JP6568819B2 - Method for producing fermented milk - Google Patents

Description

  The present invention relates to a method for producing fermented milk. The present invention particularly relates to a method for producing concentrated fermented milk.

In recent years, concentrated fermented milk having a higher solid content than conventional standard fermented milk has become popular as a product with a high-class feeling due to its creaminess and richness.
As a method for producing concentrated fermented milk, a method for increasing the milk fat content and non-fat milk solid content of a fermentation raw material (milky formula) is known. Specifically, a method of producing fermented milk by subjecting whole fat milk to membrane treatment and then fermenting is known (Patent Document 1).
It is also known that concentrated fermented milk is produced by membrane concentration of a fermented product obtained by fermenting a fermentation raw material (milk preparation liquid) (Patent Documents 2 and 3).

JP-A-6-14707 JP 2014-161237 A JP 2005-318855 A

Among the conventionally known methods for producing concentrated fermented milk, the method for increasing the solid content concentration of the milk preparation as described in Patent Document 1 may be subject to restrictions such as fermentation conditions, and achieves a good flavor. Hard to do. On the other hand, the method of concentrating a fermented product as described in Patent Documents 2 and 3 tends to be sour.
Concentrated fermented milk has an attractive rich and mild taste, and it is not preferable that the sour taste becomes too strong.

  In addition, the development of products with various tastes in the field of concentrated fermented milk, which is gaining popularity, requires the use of ingredients such as matcha and chocolate, which are one of the most popular ingredients in the confectionery field. It becomes a problem. These materials can be eaten deliciously in the vicinity of neutrality, and if the concentrated fermented milk has a strong sourness, the taste will not be balanced and will not be delicious.

  Then, this invention makes it a subject to provide the technique which manufactures concentrated fermented milk, suppressing the raise of acidity. Moreover, this invention makes it a subject to provide the technique which manufactures the concentrated fermented milk containing a non-acid raw material.

The present invention that solves the above-described problems includes a fermentation process in which a fermented milk solution is fermented to prepare a fermented product, and a concentrated fermented milk manufacturing method that includes a concentrated fermented milk product by concentrating the prepared fermented product. And before the said concentration process, the dilution process which dilutes the said fermented material with a dilution liquid and prepares a diluted fermented product is characterized by the above-mentioned.
According to the production method of the present invention, it is possible to suppress an increase in acidity due to the concentration step, and it is possible to produce concentrated fermented milk with reduced acidity.

In a preferred embodiment of the present invention, the concentration step is started during the dilution step, and the dilution step is ended during the concentration step.
By starting the concentration step during the dilution step, it is possible to efficiently produce concentrated fermented milk with reduced acidity.

In the preferable form of this invention, the said concentration process is performed so that the mass of the said concentrated fermented milk may become 2/3 or less with respect to the mass of the said fermented material.
When concentrating a fermented product in such a range, the effect which suppresses the raise of the acidity of the manufacturing method of this invention becomes remarkable.

In the preferable form of this invention, the said concentration process is performed so that the non-fat milk solid content of the said concentrated fermented milk may be 10 mass% or more.
By concentrating the fermented product in such a range, it is possible to produce concentrated fermented milk having a rich flavor such as creaminess and richness.

In the preferable form of this invention, the said dilution process is performed so that the mass of the said diluted fermented material may be 1.01-4 times with respect to the mass of the said fermented material.
By diluting in such a range, an increase in acidity due to the concentration of the fermented product can be effectively suppressed, and the production efficiency is also good.

In a preferred embodiment of the present invention, the dilution step and the concentration step are performed such that the difference between the lactic acid acidity of the concentrated fermented milk and the lactic acid acidity of the fermented product is 0.25% by mass or less.
By performing the dilution step and the concentration step so that the increase in the lactic acid acidity due to the concentration step falls within the above range, it is possible to produce concentrated fermented milk excellent in palatability by suppressing an increase in acidity.

In a preferred embodiment of the present invention, the dilution step and the concentration step are performed such that the lactic acid acidity of the concentrated fermented milk is 0.95% by mass or less, and a non-acidic material is added to the concentrated fermented milk after the concentration step. Includes an acidic material addition step.
By making the lactic acid acidity in concentrated fermented milk within the above range and adding a non-acidic material to the concentrated fermented milk, it becomes possible to produce concentrated fermented milk containing a non-acidic material with a harmonious flavor.

