Lactobacillus confusus JCM1093 to obtain fermented milk having an acidity of 0.67%.

The amount of L-lactic acid was 88.2%.

[0026]

Example 3 The starter pre-cultured in the same manner as in Example 1 was inoculated into skim milk powder (100 g / 1 l) dissolved in water in an amount of 2% each, and statically cultured at 25 ° C. for 16 hours. Lactic acid fermentation was performed.

As a result, a low-fat fermented milk with an acidity of 0.78% and a mild flavor was obtained.

The amount of L-lactic acid in this product was 92.1%.

[0029]

[Example 4] Lactococcus lactis ssp. Lactis MOS-11 (FERM P-13647) was sterilized in a general lactic acid bacterium inoculation medium (manufactured by Nissui Co., Ltd.), and Lactobacillus confusus NGB-82 (FERM P-).
13646) was inoculated into MRS broth (manufactured by Becton Dickinson) and precultured at 30 ° C. for 16 hours. After culturing, centrifuge (8000 rpm, 10 minutes)
Collect the cells at, wash with sterile water, and sterilize in advance 10%
Suspended in skim milk. These suspensions were frozen at -80 ° C to a thickness of about 1 cm and then freeze-dried.

The viable cell count of the freeze-dried powder thus obtained was Lactococcus lactis ssp. Ractis M
It was 1.3 × 10 ¹¹ / g in OS-11 and 1.1 × 10 ¹¹ / g in Lactobacillus confusus NGB-82.

The freeze-dried powders of the above are mixed in equal weights,
The seeds were used as fermented milk inoculum, and 0.2 g of each of them was added to a commercially available 1 liter paper-packed milk and fermented overnight at room temperature.

As a result, a fermented milk having a refreshing and mild flavor with an acidity of 0.75% was obtained, and the amount of L-lactic acid in this fermented milk was 90.6%.

[0033]

Comparative Example 1 Lactococcus lactis ssp. Lactis ATCC19435 was precultured in the same manner as in Example 1, and inoculated into a commercially available 1-liter paper-packed milk at a concentration of 2%, and fermented at 25 ° C. for 16 hours.

The acidity of the fermented milk thus obtained is 0.82.
%, And 97.9% was L-lactic acid.

In order to compare this product with the fermented milk of the present invention obtained in Example 4, a sensory test (compare each item of aroma, sourness, freshness and comprehensive evaluation) by 10 panelists was carried out. It was

The results are shown in Table 1.

[0037]

[Table 1]

As is clear from Table 1, Lactococcus lactis ssp. Lactic acid fermentation by using lactis alone can selectively produce L-lactic acid, but it is difficult to obtain a preferable one organoleptically, whereas according to the method of the present invention, It can be seen that fermented milk with excellent sensory properties can be obtained based on the combined use with Lactobacillus confusus.

The organic acid composition in each of the above-mentioned product samples was measured by HP.
The results measured by the LC method are shown in Table 2.

[0040]

[Table 2]

From Table 2 as well, the sample obtained in Comparative Example 1 contains almost only lactic acid (citric acid is derived from the raw material) due to the homolactic fermentation, whereas the sample obtained by the method of the present invention is different. For example, because Lactobacillus confusus carries out heterolactic fermentation, an increase in acetic acid and the like was observed in addition to lactic acid, and such a difference in the composition of the organic acid produced was
It was speculated that this would cause a difference in the above-mentioned sensory evaluation.

[0042]

Comparative Example 2 Lactobacillus acidophilus JCM1
132 was pre-cultured in milk at 37 ° C. for 24 hours, inoculated into milk in a commercial 1 liter paper pack so as to be 3%, and fermented at 37 ° C. for 48 hours.

As a result, fermented milk having an acidity of 0.77% and an L-lactic acid content of 43.8% was obtained.

[0044]

[Comparative Example 3] Lactobacillus delbruequii ssp.
Bulgaricus (formerly Lactobacillus bulgaricus)
ATCC 11842 and Streptococcus salivarius ssp. Thermophilus (formerly known as Streptococcus thermophilus) OFC492 was pre-cultured in sterilized milk at 37 ° C for 8 hours, and then pre-cultured at 100 ° C for 4 hours.
Commercially available milk that had been sterilized for 0 minutes was inoculated at 2% each and fermented at 37 ° C for 8 hours.

As a result, fermented milk having an acidity of 1.07% and an L-lactic acid content of 58.3% was obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Seiichi Shimizu 1237-2 Motomachi, Tosu City, Saga Prefecture 1002 Loire Mansion 1001 (72) Inventor Shuichi Sakamoto 2352-7, Suwano Town, Kurume City, Fukuoka Prefecture 304 Daiwa Palace 304, Suwano

Claims (2)

[Claims] 1. A lactic acid acidity of 0.4 to 1.2 and L-
Fermented milk characterized in that lactic acid accounts for 85% or more of the total lactic acid. 2. A Lactococcus lactis ssp. Characteristically, lactic acid fermentation of raw material milk is performed using lactis and Lactobacillus confusus to obtain fermented milk having a lactic acid acidity of 0.4 to 1.2 and L-lactic acid being 85% or more of the total lactic acid. Method for producing fermented milk.