JP5719752B2 - Method for producing fermented milk - Google Patents

Description

  The present invention relates to a method for producing a low fat type fermented milk and a low fat type fermented milk. Moreover, this invention relates also to the crushing apparatus used in the case of manufacture of fermented milk.

Fermented milk is attracting attention as a food containing probiotics such as lactic acid bacteria that are known to have various physiological effects.
With the recent increase in health consciousness, fermented milk of low fat or non-fat type (sometimes collectively referred to as low fat type in this specification) having a fat content of 1.5% by mass or less has been developed.
On the other hand, products with various flavor sauces and fruits added to low-fat fermented milk have appeared due to diversification of consumer preferences. Such products are manufactured by adding and mixing flavor sauces and fruits after fermentation.

By the way, fermented milk is classified into stationary type fermented milk and stirring type fermented milk by the manufacturing method. Because stationary fermented milk is manufactured by a method of fermenting a milk preparation containing fermented milk ingredients in a retail container, it is also called post-fermented fermented milk, and plain yogurt and hard yogurt are classified into this. . On the other hand, the agitation type fermented milk is manufactured by a method in which a milk preparation containing fermented milk raw material is previously fermented in a tank, and a card formed after fermentation is crushed and then filled into a retail container. Also called fermented milk, soft yogurt, drink yogurt and frozen yogurt are classified into this.
Most fermented milk to which flavor sauce or fruit is added and mixed after fermentation as described above is classified as agitation type fermented milk.

Stirring type fermented milk is normally manufactured through the fermentation process which ferments the milk solution prepared using the fermented milk raw material, and the crushing process which crushes the card | curd contained in the fermented material obtained at the fermentation process.
Among the agitation type fermented milk, fermented milk called soft yoghurt (fermented milk other than drinks and frozen yoghurt) is required to have a moderate viscosity that gives a texture and richness in addition to smoothness due to sufficient crushing of the card. The That is, it becomes a subject to make compatible reduction of the remainder of a card | curd by insufficient crushing of a card | curd, and suppression of an excessive viscosity fall.
However, if sufficient shear force is applied to reduce the card residue, the viscosity decreases, and conversely, if the shear force is suppressed to suppress the viscosity decrease, the card residue occurs.
Therefore, in the production of conventional general agitation type fermented milk, product design was performed by setting the card crushing conditions in consideration of the balance between curd residue reduction and suppression of excessive viscosity reduction. There is a fact that.

In such a background, the following techniques have been developed for the purpose of achieving both reduction of the remaining card and suppression of excessive viscosity reduction.
Patent Document 1 describes that after fermenting a fermented milk material containing a certain amount of high-purity whey protein, the curd of the obtained fermented milk is crushed with a uniform pressure in a certain range.
In patent document 2, by crushing fermented milk card | curd obtained by fermenting yoghurt mix, the said fermented milk card | curd is extruded through the several opening part of a magnitude | size of 325-1300 mesh (JIS fluy standard). It is described to do.
Patent Document 3 describes that in the method described in Patent Document 2, a yogurt mix having a protein concentration of 5 to 10% is used.

JP-A-7-104 International Publication No. 2006/057266 Pamphlet International Publication No. 2006/057265 Pamphlet

The method described in Patent Document 1 is based on the condition that the fermented milk raw material contains high-purity whey protein in a certain ratio or more, and the degree of freedom of prescription may be limited.
Since the methods described in Patent Document 2 and Patent Document 3 extrude the fermented milk card through a fine opening of 325 to 1300 mesh, a large pressure is required for the extrusion, and the load of the manufacturing process There was a problem that became larger.

Further, among fermented milk, so-called low fat type fermented milk having a fat content of 1.5% by mass or less is liable to cause a card curling problem (see Test Example 1 described later).
When producing fermented milk using such a milk preparation with a low fat content, if the card is crushed by the method described in Patent Document 2 or Patent Document 3, even if the card remaining problem can be solved, There is a problem that excessive viscosity reduction occurs.
In other words, for so-called low fat type fermented milk having a fat content of 1.5% by mass or less, there has been no effective method for suppressing excessive viscosity reduction while reducing curd residue. .

  Then, this invention makes it a subject to suppress an excessive viscosity fall, reducing curd remainder in manufacture of fermented milk whose fat content is 1.5 mass% or less. It is another object of the present invention to provide a technique that makes it possible to reduce the load of the manufacturing process as compared with a conventional method.