  ADVANTAGE OF THE INVENTION According to this invention, in manufacture of concentrated fermented milk, the raise of the acidity by concentration of fermented material can be suppressed. According to the preferable form of this invention, the concentrated fermented milk which has a mild flavor can be manufactured. Furthermore, according to the preferable form of this invention, the concentrated fermented milk which has smooth texture can be manufactured. Moreover, according to the preferable form of this invention, it becomes possible to manufacture the concentrated fermented milk containing the non-acidic material with which the flavor was harmonized.

It is a conceptual diagram which shows the manufacture flow of an Example and a comparative example. It is a figure which shows the particle size distribution of each sample of Test 1. It is a figure which shows the particle size distribution of each sample of Test 2.

Hereinafter, an embodiment for carrying out the present invention will be described.
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.

  The method for producing concentrated fermented milk according to the present invention includes a fermentation step of fermenting a milk preparation to prepare a fermented product, and a concentration step of concentrating the prepared fermented product to prepare concentrated fermented milk. It is a manufacturing method. The concentrated fermented milk produced by the present invention has a solid concentration of preferably 10% by mass or more, more preferably 11% by mass or more.

  The method for producing concentrated fermented milk according to the present invention includes a dilution step of preparing a diluted fermented product by diluting the fermented product obtained by the fermenting step with a diluent before the concentrating step. Hereinafter, embodiments of the present invention will be described.

<1> Fermentation process In embodiment of this invention, the fermentation process which ferments milk solution and prepares a fermented product is performed. Here, the “milk preparation” is a raw material obtained by preparing various raw materials including fermented milk raw materials such as milk and dairy products, which are used in the production of fermented milk.
For the preparation of the milk preparation, dairy products and other raw materials usually used for the production of fermented milk can be used without particular limitation. Examples of the dairy product used in the milk preparation include cream, skim concentrated milk, skim milk powder and the like.

  The content of non-fat milk solids in the formula can be adjusted as appropriate within the normal range used for the production of fermented milk.

  The non-fat milk solid content in the milk preparation is preferably 6 to 16% by mass, and more preferably 8 to 14% by mass. A fermented product suitable for concentration is easily obtained when the content of the non-fat milk solid content is at least the lower limit of the above range, and concentrated fermented milk having a good flavor is easily obtained when the content is less than the upper limit.

  Moreover, the milk preparation liquid may contain raw materials other than milk origin. For example, sugars such as sucrose and fructose can be contained in the milk preparation. Moreover, the milk preparation is preferably homogenized.

The milk preparation thus prepared is preferably heat-treated. In the heat treatment step, conditions usually used in the production process of dairy products such as sterilization of milk can be used.
The heating temperature is preferably 85 to 95 ° C. The heating time is preferably 5 to 15 minutes.

For fermentation of the milk preparation, a lactic acid bacterium starter used for production of ordinary fermented milk can be used without any particular limitation. As the lactic acid bacteria starter, for example, lactic acid bacteria such as Lactobacillus bulgaricus, L. lactis, Streptococcus thermophilus (S. thermophilus) and the like can be used.
It is also preferable to use a low acid lactic acid bacteria starter. The low acid lactic acid bacteria starter is a time required for the pH of the medium to fall from 5.0 to 4.6 when fermented at 40 ° C. in a reduced skim milk medium having a nonfat milk solid content of 10 mass%. It refers to a lactic acid bacteria starter that has the characteristics of being over time.
As such a low-acidic lactic acid bacteria starter, those of bacterial species such as Streptococcus thermophilus are commercially available and can be used. For example, commercially available products such as F-DVS ST-20X, F-DVS ST-BODY-2, and F-DVS ST-BODY-3 from Christian Hansen can be used. Bifidobacterium can also be added.

The addition amount of bacteria such as 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 1 × 10 ⁵ CFU / g, preferably at least 1 × 10 ⁶ CFU / g.
Fermentation conditions can also be adjusted as appropriate within a normal range. For example, a fermented material can be obtained by fermenting at a temperature of 35 to 43 ° C. for 5 to 12 hours.

Fermentation can be terminated by cooling when the pH is usually 4 to 5, preferably 4.4 to 4.8.
Moreover, the lactic acid acidity of the obtained fermented material becomes like this. Preferably it is 0.55-0.8 mass%, More preferably, it is 0.6-0.7 mass%.
By fermenting until the pH and lactic acid acidity in the above ranges are satisfied, it is possible to produce a concentrated fermented milk having a good flavor.
The card | curd in the obtained fermented material is crushed and it uses for the dilution process mentioned later. The card may be crushed either during cooling or after cooling.

