JP3101143B2 - A method for producing fermented milk with reduced acidity during storage. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention is, Lactobacillus del Burukki ssp. Bulgaricus (Lact
obacillus delbrueckii sub
sp. bulgaricus ) and the Streptococcus salivarius subspecies thermophilus ( Streptococcus saliva)
rius subsp. The present invention relates to a method for producing fermented milk using a mixed starter of two strains of lactic acid bacteria consisting of a viscous substance producing strain of S. thermophilus . The fermented milk produced by the method of the present invention is characterized by a small increase in acidity under low-temperature storage, a moderately mild acidity, and good flavor and texture.

[0002]

2. Description of the Related Art Fermented milk containing yogurt, lactic acid bacteria beverages and the like is generally prepared by mixing a raw material mixture prepared mainly from animal milk with a lactobacillus delbrucky subspecies bulgaricus ( Lactoba).
Cillus delbrueckii subsp.
bulgaricus ), Streptococcus salivarius subspecies thermophilus ( Strep)
tococcus salivarius subs
p. traditional lactic acid bacteria such as B. thermophilus and Bifidobacterium s.
species), Lactobacillus acidophilus ( L
actobacillus acidophilus )
It is produced by inoculating a useful intestinal bacterium such as the above as a starter in combination or alone and fermenting. However, in the International Dairy Federation (IDF) in 1973,
Yogurt is a starter for Lactobacillus del Brooke Subspecies Bulgarix ( Lac
tobacillus delbrueckii su
bsp. bulgaricus ) and Streptococcus salivarius subspecies thermophilus ( S
treptococcus salivarius s
ubsp. thermophilus ) [57th ID
Minutes of F (1973)], the present fermented milk mainly comprises a mixed starter of these two bacterial species.

Conventionally, the flavor of fermented milk is affected by organic acids such as lactic acid and acetic acid, carbonyl compounds such as acetaldehyde and diacetyl produced by lactic acid bacteria used as a starter, and sweeteners and flavors added to a raw material mix. Particularly, the acidity of lactic acid or the like is an important factor. That is, all of the above-mentioned lactic acid bacteria are lactose-fermentable, and ferment the lactose in the product to produce lactic acid even under low-temperature storage, so that the acidity of the product increases with time and impairs the flavor. . In particular, Lactobacillus del Brooke
Subspecies Bulgarix ( Lactobacil)
rus delbrueckii subsp. bul
garicus ) and Streptococcus salivarius subspecies thermophilus ( Streptoc)
occus salivarius subsp. th
In the fermented milk produced by the two strains mixed starter ermophilus), mainly Lactobacillus del Burukki ssp bulgaricus (Lact
obacillus delbrueckii sub
sp. bulgaricus ), the acidity of the fermented milk increases during storage.

[0004] Therefore, attempts have been made to suppress such a phenomenon that the acid production amount becomes excessive and the acidity of fermented milk becomes strong, and several methods have been reported. For example,
A method using a non-fermentable lactose artificial mutant [Japanese Patent Publication 54-
38187, Japanese Patent Publication No. 42-27293],
A method using a cold-sensitive mutant [Japanese Patent Publication No. 62-239]
Japanese Patent Application Publication No. 50-6745, G. Patent Publication No. Waes, Milchwissenschaf
t, 42 , 146-148 (1987)], a method using low-lactose skim milk from which lactose has been removed as a raw material [R. L. R
Ichter, J.M. Food Sci. , 38, 796
798 (1973)], and a method using low-acidity lactic acid bacteria [Japanese Patent Laid-Open No. 4-271777].

[0005] However, the method using a non-fermentable artificial lactose mutant relates to a method for producing fermented milk using a starter of a single strain, and is regulated by the IFO / WHO Joint Committee. In a method that does not satisfy the strain of lactic acid bacteria and uses a cold-sensitive mutant, Lactobacillus delbruchy subspecies bulgaricus ( Lactobacillus delbruecki) is used.
i subsp. bulgaricus ), which is a low-temperature sensitive mutant of Lactobacillus
Delbrooky Subspecies Bulgarix ( La
ctobacillus delbrueckiis
ubsp. bulgaricus ) ATCC 1184
Two strains were used as parent strains and cultured in an isolation medium to isolate low-temperature-sensitive mutants, which differed from the parent strain only in terms of low-temperature sensitivity, and other properties were the same as the parent strain. Although the increase in acidity is extremely low, the increase in acidity during the fermentation process is the same as usual, and the flavor of the obtained fermented milk is almost the same as that of conventional fermented milk. In addition, in the method of heating for a certain period of time at a temperature at which the bacteria do not completely die to weaken the vitality of the bacteria, the heat treatment process at a certain temperature and time is complicated, the preparation of the bacteria is difficult, and the heating process is difficult. Energy is required, and in addition, there is a problem that the quality of the product, such as flavor and texture, is likely to be reduced. Furthermore, a method of using low-lactose skim milk from which lactose has been removed as a raw material requires a process of removing lactose from the raw milk, which is not economically practical. The method of using low-acid lactic acid bacteria is a method proposed by the present inventors previously.Although the acidity increase during storage was suppressed, the quality of the product such as flavor and tissue was not always satisfactory. I couldn't do it.