In the process of producing low-fat type fermented milk and the like, the present inventor performs crushing using a mesh filter before crushing the conventional curd in the obtained fermented product. The inventors have found that the curd in the fermented product can be sufficiently crushed with a pressure smaller than the pressure necessary for sufficiently pulverizing the curd in the conventional methods as described in Patent Document 2 and Patent Document 3. As a result, it has also been found that an excessive decrease in viscosity of the produced fermented milk can be suppressed.
The present inventor has found that the above method exhibits a remarkable effect particularly in the production of so-called low fat type or non-fat type fermented milk having a fat content of 1.5% by mass or less.
The present inventor has completed the following present invention based on these findings.

This invention which solves the said subject is the manufacturing method of fermented milk including the crushing process of the card | curd in the fermented material obtained by fermenting the milk solution containing a fermented milk raw material whose fat content is 1.5 mass% or less And the said crushing process has a 1st crushing process and the 2nd crushing process performed after a 1st crushing process, and the said 1st crushing process meshes the said fermented material with a mesh. The second crushing step is performed by passing through a filter, and the second crushing step is performed under a crushing condition different from that of the first crushing step.
According to such a production method, when producing low-fat or non-fat type fermented milk, it is possible to suppress a decrease in viscosity while reducing card residue with a smaller pressure than in the conventional method, and a load on the production process. Can be reduced. When the fermented product obtained using the milk preparation having a low fat content is crushed by a method as described in conventional Patent Documents 2 and 3, an excessive decrease in viscosity occurs. Therefore, the production method of the present invention is extremely Useful.

In the preferable form of this invention, the crushing pressure in a 1st crushing process is smaller than the crushing pressure in a 2nd crushing process.
By setting the crushing pressure in the first crushing step to be smaller than the crushing pressure in the second crushing step, it is possible to sufficiently suppress the decrease in viscosity while reducing the card residue.

In a preferred embodiment of the present invention, the crushing pressure in the first crushing step is 0.01 to 0.14 MPa.
By setting the crushing pressure in the first crushing step to 0.01 to 0.14 MPa, crushing in the second crushing step can be performed efficiently, so that excessive viscosity reduction is achieved while reducing the card residue. Can be suppressed.

In a preferred form of the present invention, the flow rate of the fermentation product of it passes through a mesh filter, fermented per effective area 1 mm ² of the mesh filter is 0.01～4L / time.
By setting the flow rate of the fermented product within the above range, it is possible to sufficiently obtain the effect of reducing the card residue while suppressing a decrease in viscosity.

In a preferred embodiment of the present invention, the mesh filter has a mesh size of 10 to 40 mesh (JIS sieve standard).
By setting it as the range of such a mesh size, crushing with moderate roughness can be performed in a 1st crushing process. As a result, the subsequent second crushing step can be efficiently performed, and the card residue can be made extremely small with a crushing pressure smaller than that in the past. Moreover, a viscosity fall can fully be suppressed.

  In a preferred embodiment of the present invention, the protein content of the milk preparation is 3% by mass or more. The production method of the present invention exhibits a remarkable effect when a milk preparation having a high protein content is used. This is because a hard card is formed when such a milk preparation is used.

Moreover, this invention relates to fermented milk obtained by said manufacturing method.
Such fermented milk has a reduced curd residue and maintains an appropriate viscosity.

Further, the present invention is a crushing device comprising a crushing unit for crushing a card in a fermented product obtained by fermenting a milk preparation containing fermented milk raw material, wherein the crushing unit comprises a mesh filter. 1 crushing part, and the 2nd crushing part arrange | positioned in the back | latter stage of a 1st crushing part, The crushing coarseness of the card | curd by the said 1st crushing part, and the card | curd by the said 2nd crushing part It is characterized by different crushing roughness.
By crushing the card using such a crushing device, the card residue can be reduced while suppressing a decrease in viscosity.

According to the method for producing fermented milk of the present invention, compared with the method for producing fermented milk in which the curd is crushed in a conventional one-stage crushing process, the curd residue is reduced and excessive viscosity reduction is easily suppressed. It is possible to produce a low-fat type fermented milk having a smooth texture and an appropriate viscosity. Furthermore, this effect can be obtained with a pressure smaller than that of the conventional method. Therefore, the load of the manufacturing process in the manufacturing method of fermented milk can be reduced by using the manufacturing method of fermented milk of this invention compared with the conventional method.
In addition, the low fat type fermented milk produced by the production method of the present invention is excellent in having a good texture and richness while being smooth because curd residue is reduced and excessive viscosity reduction is suppressed. It will be a thing.
Moreover, by using the crushing apparatus of the present invention, it is possible to easily produce excellent fermented milk as described above.

