JP5568380B2 - Method for producing fermented milk - Google Patents

Description

  The present invention relates to fermented milk and a method for producing the same. More specifically, the present invention relates to a low-fat type fermented milk by lactic acid bacteria fermentation that has little water separation, has a stable structure, and does not use special raw materials and equipment, and a method for producing the same.

  Fermented milk is made from animal milk such as cow milk and fermented with lactic acid bacteria or yeast or both. In recent years, the demand for low-fat products in fermented milk has increased due to consumers' low fat preference. However, low-fat fermented milk is unstable in tissue and is prone to water separation during storage. Therefore, in low-fat fermented milk, it has been common to use additives such as stabilizers to suppress water separation.

Moreover, in patent document 1, raising the protein content in a raw material mix is performed. Specifically, it is obtained by removing lactose from milk protein concentrate separated and concentrated by membrane treatment with diafiltration membrane (Dia Filtration) or ultrafiltration membrane (Ultra Filtration) and permeate of this membrane treatment. The lactose permeate is mixed with the raw material mix.
In Patent Document 2, the fat globule is refined by applying an ultra-high pressure homogenizer to the raw material mix.

Japanese Patent No. 3755855 Japanese Patent No. 3155242

However, the method of Patent Document 1 has a problem in that a membrane treatment is required to obtain a milk protein concentrate and permeate, resulting in an increase in cost. Moreover, it was not preferable also in terms of flavor and texture. In addition, the method of Patent Document 2 has a problem in that a large capital investment is required because an ultra-high pressure homogenizer is used.
The present invention has been made in view of the above circumstances, and obtains a stable fermented milk with a tissue with little water separation, and also produces the fermented milk without using special raw materials and equipment. Let it be an issue.

The present inventors divide the raw material used for the production of fermented milk into a raw material containing fat and a raw material not containing fat, and only homogenize the raw material containing fat, and the raw material not containing fat is By not performing the homogenization treatment, it was found that the low-fat type fermented milk can suppress the water separation of the fermented milk after fermentation, and the present invention has been completed.
That is, the present invention employs the following configuration.

[1] A method for producing fermented milk having a fat content of 2.0% by mass or less, wherein a raw material (A) containing fat and a raw material (B) containing no fat are mixed and mixed (C ), A homogenization step for homogenizing only the raw material (A) prior to the mixing step, a post-sterilization step for sterilizing the mixed raw material (C) after the mixing step, and a post-sterilization step, Newsletter酵原fees fat content of 2.0 wt% or less than 0.3 mass% (E) to the mixed raw material (C) was added starter (D), comprising a fermentation step of fermenting this, the The fat content of the raw material (A) is 0.6 to 9.2% by mass, and the proportion of the protein mass derived from the raw material (A) in the protein mass contained in the fermentation raw material (E) is 50% by mass or less. der is, in the homogenizing step, to said homogenizing the raw material (a) in 10~20MPa Method for producing a fermented milk.

[2] A method for producing fermented milk having a fat content of 2.0% by mass or less, wherein a raw material (A) containing fat and a raw material (B) containing no fat are mixed and mixed raw material (C ), The homogenization step for homogenizing only the raw material (A) prior to the mixing step, and the raw material (A) and the raw material (B) after the homogenization step prior to the mixing step, respectively. After the sterilization step and the mixing step, a starter (D) is added to the mixed raw material (C) to obtain a fermented raw material (E) having a fat content of 0.3% by mass to 2.0% by mass, It comprises a fermentation process for fermenting this, the fat content of the raw material (A) is 0.6 to 9.2% by mass, and it is derived from the raw material (A) in the protein mass contained in the fermentation raw material (E). proportion of protein mass state, and are 50 wt% or less, in the homogenization process, the raw material (a) 10 to 20 m method for producing fermented milk, characterized that you homogenized at a.