<2> Dilution Step In the embodiment of the present invention, subsequently, the diluted fermented product is diluted by adding a diluent to the prepared fermented product to prepare a diluted fermented product. In the present invention, by performing this dilution step prior to the concentration step described later, lactic acid present in the fermented tissue can be efficiently removed in the concentration step, and an increase in the acidity of the fermented product accompanying concentration can be suppressed. . As shown in the examples described later, even if the fermented material prepared by fermentation is concentrated with the same efficiency, there is a significant difference in the acidity in the concentrated fermented milk depending on whether the dilution step is performed before the concentration step. Get out.

  Here, the dilution liquid may be pure water or an aqueous solution. Examples of the aqueous solution include membrane filtrates containing whey protein, minerals, lactose, acids, etc., which are by-products of membrane concentration in the concentration step described later, minerals, vitamins, proteins, sugars, fruit juices, fragrances, thickening stabilizers. An aqueous solution in which various food additives are dissolved. As will be described later, in a form in which the concentration step is started during the dilution step, a membrane filtrate that is a by-product obtained in the concentration step can be used as the dilution solution.

In the dilution step, the mass of the diluted fermented product is preferably 1.01 times or more, more preferably 1.1 times or more, with respect to the mass of the fermented product prepared by the fermentation step. More preferably, it is performed so as to be 1.5 times or more.
By diluting in such a range, lactic acid in the fermented product can be efficiently removed by the concentration step described later. Moreover, the concentration obtained through a concentration process by diluting so that the mass of the diluted fermented product is preferably 1.8 times or more, more preferably 2.5 times or more with respect to the mass of the fermented product. Fermented milk can be made into a smooth structure. More specifically, the effect of refining the particles contained in the tissue of the concentrated fermented milk is obtained with respect to the concentrated fermented milk obtained by concentrating at the same efficiency without performing the dilution step.
From the viewpoint of production efficiency, in the dilution step, the mass of the diluted fermented product is preferably 4 times or less, more preferably 3 times or less, more preferably 2 times or less with respect to the mass of the fermented product. Do as follows.

<3> Concentration step In the embodiment of the present invention, a concentration step of concentrating the diluted fermented product prepared in the dilution step to obtain concentrated fermented milk is performed. The concentration step is performed so that the mass of the concentrated fermented milk is preferably 1 or less, more preferably 2/3 or less, with respect to the mass of the fermented product prepared by the fermentation step. When the concentration step is performed with such efficiency, the increase in acidity becomes particularly significant. Therefore, when concentrating with the efficiency of the said range, the effect which suppresses the raise of the acidity of the manufacturing method of this invention becomes remarkable.

  Further, the concentration step is performed so that the mass of the concentrated fermented milk is preferably 1/5 or more, more preferably 1/3 or more of the mass of the fermented product. By concentrating in such a range, concentrated fermented milk having a good texture and flavor can be obtained.

The concentration step is performed so that the nonfat milk solid content of the concentrated fermented milk is preferably 10% by mass or more, and more preferably 11% by mass or more. The upper limit is not particularly limited, but is preferably 15% by mass or less, and more preferably 14% by mass or less.
The concentration step is performed so that the protein content of the concentrated fermented milk is preferably 5% by mass or more, more preferably 6% by mass or more. The upper limit is not particularly limited, but is preferably 11% by mass or less, and more preferably 10% by mass or less.
The concentration step is performed so that the fat content of the concentrated fermented milk is preferably 0.2% by mass or more, more preferably 0.3% by mass or more. The upper limit is not particularly limited, but is preferably 11% by mass or less, and more preferably 10% by mass or less.
By concentrating in such a range, concentrated fermented milk having a rich flavor such as creaminess and richness can be produced.

  In addition, the concentration step is such that the mass of the concentrated fermented milk is preferably 1/2 to 1/9, more preferably 1/3 to 1/6 of the diluted fermented product. Do.

  Any conventional concentration method can be used without limitation as long as it is a method used for concentration of dairy components. Examples of the concentration method include concentration by a separator and membrane concentration. Examples of filtration membranes used for membrane concentration include microfiltration membranes (MF membranes), ultrafiltration membranes (UF membranes), nanofiltration membranes (NF membranes), and reverse osmosis membranes (RO membranes). Among these, an ultrafiltration membrane (UF membrane) is preferably used from the viewpoint of realizing a good flavor. Concentration can be performed using an apparatus conventionally used for concentration of dairy products.