It is the schematic which shows the manufacturing method of fermented milk of this invention. It is the schematic which shows the crushing apparatus of this invention. It is the schematic which shows the crushing apparatus used for the test example of this invention. It is a figure which shows the relationship between the crushing pressure measured by the test example 1, the card | curd remaining, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured by the test example 1, the card | curd remaining, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured by the test example 1, the card | curd remaining, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured in the test example 2, a card | curd remainder, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured in the test example 2, a card | curd remainder, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured in the test example 2, a card | curd remainder, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured in the test example 2, a card | curd remainder, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured in the test example 2, a card | curd remainder, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured by the test example 3, a card | curd remainder, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured by the test example 3, a card | curd remainder, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured by the test example 3, a card | curd remainder, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured by the test example 3, a card | curd remainder, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured by the test example 3, a card | curd remainder, and a viscosity. It is a figure which shows the relationship between the crushing pressure measured in Test Example 4, a card | curd remaining, and a viscosity.

FIG. 1 is a schematic view showing a method for producing fermented milk of the present invention. Hereinafter, the raw material used for this invention and the process in this invention are demonstrated in detail.
In the present specification, the classification of milk and dairy products is based on “Ministerial Ordinance on Component Standards of Milk and Dairy Products” (hereinafter referred to as “Ministerial Ordinance on Milk”) unless otherwise specified.
In the present specification, “%” percent is expressed by mass unless otherwise specified.

<Milk preparation>
In the present invention, the “milk formula” is a liquid obtained by preparing various raw materials including fermented milk raw materials such as milk and dairy products.
As the fermented milk raw material contained in the milk preparation used in the present invention, those conventionally used in the production of fermented milk can be used without particular limitation.
The fat content in the milk preparation is 1.5% by mass or less. This is because a fermented product obtained by fermenting a milk preparation having a low fat content contains hard curds that tend to cause curd residue as compared with those having a high fat content. On the other hand, when a milk preparation having such a fat content is used, if it is crushed by the methods described in the conventional patent documents 2 and 3, there is a problem that excessive viscosity reduction is caused. When the crushing process described below is applied to the production of fermented milk having a fat content of 1.5% by mass or less, the curd residue can be sufficiently reduced without causing an excessive decrease in viscosity.
Moreover, the protein content in the milk preparation is preferably 3% by mass or more. This is because a fermented product obtained by fermenting a milk solution having such a protein content contains a hard curd as compared with one having a low protein content. The production method of the present invention is extremely suitable for producing fermented milk having a protein content of 3% by mass or more.

The milk preparation of the present invention preferably has a protein content of 3 to 5% by mass and a fat content of 1.5% by mass or less. The fermented product obtained by fermenting such a milk preparation is easily produced by low-fat type fermented milk with almost no curd residue and moderate viscosity by performing the crushing process described below. can do. Moreover, when the crushing process demonstrated below is performed with respect to the fermented material obtained from such a milk solution, most curd residue is carried out with the crushing pressure small compared with the conventional method of crushing in one step, for example. It is possible not to cause it. As a result, since an excessive shearing force is not applied to the fermented product, the fermented milk has an appropriate viscosity. That is, the present invention is particularly suitable as a method for producing fermented milk having a protein content of 3 to 5% by mass and a fat content of 1.5% by mass or less.
In addition, the manufacturing method of fermented milk of this invention is applicable also to the manufacturing method of fermented milk whose fat content is not 1.5 mass% or less. In particular, it is suitable for fermented milk having a high protein content and forming a relatively hard curd.

<Fermentation process>
In the present invention, the milk preparation is first fermented. For bacteria such as lactic acid bacteria added to the milk preparation, fermentation temperature, time, etc., those usually used can be used.
As the lactic acid bacteria used in the present invention, those used for the production of ordinary fermented milk can be used without any particular limitation. For example, as the genus Lactococcus, Lactococcus lactis, L. lactis subsp. Lactis, Lactococcus lactis subsp. Lactis bio Lactobacillus strains such as L. lactis subsp. Lactis biovar. Diacetylactis and L. lactis subsp. Cremoris have been designated as Lactobacillus. L. delbrueckii subsp. Lactis, L. delbrueckii subsp. Bulgaricus (Lactobacillus bulgaricus), Lactobacillus reuteri (L . reuteri), easy Strains, such as Bacillus helveticus (L. helveticus) are as Streptococcus (Streptococcus) genus, Streptococcus salivarius subsp thermophilus (S. salivarius subsp. Thermophilus) (Streptococcus thermophilus) strains, such as are used.

