JP7178789B2 - Fermented milk and its manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to fermented milk and a method for producing the same.

Fermented milk is classified into hard (solid) yoghurt, drink (liquid) yoghurt, and soft yoghurt positioned in between. In addition, as a method for producing fermented milk, a pre-fermentation type production method in which a fermented milk base to which a lactic acid bacteria starter is added is fermented before filling it in a container, and a fermented milk base to which a lactic acid bacteria starter is added is fermented into a container. There is a post-fermentation type production method of fermenting.

The soft yogurt described above is generally produced by a pre-fermentation type production method in which a fermented milk base to which a lactic acid bacteria starter is added is fermented before being filled into a container. In the pre-fermentation type production method, a fermented milk base to which a lactic acid bacteria starter is added is fermented to obtain a curd in which the fermented milk is gelled, the obtained curd is crushed in a container, and the average particle size of the fermented milk is are adjusting.

At this time, if the crushing strength of the curd is suppressed by using a filter to emphasize the texture, the average particle size of the fermented milk becomes large, which causes a rough texture. In order to smooth the structure of fermented milk, it is effective to increase the crushing strength of the curd and reduce the average particle size of the fermented milk. There is a problem that the texture is reduced, such as a rich texture.

In consideration of such problems, Patent Literature 1 discloses a production method in which predetermined amounts of gelatin and starch are added to fermented milk to adjust the texture of soft yogurt.

Japanese Patent No. 3811631

However, the addition of stabilizers/thickeners such as gelatin may affect the flavor of fermented milk. Therefore, it is desired to develop a new fermented milk that achieves both dense and smooth viscosity and rich texture without using stabilizers and thickeners.

Accordingly, an object of the present invention is to provide a novel fermented milk that achieves both dense and smooth viscosity and rich texture without using stabilizers and thickeners, and a method for producing the same.

The fermented milk according to the present invention contains 5.0% or more of milk protein, 25% or more of whey protein in the milk protein, has an average particle size of 3 μm or more and 30 μm or less, and has a viscosity of 1000 mPa at 10 ° C. - s or more.

In addition, the method for producing fermented milk according to the present invention includes a production step of producing a fermented milk base containing milk proteins including whey protein, and fermenting after adding a lactic acid bacteria starter to the fermented milk base to produce fermented milk. A fermentation step of producing curd, a crushing step of crushing the curd to make the average particle size of the fermented milk 1 μm or more and 20 μm or less, and holding the crushed fermented milk in a container to recycle the fermented milk. A holding step of producing fermented milk by setting,
The fermented milk contains 5.0% or more of the milk protein, 25% or more of the whey protein in the milk protein, the average particle size of the fermented milk is 3 μm or more and 30 μm or less, and the viscosity at 10 ° C. is 1000 mPa. - s or more.

According to the method of the present invention, a predetermined amount of whey protein is contained in the production process, and by obtaining the crushing step and the holding step, the average particle size of the fermented milk is 3 μm or more and 30 μm or less, and the viscosity at 10 ° C. is 1000 mPa · s or more, and a fermented milk having both dense and smooth viscosity and rich texture can be obtained without using a stabilizer/thickener.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.

<Outline of fermented milk of the present invention>
The fermented milk of the present invention is soft yogurt positioned between hard (solid) yogurt and drink (liquid) yogurt, and is pre-fermented fermented milk. The fermented milk of the present invention contains 5.0% or more of milk protein with respect to the whole fermented milk and 25% or more of whey protein in the milk protein in the final product.

Here, the milk protein according to this embodiment includes casein protein and whey protein. Examples of casein proteins include α-casein and β-casein, and examples of whey proteins include α-lactalbumin, β-lactoglobulin and serum albumin.

By containing 5.0% or more of milk protein in the final product, fermented milk, a rich texture can be realized, and by making it 10.0% or less, the flavor is improved. be able to. Therefore, the fermented milk preferably contains 5.0% or more and 10.0% or less of milk protein.

More preferably, the fermented milk contains 6.0% or more and 8.0% or less of milk protein. By setting the milk protein to 6.0% or more and 8.0% or less, a richer texture can be obtained, and the flavor can be further improved, and both a rich texture and a good flavor can be achieved. .