[3] A mixture containing a raw material containing fat and nonfat concentrated milk or nonfat dry milk and having a nonfat milk solid content of 5 to 20% by mass is used as the raw material (A) [1] or [2 ] The manufacturing method of fermented milk as described in any one of.
[4] The method for producing fermented milk according to any one of [1] to [3], wherein the fermented milk is stationary fermented milk.
[5] The method for producing fermented milk according to any one of [1] to [4], wherein a lactic acid bacteria starter is used as the starter (D) .

  According to the present invention, even if the fat content is small, fermented milk with little water separation and stable tissue can be obtained. In addition, fermented milk with less water separation and stable tissue can be produced without using special raw materials and equipment, which is suitable for industrial production.

  A preferred embodiment of the present invention will be described in detail. However, the present invention is not limited to the following preferred embodiments, and can be freely changed within the scope of the present invention. In the present specification, the percentage is expressed by mass (% by mass) unless otherwise specified.

[Fermented milk]
The fermented milk in the present invention may be either a stationary type fermented milk or a stirred type fermented milk, but is preferably a stationary type fermented milk in that suppression of water separation is particularly required.
The stationary type fermented milk (also called post-fermented type fermented milk or set yogurt) is coagulated fermented milk (yogurt) that is fermented by filling a food and drink container (retail container) with a fermentation raw material. That is, it is fermented milk (yogurt) that is fermented after filling a container for eating and drinking with a fermentation raw material and then put on the market without stirring.
As the varieties of stationary type fermented milk, plain yogurt to which at least sweeteners and fragrances are not added, plain yogurt to which sweeteners, fragrances, and stabilizers such as agar, gelatin and pectin are not added, and agar and gelatin And hard yoghurt to which a stabilizer such as pectin is added.
Agitated fermented milk (also called pre-fermented fermented milk) is fermented milk (yogurt) that is fermented in advance in a tank and then filled in food and drink containers (retail containers) for commercial use. It is.

[Fermentation raw material]
In the present invention, all the raw materials (fermented raw materials) used for the production of fermented milk are divided into a raw material (A) containing fat, a raw material (B) containing no fat and a starter (D), and a raw material containing fat. After homogenizing only (A), the raw material (A) and the raw material (B) are mixed to obtain a mixed raw material (C).
And the fermentation raw material (E) obtained by adding a starter (D) to a mixed raw material (C) is fermented.

The fat-containing raw material (A) refers to a raw material that causes separation of a cream layer on the surface when fermented without performing a homogenization treatment. Moreover, the raw material (B) which does not contain fat means a raw material which does not cause separation of the cream layer on the surface even if it is fermented without homogenization.
Examples of the raw material (A) containing fat include raw milk, partially skimmed milk, butter, vegetable oil and fat, cream, and creaming powder.
The cream may be a fresh cream or a synthetic cream synthesized using vegetable oils, emulsifiers, stabilizers and the like. The creaming powder may be a product obtained by drying a fresh cream or a product obtained by drying a synthetic cream.

The raw material (A) containing fat may be a raw material that causes separation of the cream layer on the surface when fermented without homogenization as a whole. Therefore, the raw material (A) containing fat may contain a raw material corresponding to the following raw material (B) not containing fat.
In particular, it is preferable to use a raw material containing non-fat milk solids such as nonfat dry milk and nonfat concentrated milk in addition to butter, cream and the like because fat emulsification can be promoted.
The non-fat milk solid content concentration of the raw material (A) containing fat is preferably 5 to 20% by mass, and more preferably 5 to 10% by mass.
In addition, non-fat milk solid content means the protein derived from milk, lactose, and a mineral.

Examples of the raw material (B) not containing fat include sucrose, starch, dextrin and the like in addition to raw materials containing non-fat milk solids such as nonfat concentrated milk, nonfat dry milk, and nonfat dry milk solution.
The raw material (B) containing no fat may be a raw material that does not cause separation of the cream layer on the surface even when fermented without homogenization. Therefore, it may contain some fat that does not cause separation of the cream layer.