[0006]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies in order to solve these problems listed in the prior art and found that various types of lactic acid bacteria having specific properties are used in combination. By adding mild mild acidity to the fermented milk, it is possible to produce fermented milk of high quality in terms of flavor and texture while maintaining mild acidity even during the low temperature storage of the fermented milk. Thus, the present invention has been completed. Accordingly, an object of the present invention is to provide a method for producing fermented milk having a moderately mild acidity without delaying the fermentation time of fermented milk and having a high palatability capable of maintaining the acidity. I do.

[0007]

The lactic acid bacteria strain used as a starter for fermented milk in the present invention is Lactobacillus delbruchy subsp. Bulgaricus isolated from fermented milk.
ckii subsp. bulgaricus ) and the Streptococcus salivarius subspecies thermophilus ( Streptococcus)
s salivarius subsp. thermo
and a viscous substance-producing strain of Lactobacillus delbruchy subspecies bulgaricus ( Lactobacillus delbruecki).
i subsp. bulgaricus ) has the property of imparting a moderately mellow flavor to fermented milk and not generating excessive acid during low-temperature storage, and the Streptococcus salivarius.
Subspecies Thermofils ( Streptoco
ccus salivarius subsp. the
rmophilus ) has the property of improving the flavor and texture of fermented milk.

Here, each strain of lactic acid bacteria used in the present invention will be described. Lactobacillus del Brooke Subspecies Bulgarix ( Lactobacill)
us delbrueckii subsp. bulg
aricus ) can be obtained as follows. Lactobacillus delbruchy subspecies bulgaricus ( Lactobacillus delbluee) isolated from commercially available fermented milk in a conventional manner.
ckii subsp. bulgaricus )
After subcultured three times in a reduced-weight skim milk medium, the resulting culture is inoculated at 1% by weight in a 12% reduced skim milk medium, cultured at 37 ° C for 16 hours, and further stored at 10 ° C for 14 days. And
From the measurement results of the lactic acid acidity before and after the start of storage, a strain having an increase rate of lactic acid acid of 0.25% or less before and after the start of storage is isolated. In the present invention, Lactobacillus delbrucky subspecies Bulgarix ( Lactobacillus delbruecki) thus separated is used.
i subsp. bulgaricus ) is referred to as an acid production inhibitory strain. Lactobacillus delbruchy subspecies bulgaricus ( Lactobacillus de var.
lbrueckii subsp. bulgaricu
s ) SBT-2118B strain (FERM P-1191
8) and SBT-1511 strain (FERM P-119)
17) can be exemplified.

[0009] Lactobacillus del Brooke Subspecies Bulgaricus ( Lactobacillus)
delbrueckii subsp. bulgar
icus ) SBT-2118B strain (FERM P-11)
Table 1 shows the mycological properties of 918).

[0010]

Table 1 A Morphological properties (1) Cell shape: Bacillus (2) Motility: None (3) Presence or absence of spores: None (4) Gram stainability: Positive (5) Heterochromosome: Yes B Growth state (1) Colony morphology on plate count agar medium (cultured at 37 ° C. for 24 to 48 hours): R-type C physiological properties (1) Nitrate reduction: negative (2) Indole formation: negative (3) Gelatin Liquefaction: Negative (4) Catalase: Negative (5) Starch degradation: Negative (6) Attitude to oxygen: Positive (7) D-lactic acid is produced from glucose by homolactic fermentation. (8) It does not produce CO ₂ from malate. (9) When cultured in a skim milk medium, it produces an acid and curds. (10) Degradability of various carbohydrates Glucose +2. Lactose + 3. Fructose + 4. Mannose +5. Galactose-6. Sucrose -7. Maltose-8. Cellobiose -9. Trehalose-10. Melibiose-11. Raffinose-12. Merezitose-13. Mannitol-14. Sorbitol-15. Esculin-16. Salicin-17. Amygdalin −

In addition, N-acetylglucosamine is decomposed, and glycerol, erythritol, D or L-arabinose, ribose, D or L-xylose, adonitol, β-methyl-D-xyloside, L-sorbose,
Rhamnose, dulcitol, inositol, α-methyl-D-mannoside, α-methyl-D-glucoside, arbutin, saccharose, inulin, amidone, glycogen, xylitol, β-gentiobiose, D-tranose, D-chyrisose, D-tagatose, D or L
-Does not decompose fucose, D or L-arabitol, gluconate, 2set-gluconate, 5set-gluconate.

From the above mycological properties, Bergey's
manual of systematic bac
teriology, vol. SBT-2118B strain (FERM P-119)
18) is Lactobacillus del Brooke Subspecies Bulgarix ( Lactobacillusd)
elbrueckii subsp. bulgaric
us ), but 37% in skim milk medium.
It was identified as an acid production-suppressed strain in that growth at ℃ was extremely slow and acid production was small. Also, this SBT-211
When the 8B strain (FERM P-11918) was subcultured, the lactic acid production ability at 10 ° C. for 14 days was always low, and the lactic acid acidity was 0.1 to 0.25%.