  During the concentration step, the temperature of the diluted fermented product is preferably maintained at 10 to 50 ° C, more preferably 40 to 45 ° C. After completion of the concentration step, it is preferable to cool to 20 ° C. or lower.

  The concentration step may be started after the above-described dilution step is completed, or may be started during the dilution step. In particular, it is preferable from the viewpoint of production efficiency to start the concentration step during the dilution step. In this case, concentrated fermented milk can be obtained by terminating the dilution step during the concentration step. As such a method, diafiltration is preferably mentioned. That is, while diluting the fermented product by removing low molecular components including water in the fermented product while supplying the diluent to the tank containing the fermented product, it can be concentrated. Here, the membrane filtrate which is a by-product obtained in the concentration step can be used as a diluent.

In the dilution step and the concentration step described above, the difference between the lactic acid acidity of the concentrated fermented milk and the lactic acid acidity of the fermented product prepared by the fermentation process is preferably within 0.25% by mass, more preferably within 0.2% by mass. Thus, it is preferable to carry out. As shown in the Example mentioned later, the acidity of concentrated fermented milk can be reduced, so that a dilution rate is made high. Moreover, the acidity of a fermented product rises, so that the mass reduction by concentration is large (concentration efficiency in an Example is a low value). Therefore, the acidity of the concentrated fermented milk can be adjusted by adjusting the dilution ratio and the concentration efficiency, respectively.
By setting the increase in the lactic acid acidity by the concentration step within the above range, it is possible to produce a concentrated fermented milk excellent in flavor.

  The lactic acid acidity of the fermented product after the completion of the concentration step is preferably 1.1% by mass or less, more preferably 1% by mass or less. Although the lower limit of the lactic acid acidity of the fermented product is not particularly limited, 0.64% by mass or more is preferable from the viewpoint of flavor as fermented milk.

The concentrated fermented milk thus obtained can be homogenized as desired. In addition, the concentrated fermented milk thus obtained is homogenized as desired, and then added or mixed with materials other than fermented milk such as syrup and fruit preserves, and the flavors of these materials are utilized. It can also be a product. As such a form, either the form which applies a raw material to concentrated fermented milk, or the form which mixes a raw material with concentrated fermented milk may be sufficient.
Among them, it is preferable to use a non-acidic material eaten near neutral as such a material because the effect of suppressing the increase in acidity of the production method of the present invention can be fully utilized.

The lactic acid acidity of the concentrated fermented milk to which the non-acidic material is added is preferably 0.6 to 0.95% by mass, more preferably 0.7 to 0.8% by mass.
By setting it as such a range, harmony of the flavor with the non-acidic material in concentrated fermented milk becomes favorable.

  In the present invention, the non-acidic material has a pH of 5 or more, preferably 5 to 7.5. Moreover, as a raw material contained in a non-acidic raw material, the raw material which demonstrates the original deliciousness of a raw material at the said pH, in other words, in the food with high acidity, the raw material which tends to impair the original flavor of a raw material is preferable. Examples include matcha, chocolate, sesame, cocoa, caramel, kinako, chanterelle, chestnut, and strawberry.

  The non-acidic material preferably contains sugar. The type of sugar is not particularly limited, and sucrose, fructose, starch syrup and the like are preferable. The sugar content of the non-acidic material is preferably 50 degrees or more and less than 70 degrees. By adjusting the sugar content of the non-acidic material to such a range, viscosity adjustment and the like can be easily performed in industrial production. Moreover, in the preservation | save in the state by which pH fall of this invention was suppressed, microbial contamination can be prevented effectively and it is advantageous to maintenance of favorable flavor.

In the present invention, the sugar content means a Brix value, and can be measured with a sugar content meter (Brix meter).
In addition, as the non-acidic material, a syrup or paste is preferably used.

  The viscosity of the non-acidic material can be adjusted by adding a thickener. As the thickener, guar gum, xanthan gum, pectin and the like can be used.

