JPH08256681A - Production of frozen yogurt - Google Patents

Abstract

PURPOSE: To obtain a frozen yogurt having adequately mild sourness of low acidity, capable of holding the high level of the number of lactic bacteria even after a long frozen storage and having an excellent taste by using a mixture of two kinds of lactobacillus strains having specific properties. CONSTITUTION: A mixed starter consisting of (A) a low lactic acid-production strain of Lactobacillus delbrueckii subsp. bulgaricus [e.g. SBT10412 strain (FERM-P-14822)] and (B) a high growth strain of Streptococcus salivarius subsp. thermophilus [e.g. SBT10398 strain (FERM-P-14821)] is seeded to a raw material mix and this is fermented followed by freezing to obtain the objective product. Concretely, e.g. a yogurt mix as a raw material having a solid component of 20-30% is sterilized at 90-95 deg.C for 30min to 1hr, subsequently cooled down to 37-43 deg.C and then the starter is seeded on this. Subsequently, the fermentation is carried out at 37-43 deg.C until the acidity of lactic acid becomes 0.4-0.8% followed by cooling down to 5-10 deg.C and freezing.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing low-acid frozen yogurt. For more information, see Lactobacillus del Brocky Subspecies Bulgarix
(Lactobacillus delbrueckii subsp.bulgaricus) with a low-acidity strain and Streptococcus salivarius (Streptococcus salivarius)
subsp. thermophilus) with a highly proliferative strain mixed starter to produce a low acidity frozen yogurt. According to the method of the present invention, it is possible to produce frozen yogurt having a low acidity, an appropriately mild sourness, and maintaining a high level of lactic acid bacterium count even during long-term cryopreservation and having high taste.

[0002]

Frozen yogurt is legally classified as fermented milk, and milk or milk containing non-fat milk solids equivalent to or higher than this is fermented with lactic acid bacteria or yeast to form a paste or liquid. It is defined as a thing or a frozen thing. In addition, its components are non-fat milk solids content of 8.0% or more, and the number of lactic acid bacteria or yeast is 10 million or more per 1 ml,
It is defined as negative for coliforms. In addition, since the conventional frozen yogurt is obtained by freezing the fermented milk as it is, it often has a strong fermentation odor and a high acidity. However, according to recent taste surveys and the like, mild frozen yogurt, which is not sour and has a good acid-sweet balance, tends to be preferred.

As a method for producing frozen yogurt, a method of adding starter lactic acid bacteria to a sterilized raw material mixture for fermentation, cooling and freezing, and a method of mixing a fermentation mix and an ice cream mix and freezing are known. ing. However, in any method, Lactobacillus delbrueckii (Lactobacillus delbrueckii
subsp. bulgaricus) and Streptococcus salivarius subspecies thermophilus (Streptococcus)
salivarius subsp. thermophilus) and the like, a step of fermenting a high solid content raw material mix using a lactic acid bacterium is required, but under the condition of fermenting such a high solid content raw material mix, the growth of lactic acid bacteria becomes poor, There was a problem that the acidity of the fermentation mix was significantly increased by the time the number of lactic acid bacteria reached a certain level (10 ⁸ cfu / ml or more).

The lactic acid bacteria in the fermentation mix have a reduced viable cell count due to physical shock during freezing or filling, or due to heat shock during freezing or freeze-hardening. There was also a problem that the viable cell count was significantly reduced in.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made extensive studies in order to solve these problems, and as a result, by using a mixture of lactic acid bacterial strains having specific properties, a low acidity can be obtained. It was found that frozen yogurt having a moderately mild sourness can be produced,
The present invention has been completed. The frozen yogurt maintained a high level of lactic acid bacteria even during frozen storage and was of high quality in terms of flavor and texture. Therefore, the present invention provides a method for producing a highly-frozen frozen yogurt having a low acidity and a moderately mild sourness and maintaining a high level of lactic acid bacterium count even during long-term cryopreservation. It is an issue.