Further, the acid production-suppressed strain has a low acid production rate during fermentation, and it may take time to obtain a predetermined lactic acidity. Therefore, the SBT-2118B strain (FERM)
P-11918) was studied for promoting the fermentation. That is, a small amount of yeast extract was added to a 12% by weight reduced skim milk medium, sterilized by heating, and then SBT-2 was added to this medium.
118B strain (FERM P-11918) and Streptococcus salivarius subspecies thermophilus ( Streptococcus salivari)
us subsp. thermophilus ) SBT
-1020 strain (FERM P-13956) was inoculated, and the fermentation time at 42 ° C was measured. Table 2 shows the results.

[0014]

[Table 2] 酵母 Yeast extract (% by weight) Fermentation time (hours) ───────── {0 4.25 0.02 4.0 0.05 3.75 0.10 3.5 0.30 3.25} ─────────────────────

As a result, the fermentation was promoted by adding 0.02 to 0.3% by weight of the yeast extract to the reduced skim milk medium, and the delay of the fermentation time was suppressed.

In addition, Lactobacillus del Bruky
Subspecies Bulgarix ( Lactobacil)
rus delbrueckii subsp. bul
garicus ) SBT-1511 strain (FERM P-
Table 3 shows the bacteriological properties of 11917).

[0017]

[Table 3] A Morphological properties (1) Cell shape: Bacillus (2) Motility: None (3) Presence or absence of spores: None (4) Gram stainability: Positive (5) Heterochromosome: Yes B Growth state (1) Colony morphology on plate count agar medium (cultured at 37 ° C. for 24 to 48 hours): R-type C physiological properties (1) Nitrate reduction: negative (2) Indole formation: negative (3) Gelatin Liquefaction: Negative (4) Catalase: Negative (5) Starch degradation: Negative (6) Attitude to oxygen: Positive (7) D-lactic acid is produced from glucose by homolactic fermentation. (8) It does not produce CO ₂ from malate. (9) When cultured in a skim milk medium, it produces an acid and curds. (10) Degradability of various carbohydrates Glucose +2. Lactose + 3. Fructose + 4. Mannose +5. Galactose-6. Sucrose -7. Maltose-8. Cellobiose -9. Trehalose-10. Melibiose-11. Raffinose-12. Merezitose-13. Mannitol-14. Sorbitol-15. Esculin-16. Salicin-17. Amygdalin −

In addition, N-acetylglucosamine is decomposed, and glycerol, erythritol, D or L-arabinose, ribose, D or L-xylose, adonitol, β-methyl-D-xyloside, L-sorbose,
Rhamnose, dulcitol, inositol, α-methyl-D-mannoside, α-methyl-D-glucoside, arbutin, saccharose, inulin, amidone, glycogen, xylitol, β-gentiobiose, D-tranose, D-chyrisose, D-tagatose, D or L
-Does not decompose fucose, D or L-arabitol, gluconate, 2set-gluconate, 5set-gluconate.

From the above mycological properties, Bergey's
manual of systematic bac
teriology, vol. 2 (1986), strain SBT-1511 (FERM P-1191).
7) is Lactobacillus del Brooke subspecies Bulgarix ( Lactobacillusde)
lbrueckii subsp. bulgaricu
s ) at 37 ° C. in skim milk medium, consistent with the mycological properties of
Was identified as an acid production-suppressed strain in that growth was extremely slow and acid production was small. In addition, this SBT-1511
When the strain (FERMP-11917) was subcultured,
Lactic acid production capacity at 10 ° C for 14 days is always low,
Lactic acidity was 0.1-0.3%.

Further, the acid production-suppressed strain has a low acid production rate during fermentation, and it may take time to obtain a predetermined lactic acidity. Therefore, the SBT-1511 strain (FERM P.
-11917) were studied. That is, after adding a small amount of yeast extract to a 12% by weight reduced skim milk medium and sterilizing by heating, SBT-1 was added to this medium.
511 strains (FERM P-11917) and Streptococcus salivarius subspecies thermophilus ( Streptococcus salivariu)
s subsp. thermophilus ) SBT-
1020 strains (FERM P-13956),
The fermentation time at 42 ° C. was measured. Table 4 shows the results.

[0021]

[Table 4] 酵母 Yeast extract (% by weight) Fermentation time (hours) ───────── {0 4.25 0.02 3.75 0.05 3.5 3.5 0.10 3.4 0.30 3.25} ─────────────────────

As a result, the fermentation was promoted by adding 0.02 to 0.3% by weight of the yeast extract to the reduced skim milk medium, and the delay of the fermentation time was suppressed.