The fermentation raw material (E) contains a protein. Raw material (A) in the amount of protein contained in fermentation raw material (E) (equal to the total amount of protein in raw material (A), protein in raw material (B), and protein in starter (C)) The proportion of the derived protein mass is 50% by mass or less, preferably 40% by mass or less, more preferably 35% by mass or less, and particularly preferably 25% by mass or less. Moreover, it is preferable that it is 2.5 mass% or more.
The lower the ratio of the protein mass derived from the raw material (A), the more remarkable the effect of the present invention is. On the other hand, when the ratio of the protein mass derived from the raw material (A) is too low, the non-fat milk solid content contained in the raw material (A) is insufficient, and the emulsification of the fat is easily inhibited.

The fat content of the fermentation raw material (E) (approximately equal to the ratio of the amount of fat contained in the raw material (A) to the amount of the fermentation raw material (E)) is 0.3% by mass or more and 2.0% by mass or less. More preferably, it is 0.3 mass% or more and less than 2.0 mass%, More preferably, it is 0.3 mass% or more and 1.5 mass% or less, 0.3 mass% or more and 1.4 mass% It is particularly preferable that the content be 0.4% by mass or more and 1.4% by mass or less.
In addition, when the fat content exceeds 2% by mass, the effect of the present invention may not be sufficiently exhibited since it is difficult to remove water from the beginning. Moreover, when the fat content is less than 0.3% by mass, there is a possibility that the suppression of water separation cannot be sufficiently expected even with the method of the present invention.
That is, as the fermented milk exhibiting the effect of suppressing water separation in the present invention, partially defatted yogurt (particularly suitable for a fat content of 0.5 to 2.0%) or defatted yogurt (for example, a fat content of 0.00). This effect is particularly enjoyed in fermented milk of a low fat type such as 5% or less), in particular, in a low fat type stationary fermented milk.
The non-fat milk solid content concentration of the fermentation raw material (E) is preferably 8 to 15% by mass, and more preferably 10 to 13% by mass.

To the fermentation raw material (E), a stabilizer having a thickening or coagulating action such as agar, gelatin, and pectin may be added. The addition of the stabilizer is preferable because the effect of suppressing water separation (low water separation) in the fermented milk of the present invention is considered to further increase.
Moreover, when raw material (A) contains creaming powder which dried synthetic cream or synthetic cream, stabilizers, such as a lecithin used for the synthesis | combination of a synthetic cream, may be included in fermentation raw material (E).

[Homogenization process]
In the homogenization step, only the raw material (A) is homogenized. Homogenization of the raw material (B) is not performed.
The homogenization is preferably performed at a temperature at which the raw material (A) is heated in advance. Emulsification can be promoted by heating.
The heating is preferably 60 to 85 ° C.
The homogeneous pressure is preferably 10 to 20 MPa. If it is 20 MPa or less, a normal high-pressure homogenizer can be used. Moreover, if it is 10 Mpa or more, a raw material (A) can fully be homogenized. An ultra-high pressure homogenizer may be used and homogenized at a homogeneous pressure exceeding 20 MPa.

[Mixing process]
In the mixing step, the raw material (A) homogenized in advance and the raw material (B) not homogenized are mixed to obtain a mixed raw material (C).
The mixing step may be performed before or after the pre-sterilization step described later.

[Sterilization process]
The sterilization process may be a pre-sterilization process or a post-sterilization process.
The pre-sterilization step is a step of separately sterilizing the raw material (A) homogenized in advance and the raw material (B) not homogenized prior to the mixing step. The post sterilization step is a step of sterilizing the mixed raw material (C) after the mixing step.
A plate type sterilizer, a tubular type sterilizer, a direct heating type sterilizer, a jacketed tank, or the like can be used for both the pre-sterilization step and the post-sterilization step. The sterilization conditions are preferably 85 to 95 ° C. for 1 to 15 minutes.