[0006]

In the present invention, as lactic acid bacteria of frozen yogurt, Lactobacillus delbrueckii subsp. Bulgar is isolated from commercially available fermented milk.
icus) and Streptococcus salivarius su
bsp. thermophilus) is mixed with the strains obtained by selecting under specific conditions. In other words, Lactobacillus del Brocky Subspecies Bulgarix (Lactoba
cillus delbrueckii subsp.bulgaricus)
Strains with low lactic acid production (low biogenicity) were selected when cultured in a medium for culturing ordinary lactic acid bacteria, and Streptococcus salivarius subsp. Thermophi was selected.
As for lus), a highly proliferative strain was selected when cultured in a high solid medium. Next, each strain that can be used as the starter lactic acid bacterium in the present invention will be described.

Lactobacillus delbrueckii s
A low-biogenic acid strain of ubsp. bulgaricus) can be obtained as follows. That is, Lactobacillus delbruckey
Subspecies Bulgaricus (Lactobacillus delbrue
ckii subsp. bulgaricus) was subcultured 3 times in a 12 wt% reduced skim milk medium, and then inoculated into the 12 wt% reduced skim milk medium at 1 wt% and cultured at 37 ° C for 16 hours to give a lactic acid content of 0.50%. The following strains are isolated and obtained. In the present invention, Lactobacillus delbrueckii subs (Lactobacillus delbrueckii subs) thus obtained
Strains of P. bulgaricus) are called low-live acidic strains. And such Lactobacillus delbruecki subspecies bulgaricus (Lactobacillus delbrueckii
subsp. bulgaricus) as a low-acidity strain of Lactobacillus delbruecki subspecies bulgaricus
(Lactobacillus delbrueckii subsp.bulgaricus) SBT1
0412 (FERM P-14822) can be exemplified. This Lactobacillus delbrueckii subsp.bulgaricu
s) The mycological properties of SBT10412 (FERM P-14822) are shown below.

A Morphological properties (1) Cell shape: Bacillus (2) Motility: None (3) Presence or absence of spores: None (4) Gram stainability: Positive (5) Heterochromosome: Yes Growth on B medium State (1) Colony morphology on plate-count agar medium (24-48 hours culture at 37 ° C): 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 toward oxygen: Positive (7) D (-) lactic acid is produced from glucose by homolactic fermentation. (8) Does not produce CO ₂ from malate. (9) When it is cultivated in a skim milk medium, it produces an acid and coagulates. (10) Degradability of various carbohydrates

1. Glucose + 2. Lactose + 3. Fructose + 4. Mannose + 5. Galactose-6. Sucrose-7. Maltose-8. Cellobiose-9. Trehalose-10. Meribiose-11. Raffinose-12. Merezitose-13. Mannitol-14. Sorbitol-15. Esculin-16. Salicin-17. Amygdalin-(+ indicates that it decomposes,-indicates that it does not decompose. .)

In addition, N acetylglucosamine is decomposed to give 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-xylisoses, D-tagatose, D or L-fucose, D or L-arabitol. , Gluconate, 2ceto-gluconate, and 5ceto-gluconate are not decomposed.

From the above-mentioned mycological properties, Bergey's Manual
SBT10412 strain (FERM P-14822) was identified by Lactobacillus delbrueckii subspecies bulgaricus (L.
(actobacillus delbrueckii subsp. bulgaricus), but it was identified as a low-acidic strain because the growth at 37 ℃ in skim milk medium was extremely slow and lactic acid production was low. Even when this SBT10412 strain (FERM P-14822) was subcultured, the production capacity of lactic acid was always low, and 1% by weight of 12% by weight reduced skimmed milk medium was inoculated and cultured at 37 ° C for 16 hours. The lactic acidity was 0.40 to 0.50%.

