WO2013039188A1

WO2013039188A1 - Low calorie yogurt and method for producing same

Info

Publication number: WO2013039188A1
Application number: PCT/JP2012/073583
Authority: WO
Inventors: 堀内　啓史; 暢子井上
Original assignee: 株式会社明治
Priority date: 2011-09-15
Filing date: 2012-09-14
Publication date: 2013-03-21
Also published as: IN2014CN02133A; SG11201400553QA; CN103781361B; HK1192118A1; CN103781361A; JPWO2013039188A1; JP6110301B2

Abstract

The purpose of the present invention is to provide a method for producing fermented milk using a raw milk of low butterfat content, wherein the present invention provides a low calorie and good flavored yogurt in which water separation is suppressed without the addition of a stabilizer, and provides a method for producing the yogurt. This purpose is achieved by the method for producing a low calorie yogurt, the method including a deoxygenation processing step for reducing the concentration of dissolved oxygen in the raw milk, and a lactose degradation step for adding lactase to degrade the lactose in the raw milk, preferably at a specified ratio of alpha-lactoalbumin and/or beta-lactoglobulin in the raw milk.

Description

Low calorie fermented milk and method for producing the same

The present invention relates to a low-calorie fermented milk and a method for producing the same.

Fermented milk is a health food that is widely eaten in general. In recent years, demand for low-calorie fermented milk has also increased. However, fermented milk with low milk fat content tends to impair the original flavor and texture of fermented milk. Until now, the method of improving the milk fat feeling of low-fat fermented milk by deoxygenating raw material milk is disclosed (patent document 1).

On the other hand, fermented milk undergoes water separation (whey-off) during refrigerated storage and the like, which also causes problems in product quality. For this reason, it is common to add stabilizers such as gelatin in order to suppress the water separation of fermented milk, and other methods for adding milk protein and whey protein concentrates are also known. (Patent Documents 2 to 4). In addition, Patent Document 5 discloses a method for producing fermented milk that performs lactose decomposition treatment and deoxygenation treatment. However, it is a method for making the flavor of fermented milk constant, and describes the water separation suppression of fermented milk. It has not been.

Japanese Patent No. 3968108 Japanese Patent Publication No. 3-52940 Japanese Unexamined Patent Publication No. 3-19838 Japanese Patent No. 2966330 WO2010 / 098086

In fermented milk with a low milk fat content, water separation is particularly likely to occur, and when a general milk protein or whey protein concentrate (whey protein concentrate (WPC), whey protein isolate (WPI)) is added. In some cases, the flavor of fermented milk may decrease. Moreover, even if a stabilizer such as gelatin is added, the original flavor and texture of fermented milk are impaired.

Therefore, an object of the present invention is to solve the above-mentioned problems in the prior art in a method for producing fermented milk using raw milk with a low milk fat content, suppress water separation without adding a stabilizer, and have a good flavor. It is in providing a certain low calorie fermented milk and its manufacturing method.

In order to solve the above-mentioned problems, the inventors of the present invention have reduced the dissolved oxygen concentration of raw milk and decomposed lactose in raw milk with lactose-degrading enzyme, while reducing the amount of milk fat. It has been found that the water separation of fermented milk is greatly suppressed. Further, by blending α-lactalbumin (α-La) and / or β-lactoglobulin (β-Lg) at a predetermined ratio, water separation is further suppressed and fermented milk having a strong curd can be obtained. As a result of further finding out and further research, the present invention has been completed.

That is, this invention relates to the following low-calorie fermented milk and its manufacturing method.
[1] A method for producing fermented milk having a low fat content, the method comprising reducing the dissolved oxygen concentration of raw material milk at the start of fermentation, and adding lactose-degrading enzyme into the raw material milk before starting fermentation .
[2] The method according to [1], wherein the low-fat fermented milk has a milk fat content of 0.01 to 2% by weight.
[3] The method according to [1] or [2], wherein the dissolved oxygen concentration of the raw material milk at the start of fermentation is 5 ppm or less.
[4] The method according to any one of [1] to [3], wherein the raw milk contains a high concentration of α-lactalbumin or β-lactoglobulin.
[5] The method according to [4], wherein the concentration of α-lactalbumin or β-lactoglobulin is 0.5 to 1.5% by weight in the raw material milk.
[6] The method according to any one of [1] to [5], wherein the raw milk has a total protein amount of 3 to 6% by weight and / or a total solid content of 8 to 11% by weight.
[7] The method according to any one of [1] to [6], wherein lactose decomposition is performed during fermentation.
[8] The method according to any one of [1] to [7], wherein the lactose decomposition rate is 75 to 90%.
[9] The method according to any one of [1] to [8], wherein no stabilizer is added.
[10] Fermented milk produced by the method according to any one of [1] to [10].
[11] Fermented milk without stabilizers having a centrifugal water separation of 50 to 10%, a hardness of 30 to 70 g, and a total calorie of 50 kcal / 100 g or less.
[12] The fermented milk according to [11], having a milk fat content of 0.01 to 2% by weight, a total protein content of 3 to 6% by weight, and a total solid content of 8 to 11% by weight.
[13] The fermented milk according to [11] to [12], which has a lactose content of 0.01 to 1% by weight.