On the other hand, Streptococcus salivarius subspecies thermophilus ( Streptoc)
occus salivarius subsp. th
A viscous-producing strain of E. thermophilus may be obtained as follows. Streptococcus salivarius subspecies thermophilus ( Streptococcus s) isolated from commercially available fermented milk in a conventional manner.
alibarius subsp. thermophil
us ) was subcultured three times in a 12% by weight reduced skim milk medium, and then inoculated into a 12% by weight reduced skim milk medium at 1% by weight.
Incubate at 16 ° C for 16 hours. And 50c at 10 ° C
A viscous strain is isolated from the observation result of the dripping state from the height of m. In the present invention, Streptococcus salivarius subsp.
Thermophilus ( Streptococcus sal)
ivarius subsp. thermophilu
The strain of s ) is referred to as a slime producing strain. As such a viscous substance producing strain, Streptococcus salivarius subspecies thermophilus ( Strept)
ococcus salivarius subsp.
thermophilus ) SBT-1020 strain (FE
RM P-13956).

[0024] Streptococcus salivarius subspecies thermophilus ( Streptococcus)
us salivarius subsp. therm
ophilus ) SBT-1020 strain (FERM P-
13956) is shown in Table 5.

[0025]

A: Morphological properties (1) Cell shape: cocci (2) Motility: None (3) Presence or absence of spores: None (4) Gram stainability: Positive (5) Heterochromosome: Yes B Growth state (1) Colony morphology on plate count agar medium (cultured at 37 ° C for 24 to 48 hours): R-type C physiological properties (1) 10 ° C growth ability: negative (2) 40 ° C growth ability: positive (3 ) 50 ° C. growth ability: positive (4) 2.0% sodium chloride growth ability: positive (5) 4.0% sodium chloride growth ability: negative (6) 6.5% sodium chloride growth ability: negative (7) 60 (8) pH 9.6 Viability: negative (9) 40% bile acid tolerance: negative (10) Nitrate reduction: negative (11) Indole production: negative (12) Gelatin liquefaction : Negative (13) Catalase: Negative (14 ) Starch degradation: Negative (15) Attitude to oxygen: Positive (16) L-(+) lactic acid is produced by homolactic fermentation from glucose. (17) It does not produce CO ₂ from malate. (18) When cultured in a non-fat milk medium, an acid is produced and curds. (19) Degradability of various carbohydrates Glucose +2. Lactose + 3. Fructose + 4. Mannose +5. Galactose-6. Sucrose +7. Maltose-8. Cellobiose -9. Trehalose-10. Melibiose-11. Raffinose-12. Merezitose-13. Mannitol-14. Sorbitol-15. Esculin-16. Salicin-17. Amygdalin −

In addition, N-acetylglucosamine, glycerol, erythritol, D or L-arabinose,
Ribose, D or L-xylose, adonitol, β
Methyl-D-xyloside, L-sorbose, rhamnose, darcitol, inositol, α-methyl-D-mannoside, α-methyl-D-glucoside, arbutin,
Saccharose, inulin, amidone, glycogen, xylitol, β-gentiobiose, D-tranose,
Does not degrade D-chyrisose, D-tagatose, D or L-fucose, D or L-arabitol, gluconate, 2set-gluconate, 5set-gluconate.

From the above mycological properties, Bergey's
manual of systematic bac
teriology, vol. SBT-1020 strain (FERM P-1395)
6) is Streptococcus salivarius subspecies thermophilus ( Streptococcus)
salivarius subsp. thermop
HIUS ), but was identified as a viscous-producing strain in that it exhibited viscosity when dropped from a height of 50 cm at 10 ° C.

In the present invention, Lactobacillus delbruchy subspecies bulgaricus ( Lactobacillus delbruec ) having the above-mentioned properties is used.
kii subsp. bulgaricus ) and Streptococcus salivarius subspecies thermophilus ( Streptococcus)
salivarius subsp. thermop
HIUS ) is used in combination as a starter lactic acid bacterium. The production of fermented milk can be performed according to a commonly used method.

Further, in the present invention, in order to promote fermentation and to control the delay of fermentation time, animal or plant protein decomposed products such as proteose peptone and animal extracts such as meat extract are used instead of yeast extract. Alternatively, a plant extract, an amino acid, or the like can be used. Examples of the amino acid include valine, leucine, methionine, histidine and glutamic acid, and these may be used alone or in combination. When a commercially available proteose starch is used as the protein degradation product, for example,
When about 5 to 0.2% by weight is added and a commercially available meat extract is used as a protein extract, for example,
It is preferable to add about 0.05 to 0.2% by weight.
Further, when an amino acid is used, it is preferable to add the aforementioned amino acid in an amount of about 0.05 to 0.2% by weight.

As described above, the production of fermented milk according to the production method of the present invention has the characteristics that the acidity increases little under low-temperature storage, exhibits moderate mild acidity, and has good flavor and texture. Fermented milk can be obtained. It is also possible to produce a lactic acid bacterium beverage having the same characteristics according to a conventional method using the fermented milk produced by the method of the present invention as a raw material. Hereinafter, the present invention will be described specifically with reference to Examples.