On the other hand, Streptococcus salphirus subspecies thermophilus (Streptococcus sal
A highly proliferative strain of ivarius subsp. thermophilus) in a high solid content yogurt mix can be obtained as follows. That is, Streptococcus salivarius subspecies thermophilus (Streptococcus salivar isolated from commercially available fermented milk according to a conventional method)
ius subsp. thermophilus) was subcultured 3 times with a yogurt mix having a solid content of 29%, and then inoculated with 1% by weight of a yogurt mix having a solid content of 29%, and cultured at 37 ° C for 3 hours to obtain a viable cell count of 10 Strains of ⁸ cfu / g or more are isolated and obtained. In the present invention, the Streptococcus salivarius subspecies thermophilus (Streptococcus) thus obtained is obtained.
A strain of salivarius subsp. thermophilus) is called a hyperproliferative strain. Then, as such a highly proliferative strain, Streptococcus salivarius subsp. Thermop
hilus) SBT10398 (FERM P-14821) can be exemplified. This Streptococcus salivarius su
The mycological properties of bsp. thermophilus) SBT10398 (FERM P-14821) are shown below.

A Morphological properties (1) Cell shape: Coccus (2) Motility: None (3) Presence or absence of spores: None (4) Gram stainability: Positive (5) Acrosome: None B Growth on medium State (1) Colony morphology on plate-count agar medium (24-48 hours culture at 37 ° C): S type C Physiological properties (1) 10 ° C viability: negative (2) 40 ° C viability: positive (3) 50 ° C Viability: Positive (4) 2.0% Sodium Chloride Viability: Positive (5) 4.0% Sodium Chloride Viability: Negative (6) 6.5% Sodium Chloride Viability: Negative (7) 60 ° C, 30 minutes Heat Resistance: Positive (8) pH 9.6 Viability: Negative (9) 40% bile acid resistance: Negative (10) Nitrate reduction: Negative (11) Indole formation: Negative (12) Gelatin liquefaction: Negative (13) Catalase: Negative (14) Decomposition of starch: Negative (15) Pair with oxygen Positive attitude (16) L (+) lactic acid is produced from glucose by homolactic fermentation. (17) Does not produce CO ₂ from malate. (18) When cultivated in a skim milk medium, an acid is produced and the milk is coagulated. (19) Degradability of various carbohydrates

1. Glucose + 2. Lactose + 3. Fructose + 4. Mannose + 5. Galactose-6. Sucrose-7. Maltose-8. Cellobiose-9. Trehalose-10. Meribiose-11. Raffinose-12. Merezitose-13. Mannitol-14. Sorbitol-15. Esculin-16. Salicin-17. Amygdalin-(+ indicates that it decomposes,-indicates that it does not decompose. .)

In addition, N-acetylglucosamine, 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-xylose, D-tagatose, D or L-fucose, D or L-. Does not degrade arabitol, gluconate, 2 ceto-gluconate, 5 ceto-gluconate.

From the above-mentioned mycological properties, Bergey's Manual
SBT10398 strain (FERM P-14821) was identified by the Method of Systematic Bacteriology, vol.2 (1986), which was consistent with the mycological properties of Streptococcus salivarius subsp. thermophilus, but with high It was identified as a highly proliferative strain because it grew very rapidly in solid yogurt mix at 37 ° C. Even when this SBT10398 strain (FERM P-14821) was subcultured, it had a property of high growth in a high solid content yogurt mix.

[0017]

[Test Example 1] Lactobacillus delbrueckii s
ubsp.bulgaricus) low-acidity strain SBT10412 (FERM P-14
822) and Streptococcus salivarius subs.
p. thermophilus) highly proliferative strain SBT10398 (FERM P-1482
1) and 1) were inoculated into 12% by weight reduced skim milk medium at 1% by weight, respectively, and mixed and cultured at 37 ° C. for 16 hours. Then, 1% by weight of this mixed culture was inoculated into a 12% by weight reduced skim milk medium at 37 ° C.
It was cultured for 16 hours. Thus, the subculture was carried out for 5 generations. The viable cell count during subculture was SBT10412 strain (FERM P-1482
2) is 1.0 to 2.0 × 10 ⁹ cfu / g and SBT10398 strain (FERM P-14
821) was 4.0 to 6.0 × 10 ⁶ cfu / g, and the balance of both strains was stable. Using the mixed culture obtained from the 5th passage as a starter, 4% by weight of yogurt mix with a solid content of 29% was added and fermented at 39 ° C for up to 9 hours, during which the total number of lactic acid bacteria and the degree of lactic acid acidity were changed. The normal yogurt starter Lactobacillus delbrueckiisu (Lactobacillus delbrueckiisu)
bsp. bulgaricus) and Streptococcus s. thermophilus (Streptococcus s)
alivarius subsp. thermophilus) compared to the case of using the mixed strain starter MRC-32. The results are shown in FIGS. 1 and 2.

