JP2023145105A - Fermented milk and method for producing the same - Google Patents

Abstract

To provide new stirring-type fermented milk having less rough texture, and a method for producing the milk, particularly a new stirring-type fermented milk with small particle diameter and less rough texture despite a high protein content. and a method for producing the milk.SOLUTION: A method for producing stirring-type fermented milk is provided, including the steps of: preparing fermented milk base mix which has 3.0 wt.% or more of protein and in which a ratio of casein protein to the total amount of whey protein and casein protein is 78 wt.% or more; fermenting a fermented milk base mix; and performing homogenizing treatment by using a homogenizer, on fermented milk after fermentation twice or more. Further, stirring-type fermented milk is provided which has 3.0 wt.% or more of protein and in which a ratio of casein protein to the total amount of whey protein and casein protein is 78 wt.% or more, and an average particle diameter is 15 μm or less.SELECTED DRAWING: None

Description

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

Stirred fermented milk such as fruit yogurt is manufactured by breaking fermented curd using a filter or homogenizer. The larger the average particle size of the crushed curd, the more rough it will feel, so in order to reduce the average particle size, it is necessary to reduce the hole size of the filter when crushing the curd or increase the homogenizing pressure. was there. However, this alone did not make it possible to reduce the average particle size of fermented milk to the extent that the graininess of the fermented milk was no longer felt.
Therefore, with existing production methods, it has been difficult to obtain fermented milk with less graininess as stirred fermented milk. In order to solve these problems, various methods shown below have been disclosed.

Patent Document 1 states that the fermented milk 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·s at 10° C. The above method for producing fermented milk has been disclosed.

Patent Document 2 discloses a yogurt that is a fermented product of a yogurt mix containing milk with a protein reduction value of 2 to 9 and whey protein and containing no stabilizer, the yogurt mix comprising: The whole contains 93-98% by mass of milk with a protein reduction value of 2-9, milk fat content of 3.8-4.5% by mass, and milk protein content of 4.3-5.8%. % by mass, and the value of the ratio of whey protein/casein protein in the milk protein is 23/77 to 30/70 (mass ratio), the median diameter of the curd is 25 to 60 μm, and the BH type A yogurt is disclosed having a viscosity of 20 to 45 Pa·s as measured by a viscometer.

On the other hand, Patent Document 3 discloses that a process of crushing curd in a fermented product obtained by fermenting a milk preparation containing a fermented milk raw material with a fat content of 1.5% by mass or less is performed by passing the curd through a mesh filter. A method is disclosed in which the method is divided into at least two stages: a crushing process, and a second crushing process performed under crushing conditions different from the first crushing process.

Further, Patent Document 4 states that the protein content is 4% by weight or more, the ratio of casein protein to whey protein is 83% by weight or more, and the pH after storage at 10°C for 7 days is 4.65 or more. A liquid fermented milk having an average particle diameter of 6 μm is disclosed.

JP 2019-170274 Publication JP 2021-16317 Publication JP2013-94076A JP 2021-141853 Publication

However, according to the above-mentioned conventional technology, since it contains a large amount of whey whey, there was a problem that the flavor was inferior (Patent Documents 1 and 2). Further, since it is necessary to prepare two types of crushing devices, there is a problem that the process is complicated and management is complicated (Patent Document 3). Moreover, the technique of Patent Document 4 relates to stationary fermented milk and liquid fermented milk, and does not disclose stirring-type fermented milk.
In light of the above, an object of the present invention is to provide a novel stirring-type fermented milk with less roughness and a method for producing the same. In particular, it is an object of the present invention to provide a novel stirring-type fermented milk that has a small particle size and less roughness even though it has a high protein content, and a method for producing the same.