[0031]

Example 1 Lactobacillus delbruchy subspecies bulgaricus ( Lactobacillus delbruecki) was added to a 12% by weight reduced skim milk medium.
i subsp. bulgaricus ), an SBT-2118B strain (FERM P-1191)
8) was inoculated at 1%. Also, Streptococcus salivarius subspecies thermophilus ( Streptococcus salivariu) was added to a 12% by weight reduced skim milk medium containing 0.05% by weight of yeast extract.
s subsp. SBT-1020 strain (FERM P-13) which is a viscous substance producing strain of S. thermophilus ).
956) was inoculated at 1%. Each of these strains was cultured at 37 ° C. for 20 hours to prepare starter lactic acid bacteria.

On the other hand, a raw material mix for yogurt 0.5 k
g was sterilized at 100 ° C. for 60 minutes, and added to the sterilized raw material mix cooled to 42 ° C., using the above Lactobacillus del Brookie Subspecies Bulgarix ( Lactobac).
illus delbrueckii subsp. b
ulgaricus ) SBT-2118B strain starter 2.67% by weight and Streptococcus salivarius subspecies thermophilus ( Strepto)
coccus salivarius subsp. t
hermophilus ) SBT-1020 strain starter 0.33% by weight. The number of viable bacteria at the time of starter inoculation was determined by Lactobacillus del Brooke subspecies Bulgarix ( Lactobaci).
llustdelbrückii subsp. bul
garicus ) is 1.3 × 10 ⁶ cfu / ml, Streptococcus salivarius subspecies thermophilus ( Streptococcus saliv).
arius subsp. thermophilus )
Was 1.5 × 10 ⁷ cfu / ml.

After fermentation at 42 ° C. until the lactic acidity reached 0.65%, the mixture was immediately cooled to obtain yogurt. The time required for this fermentation was 4 hours and 25 minutes, and the viable cell count immediately after the completion of the fermentation was determined by Lactobacillus del Brookie Subspecies Bulgarix ( Lacto).
bacillus delbrueckii subs
p. bulgaricus ) is 1.6 × 10 ⁸ cfu /
ml, Streptococcus salivarius subspecies thermophilus ( Streptococcus)
salivarius subsp. thermop
ilus ) was 5.8 × 10 ⁸ cfu / ml.

The yogurt obtained in this manner was
When stored at 14 ° C. for 14 days, the rate of increase in lactic acidity during storage was only 0.25%, and the viable cell count was determined as Lactobacillus delbrueckiis ( Lactobacillus delbrueckii).
subsp. bulgaricus ) is 1.1 × 10
⁸ cfu / ml, Streptococcus salivarius
Subspecies Thermofils ( Streptoco
ccus salivarius subsp. the
rmophilus ) was 3.9 × 10 ⁸ cfu / ml, and almost no decrease in the viable cell count was observed.

On the other hand, Lactobacillus del Brooke subspecies Bulgarix ( Lactoba)
Cillus delbrueckii subsp.
bulgaricus ) A strain isolated from commercially available yogurt in place of the SBT-2118B strain, Lactobacillus delbruchy subsp. bulgaricus ( L.
actobacillus delbrueckii
subsp. bulgaricus ) MRC-32-R
The yogurt produced using the O strain had a lactic acid acidity increase rate of 0.46% during storage, and the viable cell count was determined by Lactobacillus delbrueckis ( Lactobacillus delbrueck).
ii subsp. bulgaricus ) is 1.5x
10 ⁸ cfu / ml, Streptococcus salivarius subspecies thermophilus ( Streptto)
coccus salivarius subsp. t
thermophilus ) is 4.0 × 10 ⁸ cfu / m
l.

[0036]

Example 2 Lactobacillus delbruchy subspecies bulgaricus ( Lactobacillus delbruecki) was added to a 12% by weight reduced skim milk medium.
i subsp. bulgaricus ), an SBT-2118B strain (FERM P-1191)
8) was inoculated at 1% by weight. In addition, 0.05% yeast extract
In a 12% by weight reduced skim milk medium added by weight%, Streptococcus salivarius subspecies thermophilus ( Streptococcus salivar) was added.
ius subsp. a viscous substance-producing strain is SBT-1020 strain of thermophilus) (FERM P-
13956) was inoculated at 1% by weight. Each of these strains was cultured at 37 ° C. for 20 hours to prepare starter lactic acid bacteria. In addition, the viable cell count of these starter lactic acid bacteria is determined by Lactobacillus del Brooke subspecies Bulgarix ( Lactobacillus de
lbrueckii subsp. bulgaricu
s ) is 3.7 × 10 ⁸ cfu / ml, Streptococcus salivarius subspecies thermophilus ( Streptococcus salivarius)
subsp. thermophilus ) is 8.0 ×
It was 10 ⁸ cfu / ml.