The addition amount of lactic acid bacteria can be appropriately adjusted within a normal range. For example, it is preferable to add such an amount that the bacterial concentration in the milk preparation is at least about 1 × 10 ⁵ CFU / g, preferably at least about 1 × 10 ⁷ CFU / g.

In addition to lactic acid bacteria, a genus Bifidobacterium (Bifidobacterium) can also be used. For example, B. longum, B. breve, B. bifidum, B. infantis (B. infantis) ) And the like can be used.
When bifidobacteria are used, the card of the fermented product obtained is hardened, so that the effect of applying the production method of the present invention is remarkably obtained.

  The method for adding the fungus to the milk preparation is not particularly limited, and it can be added in the form of a fungus or in the state of a culture (culture).

  The culture temperature (fermentation temperature) may be in a range where bacteria such as lactic acid bacteria can efficiently grow, and is usually about 30 to 50 ° C, preferably about 35 to 43 ° C. Fermentation may be carried out until the lactic acid bacteria are sufficiently grown, and is usually adjusted until the pH of the milk preparation is 5.0 or less, preferably until the pH of the milk preparation is 4.8 or less, more preferably. It may be performed until the pH of the emulsion becomes about 4.2 to 4.8. The fermentation time is about 3 to 10 hours, preferably about 3 to 6 hours when the culture temperature is about 35 to 43 ° C.

<Crushing process>
After the completion of the fermentation process, a crushing process for crushing the card contained in the fermented product obtained by the above fermentation is performed. The present invention is characterized in that this crushing step includes a first crushing step and a second crushing step. The second crushing process is performed after the first crushing process.
Hereinafter, each crushing process will be described.

[First crushing step]
The first crushing step is performed by passing through a mesh filter having a plurality of openings. This is because when the mesh filter is used, the curd in the fermentation product can be roughly and uniformly crushed with a relatively small pressure.
For crushing using a mesh filter, for example, a mesh filter is installed in a pipeline that supplies a fermented product obtained by fermenting the milk preparation, and the fermented product is continuously directed toward the mesh filter installation part in the pipeline. This can be done by sending it out. The shape of the mesh filter can be used without particular limitation, such as a flat plate shape or a cylindrical shape. Examples of such a mesh filter include a cross filter (manufactured by rubberfub) and a notch wire (manufactured by Fujitok).

The flow rate when the fermented product passes through the mesh filter is preferably 0.01 to 4 L / hour, more preferably 0.1 to ² L / hour, per 1 mm ² of the effective area of the mesh filter.
In this invention, the effective area of a mesh filter means the area of the space | gap part (opening part) which can pass fermented material when fermented material passes a mesh filter.
By setting it as such a flow volume, it can crush efficiently. Moreover, moderate crushing can be performed without applying an excessive crushing pressure in the first crushing step by allowing the filter having a mesh size in the above range to pass through the filter at a flow rate in the above range. Thereby, the load of the following 2nd crushing process can be reduced, and the load of a manufacturing process can be reduced as a whole.

The mesh size of the mesh filter is JIS sieve standard, preferably 10 to 40 mesh, and more preferably 20 to 40 mesh. These mesh size ranges correspond to openings of 1.9 to 0.39 mm and 0.87 to 0.39 mm, respectively. That is, in the first crushing step, the card in the fermented product is preferably about 2.0 to 0.3 mm, more preferably about 1.0 to 0.3 mm, and more preferably about 1.0 to 0.5 mm. It can be said that it is preferable to crush using a filter having a mesh opening.
Such crushing pressure is particularly suitable for a fermented product obtained by fermenting a milk preparation having a protein content of 3 to 5% by mass and a fat content of 1.5% by mass or less.

Moreover, the crushing pressure in the first crushing step is preferably 0.01 to 0.14 MPa, more preferably 0.01 to 0.05 MPa, and more preferably 0.01 to 0.04 MPa.
The crushing pressure of the first crushing step is approximated by the difference (filter part pressure) between the supply pressure of the fermented product before subjecting to the first crushing step and the supply pressure of the fermented product before subjecting to the second crushing step. In the present invention, it can be defined by this approximate value. As a pressure measurement method, a method using a general-purpose pressure gauge can be adopted as shown in a test example described later (the same applies to the following pressure measurement methods).