In order to solve the above problems, we conducted intensive studies and found that a method for producing stirred fermented milk, which includes a step of homogenizing the fermented milk after fermentation twice or more using a homogenizer, produced the desired stirred type fermented milk. They discovered that fermented milk can be obtained and completed the present invention. That is, the present invention has the following configuration.
<1>
Stirred fermented milk having a protein content of 3.0% by weight or more, a ratio of casein protein to the total amount of whey protein and casein protein of 78% by weight or more, and an average particle diameter of 15 μm or less.
<2>
The stirred fermented milk according to <1>, wherein the protein content is 8.0% by weight or more.
<3>
The stirred fermented milk according to <1> or <2>, wherein the ratio of casein protein to the total amount of whey protein and casein protein is 84% by weight or more.
<4>
The stirred fermented milk according to any one of <1> to <3>, which has a viscosity of 1 Pa·s or more and 15 Pa·s or less.
<5>
A step of preparing a fermented milk base mix in which the protein content is 3.0% by weight or more and the ratio of casein protein to the total amount of whey protein and casein protein is 78% by weight or more;
A process of fermenting the fermented milk base mix;
A method for producing stirred fermented milk, which includes a step of homogenizing fermented milk after fermentation twice or more using a homogenizer.
<6>
The manufacturing method according to <5>, wherein the fermented milk base mix has a protein concentration of 8.0% by weight or more.
<7>
The production method according to <5> or <6>, wherein the ratio of casein protein to the total amount of whey protein and casein protein in the fermented milk base mix is 84% by weight or more.
<8>
The manufacturing method according to any one of <5> to <7>, wherein the homogeneous pressure is 0.0 MPa or more and 10 MPa or less.
<9>
The production method according to any one of <5> to <8>, wherein the fermented milk has a viscosity of 1 Pa·s or more and 15 Pa·s or less.
<10>
A method for producing stirred fermented milk, which includes a step of homogenizing fermented milk after fermentation twice or more using a homogenizer.

According to the present invention, it was possible to provide stirred fermented milk with less graininess and a method for producing the same. In particular, we were able to provide a novel stirred-type fermented milk with small particle size and less rough texture even if it has a high protein content, and a method for producing the same.

(fermented milk)
In the present invention, "fermented milk" refers to animal milk such as cow's milk, or milk containing non-fat milk solids equivalent to or higher than that, fermented with lactic acid bacteria, bifidobacteria, yeast, or any combination thereof. It is fermented. Fermented milk can be classified according to its properties and manufacturing method into 1) stationary fermented milk, 2) stirring fermented milk, and 3) liquid fermented milk.
1) Stationary fermented milk is called hard fermented milk and has a pudding-like structure that is filled into a retail container and fermented, and is produced, for example, as follows. First, a fermentation mix prepared by mixing and dissolving raw materials such as milk, dairy products, and sucrose is homogenized, sterilized, and cooled, then inoculated with lactic acid bacteria starter, filled into containers, sealed, and placed in a culture room. Fermentation is carried out in a fermentation tunnel, and as soon as the acidity reaches an appropriate level, the fermentation is terminated by cooling to below 10°C to produce the final product.
2) Stirring type fermented milk is also called soft type fermented milk, and is made by adding lactic acid bacteria starter to the fermentation mix, fermenting in a tank, and then crushing the curd and filling it into a container to obtain the final product.
3) Liquid fermented milk is produced by fermenting a fermentation mix in the same manner as stirring type fermented milk, crushing the curd, and homogenizing it to obtain a liquid fermented milk as the final product.
The present invention relates to 2) stirring type fermented milk among the above three types of fermented milk.

(Protein content)
There is no limit to the protein content of the stirred fermented milk of the present invention, but if the protein content in the fermented milk is increased, the particle size tends to increase. By performing the treatment, it becomes possible to reduce the particle size, so that the effects of the present invention can be particularly enjoyed in high-protein fermented milk. Therefore, the protein content in fermented milk is preferably 3% by weight or more, more preferably 5% by weight or more, even more preferably 8% by weight or more, even more preferably 8.8% by weight or more, and even more preferably 9% by weight or more. most preferred. The protein content range is preferably 3% by weight or more and 20% by weight or less, more preferably 5% by weight or more and 20% by weight or less, even more preferably 8% by weight or more and 20% by weight or less, and 8.8% by weight. The content is even more preferably 20% by weight or less, and most preferably 9% by weight or more and 20% by weight or less.

(Protein composition)
The ratio of the casein protein content (weight %) to the total amount (weight %) of casein protein and whey protein contained in the fermented milk of the present invention is preferably 78 weight % or more. More preferably, it is 79% by weight or more, more preferably 84% by weight or more, and even more preferably 87% or more. Further, the preferable range is 78 to 99% by weight, more preferably 79 to 95% by weight, even more preferably 84 to 93% and 87 to 90%. If the ratio of casein protein content (weight %) is less than 78%, the particle size of the fermented milk will become large and the whey protein content will increase, which will affect the flavor.