[Fermentation process]
In the fermentation process, the starter (D) is added to the mixed raw material (C) to obtain the fermented raw material (E), which is fermented. The fermentation process is performed after both the mixing process and the sterilization process (pre-sterilization process or post-sterilization process) are completed.
Examples of the starter (D) include lactic acid bacteria starters and yeasts, but it is preferable to use lactic acid bacteria starters. Examples of the lactic acid bacteria starter include lactic acid bacteria starters that are usually used in the production of yogurt such as Lactobacillus bulgaricus, L. lactis, and Streptococcus thermophilus. It is done. When a lactic acid bacteria starter is used, a bifidobacteria starter such as Bifidobacterium longum (B. longum) may be added. Commercially available lactic acid bacteria starters can also be used.

When using a lactic acid bacteria starter, after cooling a mixing raw material (C) to 35-45 degreeC, a starter (D) is added. The addition amount of the starter (D) is preferably 0.4 to 2.5% by mass with respect to the mixed raw material (C).
During fermentation, the temperature is maintained at a temperature suitable for the growth of the starter (D). Although suitable temperature changes with bacterial species, if it is lactic acid bacteria illustrated above, 37-40 degreeC is preferable.
Fermentation can be obtained by terminating fermentation when the pH reaches 4.6 to 4.7. The time required from the starter (D) addition to the end of fermentation (fermentation time) is usually 4 to 6 hours.

[Low water separation]
The fermented milk obtained by the above production method is characterized in that it is fermented milk with little water separation and stable tissue. This is considered to be an effect obtained by not homogenizing a considerable amount of the protein contained in the fermentation raw material (E).
That is, although the homogenization treatment is an essential step for suppressing cream layer separation, it is considered that the protein does not necessarily have a good influence. In other words, when the protein structure is partially destroyed by the homogenization treatment, the network is weakened, and this is presumed to cause water separation.
The fermented milk of the present invention can be stored while maintaining the appearance and flavor due to low water separation.

EXAMPLES Next, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited to a following example. In the following test examples,% indicates mass% unless otherwise specified.
(1) Preparation of fermented milk [raw material]
The raw materials used in the following test examples are as follows.
cream:
Fresh cream produced by centrifuging raw milk at Morinaga Milk Industry Co., Ltd. Fat content 45.5%, protein content 1.6%, non-fat milk solids 4.5%.
Nonfat concentrated milk:
Non-fat concentrated milk produced by centrifuging raw milk at Morinaga Milk Industry Co., Ltd. to prepare skim milk and concentrating it under reduced pressure. Fat content 0.3%, protein content 12.4%, non-fat milk solids 34.6%.
Nonfat dry milk:
Non-fat dry milk produced by spray drying the non-fat concentrated milk at Morinaga Milk Industry Co., Ltd. Fat content 1.0%, protein content 34.0%, non-fat milk solids 95.2%.
starter:
Lactobacillus bulgaricus (L. bulgaricus) and Streptococcus thermophilus (S. thermophilus) mixed culture (lactic acid bacteria starter). Fat content 0.1%, protein content 4.1%, non-fat milk solids 10%

[Preparation of raw material (A)]
The raw material composition shown in Table 1 was mixed with a raw material containing cream and skim milk powder, the balance being water, heated to 70 ° C., and homogenized at a homogeneous pressure of 15 MPa. As a homogenizer, a homogenizer manufactured by Mimaru Machinery Co., Ltd. was used. Then, it cooled to 10 degrees C or less (above 0 degree C), and obtained each raw material (A) (A-1 to A-6) shown in Table 1.
Table 1 also shows the fat content, protein content, and non-fat milk solid content of each raw material (A) calculated from the raw material composition.

[Production of fermented milk]
The fermented milk of this invention was manufactured with the following preparation method X which is a manufacturing method of the fermented milk of this invention.
(Preparation method X)
The raw materials (A) of Table 1, the nonfat concentrated milk, and water were mixed at the blending ratio shown in Table 2 to prepare a mixed raw material (C) having a nonfat milk solid content of 10%.
These mixed raw materials (C) are sterilized at 90 ° C. for 10 minutes, cooled to 38 ° C., starter (D) (lactic acid bacteria starter) is added to 1.9%, and fermentation raw materials (E ) Was prepared.
100 g of this fermentation raw material (E) is put into an inverted frustoconical paper cup having a diameter of 7 cm (bottom 5.5 cm) and a height of 5.5 cm, and cultured and fermented at 38 ° C. until the pH becomes 4.7. It cooled in the refrigerator and manufactured the fermented milk of the test samples 1-18.