On the other hand, the raw material mix for yogurt 200k
g was sterilized at 100 ° C. for 60 minutes, and added to the sterilized raw material mix cooled to 42 ° C., using the above Lactobacillus del Brookie Subspecies Bulgarix ( Lactobac).
illus delbrueckii subsp. b
ulgaricus ) SBT-2118B strain starter 2kg and Streptococcus salivarius subspecies thermophilus ( Streptococcus)
us salivarius subsp. therm
ophilus ) SBT-1020 strain starter 4kg
Were inoculated and fermented at 42 ° C. until the lactic acidity reached 0.68%, and then immediately cooled to obtain yogurt. The time required for the fermentation was 3 hours and 45 minutes, and the number of viable bacteria immediately after the completion of the fermentation was determined by Lactobacillus delbrookie subspecies Bulgarix ( Lactobac).
illus delbrueckii subsp. b
ulgaricus ) is 1.9 × 10 ⁸ cfu / ml,
Streptococcus salivarius subspecies
Thermophilus ( Streptococcus sal)
ivarius subsp. thermophilu
s ) was 8.2 × 10 ⁸ cfu / ml.

The yogurt obtained in this way was
When stored at 14 ° C. for 14 days, the rate of increase in lactic acidity during storage was only 0.22%, and the viable cell count was determined as Lactobacillus delbrueckii ( Lactobacillus delbrueckii).
subsp. bulgaricus ) is 1.8 × 10
⁸ cfu / ml, Streptococcus salivarius
Subspecies Thermofils ( Streptoco
ccus salivarius subsp. the
rmophilus ) was 8.0 × 10 ⁸ cfu / ml, and no decrease in the viable cell count was observed.

On the other hand, Lactobacillus del Brooke subspecies Bulgarix ( Lactoba)
Cillus delbrueckii subsp.
bulgaricus ) A strain isolated from commercially available yogurt in place of the SBT-2118B strain, Lactobacillus delbruchy subsp. bulgaricus ( L.
actobacillus delbrueckii
subsp. bulgaricus ) SBT-0098
The yogurt produced using the strain (FERM P-9440) had a lactic acid acidity increase rate of 0.38% during storage,
In addition, the viable cell count was determined by Lactobacillus del Brooke subspecies Bulgarix ( Lactobacill).
us delbrueckii subsp. bulg
aricus ), 3.5 × 10 ⁸ cfu / ml, Streptococcus salivarius subspecies thermophilus ( Streptococcus saliva)
rius subsp. thermophilus ) was 6.8 × 10 ⁸ cfu / ml.

Further, the sensory evaluation of these yogurts was performed by 30 sensory test panelists on the third day and the thirteenth day of storage. The yogurt produced using the SBT-2118B strain was SBT-0098 strain. The yogurt produced was evaluated to be significantly lower in sourness only, high in flavor and texture, mellow and soft.

[0041]

Example 3 12 containing 0.05% by weight of yeast extract
Lactobacillus del Brooke subspecies Bulgarix ( Lactoba)
Cillus delbrueckii subsp.
bulgaricus ), an SBT-
2118B strain (FERM P-11918) 0.6% by weight and Streptococcus salivarius subspecies thermophilus ( Streptococcus)
salivarius subsp. thermop
Hilt ) was inoculated with 2.4 wt% of SBT-1020 strain (FERM P-13956), which is a viscous substance-producing strain, and cultured at 42 ° C. for 4 hours to prepare a mixed starter of two strains. The lactic acid acidity of the two-species mixed starter was 1.10%, and the viable cell count was determined by Lactobacillus delbrueckiis ( Lactobacillus delbruecki).
i subsp. bulgaricus ) 1.5 × 10
⁸ cfu / ml, Streptococcus salivarius
Subspecies Thermofils ( Streptoco
ccus salivarius subsp. the
rmophilus ) was 7.5 × 10 ⁸ cfu / ml.

On the other hand, the raw material mix for yogurt 200k
g was sterilized at 100 ° C. for 60 minutes, and the sterilized raw material mix cooled to 42 ° C. was inoculated with 6 kg of the above two-species mixed starter and fermented at 42 ° C. until the lactic acid acidity reached 0.68%. It was immediately cooled to obtain yogurt. In addition,
The time required for the fermentation was 3 hours and 15 minutes, and the viable cell count immediately after the end of the fermentation was determined by Lactobacillus delbrookii subspecies Bulgaricus ( Lactobacillus).
delbrueckii subsp. bulgar
icus ) is 2.0 × 10 ⁸ cfu / ml, Streptococcus salivarius subspecies thermophilus ( Streptococcus salivari)
us subsp. thermophilus ).
It was 3 × 10 ⁸ cfu / ml.

The yogurt obtained in this way was
When stored at 14 ° C. for 14 days, the rate of increase in lactic acidity during storage was only 0.24%, and the viable cell count was determined as Lactobacillus delbrueckiis ( Lactobacillus delbrueckii).
subsp. bulgaricus ) is 1.7 × 10
⁸ cfu / ml, Streptococcus salivarius
Subspecies Thermofils ( Streptoco
ccus salivarius subsp. the
rmophilus ) was 8.9 × 10 ⁸ cfu / ml.