(Average particle size)
The average particle diameter of the fermented milk of the present invention is preferably 15 μm or less. This is because if it is larger than 15 μm, roughness will be felt. The average particle diameter is more preferably 13 μm or less, even more preferably 12 μm or less.
The average particle size can be measured using a laser diffraction particle size distribution measuring device, a laser diffraction/scattering particle size distribution measuring device, an image analysis type particle size distribution measuring device, a precision particle size distribution measuring device, a real-time zeta potential/nanoparticle size measuring device, and a dynamic particle size distribution measuring device. It can be measured with a device that measures particle size distribution, such as a targeted light scattering (DLS) particle size distribution measuring device or an analytical ultracentrifugation system.
The obtained volume average diameter is defined as the average particle diameter (μm), and the value after 60 seconds of measurement is used.

(viscosity)
Although there is no limit to the viscosity of the fermented milk of the present invention, it is preferably 1 Pa·s or more and 15 Pa·s or less. If it is less than 1 Pa·s, the viscosity is too low to be edible, and it exhibits properties similar to liquid type. On the other hand, if it is larger than 15 Pa·s, the structure becomes sloppy and does not melt in the mouth. The lower limit is more preferably 2 Pa·s or more, and even more preferably 5 Pa·s or more. Further, the upper limit is more preferably 14 Pa·s or less, and even more preferably 13 Pa·s or less.
The viscosity is measured using a general B-type viscometer manufactured by Toki Sangyo Co., Ltd., etc., by dispensing 100 ml of sample into a measuring container, inserting a measuring probe (rotor M4), and rotating at 30 rpm for 30 seconds. A method for measuring viscosity (Pa·s) can be exemplified.

(Raw materials for fermented milk of the present invention)
(Protein raw material)
In the fermented milk of the present invention, as described above, the ratio of the casein protein content (weight %) to the total amount (weight %) of casein protein and whey protein contained in the fermented milk is preferably 78 weight % or more. More preferably, it is 79% by weight or more, more preferably 84% by weight or more, and even more preferably 87% or more. Further, the preferable range is 78 to 99% by weight, more preferably 79 to 95% by weight, even more preferably 84 to 93% and 87 to 90%. If the ratio of casein protein content (weight %) is less than 78%, the particle size of the fermented milk will become large and the whey protein content will increase, which will affect the flavor.
The casein protein-rich raw materials used for this purpose should preferably have a ratio of casein protein content (wt%) to the total amount (wt%) of casein protein and whey protein of about 83% or more, and skim milk. Examples include concentrated milk obtained by processing with a microfiltration membrane, micellar casein, and the like.
In addition, as a raw material rich in whey protein, it is sufficient that the ratio of casein protein content (weight %) to the total amount (weight %) of casein protein and whey protein is less than 83%, and whey protein isolate (Whey Protein Isolate: WPI), whey protein concentrate (WPC), whey powder, milk protein concentrate (MPC), raw milk, skim milk, skim milk powder, etc.
By combining the above casein protein-rich raw materials and whey protein-rich raw materials, the ratio of casein protein content (wt%) to the total amount (wt%) of casein protein and whey protein is adjusted to a desired range. I can do it.

(Other raw materials)
The fermented milk of the present invention can use raw materials that can be used in foods as long as the effects of the present invention are not impaired.

(Method for producing stirred fermented milk)
Typical steps in the method for producing stirred fermented milk are as follows.
(1) A step of preparing a fermented milk base mix, (2) A step of homogenizing the fermented milk base mix, (3) A step of sterilizing the fermented milk base mix, and (4) Adding lactic acid bacteria to the fermented milk base mix. This method includes a step of adding and fermenting, and (5) a step of homogenizing two or more times using a homogenizer.
A specific embodiment of the method for producing stirred fermented milk will be described below.
(1) is a step of preparing a fermented milk base mix in which the ratio of casein protein content (weight %) to the total amount (weight %) of protein, casein protein, and whey protein is adjusted. If you want a low-fat or fat-free type, prepare such a fermented milk base mix.
Next, the prepared fermented milk base mix is subjected to (2) homogenization and (3) sterilization treatment. There is no restriction on the order of the homogenization treatment and the sterilization treatment, and the sterilization temperature and homogenization pressure are set as appropriate within a range that does not impede the effects of the present invention, with reference to conventional methods. In the present invention, the homogenization step (2) is not an essential step, and may be performed as appropriate to obtain the desired fermented milk.