In a yogurt mix having a solid content of 29%, SBT10412 strain (FERM P-14822) and SBT10398 strain (FERM P-14822)
It was found that when a mixed starter with P-14821) was used, the proliferative property was good and the acid production remained low.

[0019]

[Test Example 2] Lactobacillus delbrueckii s
ubsp.bulgaricus) low-acidity strain SBT10412 (FERM P-14
822) and Streptococcus salivarius subs.
p. thermophilus) highly proliferative strain SBT10398 (FERM P-1482
1) and 1) were inoculated into 12% by weight reduced skim milk medium at 1% by weight, respectively, and cultured at 37 ° C. for 16 hours. And this mixed culture
A 12% by weight reduced skim milk medium was inoculated with 1% by weight and cultured at 37 ° C. for 16 hours. Thus, the subculture was carried out for 5 generations.
SBT10412 strain (FERM P-14822) showed the viable cell count during subculture.
1.0 to 2.0 × 10 ⁹ cfu / g, SBT10398 strain (FERM P-14821)
Was 4.0 to 6.0 × 10 ⁶ cfu / g, and the ratio of both strains was stable. Using this mixed culture obtained after 5 passages as a starter, 4 wt% was added to yogurt mix with a solid content of 18.7%.
Lactobacillus delbrueckii subsp. Bugarix (Lactobacillus delbrueckii subsp.
lgaricus) and Streptococcus salivariu (Streptococcus salivariu)
s subsp. thermophilus) mixed strain starter (MRC-3
Compared with the case of using 2). The results are shown in FIGS. 3 and 4.

In the yogurt mix with a solid content of 18.7%, SBT10412 strain (FERM P-14822) and SBT10398 strain (FEM
It was found that when the mixed starter of RM P-14821) was used, the proliferative property was good and the acid production was low.

In the present invention, Lactobacillus delbrueckii subsp. Bulgaricus having the above-mentioned properties.
Low-acidity strains of Streptococcus salivar and Streptococcus salivarius subspecies thermophilus
It is characterized by using a highly proliferative strain of ius subsp. thermophilus) as a starter lactic acid bacterium.

The frozen yogurt may be manufactured as follows. The yogurt mix having a solid content of 20 to 30% is sterilized at 90 to 95 ° C for 30 minutes to 1 hour, cooled to 37 to 43 ° C, and inoculated with a starter. Next, it is fermented at 37 to 43 ° C., and when the lactic acid acidity reaches 0.40 to 0.80%, it is cooled to 5 to 10 ° C. and frozen according to the ice cream production process to obtain frozen yogurt. Also, 15-20
After sterilizing the yogurt mix of 90% solids for 30 minutes to 1 hour at 90-95 ℃, cool it to 37-43 ℃, inoculate the starter and ferment it at 37-43 ℃, and make the lactic acid acidity 0.80-1.60%. When reached, cool to 5-10 ° C. Next, 90 ~ 95 ℃ for 30 minutes ~
After sterilizing for 1 hour, ice cream mix of 15 to 20% solid content cooled to 5 to 10 ° C and yogurt mix after fermentation are mixed, and frozen yogurt can be obtained by freeze hardening according to the production process of ice cream. it can.

As described above, the frozen yogurt produced by the present invention has a low acidity and an appropriately mild sourness, and maintains the lactic acid bacterium count at a high level even during long-term cryopreservation. Will be things. Hereinafter, the present invention will be specifically described with reference to examples.

