JP2021023207A - Production method of fermented milk, and method of suppressing water separation from fermented milk - Google Patents

Abstract

To provide a production method of fermented milk capable of suppressing water separation in spite of containing digestible dextrin.SOLUTION: In a production method of fermented milk, a raw material liquid containing a milk raw material and indigestible dextrin is subjected to heat treatment at a heating temperature of 80°C or higher for a holding time of 1 minute or more and then fermented by adding lactic acid bacteria to obtain fermented milk. The heat treatment is conducted so that the ratio b2/b1 is 1.95 or less, where b1 is a b*value in a CIEL*a*b*color system of the raw material liquid before the heat treatment and b2 is the b*value of the raw material liquid when the lactic acid bacteria are added.SELECTED DRAWING: None

Description

The present invention relates to a method for producing fermented milk and a method for suppressing water separation of fermented milk.

Usually, the conditions for heat treatment of the raw material liquid for producing fermented milk are (i) temperature 85 ° C. for 30 minutes, (ii) temperature 90 to 95 ° C. for 10 minutes to 5 minutes, and (iii) temperature 120 ° C. 5 to 3 seconds is generally known (Non-Patent Document 1).

"Latest Food Processing Course Milk and Its Processing" First Edition, published by Kenjosha, 1987, p. 282.

Amid growing health consciousness, fermented milk containing various efficacy ingredients has been developed.
The present inventors have found that when fermented milk is produced by a method of fermenting a raw material liquid to which indigestible dextrin, which is a water-soluble dietary fiber, is added, water separation is likely to occur.
The present invention provides a method for producing fermented milk, which contains indigestible dextrin but is unlikely to cause water separation, and a method for suppressing water separation from fermented milk.

As a result of diligent research, the present inventors have found that when a raw material solution containing a dairy raw material and indigestible dextrin is heat-treated, browning (coloring) is likely to occur after the heat treatment, and when browning occurs, water separation after fermentation is likely to occur. The present invention has been made by finding that water separation after fermentation can be suppressed by adjusting the heat treatment conditions to control the degree of browning.

The present invention has the following aspects.
[1] A method in which a raw material solution containing a milk raw material and indigestible dextrin is heat-treated at a heating temperature of 80 ° C. or higher and a holding time of 1 minute or longer, and then lactic acid bacteria are added and fermented to obtain fermented milk. Assuming that the b * value of the raw material liquid before the heat treatment is b1 in the CIE L * a * b * color system and the b * value of the raw material liquid at the time of adding the lactic acid bacteria is b2, b2 / b1 A method for producing fermented milk, wherein the heat treatment is performed so that the ratio of lactic acid is 1.95 or less.
[2] The production method according to [1], wherein the content of the indigestible dextrin is 2.5 to 7% by mass with respect to the total mass of the raw material liquid.
[3] The production method of [1] or [2], wherein the non-fat milk solid content is 8% by mass or more with respect to the total mass of the raw material liquid.
[4] The production method according to any one of [1] to [3], wherein the heating temperature of the heat treatment is 80 to 96 ° C. and the holding time is 1 to 10 minutes.
[5] A method for suppressing water separation of fermented milk fermented by adding lactic acid bacteria after heat treatment of a raw material solution containing a milk raw material and indigestible dextrin at a heating temperature of 80 ° C. or higher and a holding time of 1 minute or longer. It is assumed that the b * value of the raw material liquid before the heat treatment is b1 in the CIE L * a * b * color system and the b * value of the raw material liquid at the time of adding the lactic acid bacteria is b2. A method for suppressing water separation of fermented milk, wherein the heat treatment is performed so that the ratio of b2 / b1 is 1.95 or less.

According to the present invention, fermented milk containing indigestible dextrin but less likely to cause water separation can be produced.