Whey protein can increase the hardness of fermented milk curd (hereinafter also simply referred to as curd) by containing 25% or more of whey protein in milk protein in fermented milk, which is the final product. Moreover, by setting the whey protein in the milk protein to 35% or less, excellent heat resistance and good flavor can be obtained. Therefore, it is desirable that the fermented milk contains 25% or more and 35% or less of the whey protein in the milk protein.

The content (% by mass) of milk protein in the fermented milk and the content (% by mass) of whey protein in the milk protein can be measured by the Kjeldahl method. When the Kjeldahl method is used, the nitrogen/protein conversion factor is 6.38.

Moreover, the average particle size of the fermented milk of the present invention is desirably 3 μm or more and 30 μm or less. By setting the average particle size of the fermented milk to 3 μm or more and 30 μm or less, it is possible to make the texture less rough and smooth.

More preferably, the average particle size of the fermented milk is 5 μm or more and 20 μm or less. By setting the average particle size of the fermented milk in the final product to 5 μm or more and 20 μm or less, roughness is further reduced, and a smoother texture can be achieved.

Furthermore, the fermented milk of the present invention preferably has a viscosity of 1000 mPa·s or more at 10°C. By setting the viscosity of the fermented milk at 10°C to 1000 mPa·s or more, it is possible to obtain a rich and full-bodied texture. Also, by setting the viscosity of the fermented milk at 10° C. to 20000 mPa·s or less, it is possible to make the texture not too hard and easy to eat.

More preferably, the viscosity of the fermented milk at 10°C is 3000 mPa·s or more and 10000 mPa·s or less. By setting the viscosity at 10° C. of the fermented milk in the final product to 3000 mPa·s to 10000 mPa·s, it is possible to achieve a rich texture and an easy-to-eat texture that is not too hard.

In addition, sugar, pulp, fruit juice, etc. may be added to the fermented milk mentioned above. When solids such as pulp are added to the fermented milk, the above average particle size and viscosity are the average particle size and viscosity of the fermented milk portion excluding solids such as pulp.

<Method for producing fermented milk of the present invention>
The fermented milk of the present invention is pre-fermented soft fermented milk, and can be produced by the following production method. First, a fermented milk base, which is raw material milk, is prepared. The fermented milk base is prepared, for example, by adding skim milk powder, skim concentrated milk, fresh cream, butter, milk protein concentrate, raw water, etc. to raw milk, and further adding a predetermined amount of whey protein and mixing. . Although the fermented milk base used in the present invention is not limited, the non-fat milk solids (SNF) preferably has a ratio of SNF to the total fermented milk base of 10 to 18%, more preferably 11 to 16%. is desirable. In addition, the fat content (FAT) is preferably from 0 to 5.0%, more preferably from 2.0 to 4.0%, with respect to the whole fermented milk base. However, the contents of these SNF and FAT are not limited to these. In addition, sugar, fruit juice, etc. may be added to the fermented milk base.

At this time, the content of milk protein in the fermented milk in the final product can be adjusted by adjusting the content of powdered skim milk, concentrated skim milk, fresh cream, butter, milk protein concentrate, and the like.

Whey protein can be included by adding whey powder, whey protein concentrate (WPC), whey protein isolate (WPI), etc. to the fermented milk base. At this time, by adjusting the content of the whey protein concentrate, etc., the content of whey protein in the fermented milk in the final product (ratio (%) of whey protein in the milk protein) can be adjusted.

Next, the prepared fermented milk base is sterilized by heating between about 90° C. and 120° C. for 60 seconds or longer, and then fermented by adding a lactic acid bacteria starter to produce a gelled curd of fermented milk. As the lactic acid bacteria starter, for example, lactic acid bacteria such as Bulgaria bulgaricus and Thermophilus can be used. Fermentation conditions may be the same as conventional ones. For example, the fermented milk base is fermented at around 40° C. for 3 to 5 hours.