[0024]

[Example 1] skimmed condensed milk 13 kg, skim milk powder 6 kg, mixed oil and fat 3
The yogurt mix (solid content 29%) prepared by mixing 1 kg, 2 kg of sugar, 9 kg of powdered starch syrup and 63 kg of water was sterilized at 95 ° C for 30 minutes and then cooled to 39 ° C. This pasteurized yogurt mix is mixed with Lactobacillus delbrueckii subs.
p. bulgaricus) SBT10412 (FERM P-1482)
2) and Streptococcus salivarius subsp.
thermophilus) highly proliferative strain SBT10398 (FERM P-14821)
Frozen yogurt was obtained by inoculating 4 kg of a starter obtained by mixing and cultivating and with 12% by weight reduced skim milk medium, fermenting the mixture at 39 ° C. until the lactic acid acidity reached 0.4%, cooling and freezing. In addition, as shown in FIG. 5, the number of lactic acid bacteria in the frozen yogurt thus obtained was 6.0 × 10 ⁸ cfu / g immediately after production and frozen (treated at −5 to −20 ° C.).
It was 2.0 × 10 ⁸ cfu / g after storage for ⁸ months.

[0025]

Example 2 Fresh cream 10 kg, skim milk powder 10.75 kg, refined coconut oil 0.5 kg, sugar 7 kg, powdered starch syrup 4 kg and water 63.75 kg
Yogurt mix prepared by mixing (solid content 26%)
Was sterilized at 95 ° C for 30 minutes and then cooled to 39 ° C. This sterilized yogurt mix is mixed with Lactobacillus del Spices bulgaricus.
brueckii subsp.bulgaricus) SBT10412
(FERM P-14822) and Streptococcus salivarius
Subspecies Thermophilus (Streptococcus saliv
arius subsp. thermophilus) SBT10398 (F
ERM P-14821) was mixed with 12 wt% reduced skim milk medium and inoculated with 4 kg of starter, fermented at 39 ° C until the lactic acid acidity reached 0.4%, then cooled and frozen to obtain frozen yogurt. Obtained. The number of lactic acid bacteria in the frozen yogurt thus obtained was 5.5 × 10 ⁸ cfu / g immediately after production, and 3.0 × 10 ⁸ cfu / g after 6 months of storage after freezing (−5 to −20 ° C. treatment). Met.

[0026]

Example 3 A yogurt mix (solid content 18.7%) prepared by mixing 13 kg of skimmed milk powder, 4 kg of mixed oils and fats, 2 kg of sugar and 77 kg of water was sterilized at 95 ° C for 30 minutes and then cooled to 39 ° C. To this pasteurized yogurt mix, Lactobacillus
Delbrucky Subspecies Bulgarix (Lacto
bacillus delbrueckii subsp.bulgaricus) with a low-acidity strain SBT10412 (FERM P-14822) and Streptococcus salivarius subspecies thermophilus (Strepto)
coccus salivarius subsp. thermophilus)
4 kg of a starter obtained by mixing and culturing SBT10398 (FERM P-14821) in a 12% by weight reduced skim milk medium was inoculated, fermented at 39 ° C. until the lactic acid acidity reached 0.5%, and then cooled. Then, 15 kg of skimmed condensed milk, 4 kg of skimmed milk powder, 3 kg of mixed fats and oils, 5 kg of sugar, 22 kg of powdered starch syrup and 51 kg of water were mixed in equal amounts and then frozen to freeze the lactic acidity. I got 0.3% frozen yogurt. As shown in FIG. 6, the number of lactic acid bacteria in this frozen yogurt was 9.0 × 10 ⁸ cfu / g immediately after production, and 6.5 × 10 ⁸ cfu / g after storage for 6 months after freezing (treatment at −5 to −20 ° C.). g
Met.