In the present specification, the numerical range represented by "~" means a numerical range in which the numerical values before and after ~ are the lower limit value and the upper limit value.
In the present specification, the b * value in the CIE L * a * b * color system is the chromaticity (CIE L * a * b * color system) defined by the International Commission on Illumination (CIE). It is one of a * value, b * value, L * value). In the CIE L * a * b * color system, the L * axis is the brightness axis indicating brightness, and when it is close to 0, it represents black, and when it is close to 100, it represents white. The a * axis represents green to red, minus represents green, and plus represents red. The b * axis represents blue to yellow, minus represents blue, and plus represents yellow.

Fermented milk includes agitated fermented milk and static fermented milk depending on the manufacturing method. Stirring fermented milk (also called pre-fermented fermented milk) is made by fermenting fermented milk raw materials in a tank or the like, stirring and crushing the formed curd to make it fluid, and making it a product container (container for eating and drinking). ) Is filled.
In static fermented milk (also called post-fermented fermented milk), the fermented milk raw material is filled in a product container (container for eating and drinking) and then fermented, and the curd formed in the container is put on the market without stirring. The final product is fermented milk (curd) in a solid state that does not have fluidity.
The method for producing fermented milk of the present embodiment can be applied to either static fermented milk or agitated fermented milk.

<Indigestible dextrin>
The indigestible dextrin used in this embodiment is a kind of water-soluble dietary fiber obtained from starch. "Indigestible" means that it is difficult to be digested by human digestive enzymes.
For example, roasted dextrin obtained by acidifying (adding mineral acid) and / or heating plant-derived starch such as corn, wheat, barley, rice, beans, potatoes (potato, sweet potato), tapioca is required. It is a water-soluble dietary fiber that has been enzymatically treated with α-amylase and / or glucoamylase, and then desalted and decolorized as necessary, and has a characteristic of being indigestible.

Indigestible dextrin is a low-calorie, low-fat food material that has physiologically active effects such as intestinal regulation, blood sugar elevation suppression, serum cholesterol lowering, intestinal environment improvement, and triglyceride lowering. (For example, Reference 1 (Japanese Patent Laid-Open No. 2001-52064), Reference 2 (Japanese Patent Laid-Open No. 04-1591765, etc.).
For the method for producing indigestible dextrin, for example, Reference 1 and Reference 2 can be referred to. The plant-derived starch that is the raw material of the indigestible dextrin is not particularly limited, but corn starch is particularly preferable. Examples of the mineral acid at the time of acidification include hydrochloric acid, nitric acid, sulfuric acid and the like, of which hydrochloric acid is preferable.

For indigestible dextrin, high performance liquid chromatograph method, which is an analysis method of dietary fiber described in Eshin No. 13 (“Analysis method of nutritional components, etc. in nutrition labeling standards”) dated April 26, 1999. A dextrin containing an indigestible component measured by (enzyme-HPLC method), preferably a dextrin containing 85 to 95% by weight of the indigestible component, and the like are included.
For convenience, the indigestible dextrin used in the present embodiment also includes a reduced product of the indigestible dextrin produced by hydrogenation.
Indigestible dextrin and its reduced product (reduced indigestible dextrin) are commercially available in the form of powder, fine granules, granules and the like, and any form can be used.

<Manufacturing method of fermented milk>
[Preparation of raw material solution]
In the method for producing fermented milk of the present embodiment, lactic acid bacteria are added to the raw material liquid and fermented to produce fermented milk.
First, a raw material solution containing a dairy raw material and indigestible dextrin is prepared. Specifically, a raw material liquid is obtained by mixing a milk raw material, indigestible dextrin, and other components as required with water.
In the present specification, the raw material liquid means a liquid from at least one or more of a dairy raw material and a raw material other than the dairy raw material mixed until lactic acid bacteria are added.