[Second crushing step]
The second crushing step is performed after the first crushing step, and is performed under crushing conditions different from those of the first crushing step.
Here, the crushing conditions include conditions that can affect the degree of crushing, such as the crushing method, crushing pressure, and crushing time described above.
The crushing method used for the 2nd crushing process can use the crushing method used for the crushing of the card | curd contained in the fermented product of normal milk liquid. For example, the above-described filter method, pressure valve method, mixer method, and the like can be given. In particular, a pressure valve system or a filter system is preferable. By using the pressure valve method or the filter method, the uniformity of crushing can be increased, and the card residue can be easily reduced.
The crushing by the pressure valve method can be performed by an apparatus called a diaphragm valve or a back pressure valve. Examples of the diaphragm valve include those manufactured by Gemu, and examples of the back pressure valve include those manufactured by Cofrock Co., Ltd.
The crushing device is not particularly limited as long as it can apply pressure to the crushing object by narrowing the flow path of the crushing object, for example, conventionally crushing the card of fermented milk It can use without a restriction | limiting especially including what is used for. Moreover, the sanitary valve etc. which are conventionally used in field | areas other than fermented milk can also be used. Regarding the setting of the conditions of these crushing apparatuses, the conditions used in the conventional one-stage crushing process can be used as they are, but can be adjusted so that an appropriate pressure is appropriately applied according to the crushing apparatus.

Moreover, it is preferable that the crushing roughness in a 2nd crushing process is smaller than the crushing roughness in a 1st crushing process. By making the crushing roughness in the second crushing process smaller than the crushing roughness in the first crushing process, it is possible to suppress the load on the entire crushing process.
The relative size of the crushing roughness is, for example, the average particle diameter or the mass of particles with a certain size or more when the uncrushed fermented product (crushed object) is crushed by the method and conditions in each crushing process (card The remainder can be found by comparing the test example 1).

Moreover, it is preferable that the crushing pressure in a 2nd crushing process is larger than the crushing pressure in a 1st crushing process. By making the crushing pressure in the second crushing step larger than the crushing pressure in the first crushing step, the load on the whole crushing step can be reduced.
The crushing pressure in the second crushing step can be approximated by the supply pressure of the fermented product before being subjected to the second crushing step, and can be defined by this approximate value in the present invention.

As described above, by performing the first crushing process using a mesh filter before the second crushing process, it is possible to give an appropriate shearing force to the fermented product, and suppress an excessive decrease in viscosity. Can do. Further, as a whole, the effect of reducing the remaining card can be sufficiently obtained with a crushing pressure smaller than that of the conventional one-stage crushing method.
Such a crushing pressure is particularly suitable for a fermented product obtained by fermenting a milk preparation having a protein content of 3 to 5% by mass and a fat content of 1.5% by mass or less.

  In addition, although the 1st crushing process and the 2nd crushing process were demonstrated until now, the crushing process does not necessarily need to be two steps, the 1st crushing process and the 2nd before the 1st crushing process. Another crushing step may be included between the crushing step and after the second crushing step.

  As a combination of the first crushing process and the second crushing process, the crushing apparatus of the present invention shown in FIG. Is preferably performed by a pressure valve system.

Here, an embodiment in which the above-described crushing process is performed using the crushing apparatus of the present invention will be described with reference to FIG.
The crushing device 1 includes a hopper 2 that inputs a fermented product obtained by fermenting the milk preparation, a pump 3 that continuously feeds the input fermented product, and a crushing unit 4 that crushes the card in the fermented product. It arrange | positions toward the back | latter stage of the pipe line 6 in this order. The crushing part 4 has a first crushing part made of a mesh filter 41 and a second crushing part made of a diaphragm valve 42.
As the mesh filter 41, those having the above-described mesh size and shape can be preferably used.

First, the fermented material put into the hopper 2 is continuously pushed out toward the crushing portion 4 by a pump 3 at a predetermined pressure. The fermented product supplied to the mesh filter 41 passes through the mesh filter 41 at a flow rate of about 0.01 to 4 L / hour per 1 mm ² of the effective area of the mesh filter. As a result, the curd is crushed to a predetermined roughness, and the fermented product that has passed through the mesh filter is supplied to the diaphragm valve 42 at a pressure higher than the crushing pressure in the mesh filter. The fermented product supplied to the diaphragm valve 42 is further finely crushed while passing through a preset narrow space in the diaphragm valve 42.

  The crushed fermented product is cooled to 10 ° C. or lower, and then filled into a container and sealed by a filling machine (not shown).