Then, by crushing the produced curd, fermented milk having an average particle size of 1 μm or more and 20 μm or less and a viscosity at 10° C. of 100 mPa·s or more and 3000 mPa·s or less can be produced. Curd crushing is desirably performed using, for example, a homogenizer. It is preferable to homogenize the curd at a pressure of 1 MPa or more and 20 MPa or less in crushing with a homogenizer. By homogenizing the curd at 1 MPa or more, it is possible to obtain a smooth texture with little roughness, and by making it 20 MPa or less, excessive damage to the curd can be suppressed.

In the case of this embodiment, by crushing the curd with a high crushing strength using a homogenizer, compared to crushing using a filter, the average particle size of the fermented milk can be further reduced, and the final product can be obtained. The texture of fermented milk can be made dense and smooth.

Next, after filling the container with the crushed fermented milk, the container is held at 20° C. or higher and 50° C. or lower for 1 hour or longer, or at 0.5° C. or higher and lower than 20° C. for 2 hours or longer. As a container to be filled with crushed fermented milk, other various containers such as a box-shaped container can be applied in addition to the tank. By maintaining fermented milk enriched with whey protein under the above conditions, the surface hydrophobicity of casein micelles increases due to the induction of heat denaturation, and after crushing the curd, the distance between particles decreases, and the hydrophobicity between milk proteins increases. It is possible to enhance the expression effect of interaction (resetting). Here, resetting refers to a phenomenon in which the average particle size of the crushed fermented milk increases (increase in diameter) and the viscosity increases (increases), resulting in gelation again.

Thus, in the manufacturing method according to the present invention, by crushing and homogenizing the curd and then holding the curd under predetermined conditions, it is possible to induce diameter increase and thickening due to resetting. Therefore, fermented milk having an average particle size of 3 μm or more and 30 μm or less and a viscosity of 1000 mPa·s or more at 10° C. can be produced even after the curd is finely crushed.

<Action and effect>
In the above configuration, in the production method according to the present invention, the curd obtained by fermenting a fermented milk base containing 5% milk protein and containing 25% or more whey protein in the milk protein is processed by a homogenizer. made to homogenize. As a result, the average particle size of the fermented milk is 1 μm or more and 20 μm or less. Then, the crushed fermented milk was held at 20° C. or higher and 50° C. or lower for 1 hour or longer, or at 0.5° C. or higher and lower than 20° C. for 2 hours or longer.

As a result, in this production method, the retention step after homogenization induces diameter increase and thickening due to resetting, contains 5.0% or more of milk protein, and 25% or more of whey protein in milk protein, Fermented milk having an average particle size of 3 μm or more and 30 μm or less and a viscosity of 1000 mPa·s or more at 10° C. can be produced. In the present invention, fermented milk having both dense and smooth viscosity and rich texture can be realized without using a stabilizer/thickener.

EXAMPLES The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples.

<Example 1>
In Example 1, 630 g of raw milk, 10 g of fresh cream, 230 g of skimmed concentrated milk, 30 g of milk protein concentrate, 6 g of whey protein isolate (WPI), and 64 g of raw water were mixed to form a fermented milk base (SNF 15.5%, FAT 3.0%) was prepared.

Next, after sterilizing the prepared fermented milk base at 95 ° C. for 5 minutes, 30 g of lactic acid bacteria starter, which is obtained by culturing lactic acid bacteria separated from Meiji Bulgaria Yogurt LB81 in a 10% skim milk medium, is added and kept at 43 ° C. for 3 to 5 hours. , fermented until the pH was 4.4.

The resulting fermented milk curd was crushed and homogenized using a homogenizer (manufactured by Izumi Food Machinery Co., Ltd.) at a flow rate of 135 L/h and a pressure of 5 MPa. Next, the crushed fermented milk was filled in a container and held at 25° C. for 1 hour to reset, thereby producing the fermented milk of Example 1.

<Example 2>
In Example 2, in order to change the content of milk protein from Example 1 described above, the contents of fresh cream, concentrated skim milk, and raw water were changed. Specifically, in Example 2, 630 g of raw milk, 13 g of fresh cream, 80 g of skimmed concentrated milk, 30 g of milk protein concentrate, 6 g of whey protein isolate (WPI), and 211 g of raw water were mixed, and the fermented milk base (SNF 11.4%, FAT 3.0%) were prepared.