Table 2 also shows the fat content of the fermentation raw material (E) calculated from the raw material composition and “homogenized protein (%)”. “Homogenized protein (%)” in the case of the preparation method X is the ratio of the protein derived from the raw material (A) to the protein contained in the entire fermentation raw material (E).
For example, the protein content of test sample 1 is a value determined as follows.
Protein (A) -derived protein in 100 g of fermentation raw material (E) = 2.7 × 0.021 = 0.057 g
Protein derived from defatted concentrated milk in 100 g of fermentation raw material (E) = 12.4 × 0.279 = 3.460 g
Starter-derived protein in 100 g of fermentation raw material (E) = 4.1 × 0.019 = 0.078 g
Homogenized protein (%)
= {0.057 / (0.057 + 3.460 + 0.078)} × 100 = 16%

Moreover, fermented milk used as a control sample was produced by the following preparation method Y, which is a method of homogenizing the raw material containing fat and the raw material not containing fat.
(Preparation method Y)
Cream, skimmed concentrated milk, and water were mixed at the blending ratio shown in Table 3 to prepare a mixed raw material (C) having a nonfat milk solid content of 10%.
These mixed raw materials were heated to 70 ° C. and homogenized at a homogeneous pressure of 15 MPa. As a homogenizer, a homogenizer manufactured by Mimaru Machinery Co., Ltd. was used. Then, it sterilized at 90 degreeC for 10 minutes, cooled to 38 degreeC, and added starter (D) (lactic acid bacteria starter) to this so that it might become 1.9%, and the fermentation raw material (E) was obtained.
100 g of this fermentation raw material (E) is put into an inverted frustoconical paper cup having a diameter of 7 cm (bottom 5.5 cm) and a height of 5.5 cm, and cultured and fermented at 38 ° C. until the pH becomes 4.7. It cooled in the refrigerator and manufactured fermented milk of the control samples 1-6.

Table 3 also shows the fat content of each fermented milk calculated from the raw material composition and “homogenized protein (%)”. The “homogenized protein (%)” in the case of the preparation method Y is the ratio of the protein derived from the mixed raw material (the protein derived from the cream and the defatted concentrated milk) to the protein contained in the entire fermentation raw material.
For example, the protein content of the control sample 1 is a value determined as follows.
Protein derived from cream in 100 g of fermentation raw material (E) = 1.6 × 0.004 = 0.006 g
Protein derived from defatted concentrated milk in 100 g of fermentation raw material (E) = 12.4 × 0.283 = 3.509 g
Starter-derived protein in 100 g of fermentation raw material (E) = 4.1 × 0.019 = 0.078 g
Homogenized protein (%)
= {(0.006 + 3.509) / (0.006 + 3.509 + 0.078)} × 100 = 3.515 / 3.593 × 100 = 97.8%

(2) Evaluation The fermented milk of each sample was left at 10 ° C. in a paper cup having a diameter of 7 cm (bottom 5.5 cm) and a height of 5.5 cm, and the amount of water that appeared on the surface on the seventh day after production. (Water separation amount) was measured, and the water separation rate was determined based on the following equation (1). The results are shown in Table 4.
Water separation rate (%)
= [Water separation per paper cup (g) / Fermentation raw material filled in paper cup (E) (g)] × 100
... (1)
Moreover, about each test sample, based on the following Formula (2), the water separation improvement effect compared with the control sample with the same fat content was calculated | required as water separation improvement rate, and it showed in Table 4.
Water separation improvement rate (%)
= 100- (water separation rate of the test sample / water separation rate of the control sample having the same fat content as the test sample) × 100
... (2)