The method for producing fermented milk of the present invention can suppress water separation of fermented milk without adding (compounding) a stabilizer or the like even when raw milk having a low total solid content and milk fat content is used. Further, by blending α-lactalbumin and / or β-lactoglobulin at a predetermined ratio, water separation is further suppressed and fermented milk having a strong curd can be obtained. Therefore, the fermented milk of the present invention has excellent storage stability and is suitable for long-distance transportation.

In the method for producing fermented milk of the present invention, lactose in the raw material milk is decomposed by lactose-degrading enzyme, so that the fermented milk is not only sweetened but also the fermentation process is stabilized. Therefore, the flavor and quality of fermented milk can be made constant, and low-calorie fermented milk with little water separation can be provided stably. Furthermore, the flavor and texture derived from the original milk fat of fermented milk can be obtained by using the production method of fermenting by reducing the dissolved oxygen concentration of the raw milk, even if low-fat raw material milk is used.

In addition, the method for producing fermented milk of the present invention has a high content of α-lactalbumin or β-lactoglobulin in the total protein of raw milk, and therefore a general milk protein or whey protein concentrate (WPC, WPI) Unlike the case of adding etc., there is little influence on the flavor of fermented milk such as miscellaneous taste. By adopting WPC having a higher α-lactalbumin content or β-lactoglobulin content than a general whey protein concentrate (WPC, WPI), for example, the WPC has a protein content of 80% or less. Even if it mix | blends with raw material milk, the strong fermented milk of a card | curd can be stably manufactured using the concentrate of whey protein as a milk component on the description of a product here.

Therefore, the method for producing fermented milk of the present invention can efficiently improve the quality of fermented milk having a low milk fat content, has a good flavor, and has a low calorie fermented milk having a low total solid content and a low fat content. Can be provided.

The method for producing fermented milk of the present invention includes a step of reducing the dissolved oxygen concentration in raw material milk (deoxygenation treatment step), and a step of degrading lactose in raw material milk by a lactose-degrading enzyme (lactose decomposition step), Preferably, α-lactalbumin (α-La) and / or β-lactoglobulin (β-Lg) is contained in the raw milk in a predetermined ratio.

As used herein, “fermented milk” includes “fermented milk” defined by a ministerial ordinance (Ministerial Ordinance on Milk, etc.) regarding ingredient standards of milk and dairy products. For example, fermented milk can be raw milk, milk, special milk, raw goat milk, pasteurized goat milk, raw noodle milk, ingredient-adjusted milk, low-fat milk, non-fat milk, processed milk, etc. Milk or the like containing milk solids is fermented with lactic acid bacteria or yeast to form paste or liquid, or those frozen. These include a variety of yogurts, but are typically set-type yogurts herein.

Generally, a set type yogurt such as plain yogurt is manufactured by filling a raw material milk in a container and then fermenting it (post-fermentation). On the other hand, soft yogurt and drink yogurt are manufactured by filling fermented fermented milk into a container (pre-fermentation) after atomization or homogenization.

Raw milk “Raw milk” is a raw material for fermented milk such as yogurt, and is also called yogurt mix or fermented milk mix. In the present invention, known raw material milk can be appropriately used. The raw milk includes those before sterilization and those after sterilization. Specific materials (raw materials) of raw material milk may include water, raw milk, pasteurized milk, skim milk, whole milk powder, skim milk powder, butter milk, butter, cream and the like.

The production method of the present invention can be applied to the production of ordinary fermented milk, but is particularly suitable for producing low-calorie fermented milk, and the raw material milk used in this case is preferably low-fat milk. In order to obtain an appropriate hardness (card tension), it is preferable to have a predetermined total protein amount. The low calorie fermented milk of the present invention is mainly due to low total solids and low fat.
Although the raw material milk used for the manufacturing method of this invention is not specifically limited, It is preferable to have the following components. In this specification,% means weight% (w / w).