Next, the prepared fermented milk base was sterilized at 95° C. for 5 minutes, then 30 g of lactic acid bacteria starter was added and fermented at 43° C. for 3 to 5 hours until the pH reached 4.4.

The resulting fermented milk curd was crushed and homogenized using the same homogenizer as above at a flow rate of 135 L/h and a pressure of 5 MPa. Next, the crushed fermented milk was filled in a container and held at 25° C. for 1 hour to reset, thereby producing the fermented milk of Example 2.

<Comparative Example 1>
In Comparative Example 1, the same fermented milk base as in Example 1 was used, and the crushing method was different from that in Example 1 described above. Specifically, the same fermented milk base as in Example 1 is prepared, sterilized at 95 ° C. for 5 minutes, 30 g of lactic acid bacteria starter is added, and the pH is 4.4 at 43 ° C. for 3 to 5 hours. fermented.

The resulting fermented milk curd was crushed using a 60-mesh filter. After that, the filtered fermented milk was held at 25° C. for 1 hour in a container for resetting, and fermented milk of Comparative Example 1 was produced.

<Comparative Example 2>
Comparative Example 2 provided a fermented milk base that did not contain whey protein isolate. Specifically, 630 g of raw milk, 13 g of fresh cream, 80 g of skimmed concentrated milk, 30 g of milk protein concentrate, and 217 g of raw water were mixed to prepare a fermented milk base (SNF 11.4%, FAT 3.0%).

Next, the prepared fermented milk base was sterilized at 95° C. for 5 minutes, then 30 g of lactic acid bacteria starter was added and fermented at 43° C. for 3 to 5 hours until the pH reached 4.4.

The resulting fermented milk curd was crushed and homogenized using the same homogenizer as above at a flow rate of 135 L/h and a pressure of 5 MPa. Next, the pulverized fermented milk was filled in a container and held at 25° C. for 1 hour to reset and prepare fermented milk of Comparative Example 2.

<Content of milk protein and whey protein>
Regarding the fermented milks obtained in Examples 1 and 2 and Comparative Examples 1 and 2, the ratio (%) of milk protein to the whole fermented milk (indicated as “milk protein” in Table 1) and fermented milk The ratio (%) of whey protein to the whole (indicated as "whey protein" in Table 1) and the ratio (%) of whey protein to the whole milk protein (in Table 1, "milk "Clear protein/milk protein") was examined by the Kjeldahl method, and the results shown in Table 1 below were obtained. When using the Kjeldahl method, the nitrogen/protein conversion factor was 6.38.

<Average particle size>
Next, the average particle size was measured for Examples 1 and 2 and Comparative Examples 1 and 2 described above. Here, the average particle size of the fermented milk was measured using a laser diffraction particle size distribution analyzer SALD-2200 (manufactured by Shimadzu Corporation). Specifically, the fermented milk was diluted with ion-exchanged water and adjusted so that the maximum value of the light intensity distribution of this diffraction/scattering was 35 to 75% (absolute value: 700 to 1500). The distribution of light intensity was analyzed using WingSALD II software for a particle size distribution analyzer, the particle size distribution of particles constituting the solid content in the fermented milk was determined, and the average particle size was determined. As a result, the results shown in Table 1 below were obtained.

As shown in Table 1, in Comparative Example 1 in which a filter was used for pulverization, the average particle size of the fermented milk was 55 μm, which is 20 μm or more. On the other hand, in Examples 1 and 2 and Comparative Example 2, in which a homogenizer was used for crushing, the average particle size of the fermented milk was 20 µm or less, and it was confirmed that the particles were finer than when a filter was used.

<Viscosity>
Next, when the viscosities of Examples 1 and 2 and Comparative Examples 1 and 2 were measured, the results shown in Table 1 were obtained. In this specification, the viscosity of the fermented milk is measured using a rotary type B-type viscometer (eg, "TVB10 type viscometer" manufactured by Toki Sangyo Co., Ltd.) at a measurement temperature of 10°C. 4 rotor (code M23) is inserted into the measurement object and rotated (60 rpm, 30 seconds).