The fermented milk base mix subjected to homogenization and sterilization treatment is heated to about 35 to 45°C, (4) lactic acid bacteria are added, and fermentation is carried out at about 35 to 45°C, preferably until the pH becomes 5.2 or less. Fermentation ends when the pH reaches about 4.0 to 4.8. Next, (5) the fermented milk after fermentation is subjected to homogenization treatment using a homogenizer multiple times to obtain the stirred fermented milk of the present invention. Since it is performed multiple times, it can be performed twice, three times, four times, five times, etc. to obtain the desired particle size. Further, although it may be performed continuously or a second time may be performed after a certain period of time, it is preferable to perform it continuously because it is more efficient.
Further, the homogenization process may be performed multiple times using a single homogenizer or multiple homogenizers. For example, the homogenization process may be performed twice by passing the fermented milk through two homogenizers in succession. Although there is a limit to the miniaturization of particle size in one homogenization process, fermented milk with a very small average particle size of 15 μm or less can be produced by homogenizing process twice or more. In particular, increasing the protein content in fermented milk tends to increase the particle size, but according to the present invention, the particle size can be reduced by increasing the casein ratio and performing homogenization twice. can.
The homogenizer used for the homogenization process may be a pressure-type homogenizer, and is also called a pressure-type homogenizer. The homogenization pressure, homogenization temperature, and homogenization flow rate of the homogenization treatment can be appropriately set within a range that does not impede the effects of the present invention with reference to conventional methods.

In the present invention, the pressure for homogenization using a homogenizer is preferably from zero pressure (0 MPa) to 10.0 MPa. This is because if it is higher than 10 MPa, it approaches liquid type (drink type) fermented milk, and the lower limit was set to 0 MPa. This is because the particle size becomes smaller. The lower limit of the homogenization pressure is more preferably 0.5 MPa or more, even more preferably 1.0 MPa or more, and even more preferably 1.3 MPa or more. The upper limit of the homogenization pressure is more preferably 9.0 MPa or less, even more preferably 8.0 MPa or less, and even more preferably 7.0 MPa or less. The pressure range for homogenization includes a combination of the above lower limit and upper limit.

In the present invention, the homogenization temperature is preferably in the range of 10 to 45°C. There is no problem if the homogenization flow rate is within the specification range of the homogenizer.
Furthermore, the homogenization process can be performed multiple times after adding the sugar solution or sauce to the fermented milk, or the sugar solution or sauce can be added after the homogenization process. Moreover, after the homogenization process, it can be filled into a container to obtain a final product.

Next, the present invention will be specifically explained with reference to Examples. However, the present invention is not to be interpreted as being limited to the examples.
[Examples and comparative examples]
1. Method for Preparing Fermented Milk According to the formulations shown in Table 1, fermented milks of formulation examples A to D were prepared by the following preparation method. In the preparation of fermented milk, fermented milk-based raw materials were mixed and dissolved using a homomixer to prepare a fermented milk base mix. The fermented milk base mix was heated to 65°C, homogenized under a homogeneous pressure of 15 MPa, and then heat sterilized at 95°C for 5 minutes. Thereafter, the mixture was cooled to 40°C, 1.5% by weight of Lactobacillus bulgaricus and 0.15% by weight of Streptococcus thermophilus were added, fermented at 41°C, and the fermentation was terminated when the pH reached 4.7. .

2. Homogenization treatment After stirring the fermented curd with a spatula to break it up, the curd was homogenized using a homogenizer (G5-5.8B manufactured by SPX Flow Technology) at 41°C and a flow rate of 200 L/h to the homogenization pressure shown in Table 2. Homogenization treatment was performed for several times and then cooled to 10° C. using a tubular cooler (Examples 1 to 7, Comparative Examples 1 to 7). Note that the homogenization pressure of 0 MPa indicates that the fermented milk was introduced into the homogenizer and homogenized in a non-pressure state.

