JPH03292853A - Fermented milk depressed in enhancement of acidity during storage and preparation thereof - Google Patents

Abstract

PURPOSE:To prepare a fermented mild having a good taste and not producing an excessive amount of acids during an appreciation period thereof to maintain the suitable acidic taste thereof by adding chitosan and a fermentation starter to a raw material milk. CONSTITUTION:A raw material milk such as milk or defatted milk is mixed with a small amount of chitosan and with a fermentation starter containing the Lactobacillus bacteria or the Bifidobacterium bacteria and subsequently cultured at approximately 37-40 deg.C for several hours to ten and several hours to prepare a fermented milk preventing the production of acids. The fermentation starter employed therein includes a starter containing at least one of Lactobacillus.helveticus, Lactobacillus.bulgarius, Lactobacillus.acidophilus and the Bifidobacterium bacteria.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to fermented milk whose acidity hardly increases during storage. "Fermented milk" here includes yogurt in a broad sense, lactic acid bacteria drinks, etc.

[Prior art]

Fermented milks, including yogurt, lactic acid bacteria drinks, and their analogues, are generally made by adding Lactobacillus bulgaricus to the raw material mix prepared from animal milk.
Streptococcus 14aricus), Streptococcus 1 thermophilus
therm.

Traditional lactic acid bacteria such as B. philus and Bifidobacterium 5pecies
), Lactobacillus acidophilus (Lactob
It is produced by using bacteria useful for the intestine, such as Acillus acidophilus, in combination or alone.

The flavor and aroma of fermented milk differs depending on the type of fermented milk, and brain yogurt, which consists only of milk-derived ingredients, depends on the type and strain of bacteria used, and contains organic acids such as lactic acid and acetic acid produced by the strain used, as well as small amounts. characterized by by-products (carbonyl compounds such as acetaldehyde, etc.).

In addition, fermented milk other than plain yogurt (for example, Frappert yogurt, fruit yogurt, etc.) is also affected by added ingredients such as sweeteners and flavorings.

Therefore, in order for any type of fermented milk to be delicious and have a good flavor, the most important factor is that it exhibits appropriate sourness due to lactic acid or the like.

In other words, the lactic acid bacteria used in fermented milk are still alive and the acidity becomes stronger over time, so the normal shelf life is about 14 days, and after a week, acid production becomes excessive and the sourness becomes stronger. The problem arises that it becomes too strong. especially,
This tendency is remarkable in fermented milk containing lactic acid bacteria such as Lactobacillus helveticus and Lactobacillus bulgaricus in the starter.

Conventionally, the following methods have been reported in order to suppress the phenomenon in which the amount of acid produced becomes excessive and the sour taste becomes strong.

■ Method using low-temperature sensitive mutant strains (Japanese Patent Application Laid-open No. 6223
No. 9), method using lactose non-fermenting artificial mutant strain (Japanese Patent Application Laid-open No. 54-38187, Japanese Patent Publication No. 42-27293),
Furthermore, there is a method using lactose-fermenting natural mutant strains (JP-A-2-53437); ■ A method of weakening the vitality of bacteria by heating for a certain period of time at a temperature that does not completely kill the bacteria [JP-A-50-67451] , G. Wae
s “Milchiwj
ssenschaft), niece, (3) 146-14
8 (1987) ], and ■ A method using low lactose skimmed milk from which lactose has been removed as a raw material (R, L, Richte
r et al: r Journal Op Food Science” (J, Food Sci,), 38,796-798 (
1973) etc.

However, among these methods, method (①) has the limitation that it is only effective when using a specific mutant strain, and in addition, the flavor and texture of the obtained product may be rather inferior, so it should not be used appropriately. Even if it has a strong acid-generating ability, it is not suitable for practical use.

In addition, in the above method (■), the heat treatment process at a constant temperature and time is complicated and difficult to adjust, requires energy for heating, and in addition, it causes a decline in the quality of the product, such as flavor and structure. There is a simple drawback. Furthermore, method (1) above requires a process for removing lactose from raw milk, and is not economically practical.

[Problem to be solved by the invention]

The present invention was made to solve the problems of soft soil seen in the prior art, and has a normal shelf life (approximately 14
An object of the present invention is to develop a method for producing fermented milk with high palatability that maintains an appropriate sourness without producing excessive acid.

[Means to solve the problem]

In the present invention, a fermented milk starter containing Lactobacillus and Bisuisus bacteria is added to raw milk such as milk or skim milk that is normally used for fermented milk, and a small amount of chitosan is added to it.
Fermented milk in which acid production is suppressed can be obtained by culturing at a temperature of about 0°C for several hours to more than ten hours. Sweeteners, flavoring agents, etc. may be appropriately added to the raw milk according to conventional methods.