From Comparative Example 2 in Table 1, when the ratio of whey protein to the total milk protein is less than 25%, it is difficult to reset after homogenizing the curd using a homogenizer, and the viscosity at 10 ° C. is 460 mPa.・It was confirmed that it became almost liquid. On the other hand, as shown in Examples 1 and 2, by setting the ratio of whey protein to 25% or more relative to the total milk protein, the fermented milk can be reset to 10% even if a homogenizer is used. It was confirmed that a high viscosity of 1000 mPa·s or more can be obtained at ℃.

<Sensory evaluation test>
Next, the fermented milks of Examples 1 and 2 and Comparative Examples 1 and 2 described above were subjected to a sensory evaluation test by 10 people to evaluate texture. In this sensory evaluation test, 70 g of each of the fermented milks of Examples 1 and 2 and Comparative Examples 1 and 2 were eaten, and the texture on the tip of the tongue and in the mouth at that time was evaluated. Table 1 shows the results.

As shown in Table 1, the texture of the fermented milk of Comparative Example 1, which has an average particle size of 55 μm and a viscosity of 3300 mPa s at 10° C., has a large average particle size of more than 30 μm, and therefore a strong roughness was felt. . From this, it was confirmed that when a filter is used to crush the curd and the crushing strength is kept low, the viscosity is high and the curd is chewy, but the average particle size is also large, resulting in a rough texture.

On the other hand, in Comparative Example 2 in which a homogenizer was used to crush the curd to give the curd a high crushing strength, the average particle size was small, the texture was not rough, and the smoothness was increased, but the viscosity was less than 1000 mPa s. Since it has decreased, the eating response such as richness has decreased.

On the other hand, the fermented milk of Example 1, which has an average particle size of 5 μm and a viscosity of 5690 mPa·s at 10° C., has a small average particle size and a smooth texture without feeling rough. Furthermore, although the texture was smooth, the viscosity was also high, and the texture such as richness was felt. Even the fermented milk of Example 2, which has an average particle size of 10 μm and a viscosity of 4200 mPa·s at 10° C., had a smooth mouthfeel and a rich texture.

In Examples 1 and 2, the curd crushing was performed with a high crushing strength using a homogenizer, but by containing whey protein, resetting occurred in the holding process after crushing, increasing It was possible to induce diameter and thickening. As a result, we were able to achieve both a dense and smooth viscosity and a rich and full-bodied texture.

From the above, it is possible to realize fermented milk that has both dense and smooth viscosity and richness by adding whey protein and performing curd crushing with high crushing strength without using a stabilizer or thickener. was confirmed.

Claims (6)

6.0 % or more of milk protein, 25% or more and 35% or less of whey protein in the milk protein, the average particle size of the fermented milk is 3 μm or more and 30 μm or less, and the viscosity at 10 ° C. is 3000 mPa s or more Yes, fermented milk. The fermented milk according to claim 1, wherein the viscosity is 4200 mPa·s or more. a production step of producing a fermented milk base containing milk proteins, including whey proteins;
A fermentation step of adding a lactic acid bacteria starter to the fermented milk base and then fermenting it to produce a fermented milk curd;
A crushing step of crushing the curd using a homogenizer to make the average particle size of the fermented milk 1 μm or more and 20 μm or less;
A holding step of producing fermented milk by holding the crushed fermented milk in a container and resetting the fermented milk,
The fermented milk contains 6.0 % or more of the milk protein, 25% or more and 35% or less of the whey protein in the milk protein, and the average particle size of the fermented milk is 3 μm or more and 30 μm or less, at 10 ° C. A method for producing fermented milk, wherein the viscosity is 3000 mPa·s or more. The method for producing fermented milk according to claim 3, wherein the viscosity is 4200 mPa·s or more. The crushing step includes
The method for producing fermented milk according to claim 3 or 4 , wherein the curd is homogenized at a pressure of 1 MPa or more and 20 MPa or less. The holding step includes
The fermented milk according to any one of claims 3 to 5, wherein the fermented milk is held in the container at 20°C or higher and 50°C or lower for 1 hour or longer, or at 0.5°C or higher and lower than 20°C for 2 hours or longer. A method for producing fermented milk.