On the other hand, Lactobacillus del Brooke subspecies Bulgarix ( Lactoba)
Cillus delbrueckii subsp.
bulgaricus ) A strain isolated from commercially available yogurt in place of the SBT-2118B strain, Lactobacillus delbruchy subsp. bulgaricus ( L.
actobacillus delbrueckii
subsp. bulgaricus ) SBT-0098
The yogurt produced using the strain (FERM P-9440) requires 3 hours and 15 minutes for fermentation, the rate of increase in lactic acidity during storage is 0.45%, and the viable cell count is Lactobacillus Delbrooky Subspecies Bulgarix ( Lactobacillus delbrueck)
ii subsp. bulgaricus ) is 3.5 ×
10 ⁸ cfu / ml, Streptococcus salivarius subspecies thermophilus ( Streptto)
coccus salivarius subsp. t
hermophilus ) is 7.1 × 10 ⁸ cfu / m
l.

Further, the sensory evaluation of these yogurts on the third day and the thirteenth day of storage by 30 sensory test panelists showed that the yogurt produced using the SBT-2118B strain was the SBT-0098 strain. The yogurt produced was evaluated to be significantly lower in acidity only, distinctly higher quality in terms of flavor and texture, mellow and softer.

[0046]

Example 4 12 containing 0.05% by weight of yeast extract
Lactobacillus del Brooke subspecies Bulgarix ( Lactoba)
Cillus delbrueckii subsp.
bulgaricus ), an SBT-
2118B strain (FERM P-11918) and SB
0.3% by weight of each of the T-1511 strain (FERM P-11917) and Streptococcus salivarius.
Subspecies Thermofils ( Streptoco
ccus salivarius subsp. the
rmophilus ), a viscous matter-producing strain of SBT-1
020 strain (FERM P-13956) (2.4% by weight) was inoculated, and cultured at 42 ° C for 4 hours to prepare a mixed starter of two strains. The lactic acid acidity of the two-species mixed starter was 1.20%, and the viable cell count was determined by Lactobacillus delbruchys ( Lactobacillus delbluee).
ckii subsp. bulgaricus ).
8 × 10 ⁸ cfu / ml, Streptococcus salivarius subspecies thermophilus ( Strep
tococcus salivarius subs
p. thermophilus ) is 8.0 × 10 ⁸ cf
u / ml.

On the other hand, the raw material mix for yogurt 200k
g was sterilized at 100 ° C. for 60 minutes, and the sterilized raw material mix cooled to 42 ° C. was inoculated with 6 kg of the above two-species mixed starter and fermented at 42 ° C. until the lactic acid acidity reached 0.68%. It was immediately cooled to obtain yogurt. In addition,
The time required for the fermentation was 3 hours and 20 minutes, and the number of viable bacteria immediately after the completion of the fermentation was determined by Lactobacillus del Brookie Subspecies Bulgarix ( Lactobacillus).
delbrueckii subsp. bulgar
icus ) is 2.1 × 10 ⁸ cfu / ml, Streptococcus salivarius subspecies thermophilus ( Streptococcus salivari)
us subsp. thermophilus ).
It was 2 × 10 ⁸ cfu / ml.

The yogurt obtained in this manner was
When stored at 14 ° C. for 14 days, the rate of increase in lactic acidity during storage was only 0.25%, and the viable cell count was determined as Lactobacillus delbrueckiis ( Lactobacillus delbrueckii).
subsp. bulgaricus ) is 1.8 × 10
⁸ cfu / ml, Streptococcus salivarius
Subspecies Thermofils ( Streptoco
ccus salivarius subsp. the
rmophilus ) was 8.8 × 10 ⁸ cfu / ml.

The yogurt was heated at 10 ° C.
When the lactic acidity during storage was measured over time, the increase in lactic acidity during storage was small, and it was found that a moderate soft acidity was maintained without generating excess acid during the normal taste period. . The result is shown in FIG.

On the other hand, Lactobacillus del Brooke subspecies Bulgarix ( Lactoba)
Cillus delbrueckii subsp.
bulgaricus ) A strain isolated from commercially available yogurt in place of the SBT-2118B strain, Lactobacillus delbruchy subsp. bulgaricus ( L.
actobacillus delbrueckii
subsp. bulgaricus ) SBT-0098
The yogurt produced using the strain (FERM P-9440) requires 3 hours and 20 minutes for fermentation, the rate of increase in lactic acidity during storage is 0.47%, and the viable cell count is Lactobacillus Delbrooky Subspecies Bulgarix ( Lactobacillus delbrueck)
ii subsp. bulgaricus ) is 3.6x
10 ⁸ cfu / ml, Streptococcus salivarius subspecies thermophilus ( Streptto)
coccus salivarius subsp. t
thermophilus ) is 7.0 × 10 ⁸ cfu / m
l.

Further, the sensory evaluation of these yogurts was performed by 30 sensory test panelists on the 3rd and 13th days of storage. The yogurt produced using the SBT-2118B strain was obtained using the SBT-0098 strain. The yogurt produced was evaluated to be significantly lower in sourness only, clearly higher quality in terms of flavor and texture, mellow and softer.