As the composition of the non-acidic material, for example, the following prescription is preferably exemplified.
Saccharose selected from sucrose, fructose, and starch syrup: 30-80% by mass
Water: 0 to 40% by mass
Ingredients used for flavoring (sesame, chocolate, matcha): 4-40% by mass
Thickener: 0 to 0.5% by mass

The addition of the non-acidic material to the concentrated fermented milk is performed with a content of preferably 5% by mass or more and less than 30% by mass, and more preferably 10% by mass or more and less than 25% by mass with respect to the total amount of the fermented product. By adding a non-acidic material in such a range, the pH of the concentrated fermented milk produced becomes a favorable range.
Moreover, the addition of the non-acidic material to the fermented product may be performed so that the pH of the concentrated fermented milk after adding the non-acidic material is 4.7 or more, preferably about pH 4.9 to 5.0. preferable.

  Further, the amount of the non-acidic material added may be an amount such that the sugar content of the concentrated fermented milk is 15 degrees or more and less than 30 degrees. By mixing non-acidic materials in such a range, not only can fermented milk with high taste taking advantage of the flavor of the materials be produced, but also in storage in a state where the pH reduction of the present invention is suppressed, microbial contamination is prevented. It can be effectively prevented and is advantageous for maintaining a good flavor.

The produced concentrated fermented milk is filled in a container of about 80 to 500 ml, preferably about 80 to 250 ml, and sealed. About the concentrated fermented milk of the form which adds a non-acidic raw material, it is good also as a packaging form which fills a non-acidic raw material into a portion container etc. separately from concentrated fermented milk, and adds a non-acidic raw material when eating.
The product in a container is usually stored at 10 ° C. or lower, preferably 5 ° C. or lower.
The container is preferably made of paper, glass, or plastic (for example, polypropylene, polyethylene terephthalate (PET), polystyrene, or polyethylene).

[Test 1]
This test was performed in order to measure the inhibitory effect on the increase in acidity of the method of the present invention (a method including a dilution step before the concentration step).

<Comparative Example 1>
A milk preparation was prepared according to the formulation shown in Table 1, the milk preparation was homogenized at 15 MPa with a homogenizer, and heat-treated at 90 ° C. for 10 minutes using a plate heater to prepare a fermented milk base. Subsequently, lactic acid bacteria starter (manufactured by Christian Hansen, YF-L904) was added to the prepared fermented milk base at a rate of 0.001% by mass, and when the pH reached 4.4, the fermentation was terminated by cooling. The curd in the fermented product was crushed. About 500 g of the obtained fermented product, concentration was performed using an ultrafiltration membrane (UF membrane) until the mass became a half, and 250 g of concentrated fermented milk as Comparative Example 1 was obtained. The component composition before and after concentration of the fermented product is shown in Table 2.
Moreover, the outline of the manufacturing flow of the comparative example 1 and the concept of increase / decrease in the mass of fermented material are shown in FIG.

<Example 1>
After mixing 500 g of pure water (diluted solution) to 500 g of the fermented product obtained by the same method as Comparative Example 1, the mass of the diluted fermented product is 4 using an ultrafiltration membrane (UF membrane). Concentration was performed until it became a fraction, and 250 g of concentrated fermented milk as Example 1 was obtained. The outline of the manufacturing flow of Example 1 and the concept of the increase / decrease in the mass of fermented material are shown in FIG. The composition of the non-fat milk solid content, fat, and protein of the concentrated fermented milk was the same as in Comparative Example 1.

<Comparative Example 2>
500 g of pure water (diluent) was mixed with 500 g of the milk preparation prepared in the same manner as in Comparative Example 1, and then fermentation was performed until the pH reached 4.4. Subsequently, 250 g of concentrated fermented milk as Comparative Example 2 was obtained by performing concentration using an ultrafiltration membrane (UF membrane) until the mass of the fermented product became 1/4. The outline of the manufacturing flow of the comparative example 2 and the concept of the increase / decrease in the mass of fermented material are shown in FIG. The composition of the non-fat milk solid content, fat, and protein of the concentrated fermented milk was the same as in Comparative Example 1.

Table 3 shows the dilution rate, concentration efficiency, post-fermentation pH, post-fermentation acidity, post-concentration acidity, acidity increase, acidity increase rate, and acidity increase inhibition rate relative to Comparative Example 1 in Examples and Comparative Examples. In the table, the dilution rate is expressed as the mass of diluted fermented product / the mass of fermented product after fermentation. Moreover, the concentration efficiency with respect to a fermented product is represented by the mass of concentrated fermented milk / the mass of the fermented product after fermentation, and the concentration efficiency with respect to a diluted fermented product is represented by the mass of concentrated fermented milk / the mass of the diluted fermented product. The acidity is lactic acid acidity. The rate of increase in acidity is expressed by (acidity after concentration−acidity after fermentation) / acidity after fermentation (both are the same in Test 2 and Test 3).
Moreover, the result of having measured the particle size distribution of the obtained concentrated fermented milk in FIG. 2 using LA-950 (made by HORIBA) is shown.