The dairy raw material is a milk-derived raw material, and a known dairy raw material used in the production of fermented milk can be used. For example, milk, buffalo milk, sheep milk, goat milk, horse milk, defatted milk, defatted concentrated milk, defatted powdered milk, concentrated milk, whole fat powdered milk, cream, butter, butter milk, condensed milk, milk protein can be mentioned. Only one type of these may be used, or two or more types may be mixed and used.
The content of the dairy raw material is preferably 8% by mass or more, preferably 12% by mass or less, and more preferably 8 to 10% by mass, based on the total mass of the raw material liquid. When it is at least the lower limit of the above range, an appropriate milky taste is exhibited, and a good flavor can be easily obtained. When it is less than the upper limit, aggregation of milk protein due to heat sterilization is likely to be suppressed.

The content of the indigestible dextrin is preferably 2.5 to 7% by mass, more preferably 3 to 6% by mass, based on the total mass of the raw material liquid. If it is at least the lower limit of the above range, a physiological effect can be expected, and if it is at least the upper limit, a preferable flavor can be easily obtained.

The raw material liquid contains water in addition to the above dairy raw material and indigestible dextrin. Further, other components can be contained as long as the effects of the present invention are not impaired.
Other ingredients include, for example, rare sugars, fructose, psicose, allose, lactulose, sucrose and other sugars, low-calorie sweeteners, casein hydrolysates, vegetable fats, stabilizers (agar, gelatin, pectin, etc.), fragrances. , PH adjuster and the like.
Rare sugars generally refer to monosaccharides and sugar alcohols that are abundant in nature.
Examples of low-calorie sweeteners include aspartame, acesulfame K, sucralose (also known as 4,1', 6'-trichlorogalactosucrose), stevia sweeteners, saccharin, sodium saccharinate, and citrus extract.

The pH of the raw material solution at 25 ° C. is preferably 6.4 to 6.9, more preferably 6.5 to 6.7. When the pH of the raw material liquid is in the above range, aggregation is unlikely to occur when the raw material liquid is heated.

[Heat treatment]
The raw material liquid is heat-treated at least once before adding lactic acid bacteria.
The heat treatment in the present specification means a treatment in which the heating temperature is 80 ° C. or higher and the holding time is 1 minute or longer. The holding time means the time for holding at a predetermined heating temperature. The holding time does not include the temperature raising time and the temperature lowering time up to the predetermined heating temperature.
When the heat treatment conditions of the raw material liquid are a heating temperature of 80 ° C. or higher and a holding time of 1 minute or longer, browning (coloring) is likely to occur after the heat treatment and water separation after fermentation is likely to occur. Therefore, the effect of applying the present invention is effective. large.

In this embodiment, the heat treatment may be performed twice or more. For example, the temperature may be lowered after being held at a first heating temperature of 80 ° C. or higher for 1 minute or longer, and then kept at a second heating temperature of 80 ° C. or higher for 1 minute or longer. The first heating temperature and the second heating temperature may be the same or different. It is preferable that at least one of the heat treatments is a heat sterilization treatment.
If the heating temperature of the heat treatment is too high or the holding time is too long, fermentation delay and water separation are likely to occur, which is not preferable. For example, the upper limit of the heating temperature is preferably 96 ° C. or lower, more preferably 90 ° C. or lower. The upper limit of the holding time is preferably 10 minutes or less.
The lower limit of the heating temperature of the heat treatment is 80 ° C. or higher, but 85 ° C. or higher is preferable from the viewpoint of tissue formation of fermented milk.

In the present embodiment, the heating temperature and holding time of the heat treatment are such that the ratio of b2 / b1 is 1 when the b * value of the raw material liquid before the heat treatment is b1 and the b * value of the raw material liquid when the lactic acid bacteria are added is b2. Set so that it is .95 or less.
In the present specification, the term "when lactic acid bacteria are added" is a concept including immediately before, at the same time as, and immediately after the addition of lactic acid bacteria.
When browning (coloring) occurs due to the heat treatment of the raw material liquid, b2 becomes larger than b1. If the heating temperature is the same, the longer the holding time, the larger the ratio of b2 / b1 tends to be. If the holding time is the same, the higher the heating temperature, the larger the ratio of b2 / b1 tends to be.
When the ratio of b2 / b1 is 1.95 or less, the effect of suppressing water separation is excellent. The ratio of b2 / b1 is preferably 1.8 or less, more preferably 1.6 or less. The lower limit of the ratio of b2 / b1 is more than 1, and is not particularly limited. In reality, 1.1 or more is preferable.