In the fermented milk produced by the method of the present invention, the water separation rate on the 7th day after production is preferably 3.0% or less, and particularly preferably 2.3% or less. If the water separation rate is 3.0% or less, it is preferable in terms of the stability of the tissue that contributes to the appearance and flavor, and particularly suitable for stationary fermented milk.
As is apparent from Table 4, according to the production method of the present invention, the water separation rate on the 7th day is 3.0% or less over the entire range of fat content of 0.3 to 2.0%, and the structure is sufficient. Was stable. From this, it was confirmed that the production method of the present invention is preferable for the production of low-fat fermented milk and that high-quality stationary fermented milk can be obtained according to the production method of the present invention.
Further, a high water separation improvement rate of 30% or more was observed when the fat content was 1.5% or less, particularly 0.4% or more and 1.4% or less. From this, it has confirmed that the manufacturing method of this invention was preferable for especially manufacture of fermented milk with a low fat content.
In addition, when the fat content is 1.4 to 2.0%, the water separation rate of the control sample is also 3.0% or less, but also in these cases, a high water separation improvement rate was obtained. From this, it was found that even when the fat content is 1.4 to 2.0%, the present invention can obtain a more stable fermented milk with less water separation.
Further, it was confirmed that the effect of suppressing water separation was higher as the homogenized protein mass (%) was lower. In particular, when the fat content is in the range of 0.4% to 1.4% and the proportion of protein homogenized at the time of production is 40% or less, the water separation improvement rate is 50% or more, and a particularly remarkable water separation inhibiting effect. Was found to be effective.

Claims (5)

A method for producing fermented milk having a fat content of 2.0% by mass or less,
A mixing step of mixing the raw material (A) containing fat and the raw material (B) not containing fat to obtain a mixed raw material (C);
Prior to the mixing step, a homogenization step of homogenizing only the raw material (A),
A post-sterilization step of sterilizing the mixed raw material (C) after the mixing step;
After the post-sterilization step, a starter (D) is added to the mixed raw material (C) to obtain a fermented raw material (E) having a fat content of 0.3% by mass to 2.0% by mass, and this is fermented. With a fermentation process,
The fat content of the raw material (A) is 0.6 to 9.2% by mass,
The ratio of the protein mass derived from the raw material (A) to the protein mass contained in the fermentation raw material (E) is 50% by mass or less,
In the said homogenization process, the said raw material (A) is homogenized at 10-20 MPa, The manufacturing method of fermented milk characterized by the above-mentioned. A method for producing fermented milk having a fat content of 2.0% by mass or less,
A mixing step of mixing the raw material (A) containing fat and the raw material (B) not containing fat to obtain a mixed raw material (C);
Prior to the mixing step, a homogenization step of homogenizing only the raw material (A),
Prior to the mixing step, the raw material (A) after the homogenization step and the raw material (B) are sterilized before sterilization,
After the mixing step, the starter (D) is added to the mixed raw material (C) to obtain a fermented raw material (E) having a fat content of 0.3% by mass or more and 2.0% by mass or less, and fermentation for fermenting this. With a process,
The fat content of the raw material (A) is 0.6 to 9.2% by mass,
The ratio of the protein mass derived from the raw material (A) to the protein mass contained in the fermentation raw material (E) is 50% by mass or less,
In the said homogenization process, the said raw material (A) is homogenized at 10-20 MPa, The manufacturing method of fermented milk characterized by the above-mentioned.   Fermentation according to claim 1 or 2, wherein a mixture containing a raw material containing fat and nonfat concentrated milk or nonfat dry milk and having a nonfat milk solid content of 5 to 20% by mass is used as the raw material (A). Milk production method.   Fermented milk is stationary type fermented milk, The manufacturing method of fermented milk as described in any one of Claims 1-3.   The method for producing fermented milk according to any one of claims 1 to 4, wherein a lactic acid bacteria starter is used as the starter (D).