The chitosan used here is a cationic polymer with many amino groups and is a naturally occurring substance, so it is a material that is expected to be applied to foods, but there are no reports yet on its use in fermented milk. I can't see it.

The present inventor has come up with the present invention based on the results of examining the microbial effects of chitosan on various lactic acid bacteria and the physical and chemical effects on the product when using chitosan for fermented milk.

Next, we will show the results of investigating the effects of chitosan on fermented milk starter and fermented milk.

〔Test method〕

Raw milk - milk (non-fat milk solids content 9.5%, milk fat bone 3.0
%) with chitosan in 0.00%, 0.005%, 0.01
% and 0.02%, each of the following fermented milk starters was inoculated at 5% by weight, and the mixture was heated at 38°C.
The cells were incubated at a temperature of C for 18 hours.

Fermented milk starter Lactobacillus: Lactobacillus helveticus
Lactobacillus pulgaricus) SBT 2161 Lactobacillus pulgaricus
S B T 2188 A Lactobacillus acidophilus tobacillus SBT
2062 Lactic acid coccus: Streptococcus thermophilus-6 y≧o
ccus thermo hilus) SBT 102
SBT
1021A Bifidobacterium: Bifidobacterium longum
Lactobacillus bulgaricus (Lact-o) SBT 2933R
bacillus bul aricus) SBT 2
188^ and Streptococcus thermophilus (
SBT
1020, and Bifidobacterium longum (Bifidobacterium longum).
terium ton um) SBT 2933R, Lactobacillus acidophilus (Lactobacillus acidophilus)
SBT 2062 and Streptococcus thermophilus
cus thermo hilus) SBT 102L
A similar experiment was conducted using a 3-bacteria mixed starter containing A.

The above test results are shown in Tables 1.1 and 1.2 and Tables 2.1 and 2.
As shown in 2.

(Margin below) o, ooo % 0.23 0.005% 0.23 0.010% 0.23 0.020% 0.23 0.030% 0.23 Armorer λ Todan L o, ooo % 0.26 0.005% 0.26 0.010% 0.25 0,020% 0.25 SBT 2062 o, ooo % 0.25 0.005% 0.24 0.010% 0.25 0.020% 0.24 SBT 1020 o, ooo % 0.20 0.005% 0.20 0.010% 0゜21 0.020% 0.20 0.40 0.41 0.42 0.42 0.40 0.48 0.51 0.49 0.51 0.40 0.40 0.40 0.40 0.35 0.33 0.36 0.35 1.07 1.09 1.09 1.03 0.98 0.69 0.71 0.68 0.69 0.78 0.76 0.75 0.74 0.48 0.47 0.48 0.46 1.61 1.62 -1.58 1.45 - 1.43 0.93 0.94 0.92 0.89 0.95 0.96 0.92 0.91 0.95 0.94 0.92 0.92 1.08 1.07 1.05 1.04 0.63 0.60 0.64 0.60 0.65 0.64 0.66 0.65 1.67 1°67 1.66 1.57 1.54 0.96 0.98 0.95 0.94 1.19 1.14 1.13 1.11 0.70 668 0.70 0.69 1.76 1.74 1.72 1.64 1.63 1.03 1.04 0.98 0.96 1.26 1.22 1.20 1.19 0.73 0.71 0.73 0.71 SBT 1021A o, ooo % 0.005% o, oio % 0.020% 0.20・0.44 0.20 0.45 0.21 0.44 0.20 0.45 0.64 0.65 0.64 0.62 0.68 0.69 0.67 0.68 0.73 0.72 0.73 0.74 0.75 0.74 0.74 0.74 0.75 0.75 0.75 0.76 o, oo.

O,005 0,010 0,020 0,24 0,24 0,23 0,24 0,30 0,28 0,30 0,31 0,44 0,43 0,41 0,40 0,50 0, 46 0,44 0,44 0,55 0,52 0,51 0,51 0,57 0,54 0,53 0,53 0,60 0,58 0,57 0,55 (blank below) 0.010 % 0.23 0.47 0.70 0.
79 0.89 1.02 1.320.020%
0.22 0.4B 0.69 0.81 0.8
9 0.97 1.31SBT 1021A.