The value of b2 is preferably 1 to 8, and more preferably 3 to 7. If it is at least the lower limit of the above range, a preferable milk flavor can be easily obtained, and if it is at least the upper limit, fermentation delay and water separation can be easily suppressed.
The value of b1 changes depending on the composition of the raw material liquid. It also changes depending on the lot of raw materials.

In the present embodiment, in addition to performing the heat treatment once or more on the raw material liquid before adding the lactic acid bacteria, heat treatment other than the heat treatment may be performed once or more, if necessary. The other heat treatment may be before or after the heat treatment.
For example, the heating step in which the holding time is less than 1 minute even when the heating temperature is 80 ° C. or higher is another heat treatment. If the heating temperature is less than 80 ° C., another heat treatment is performed even if the holding time is 1 minute or more. Other heat treatments are less likely to cause browning (coloring) after treatment.
For example, as another heat treatment, a heat sterilization treatment having a heating temperature of 90 ° C. or higher and a holding time of less than 1 minute may be performed.

It is preferable that the raw material liquid after the heat treatment and other heat treatments if necessary are cooled to the fermentation temperature in the next fermentation step. Alternatively, when it is stored in a tank or the like after heat treatment or other heat treatment, it is preferably cooled to 10 ° C. or lower.

[fermentation]
Lactic acid bacteria are added to the heat-treated raw material solution and fermented at a predetermined fermentation temperature to obtain fermented milk. Fermentation forms curds.
As the lactic acid bacterium, a known lactic acid bacterium can be used in the production of fermented milk. For example, one of the lactic acid bacteria starters commonly used in the production of fermented milk, such as Lactobacillus bulgaricus, Lactococcus lactis, S. thermophilus, or It is preferable to use two or more kinds.
The amount of lactic acid bacteria added can be appropriately adjusted within a normal range.

Since acid is produced in fermentation with lactic acid bacteria, the pH of the raw material liquid after fermentation is started decreases with time. The ultimate pH in the fermentation step is preferably 4.2 to 4.8.
The fermentation temperature is preferably, for example, 35 to 43 ° C. The fermentation time is preferably 7 hours or less, more preferably 6 hours or less. If the fermentation time exceeds 7 hours, it is not preferable in terms of production efficiency.
When the pH reaches the target value (reached pH), the mixture is cooled to 10 ° C. or lower to obtain fermented milk. The time when the temperature is cooled to 10 ° C. or lower is defined as the end of the fermentation process.

When producing static fermented milk, lactic acid bacteria are added to the raw material liquid and then filled in a product container (food and drink container) for fermentation.
When producing agitated fermented milk, after adding lactic acid bacteria to the raw material liquid, for example, ferment it in a tank, stir and crush the resulting curd, and if necessary, a stabilizer solution or food other than curd. Mix with ingredients and fill product containers (food and drink containers). Examples of food materials other than fermented milk include pulp, sauce, and jelly. The agitated fermented milk may be a solid type that is scooped up with a spoon or the like and eaten, or a drink type.

The method for producing fermented milk of the present embodiment can produce fermented milk containing indigestible dextrin and having little water separation, regardless of whether it is static fermented milk or stirring fermented milk. With less water separation, changes in appearance and flavor during storage are suppressed.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
<Measurement method>
The b * value of the raw material solution was measured using a color difference meter (product name: Color Reader CR-13, manufactured by Konica Minolta Japan Co., Ltd.). Specifically, after adjusting the temperature of the raw material liquid to 10 ° C., it was filled in a light-shielding cup, and the measuring part of the color reader was applied vertically to measure the chromaticity.