3. Evaluation method and evaluation results of fermented milk Table 2 shows the characteristics of the fermented milk of Examples 1 to 7 and Comparative Examples 1 to 7.
The average particle diameter is the value of fermented milk immediately after preparation, and the viscosity and roughness are the values of fermented milk one day after preparation at a product temperature of 10°C. The average particle size was measured using a laser diffraction/scattering particle size distribution analyzer (Microtrac MT3000II) manufactured by Nikkiso Co., Ltd., and the average particle size was measured 60 seconds after sample injection.
The viscosity was measured using a B-type viscometer (TVB-10) manufactured by Toki Sangyo Co., Ltd., when 100 ml of the sample was dispensed into a measurement container, a measurement probe (rotor M4) was inserted, and the measurement probe was rotated at 30 rpm for 30 seconds. The viscosity (Pa·s) was measured.
Roughness was evaluated by three persons in charge, and the presence or absence of roughness was evaluated. The presence or absence of roughness was evaluated in three stages: present, slightly present, and absent, and the results showed that two or more people's evaluations were in agreement.

4. Discussion According to the present results, in Examples 1 to 7 in which the homogenization treatment was performed twice, the average particle diameter was 15 μm or less, there was no roughness, and the particles had appropriate viscosity. Both have excellent characteristics as stirred fermented milk. On the other hand, in Comparative Examples 1 to 3 and 5 to 7, in which the composition of the fermented milk was the same and the homogenization treatment was performed only once, although the composition was the same as that of Examples 1 to 3 and 5 to 7, the roughness was The average particle diameter was also large. For example, when comparing Example 1 and Comparative Example 1, the average particle diameter could be reduced to 6.0 μm by performing the test twice at 1.3 MPa, but it was as large as 22.4 μm by performing the test once. Further, in Comparative Example 2, even at a high pressure of 2.0 MPa compared to 1.3 MPa in Example 1, the size was reduced to only 16.0 μm in one homogenization treatment. Further, from Examples 4 and 5 and Comparative Examples 4 and 5, it was found that even if the pressureless homogenization treatment was performed twice, the particle size could be sufficiently reduced. Furthermore, since the fermented milks of Formulation Examples A to C have a high protein content, the particle size tends to be large, but the two-time homogenization treatment of the present invention made it possible to reduce the particle size. In particular, formulation examples A and B have a high protein content of 9.6% protein, but are significant in that they were able to achieve an average particle diameter of 15.0 μm or less by performing two treatments even under a low homogeneous pressure of 1.3 MPa. Furthermore, by comparing Example 4 and Comparative Example 4, even if the same two homogenization treatments were performed, if the ratio of casein protein to the total amount of whey protein and casein protein was less than 78%, the average particle diameter was reduced to 15 μm. It was also found that the following cannot be done.

According to the present invention, in the production of stirred fermented milk, it has become possible to reduce the average particle size by performing homogenization treatment two or more times using a homogenizer. In particular, by applying the present invention to the production of fermented milk with a high protein content, it is possible to provide stirred fermented milk with less roughness and small particle size.

Claims (10)

Stirred fermented milk having a protein content of 3.0% by weight or more, a ratio of casein protein to the total amount of whey protein and casein protein of 78% by weight or more, and an average particle diameter of 15 μm or less. The stirred fermented milk according to claim 1, wherein the protein content is 8.0% by weight or more. The stirred fermented milk according to claim 1 or 2, wherein the ratio of casein protein to the total amount of whey protein and casein protein is 84% by weight or more. The stirred fermented milk according to any one of claims 1 to 3, which has a viscosity of 1 Pa·s or more and 15 Pa·s or less. A step of preparing a fermented milk base mix in which the protein content is 3.0% by weight or more and the ratio of casein protein to the total amount of whey protein and casein protein is 78% by weight or more;
A process of fermenting the fermented milk base mix;
A method for producing stirred fermented milk, which includes a step of homogenizing fermented milk after fermentation twice or more using a homogenizer. The manufacturing method according to claim 5, wherein the fermented milk base mix has a protein concentration of 8.0% by weight or more. The production method according to claim 5 or 6, wherein the ratio of casein protein to the total amount of whey protein and casein protein in the fermented milk base mix is 84% by weight or more. The manufacturing method according to any one of claims 5 to 7, wherein the homogeneous pressure is 0.0 MPa or more and 10 MPa or less. The production method according to any one of claims 5 to 8, wherein the fermented milk has a viscosity of 1 Pa·s or more and 15 Pa·s or less. A method for producing stirred fermented milk, which includes a step of homogenizing fermented milk after fermentation twice or more using a homogenizer.