The milk fat content in the raw milk is desirably 3% or less, preferably 0.01 to 2%, more preferably 0.05 to 1%, and still more preferably 0.1 to 0.5%.
The total solid content in the raw milk is desirably 11% or less, preferably 8 to 11%, more preferably 8.5 to 10.5%, and further preferably 9 to 10.2%.
The total amount of protein in the raw milk is desirably 3 to 6%, more preferably 3.5 to 5.5%, still more preferably 4 to 5%.
The lactose content in the raw milk is desirably 5 to 8%, more preferably 5.5 to 7.5%, and further preferably 6 to 7%.

Whey protein may be added (blended) to the raw milk used in the production method of the present invention, and a whey protein concentrate having a high α-lactalbumin content or β-lactoglobulin content is preferably used.
As used herein, the “whey protein concentrate” includes a whey protein concentrate (Whey Protein Concentrate) obtained by concentrating main protein of whey and the like by ultrafiltration (UF) method and the like and then drying. "WPC"), degreased WPC (low-fat, high-protein), whey that has been subjected to drying treatment after removing fat by microfiltration (MF) method or centrifugation method, and then concentrated by UF method Whey Protein Isolate (“WPI”), nanofiltration (NF) method, and electrodialysis Demineralized whey that has been desalted by the desalting method, etc., and the mineral concentration that has been concentrated by centrifugation, etc. Includes reduced whey. Major “whey proteins” include α-lactalbumin (α-La), β-lactoglobulin (β-Lg), and the like.

In the present invention, whey protein concentrate (WPC) or whey protein isolate (WPI) having a high α-lactalbumin content or β-lactoglobulin content is preferably used, and more preferably α-lactalbumin content or β-lacto A high globulin content whey protein concentrate (WPC) is used. These may use a plurality of types simultaneously.

Α-Lactalbumin, whey protein having a high α-lactalbumin content, β-lactoglobulin, and a whey protein having a high β-lactoglobulin content can be obtained, for example, by a method of selectively separating from whey. Examples of such separation methods include ion exchange chromatography, hydrophobic chromatography, gel filtration, ultrafiltration, isoelectric point separation, coprecipitation with a polymer electrolyte, salting out, temperature treatment separation, etc. This technique is also disclosed in Japanese Patent Application Laid-Open Nos. 7-203863, 61-268138, and 63-39545.

In addition, α-lactalbumin (α-La) and β-lactoglobulin (β-Lg) itself are commercially available, and WPC and WPI having a high content thereof are also commercially available. For example, α-La rich WPC (Domo), β-Lg rich WPC (Domo), α-Larich WPC (Davisco), β-Lrich WPC (Davisco), α-La rich WPC (manufactured by Leprino Foods), β-Lg rich WPC (manufactured by Leprino Foods), ALACEN WPI 895 (manufactured by Fonterra) or the like may be used. Here, the total protein of WPC such as α-La rich WPC or β-Lg rich WPC and WPI preferably has an α-lactalbumin content of 60-100%, more preferably 80-95%, or preferably Those having a β-lactoglobulin content of 65 to 100%, more preferably 80 to 95% can be suitably used. Further, α-lactalbumin and β-lactoglobulin itself, or a combination of these WPC and WPI can also be used.
The protein content is preferably 30 to 95%, more preferably 35 to 80%, still more preferably 65 to 75% in the total solid content of WPC and WPI such as α-La rich WPC or β-Lg rich WPC. Can be preferably used.

In the method for producing fermented milk of the present invention, the raw milk preferably contains a high concentration of α-lactalbumin or β-lactoglobulin.
It is desirable that α-lactalbumin is contained in the total protein of the raw milk at a ratio of 7% or more, preferably 12 to 40%, more preferably 17 to 25%. Further, it is desirable that the whole raw milk is contained at a ratio of 0.3% or more, preferably 0.5 to 1.5%, more preferably 0.7 to 1%.
It is desirable that β-lactoglobulin is contained in the total protein of the raw milk in a proportion of 10% or more, preferably 12 to 40%, more preferably 15 to 25%. In addition, the whole raw milk is desirably contained at a ratio of 0.4% or more, preferably 0.5 to 1.5%, more preferably 0.6 to 1%.