<Raw materials>
Skim milk concentrate: Made by Morinaga Milk Industry Co., Ltd.
Cream: Made by Morinaga Milk Industry Co., Ltd.
Casein hydrolyzate: The casein hydrolyzate obtained in Preparation Example 1 below.
Indigestible dextrin: Matsutani Chemical Industry Co., Ltd. Product name Fiber Sol 2.
Sucralose: Made by Saneigen FFI.
Rare sugar-containing syrup: Matsutani Chemical Industry Co., Ltd. Product name Contains rare sugar sweet, 31% by mass of D-fructose, 44% by mass of D-glucose, 6% by mass of D-psicose, and 4% by mass of D-allose.
Syrup containing lactulose: Morinaga Milk Industry Co., Ltd. Product name Contains milk oligosaccharide MLS (R) -50 and 50% by mass of lactulose.
Agar: Saneigen FFI Co., Ltd. Product name Agar UP-6.
Fragrance: Yogurt flavor, manufactured by Saneigen FFI.
Lactic Acid Bacteria Starter: YO-MIX (R), a product name of Danisco, a mixed culture of S. thermophilus and L. delbrueckii subspecies bulgaricus.
Pectin: Saneigen FFI Co., Ltd. Product name SM-MN-2779.

[Preparation Example 1]
Add 900 mg of water to 100 mg of commercially available casein (derived from milk, manufactured by New Zealand Daily Board), disperse well, add sodium hydroxide to adjust the pH of the solution to 7.0, completely dissolve the casein, and concentrate. About 10% casein aqueous solution was prepared. The obtained casein aqueous solution was sterilized by heating at 85 ° C. for 10 minutes, the temperature was adjusted to 50 ° C., sodium hydroxide was added to adjust the pH to 9.0, and then pancreatin 2 mg (manufactured by Amano Enzyme) and protease. A4 mg (manufactured by Amano Enzyme) was added to initiate a hydrolysis reaction. After 8 hours, the mixture was heated at 80 ° C. for 6 minutes to inactivate the enzyme, stop the enzyme reaction, and cool to 10 ° C.
The obtained hydrolyzate was ultrafiltered with an ultrafiltration membrane (manufactured by Nippon Paul Co., Ltd.) having a molecular weight cut off of 1000, concentrated and then freeze-dried to obtain 85 mg of casein hydrolyzate.

[Test Examples 1 to 4]
In order to investigate the causes of browning (coloring) and water separation of fermented milk when the raw material liquid containing dairy raw material and indigestible dextrin is heat-treated, solid fermented milk (stationary yogurt) with the formulation shown in Table 1 Manufactured.
Test Examples 1 and 2 are examples containing indigestible dextrin, and Test Examples 3 and 4 are examples not containing indigestible dextrin.

First, raw materials other than the lactic acid bacterium starter were mixed with a mixer to prepare a raw material liquid (70 ° C.). Then, it was heated and homogenized with a homogenizer (temperature 85 ° C., 2 seconds, pressure 20 MPa). The homogenized raw material solution (85 ° C.) was heat sterilized at 90 ° C. for 10 minutes and then cooled to 42 ° C.
Immediately after adding the lactic acid bacterium starter to the raw material liquid after cooling, the container was filled and kept at 40 ° C. for fermentation. When the pH reached 4.6, the temperature was cooled to 10 ° C. or lower to terminate the fermentation.
The time from the addition of the lactic acid bacterium starter to the end of fermentation is defined as the fermentation time (hereinafter, the same applies). The fermentation time of each example is shown in Table 1.
The obtained static yogurt was stored at 10 ° C. for 3 days and then visually observed to check for browning and water separation. The results are shown in Table 1.

As shown in the results of Table 1, the fermentation time of Test Examples 1 and 2 was longer than that of Test Examples 3 and 4, and the fermented milk was clearly browned. Further, in Test Examples 1 and 2, there was a gap between the inner wall of the container and the solid fermented milk, and water separation occurred remarkably.
From the results of Test Examples 1 to 4, it was found that indigestible dextrin causes fermentation delay and water separation.