[0027]

[Example 4] skim milk powder 12.5 kg, refined coconut oil 1 kg, sugar 2
Yogurt mix prepared with Kg and water 80.5Kg (solid content 1
5.0%) was sterilized at 95 ° C for 30 minutes and then cooled to 39 ° C. To this, using a sterilized 12% by weight reduced skim milk medium, a low-acidity strain SBT10412 (FERM P-14822) of Lactobacillus delbrueckii subsp. Bulgaricus and Streptococcus salivarius subspecies were used.・ Thermofils
(Streptococcus salivarius subsp. Thermophilus) and a highly proliferative strain SBT10398 (FERM P-14821) were mixed and cultivated, 4 kg of a starter was inoculated, fermented at 39 ° C until the lactic acid content reached 0.5%, and then cooled. And 20 kg of fresh cream,
An ice mix (solid content 35.0%) prepared by mixing 9 kg of skim milk powder, 10 kg of sugar, 8 kg of powdered starch syrup and 53 kg of water was mixed, and then frozen to obtain frozen yogurt having a lactic acid content of 0.3%. The number of lactic acid bacteria in frozen yogurt was 8.5 × 10 ⁸ cfu / g immediately after production, and 6.0 × 10 ⁸ cfu / g after storage for 6 months after freezing (−5 to −20 ° C. treatment).
Met.

[0028]

INDUSTRIAL APPLICABILITY As in the present invention, Lactobaci delbrueckii subspecies bulgaricus
llus delbrueckii subsp.bulgaricus) Strain of low-acidity S
BT10412 (FERM P-14822) and Streptococcus salivarius subspecies thermophilus (Streptococc
us salivarius subsp. thermophilus) highly proliferative strain SBT
By using a mixed culture with 10398 (FERM P-14821) as a starter lactic acid bacterium, it has a low acidity and mild sourness, and maintains a high level of lactic acid bacterium count even during long-term cryopreservation. It becomes possible to provide high frozen yogurt.

[Brief description of drawings]

FIG. 1 shows the change in the total number of lactic acid bacteria in the culture in Test Example 1.

[Explanation of symbols]

● indicates an example using the mixed starter of the present invention, ○ indicates MRC-
32 mixed starters are shown respectively.

FIG. 2 shows the transition of the lactic acid acidity of the culture in Test Example 1.

[Explanation of symbols]

● indicates an example using the mixed starter of the present invention, ○ indicates MRC-
32 mixed starters are shown respectively.

FIG. 3 shows changes in the total number of lactic acid bacteria in the culture in Test Example 2.

[Explanation of symbols]

● indicates an example using the mixed starter of the present invention, ○ indicates MRC-
32 mixed starters are shown respectively.

FIG. 4 shows changes in the lactic acid acidity of the culture in Test Example 2.

[Explanation of symbols]

● indicates an example using the mixed starter of the present invention, ○ indicates MRC-
32 mixed starters are shown respectively.

FIG. 5 shows changes in the total number of lactic acid bacteria during storage of frozen yogurt in Example 1.

FIG. 6 shows changes in the total number of lactic acid bacteria during storage of frozen yogurt in Example 3.

Claims (4)

[Claims] 1. A raw material mix containing Lactobaci delbruecki subspecies bulgaricus
llus delbrueckii subsp. bulgaricus) with a low-acidity strain and Streptococcus salivarius subspecies
Thermophilus (Streptococcus salivarius subsp. The
rmophilus) with a highly proliferative strain, inoculated with a mixed starter, fermented, and then frozen, to produce a low-acid frozen yogurt. 2. A Lactobacillus delbrueckii Lactobacillus delbrueckii
subsp. bulgaricus) is an SBT10412 strain (FERM
P-14822), and Streptococcus salphilus subspecies thermophilus (Streptococcus sal
ivarius subsp. thermophilus) is a highly proliferative strain of SBT10398
The method according to claim 1, which is a strain (FERM P-14821). 3. The method according to claim 1, wherein a raw material mix having a solid content of 25 to 30% is used. 4. The method according to claim 1, wherein a raw material mix having a solid content of 15 to 25% is used, and an ice mix is further mixed before freezing.