In the method for producing fermented milk of the present invention, the raw milk preferably contains α-La rich WPC or β-Lg rich WPC.
The blending amount of α-La rich WPC into raw milk varies depending on the content of α-La in α-La rich WPC, but it is desirable that the whole raw milk is contained at a ratio of 0.5% or more. Preferably it is 0.6 to 2%, more preferably 0.75 to 1.5%.
The blending amount of β-Lg rich WPC into raw material milk varies depending on the content of β-Lg in β-Lg rich WPC, but it is desirable that the total amount of raw material milk is 0.55% or more. Preferably it is 0.65 to 2%, and more preferably 0.8 to 1.5%.

In the case where the concentration of α-lactalbumin or β-lactoglobulin is within a preferable range, a water separation inhibiting effect can be expected. As these concentrations increase, the hardness tends to increase. In addition, in these preferable ranges, miscellaneous taste is hardly generated.
As used herein, the term “water separation” includes a phenomenon in which a whey liquid separates, and can be measured, for example, by a centrifugal water separation rate obtained by centrifugation.

The raw material milk is homogenized and sterilized, and then cooled to a predetermined temperature (about the fermentation temperature). Next, a starter is inoculated, and in the case of pre-fermentation, filling is started in a tank or the like to start fermentation, and in the case of post-fermentation, filling is started in a personal food container for distribution or the like to start fermentation.
Further, a stabilizer or the like may be added. However, in the method for producing fermented milk of the present invention, since the curd is strong and fermented milk that is difficult to be removed can be obtained without adding a stabilizer or the like. Is preferably not added. In the present specification, the term “stabilizer” means a stabilizer generally used for fermented milk such as gelatin, pectin, agar, starch, carboxymethylcellulose, carrageenan, and thickening polysaccharides such as xanthan gum.

Deoxygenation process The deoxygenation process is a process for removing oxygen present in raw milk. As a method for reducing the dissolved oxygen concentration in the raw milk, for example, a method by gas replacement treatment with an inert gas, a membrane separation method using a deoxygenation membrane, a method of degassing at a low pressure or vacuum, etc. may be used. it can. In the deoxygenation treatment step, for example, deoxygenation may be carried out until the amount of oxygen dissolved in the raw milk (dissolved oxygen concentration, DO) is 5 ppm or less, preferably 3 ppm or less, more preferably 2 ppm or less.

The lower the concentration of dissolved oxygen in raw milk at the start of fermentation, the better. For example, when the temperature of the raw milk is about 40 ° C., it is preferably 5 ppm or less, more preferably 3 ppm or less. Since the fermentation time is shortened by lowering the dissolved oxygen concentration, even when the fermentation temperature is lowered, the fermentation time is set to a relatively short range of 3 to 7 hours, and the fermentation is performed. be able to. These deoxygenation treatment steps are also described in Japanese Patent Nos. 3666871, 3644505 and 3968108.

The deoxygenation treatment step may be performed during the stage of preparing raw milk, after homogenization and sterilization, and after the start of fermentation such as after adding a starter. However, since it is important that the dissolved oxygen concentration is maintained in a reduced state at the start of fermentation, the deoxygenation treatment step is desirably performed immediately before, immediately after, or simultaneously with the addition of the starter.

When performing a gas replacement process (inert gas replacement) with an inert gas, typically, nitrogen gas is used as an inert gas normally used in foods. In addition to nitrogen gas or the like, a rare gas such as helium, neon, argon, or xenon may be used as the inert gas. As a method for replacing dissolved oxygen with an inert gas, a known method such as a method of directly bubbling the inert gas into the mix, a method using a static mixer, or a gas mixed in the mixer with the mix is used. be able to. Inert gas replacement can be performed even after the starter is added, and there are few process restrictions compared to methods such as membrane separation.

When performing a membrane separation method (deoxygenation membrane gas replacement) using a deoxygenation membrane, a hollow fiber membrane (Mitsubishi Rayon MHF304KM) or the like can be used as the deoxygenation membrane. The method of using such a deoxygenating film may be based on the conventional method of use, and the deoxygenating film gas replacement can be performed before applying the starter by applying to the raw milk.
Further, instead of using an inert gas or using a deoxygenation film, oxygen dissolved in the raw material milk may be removed by deaeration. Such a deaeration device is also disclosed in Japanese Patent Application Laid-Open No. 2002-370006 or Japanese Patent Application Laid-Open No. 2005-304390.