[Examples 1 to 11]
With the formulation shown in Table 2, a stationary yogurt was produced by the same procedure as in Test Example 1. However, the conditions of heat sterilization treatment were changed as shown in Table 3.
In addition, the b * value (b1) of the raw material liquid (85 ° C. adjusted to 10 ° C.) after the homogenization treatment and before the heat sterilization treatment, and the raw material liquid (40 ° C. to 10 ° C.) when the lactic acid bacterium starter was added. The b * value (b2) of the temperature-controlled temperature) was measured, and the ratio of b2 / b1 was calculated. The results are shown in Table 3.

Evaluation (1) Fermentation delay inhibitory fermentation time is shown in Table 3. The fermentation delay inhibitory property was evaluated according to the following criteria.
〇: Fermentation time is 7 hours or less.
X: Fermentation time is over 7 hours.
(2) Inhibitory of water separation After storing the obtained static yogurt at 10 ° C. for 3 days, the inside of the container opening was visually observed from above, and a gap was formed between the inner wall of the container and the solid fermented milk. The total length R of the portion in the circumferential direction was measured. The ratio (unit:%) of the total length R in the circumferential direction to the entire circumference of the container opening was calculated and used as the degree of wall peeling. The water separation inhibitory property was evaluated according to the following criteria. The results are shown in Table 3.
⊚: The degree of wall peeling is 0%.
〇: The degree of wall peeling is more than 0% and less than 20%.
X: The degree of wall peeling is over 20%.

[Examples 12 and 13]
A stationary yogurt was produced by changing the heat treatment conditions.
Raw materials other than the lactic acid bacterium starter were mixed with a mixer according to the formulation shown in Table 2 to prepare a raw material solution (70 ° C.). Then, it was heated and homogenized by a homogenizer (temperature 80 ° C., 2 seconds, pressure 20 MPa).
In Example 12, the raw material liquid (80 ° C.) after the homogenization treatment was subjected to heat sterilization treatment (1) at 97 ° C. for 17 minutes and then cooled to 10 ° C. Then, heat sterilization treatment (2) was performed at 90 ° C. for 10 seconds, and then the mixture was cooled to 40 ° C.
In Example 13, the raw material liquid (80 ° C.) after the homogenization treatment was subjected to heat sterilization treatment (1) at 96 ° C. for 5 minutes and then cooled to 10 ° C. Then, heat sterilization treatment (2) was performed at 90 ° C. for 10 seconds, and then the mixture was cooled to 40 ° C.
In Examples 12 and 13, a lactic acid bacterium starter was added to the cooled raw material solution, filled in a container, and kept at 40 ° C. for fermentation. When the pH reached 4.6, the temperature was cooled to 10 ° C. or lower to terminate the fermentation.
The fermentation time of each example is shown in Table 4. The fermentation delay inhibitory property and water separation inhibitory property were evaluated by the above method. The results are shown in Table 4.

[Examples 14 and 15]
A stationary yogurt was produced by changing the heat treatment conditions.
Raw materials other than the lactic acid bacterium starter were mixed with a mixer according to the formulation shown in Table 2 to prepare a raw material solution (70 ° C.). Then, it was heated and homogenized by a homogenizer (temperature 80 ° C., 2 seconds, pressure 20 MPa).
In Example 14, the homogenized raw material solution (80 ° C.) was heat-sterilized (1) at 85 ° C. for 6 minutes and then cooled to 10 ° C. Next, heat sterilization treatment (2) was performed at 90 ° C. for 5 seconds, and then the mixture was cooled to 40 ° C.
In Example 15, the raw material liquid (80 ° C.) after the homogenization treatment was subjected to heat sterilization treatment (1) at 85 ° C. for 6 minutes and then cooled to 5 ° C. Next, heat sterilization treatment (2) was performed at 85 ° C. for 60 minutes, and then the mixture was cooled to 40 ° C. That is, the heat treatment at 85 ° C. or higher for 1 minute or longer was performed twice.
In Examples 14 and 15, a lactic acid bacterium starter was added to the cooled raw material solution, filled in a container, and kept at 40 ° C. for fermentation. When the pH reached 4.6, the temperature was cooled to 10 ° C. or lower to terminate the fermentation.
The fermentation time of each example is shown in Table 4. The fermentation delay inhibitory property and water separation inhibitory property were evaluated by the above method. The results are shown in Table 4.