The fermented milk produced by the method of the present invention has a reduced curd residue, maintains an appropriate viscosity, and is extremely excellent in texture.
The card | curd remainder of fermented milk of this invention becomes like this. Preferably it is 2 mass% or less, More preferably, it is 1 mass% or less, More preferably, it is 0.5 mass% or less. In the present invention, the remaining card can be defined as a value measured by the method used in Test Example 1 described later.
Further, the viscosity of the fermented milk of the present invention is preferably 2800 mPa · s or more, more preferably 3000 mPa · s or more, and more preferably 4000 mPa · s or more. In the present invention, the viscosity can be defined as a value measured by the method used in Test Example 1 described later.

<Test Example 1>
In order to examine the effect of crushing in two stages in the method for producing fermented milk of the present invention, a crushing test was performed on fermented products obtained from milk preparations having various compositions.
Using the crushing apparatus 1 having the configuration shown in FIG. 3, the fermented materials of Sample 1, Sample 2 and Sample 3 shown in Table 1 were crushed. That is, each sample was put into the hopper 2 and continuously supplied to the crushing unit 4 by the pump 3. The mesh filter 41 (first crushing part) constituting the crushing part has a 20 mesh (mesh opening 0.87 mm) cross filter (made by rubberfub), and the diaphragm valve 42 (second crushing part) has a gemumu. A (GEMU) product was used. The setting of the diaphragm valve 42 was appropriately adjusted so that the crushing pressure was 0.06 to 0.42 MPa. Moreover, in the manufacturing apparatus shown in FIG. 3, the sample was similarly crushed using the apparatus from which the mesh filter 41 was removed.
In the crushing test, by changing the supply pressure of the fermented product by the pump 3, the crushing pressure in the first crushing part was changed, and the card residue and the viscosity when crushing at each crushing pressure were measured and recorded. .

As shown in FIG. 3, the crushing pressure is measured by installing a pressure gauge 51 and a pressure gauge 52 at two locations on the upstream and downstream sides of the mesh filter 41 and measuring the pressure a and the pressure b, respectively. It was done by doing.
The measurement of the remainder of a card | curd is by filtering 100g of crushed fermented products on a mesh filter of 60 mesh size, using the thing remaining on the filter as a card | curd, and calculating the ratio (mass%) of the card | curd which occupies in fermented products. went.
The viscosity was measured using a B-type viscometer under the following conditions. The measurement was performed immediately after production (D + 0) and 1 day after production (D + 1).
No. 4 rotors, 60 rpm, 10 seconds, sample temperature 10 ° C

The test results for Sample 1 are shown in FIG.
As shown in FIG. 4, when a filter was installed (in the case of two-stage crushing), the crushing pressure was 0.14 MPa, and the card residue was reduced to about 0.9% by mass (1% by mass or less). On the other hand, when the filter was not installed (in the case of one-stage crushing), a crushing pressure of about 0.25 MPa was required in order to reduce the remaining curd to 1 mass% or less.
Moreover, when the filter was installed, the crushing pressure was 0.25 MPa, and the card residue was reduced to about 0.2% by mass (0.5% by mass or less). On the other hand, when the filter is not installed, a crushing pressure of about 0.33 MPa is required to reduce the remaining card amount to 0.5% by mass or less.
Further, when the viscosities of the respective samples were compared when the remaining card amount was 1% by mass or less or 0.5% by mass or less, the viscosity was relatively higher when the filter was installed.
As can be seen from the relationship between pressure, card residue, and viscosity shown in Fig. 4, when a filter is installed, the card residue can be effectively reduced with a smaller crushing pressure than when no filter is installed. As a result, it can be seen that a decrease in viscosity can be suppressed.

The test results for Sample 2 are shown in FIG.
As shown in FIG. 5, when a filter is installed (in the case of two-stage crushing), the crushing pressure is 0.09 MPa, and the card residue is reduced to about 0.4 mass% (0.5 mass% or less). did. On the other hand, when no filter was installed (in the case of one-stage crushing), a crushing pressure of about 0.33 MPa was required to make the remaining card amount 0.5% by mass or less.
Moreover, when the viscosity of each sample when the card | curd remainder became 0.5 mass% or less was compared, the direction at the time of installing a filter showed a relatively high viscosity.
As can be seen from the relationship between pressure, remaining card and viscosity shown in Fig. 5, when a filter is installed, the remaining card can be effectively reduced with a smaller crushing pressure than when no filter is installed. As a result, it can be seen that a decrease in viscosity can be suppressed.