  As can be seen from Table 3, the concentrated fermented milk produced by the method of Example 1 suppresses the increase in acidity by 11% compared to the concentrated fermented milk produced by the method of Comparative Example 1 (conventional method). I was able to. Further, as can be seen from FIG. 2, the concentrated fermented milk produced by the method of Example 1 had a particle size distribution that approximated that of the concentrated fermented milk produced by the method of Comparative Example 1. From this, in the production of concentrated fermented milk, it is possible to produce concentrated fermented milk with reduced acidity while maintaining the texture of the concentrated fermented milk by performing a dilution step after the fermentation step and before the concentration step. all right.

  On the other hand, the concentrated fermented milk produced by the method of Comparative Example 2 significantly increased the acidity after concentration. Moreover, compared with the concentrated fermented milk manufactured with the method of the comparative example 1, the ratio of the particle | grains with a large particle diameter increased, and it became a rough and rough structure. From this, it turned out that the method of diluting at the time of preparation of milk preparation liquid cannot manufacture concentrated fermented milk which reduced acidity and was excellent in flavor and texture.

[Test 2]
This test was performed in order to measure the influence on the inhibitory effect of the increase in acidity by changing the dilution factor.

<Comparative Example 3>
Concentrated fermented milk was produced in the same manner as in Comparative Example 1. However, in Comparative Example 3, the fermentation was terminated by cooling when the pH reached 4.8.
About 1000 g of the obtained fermented product, concentration was performed using an ultrafiltration membrane (UF membrane) until the mass of the fermented product was reduced to one half, and 500 g of concentrated fermented milk as Comparative Example 3 was obtained. The composition of the non-fat milk solid content, fat, and protein of the concentrated fermented milk was the same as in Comparative Example 1.

<Examples 2 and 3>
Concentrate while mixing 500 g or 2000 g of pure water (diluent) with respect to 1000 g of the fermented product obtained by the same method as in Comparative Example 3, and 500 g of each of concentrated fermentations in Example 2 and Example 3, respectively. I got milk. The dilution step and the concentration step were performed in the same manner as in Example 1. About the concentrated fermented milk obtained in any Example, the composition of non-fat milk solid content, fat, and protein was the same as that of the comparative example 1.

  Table 4 shows the dilution ratio, concentration efficiency, post-fermentation pH, post-fermentation acidity, post-concentration acidity, acidity increase, acidity increase rate, and acidity increase inhibition rate relative to Comparative Example 3 in Examples and Comparative Examples. Moreover, the particle size distribution of each concentrated fermented milk is shown in FIG. The particle size distribution was measured in the same manner as in Test 1.

As can be seen by comparing Example 1 in Table 3 (2% dilution with an acidity increase suppression rate of 11%) and Example 4 in Table 4 (1.5 dilution with an acidity increase suppression rate of 24%), It turned out that the acidity raise inhibitory effect by a dilution process can be acquired more notably by adjusting low the acidity of the fermented material after a fermentation process. Further, in the method of Example 3, an acidity increase suppression rate of 32% could be obtained.
In addition, the concentrated fermented milk produced by the method of Example 3 has an increased proportion of particles with a small particle size compared to the concentrated fermented milk produced by the method of Comparative Example 3 (conventional method), and a smooth tissue. became. From this, it is possible to produce concentrated fermented milk with particularly smooth texture by diluting at a dilution ratio such that the mass of the diluted fermented product is 3 times or more that of the fermented product prepared by fermentation. all right.

[Test 3] This test was conducted for the purpose of examining a preferable range of dilution ratio.
<Comparative example 4>
Concentrated fermented milk was produced in the same manner as in Comparative Example 1. However, in Comparative Example 4, the fermentation was terminated by cooling when the pH reached 4.8.
About 1000 g of the obtained fermented product, concentration was performed using an ultrafiltration membrane (UF membrane) until the mass of the fermented product was reduced to one half, and 500 g of concentrated fermented milk as Comparative Example 4 was obtained. The composition of the non-fat milk solid content, fat, and protein of the concentrated fermented milk was the same as in Comparative Example 1.