[Example 16]
In this example, agitated fermented milk (drink yogurt) was produced.
With the composition of the raw material liquid shown in Table 5, raw materials other than the lactic acid bacterium starter were mixed with a mixer to prepare a raw material liquid (70 ° C.). Then, it was heated and homogenized by a homogenizer (temperature 85 ° C., pressure 20 MPa at 2 seconds). The homogenized raw material solution (85 ° C.) is heat sterilized (1) at 80 ° C. for 6 minutes, and then heat sterilized (2) at 121 ° C. for 2 seconds. After that, it was cooled to 40 ° C.
After adding a lactic acid bacterium starter to the cooled raw material solution, the mixture was kept at 40 ° C. in a tank and fermented until the pH reached 4.6, and cooled to 5 ° C. to complete the fermentation. Then, a pre-prepared pectin solution (5 ° C.) was added, and the mixture was stirred and mixed while crushing the fermented milk. A mixture of crushed fermented milk and a pectin solution was filled in a container to obtain a drink yogurt.
Table 6 shows the fermentation time of this example and the results of evaluating the fermentation delay inhibitory property based on the above criteria.

The obtained drink yogurt was allowed to stand at 10 ° C. for 8 days, and then the mass of water separation (supernatant portion) generated in the yogurt in the container was measured. The ratio of water separation (unit: mass%) to the total mass of drink yogurt was defined as the amount of water separation generated. The water separation inhibitory property was evaluated according to the following criteria. The results are shown in Table 6.
〇: The amount of water separation generated is 20% by mass or less.
X: The amount of water separation generated exceeds 20% by mass.

As shown in the results of Tables 3, 4 and 6, when the ratio of b2 / b1 was 1.95 or less, fermented milk containing indigestible dextrin but less likely to cause water separation was obtained.

Claims (5)

A method of obtaining fermented milk by subjecting a raw material solution containing a dairy raw material and indigestible dextrin to a heat treatment at a heating temperature of 80 ° C. or higher and a holding time of 1 minute or longer, and then adding lactic acid bacteria and fermenting the milk.
Assuming that the b * value of the raw material liquid before the heat treatment is b1 in the CIE L * a * b * color system and the b * value of the raw material liquid at the time of adding the lactic acid bacteria is b2, b2 / b1 A method for producing fermented milk, wherein the heat treatment is performed so that the ratio is 1.95 or less. The production method according to claim 1, wherein the content of the indigestible dextrin is 2.5 to 7% by mass with respect to the total mass of the raw material liquid. The production method according to claim 1 or 2, wherein the non-fat milk solid content is 8% by mass or more with respect to the total mass of the raw material liquid. The production method according to any one of claims 1 to 3, wherein the heating temperature of the heat treatment is 80 to 96 ° C. and the holding time is 1 to 10 minutes. This is a method of suppressing water separation of fermented milk fermented by adding lactic acid bacteria after heat treatment of a raw material solution containing a dairy raw material and indigestible dextrin at a heating temperature of 80 ° C. or higher and a holding time of 1 minute or longer. ,
Assuming that the b * value of the raw material liquid before the heat treatment is b1 in the CIE L * a * b * color system and the b * value of the raw material liquid at the time of adding the lactic acid bacteria is b2, b2 / b1 A method for suppressing water separation of fermented milk, wherein the heat treatment is performed so that the ratio is 1.95 or less.