The test results for Sample 3 are shown in FIG.
As shown in FIG. 6, when a filter is installed (in the case of two-stage crushing), the crushing pressure is 0.09 MPa and the remaining card is reduced to about 0.2% by mass (0.5% by mass or less). did. On the other hand, when the filter was not installed (in the case of one-stage crushing), a crushing pressure of about 0.14 MPa was required to make the remaining card amount 0.5% by mass or less.
Moreover, when the viscosity of each sample when the card | curd remainder became 0.5 mass% or less was compared, the direction at the time of installing a filter showed a relatively high viscosity.
As can be seen from the relationship between pressure, card residue, and viscosity shown in Fig. 6, when a filter is installed, the card residue can be effectively reduced with a smaller crushing pressure than when no filter is installed. As a result, it can be seen that a decrease in viscosity can be suppressed.

From the above results, it was found that the crushing step in the production method of the present invention is suitable for fermented products containing curds obtained from milk preparations of various compositions. Especially, it turned out that it is especially suitable when stirring type fermented milk is manufactured using the milk preparation liquid which forms the comparatively hard curd of the low fat like the sample 1 and the high protein like the sample 2.
Moreover, when the flow volume of the fermented material in the said test was computed, it was the range of 0.13-1.6L / hour per 1 mm < ² > of effective areas of a mesh filter.

<Test Example 2>
Next, the fat content of the milk preparation was changed, and the composition of the milk preparation particularly suitable for the crushing step in the production method of the present invention was examined.
Using samples with different fat contents shown in Table 2, the crushing test was conducted in the same manner as in Test Example 1.

The test results for each sample are shown in Table 3 and FIGS.
In addition, the viscosity with the filter when the card residue is 1% by mass, the difference in viscosity between the case with and without the filter at that time, and the crushing pressure with and without the filter at that time The difference (pressure reduction effect) was calculated and these are also summarized in Table 3.

As can be seen from Table 3, in any case, the viscosity at the time when the remaining amount of the card was 1% by mass was larger when the filter was installed. From this, it was confirmed that by performing a two-stage crushing process using a filter, it is possible to effectively reduce the decrease in viscosity while effectively reducing the card residue.
Further, as can be seen from the table, the pressure difference in the presence or absence of the filter at the time when the remaining amount of the card became 1% by mass tended to increase as the fat content decreased. In this regard, as can be seen from FIGS. 7 to 10, for the samples 4 to 7 having a fat content of 0.1 to 1.5 mass%, the remaining card amount is sufficiently reduced (for example, 1.0 mass% or less). The required crushing pressure was different depending on the presence or absence of the filter.
On the other hand, as can be seen from FIG. 11, for the sample 8 having a fat content of 2.0% by mass, there was no significant difference in the crushing pressure required to effectively reduce the card residue depending on the presence or absence of the filter.
From this, it was found that the crushing step in the production method of the present invention is particularly effective when using a milk preparation having a fat content of 1.5% by mass or less.

<Test Example 3>
Next, the filter size of the filter was changed, and a suitable range of crushing conditions in the first crushing step in the production method of the present invention was examined. For the test, Sample 1 described above was used. The test method is the same as in Test Example 2.

The test results are shown in Table 4 and FIGS.
In addition, the viscosity with the filter when the card residue is 1% by mass, the difference in viscosity between the case with and without the filter at that time, and the crushing pressure with and without the filter at that time The difference (pressure reduction effect) was calculated and these are also summarized in Table 4.

As can be seen from Table 4 and FIGS. 12 to 16, when a 20 mesh filter is used and when a 40 mesh filter is used, the viscosity at the time when the remaining amount of the card is 1% by mass is When installed, it was bigger. In particular, when a 20 mesh filter was used, the difference was remarkable.
On the other hand, when a filter of 60 mesh or more was used, the viscosity when the remaining amount of the card reached 1% by mass was slightly higher when the filter was not installed.
In this test example, when a filter of 60 mesh or more was used, the crushing pressure (pressure a-pressure b) applied when passing through the filter was larger than the pressure b after passing through the filter. That is, when the crushing pressure in the first crushing step is larger than the crushing pressure in the second crushing step, a large shearing force is applied in the first crushing step, which can easily cause a decrease in viscosity. I understood.

  Moreover, in the crushing of the fermented product obtained from the milky lotion represented by the sample 1 and having a fat content of 0.5% by mass or less and a protein content of about 3 to 5% by mass, the mesh size is 10 to 40 mesh. It was found that a filter is preferably used, a filter having a mesh size of 20 to 40 mesh is more preferably used, and a filter having a mesh size of about 20 mesh is more preferably used.