<Example 4>
10 g of pure water (diluent) was concentrated while mixing with 1000 g of the fermented product obtained in the same manner as in Comparative Example 4, and 500 g of concentrated fermented milk as Example 4 was obtained. The dilution step and the concentration step were performed in the same manner as in Example 1. The composition of the non-fat milk solid content, fat, and protein of the concentrated fermented milk was the same as in Comparative Example 1.

  Table 5 shows the dilution ratio, concentration efficiency, post-fermentation pH, post-fermentation acidity, post-concentration acidity, acidity increase, acidity increase rate, and acidity increase inhibition rate relative to Comparative Example 4 in Example 4 and Comparative Example 4.

  As shown in Table 5, in Example 4, an acidity increase suppression rate of 12% could be obtained. From this, it was found that even if the dilution ratio is a relatively low value of 1.01, the effect of suppressing the increase in acidity of the present invention can be obtained.

[Test 4]
This test was conducted to evaluate the flavor when a non-acidic material was added to the concentrated fermented milk produced by the method of the present invention.
Sensory evaluation was performed by six trained panelists. About the concentrated fermented milks of Comparative Example 3 and Examples 2 and 3 produced in Test 2, the “taste mildness” in plain and chocolate syrup (Hershey Chocolate Syrup, Hershey Japan Co., Ltd.) “Compatibility with chocolate syrup” was evaluated according to the following criteria in five stages. The evaluation results are shown in Table 6 as the average value of the scores given by each panelist.

(Evaluation criteria)
[Mild taste]
1: Sour 2: Slightly sour 3: Slightly mild 4: Mild 5: Very mild

[Compatibility with chocolate syrup]
1: Does not fit 2: Does not fit slightly 3: Fits slightly 4: Fits 5: Fits very well

  As shown in Table 6, the concentrated fermented milk produced by the methods of Examples 2 and 3 is milder than the concentrated fermented milk produced by Comparative Example 3 (conventional method) and has good compatibility with chocolate syrup. It became the result. In particular, in Example 3 where the acidity after concentration was 0.77% by mass, it was found that the compatibility with chocolate syrup was good. From this, it was found that the acidity after concentration is preferably 0.95% by mass or less and particularly preferably 0.8% by mass or less from the viewpoint of compatibility with the non-acidic material.

  INDUSTRIAL APPLICATION This invention can be utilized for manufacture of the concentrated fermented milk using the flavor of a non-acidic material.

Claims (7)

A method for producing concentrated fermented milk, comprising a fermentation step of fermenting a milk preparation to prepare a fermented product and a concentration step of concentrating the prepared fermented product to prepare a concentrated fermented milk,
Before the said concentration process, the manufacturing method of concentrated fermented milk characterized by including the dilution process which dilutes the said fermented material with a diluent, and prepares a diluted fermented material.   The method for producing concentrated fermented milk according to claim 1, wherein the concentration step is started during the dilution step, and the dilution step is ended during the concentration step.   The said concentration process is performed so that the mass of the said concentrated fermented milk may become 2/3 or less with respect to the mass of the said fermented material, The manufacture of concentrated fermented milk of Claim 1 or 2 characterized by the above-mentioned. Method.   The said concentration process is performed so that the non-fat milk solid content of the said concentrated fermented milk may be 10 mass% or more, The manufacturing method of the concentrated fermented milk in any one of Claims 1-3 characterized by the above-mentioned.   The said dilution process dilutes so that the mass of the said diluted fermented product may be 1.01-4 times with respect to the mass of the said fermented product, The one in any one of Claims 1-4 characterized by the above-mentioned. A method for producing concentrated fermented milk.   The said dilution process and concentration process are performed so that the difference of the lactic acid acidity of the said concentrated fermented milk and the lactic acid acidity of the said fermented product may be 0.25 mass% or less, The any one of Claims 1-5 characterized by the above-mentioned. The manufacturing method of the concentrated fermented milk of crab.   The dilution step and the concentration step include a non-acidic material addition step of adding a non-acidic material to the concentrated fermented milk after the concentration step, so that the lactic acid acidity in the concentrated fermented milk is 0.95% by mass or less. The manufacturing method of the concentrated fermented milk in any one of Claims 1-6 characterized by these.