Fermentation process In order to ferment lactic acid fermentation of raw material milk in which the dissolved oxygen concentration is reduced, a starter is blended (mixed) with the raw material milk for fermentation. As these starters, known starters can be used as appropriate, and lactic acid bacteria starters are preferable. And as a lactic acid bacteria starter, Lactobacillus bulgaricus (L.bulgaricus), Streptococcus thermophilus (S.thermophilus), Lactobacillus lactis (L.lactis), Lactobacillus gasseri (L.gasseri) or Bifidobacterium In addition to um (Bifidobacterium), one or more of lactic acid bacteria, bifidobacteria, and yeasts commonly used in the production of fermented milk can be used.

Of these starters, a starter based on a mixed starter of Lactobacillus bulgaricus (L. bulgaricus) and Streptococcus thermophilus (S. thermophilus), which is standardized as a yogurt starter in the Codex standard, is more preferable. Based on this yogurt starter, depending on the actual fermented milk to be obtained, other lactic acid bacteria and bifidobacteria such as Lactobacillus gasseri (L. gasseri) and Bifidobacterium are added (mixed) May be. What is necessary is just to employ | adopt suitably the quantity etc. which are employ | adopted in the manufacturing method of well-known fermented milk as the addition amount of a starter. The addition (inoculation) of the starter may be performed according to a known method generally used for producing fermented milk.

In the present invention, the starter can be fermented with the addition amount of the starter being lower than the addition amount of a normal starter. The normal starter addition amount, which is the standard for the starter addition amount, is a raw material milk (yogurt mix) that has not been subjected to a deoxygenation treatment process (treatment for reducing the dissolved oxygen concentration), and a fermentation temperature of 43 ° C., This is the amount of starter used when fermentation is performed to give 0.7% in terms of lactic acidity with a fermentation time of 3 hours, and the quantity is expressed as 100%. Specifically, under normal fermentation conditions, the addition amount of the starter is about 2% with respect to the total amount of the raw material milk, whereas the addition amount of the starter in the present invention is about 0.2% with respect to the total amount of the raw material milk. It is 5 to 1.0%, and is about 25 to 50% of the usual starter addition amount.

Lactose decomposition step The lactose decomposition step is a step in which lactose is decomposed by a lactose decomposing enzyme (lactase). In principle, lactose-degrading enzyme may be added at any stage of the production process. For example, from the viewpoint of reducing the risk of bacterial contamination, the raw milk can be kept at a low temperature, and lactose can be decomposed and then heat sterilized to deactivate the enzyme before fermentation can proceed. On the other hand, after heat-sterilizing raw material milk, a starter and a lactose-degrading enzyme may be mixed (mixed) and fermentation may proceed in a state where the enzyme has activity. Then, fermentation of the raw milk progresses, lactose is decomposed into lactic acid to produce an acid, and the enzyme may be deactivated as the pH value decreases. By performing such treatment, the lactose decomposition rate can be effectively increased.

In addition, when mixing starter and lactose-degrading enzyme into raw milk and fermenting it, it is not necessary to advance the enzymatic reaction before heat-sterilizing the raw milk, so the production process of fermented milk can be simplified, You will be able to make the most of the original flavor of fermented milk. Furthermore, by performing such a treatment, the lactose decomposition rate can be effectively increased, so it is not necessary to keep managing the lactose decomposition rate and the degree of fermentation (change in acidity) individually. Management becomes extremely easy.

Therefore, in the present invention, it is preferable to add (blend) the lactose-degrading enzyme to the raw milk together with the starter, but there is no particular limitation. Even if it is added to the raw milk before adding the starter, the starter is added. It may be added to the raw milk at the same time or after adding the starter. When using raw milk mixed with lactose-degrading enzyme and starter, lactose in the raw milk is decomposed as the fermentation process progresses. Further, the lactose-degrading enzyme may be added to the raw milk before the deoxygenation treatment step, or may be added to the raw milk after the deoxygenation treatment step. Such a lactose decomposition step is also disclosed in WO2010 / 098086.