[0052]

Test Example 1 Here, the smoothness and taste of yogurt produced by the method of the present invention and yogurt produced by using a normal lactic acid bacteria strain were compared. Lactobacillus del Burukki ssp bulgaricus as a comparative example with the yogurt prepared in Example 4 (Lacto
bacillus delbrueckii subs
p. bulgaricus ) SBT-0098 strain (FE
RM P-9440) and Streptococcus salivarius subspecies thermophilus ( Strept)
ococcus salivarius subsp.
thermophilus ) SBT-0104 strain (FE
The sensory evaluation of smoothness and deliciousness was carried out by 30 sensory test panelists on the yogurt similarly produced using the mixed starter of two bacterial species (RMP-9442). Approximately 50 ml of each yogurt sample was dispensed into a plastic container and tested. The room temperature was 23 ° C and the sample test temperature was 1
0 ° C. For smoothness, a two-point discrimination method was performed, and a two-point preference method was continuously performed on correct respondents. The taste was evaluated by a two-point preference method. Table 6 shows the results.

[0053]

[Table 6] ──────────────────────────────────── Smoothness 2-point discrimination test method ^** Correct answer Number Number of wrong answers 23 7 2-point preference test method ^* Comparative example Example 6 17 ──────────────────────────────── ──── Deliciousness 2-point preference test method Comparative Example Example 12 18 ───────────────────────────────── ─── ^* indicates a significant difference of 5%, and ^** indicates a significant difference of 1%.

According to the results, the smoothness was significantly identified, and the yogurt of the example was felt overwhelmingly smooth and was preferred. Further, with respect to the taste, the yogurt of the example tended to be preferred to the comparative example.

[0055]

Test Example 2 Here, the tissue and texture of the yogurt manufactured in Example 3 and the yogurt manufactured in Example 4 during storage at 10 ° C. were evaluated. Regarding the tissue, the yogurt was spread in one direction in a petri dish, the state of grain generation was photographed, and rated by a 10-point method. (The better the tissue, the higher the score.) Regarding the texture, the sensory evaluation of mouthfeel, tongue, and throat when eating yogurt was rated as 1 for good and 2 for very good. Table 7 shows the results.

[0056]

[Table 7] ──────────────────────────────────── Save 1st day Save 7th day Save 14 Day ──────────────────────────────────── Example 3 Organization 8 4 4 Texture 1 1 1 Example 4 Texture 8 7 7 Texture 2 2 2

[0057] According to this result, Lactobacillus del Burukki ssp. Bulgaricus (Lact
obacillus delbrueckii sub
sp. bulgaricus ), the SBT-2118B strain (FERM P-1191)
8) and SBT-1511 strain (FERM P-119)
It was found that the use of the two strains 17) further improved the texture and texture of the yogurt.

[0058]

As in the present invention, according to the present invention, Lactobacillus del Burukki ssp. Bulgaricus (Lact
obacillus delbrueckii sub
sp. bulgaricus ) and the Streptococcus salivarius subspecies thermophilus ( Streptococcus saliva)
rius subsp. fermented milk produced by using a viscous substance producing strain of S. thermophilus ) as a starter lactic acid bacterium has a moderately soft acidity and can be stored under low temperature (1
(0 ° C., 14 days), it is possible to maintain an appropriate acidity without generating excess acid during the normal expiration period, and to provide high quality fermented milk with high flavor and texture. Becomes

[Brief description of the drawings]

FIG. 1 shows Lactobacillus del Brooke Subspecies Bulgaricus ( Lactobacillus).
delbrueckii subsp. bulgar
icus ), SBT-2118B and SBT-1511 strains which are acid-suppressed strains, and Streptococcus salivarius subspecies thermophilus ( Stre)
ptococcus salivarius subs
p. Yogurt and Lactobacillus del and SBT-1020 strain is a viscous substance producing strain was prepared using a two bacterial species mixed starter thermophilus) Burukki ssp bulgaricus (Lactoba
Cillus delbrueckii subsp.
bulgaricus ) SBT-0098 strain as a starter shows the change over time of the lactic acidity when stored at 10 ° C.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-271777 (JP, A) JP-A-2-53437 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A23C 9/12-9/137 BIOSIS (DIALOG)

Claims (2)

(57) [Claims] 1. Lactobacillus del Brooke subspecies Bulgaricus ( Lactobacillus)
s delbrueckii subsp. bulga
acidus- suppressed strain of Streptococcus salivarius subspecies thermophilus ( Str.
eptococcus salivarius sub
sp. A method for producing a fermented milk in which the increase in acidity during storage is suppressed, wherein a viscous substance-producing strain of S. thermophilus ) is used as a starter lactic acid bacterium. 2. Lactobacillus del Brooke subspecies Bulgaricus ( Lactobacillus)
s delbrueckii subsp. bulga
ricus ) is an SBT-2118B strain (FERMP-11918) and / or SBT-1
511 strain (FERM P-11917) and Streptococcus salivarius subspecies thermophilus ( Streptococcus saliva).
rius subsp. thermophilus ) is a strain of SBT-1020 (FERM P-
13956).