<Test Example 4>
Next, a sample 7 (fat content: 1.5% by mass) was used, a filter having a filter size of 20 mesh was used, and a comparison was made with no filter.
The results are shown in Table 5 and FIG.

As can be seen from Table 5 and FIG. 17, the viscosity at the time when the remaining amount of the card reached 1% by mass was greater when the filter was installed than when the filter was not installed.
From this, when using a milk preparation with a fat content of about 1 to 1.5% by mass and a protein content of about 3 to 5% by mass, the filter size is about 20 mesh and the mesh size is 0.5 to 1.0 mm. It turned out that it is preferable to set it as a grade.

  When the results of Test Example 3 are also combined, in the crushing of the fermented product obtained from the milk solution having a fat content of 1.5% by mass or less and a protein content of about 3 to 5% by mass, the mesh size is 20 to 40 mesh. It has been found preferable to use a filter.

  Fermented milk was manufactured by the following method using the milk preparation liquid (fat content 0.1 mass%, protein content 4.2 mass%) of the mixing | blending shown in Table 6.

The milk preparation is sterilized at 95 ° C. for 6 minutes, cooled, and lactic acid bacteria starter (bacterial name Streptococcus thermophilus, Lactobacillus bulgaricus, manufactured by Christian Hansen) and bifidobacteria (bacterial name Bifidobacterium Longum (manufactured by Morinaga Milk Industry Co., Ltd.) was added and fermented at 37 ° C. for 7 hours (until the pH reached 4.6). The obtained fermented product was put into the hopper 2 of the crushing apparatus 1 having the configuration shown in FIG. 2, and continuously supplied to the crushing unit 4 through the inside of the conduit 6 using a pump. A 20 mesh (0.87 mm) cross filter (manufactured by rubberfub) was used for the mesh filter 41 (first crushing part), and a diaphragm valve manufactured by GEMU was used for the diaphragm valve 42. The diaphragm valve 42 was adjusted so that the crushing pressure was 0.13 MPa.
The flow rate was set to 0.6 L / hour per 1 mm ² of the effective area of the mesh filter.
The fermented material that passed through the diaphragm valve was cooled to 10 ° C., and then filled into an 80 ml plastic container and sealed with a seal to obtain a product.
One day later, the product seal was opened, and the curd residue and viscosity of the fermented milk were measured. As a measuring method, the method described in the above test example was used.
As a result, the remaining card was as small as 0.3% by mass, and the viscosity was moderate at 4800 mPa · s.
Moreover, when this fermented milk was eaten, it was smooth and moderate in viscosity, and had a good texture.

  The production method and crushing apparatus of the present invention are used for industrial production of fermented milk.

1 Crushing device 2 Hopper 3 Pump 4 Crushing section
41 Filter (first crushing part)
42 Diaphragm valve (second crushing part)
51, 52 Pressure gauge 6 Pipe line

Claims (7)

A method for producing fermented milk comprising a step of crushing curd in a fermented product obtained by fermenting a milk preparation containing a fermented milk raw material having a fat content of 1.5% by mass or less,
The crushing step includes a first crushing step and a second crushing step performed after the first crushing step,
The first crushing step is performed by passing the fermented product through a mesh filter having a mesh size of 20 to 40 mesh ,
The second crushing step is performed using a pressure valve system .
A method for producing fermented milk.   The method for producing fermented milk according to claim 1, wherein the crushing pressure in the second crushing step is larger than the crushing pressure in the first crushing step.   The manufacturing method of fermented milk of Claim 1 or 2 whose crushing pressure in a said 1st crushing process is 0.01-0.14 Mpa. The fermented milk according to any one of claims 1 to 3, wherein a flow rate of the fermented product per 1 mm ^{2 of} an effective area of the mesh filter when the fermented product passes through the mesh filter is 0.01 to 4 L / hour. Manufacturing method. The method for producing fermented milk according to any one of claims 1 to 4 , wherein the protein content of the formula is 3% by mass or more. Fermented milk obtained by the production method according to any one of claims 1 to 5 . A crushing device equipped with a crushing unit for crushing a card in a fermented product obtained by fermenting a milk preparation containing fermented milk ingredients,
The crushing part includes a first crushing part having a mesh filter having a mesh size of 20 to 40 mesh, a second crushing part arranged at a subsequent stage of the first crushing part, and composed of a pressure valve type crushing apparatus , Have
A crushing apparatus, wherein the crushing roughness of the card by the first crushing portion is different from the crushing roughness of the card by the second crushing portion.

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