SBT 2933R) o, ooo% 0.005% 0.010% 0.020% 0.26 0.27 0.26 0.26 0.36 0.38 0.39 0.36 0.57 0.58 0.58 0.56 0.63 0.64 0.64 0.64 0.71 0.71 0.70 0.70 0.76 0.76 0.76 0.75 1.21 1.18 1.18 1.16 SBT 102OA 7 hours.

0.005% 0.87 0.010% 0゜87 0.020'o O,83 (blank below) As seen in Tables 1.1 and 1.2 and Tables 2.1 and 2.2, Lactobacillus helveticus SBT 2161, Lactobacillus bulgaricus SBT 2188^, and Lactobacillus andophilus SBT 2062, as well as Bifidobacterium longum SBT 2933R, are affected by acid production and viable bacterial growth by chitosan. while Streptococcus thermophilus 5BT102 tends to be suppressed.
0 and Streptococcus thermophilus SB71
It can be seen that 021A is not affected by chitosan.

That is, since chitosan suppresses acid production and viable bacterial growth of Lactobacillus and Bifidobacterium, at least one species selected from the above-mentioned Lactobacillus and Bifidobacteria is used in the fermented milk starter in the present invention. Note that a mixture of the above-mentioned selected bacteria and lactic acid cocci may be used as the fermented milk starter.

Moreover, the effect of suppressing acid production is recognized when the amount of chitosan added to the raw milk is about 0.010% to 0.030% from the above-mentioned test results.

The present invention will be specifically explained below using Examples.

Example 1 Lactobacillus spp.
Helveticus SBT 2161 was inoculated and cultured at 37°C for 16 hours and used as a fermented milk starter. The lactic acid acidity after culture was 2.25%, pH 3.6,
The number of viable bacteria is 8. OXIO"cfu7g.

As raw milk, 78.5% by weight of milk and 2.5% of skim milk powder
% by weight, and 0.25% of chitosan was added to this.
Fermented milk was prepared by adding 16% by weight of the % solution (bactericide) and 3.0% by weight of the above fermented milk starter.

Obtained fermented milk (chitosan content 0.04031i amount%)
) is milk fat rib 3.0% by weight, non-fat milk solids 9.5% by weight
It had the following composition. This fermented milk was stored at 10°C for 14 days, and changes in lactic acid acidity over time were examined during that time.

The results are shown in Figure 1 for addition.

As seen in FIG. 1, the chitosan-containing fermented milk had a significantly less increase in lactic acid acidity during the storage period, and had a moderate sourness.

Example 2 Lactobacillus fergaricus SBT 21888 and Streptococcus thermophilus SBT 10
20 was inoculated into a skim milk medium with a non-fat solid content of 11.0%,
A mixed starter of two bacterial species was prepared by culturing at 40°C for 4 hours. The acidity of lactic acid after culturing was 1.0%, the pH was 4.6, and the number of viable bacteria was Lactobacillus bulgaricus SBT 21.
888 is 1.0X108cfu/g, Streptococcus thermophilus SBT 1020 is 4.0X10
”cfu/g.

Milk as raw material: 82.8% by weight of milk and 2.2% skimmed milk powder
% by weight, add 12% by weight of 0.25% chitosan solution (sterilization method), and add the above fermented milk starter 3.
．． Fermented milk was prepared by adding 0% by weight.

The obtained fermented milk (chitosan content: 0.033 weight percent) had a composition of milk fat ribs of 3.0% by weight and non-fat milk solids of 9.5% by weight. This fermented milk was stored at 10° C. for 14 days, during which time changes in lactic acid acidity were examined.

The results are shown in Figure 2.

As seen in the figure, the fermented milk containing 0.02% by weight of chitosan had a moderate sour taste with significantly less increase in lactic acid acidity during the storage period.

[Brief explanation of drawings]

FIG. 1 shows the change in lactic acid acidity over time during storage of the fermented milk obtained in Example 1, and FIG. 2 shows the same for the fermented milk obtained in Example 2. Storage days

Claims (5)

[Claims] (1) Fermented milk containing chitosan and suppressing increase in acidity. (2) The fermented milk is obtained using at least one species selected from the group consisting of Lactobacillus helveticus, Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus and Bifidobacteria. Fermented milk as described. (3) A method for producing fermented milk that suppresses an increase in acidity, which is characterized by adding chitosan and fermented milk starter to raw milk and culturing it. (4) Chitosan in a ratio of 0.010 to 0.080 to raw milk
The manufacturing method according to claim (3), wherein the amount is added by weight%. (5) The fermented milk starter contains at least one species selected from the group consisting of Lactobacillus helveticus, Lactobacillus bulgaricus, Lactobacillus acidophilus, and Bifidobacteria.
).