The lactose-degrading enzyme of the present invention is preferably an enzyme that has an optimum pH of activity in a neutral region and deactivates in an acidic region, and can decompose lactose in an active state. Examples of lactose-degrading enzymes include those derived from bacteria or yeast. The optimum pH for activity is 6.3 to 7.5 or less, and the deactivation pH is 6 to 4. The lactose-degrading enzyme is preferably a lactose-degrading enzyme derived from Kluyveromyces lactis or a lactose-degrading enzyme derived from Kluyveromyces fragilis. Lactose-degrading enzymes derived from Kluyveromyces lactis include not only Kluyveromyces lactis itself but also lactose-degrading enzymes derived from Kluyveromyces lactis. Lactose-degrading enzymes are commercially available. Examples of commercially available lactose-degrading enzymes include lactase F (manufactured by Amano Enzyme), lactres L-3 (manufactured by Yamato Kasei), and lactres L-10 (Yamato Kasei). And lactase (GODO-YNL, manufactured by Godo Shusei Co., Ltd.).

The lactose decomposition rate is not limited, but may be 65% or more, preferably 75 to 90%, more preferably 80 to 90%. Further, lactose-degrading enzyme may be added to raw milk so as to correspond to 5 U / g or more, preferably 7 to 20 U / g, more preferably 10 to 15 U / g. When the lactose decomposition rate is low, the effects of the present invention such as the effect of improving the water separation rate tend not to be sufficiently obtained.

Fermentation conditions and lactose decomposition conditions Generally, fermentation conditions such as fermentation temperature and fermentation time are prepared in consideration of the type of lactic acid bacteria added to the raw milk and the flavor of fermented milk that is actually required. The temperature in the fermentation chamber (fermentation temperature) is maintained at about 30-50 ° C.
In the method for producing fermented milk of the present invention, it can be fermented at a relatively low temperature, preferably 30 to 39 ° C., more preferably 32 to 38 ° C., still more preferably 34 to 37 ° C. .

On the other hand, when using a starter of about 25 to 50% of the normal starter addition amount (that is, 0.5 to 1.0% based on the total amount of raw milk), it is about the same as the normal fermentation temperature. Fermentation may be performed at 38 to 46 ° C, preferably 38 to 45 ° C, more preferably 39 to 43 ° C.
When this method is adopted, it can be fermented at the usual fermentation temperature, so that the temperature in the fermentation chamber can be easily controlled in the same way as normal products, and there are risks such as propagation of various bacteria. There is also an advantage that can be reduced.

Fermentation time can be the time until the lactic acid acidity of fermented milk reaches about 0.7%. In the production method of the present invention, the fermentation time is preferably 3 to 7 hours, more preferably 3 to 5 hours. At this time, the lactic acid acidity can be calculated by titration using NaOH or a phenolphthalein indicator.

Even when lactose in raw milk is degraded before fermentation, lactose decomposition may be performed at 0 to 55 ° C., where the lactose degrading enzyme maintains activity, preferably 30 to 50 ° C., more preferably 35 ~ 45 ° C. The condition of lactose decomposition can be achieved by maintaining a suitable temperature of general lactose decomposing enzyme at 35 to 45 ° C. for 1 hour or longer.

Fermented milk Even if the fermented milk obtained by the production method of the present invention has a low total solid content and a low fat content, the curd is strong and difficult to separate. Adjustment of components such as milk fat content and protein amount of fermented milk can be achieved by adjusting the blending ratio of skim milk powder and whey protein in raw material milk. The fermented milk of the present invention is not particularly limited, but preferably has the following characteristics.

The centrifugal water separation rate of the fermented milk of the present invention is desirably 60% or less, preferably 50 to 10%, more preferably 40 to 15%.
The hardness of the fermented milk of the present invention is desirably 30 g or more, preferably 30 to 70 g, and more preferably 40 to 60 g.
The total calories (kcal / 100 g) of the fermented milk of the present invention is desirably 50 kcal / 100 g or less, preferably 15 to 45 kcal / 100 g, and more preferably 20 to 40 kcal / 100 g.
The term “low calorie” as used herein includes 50 kcal / 100 g or less. Therefore, the low-calorie fermented milk of the present invention can be 50 kcal / 100 g or less, 45 kcal / 100 g or less, or 40 kcal / 100 g or less.

The centrifugal water separation rate can be determined by measuring a ratio (% by weight) of a supernatant (whey) separated by centrifuging fermented milk. For example, it is obtained by centrifuging at 3000 rpm (2150 × g) for 10 minutes at room temperature. Further, the hardness (card tension: CT) can be measured by a general apparatus such as Neo Card Meter ME305 (manufactured by I-Techno Engineering Co., Ltd.), and the total calories are generally determined from the numerical values of each nutritional component. It can be calculated by the method.

The milk fat content of the fermented milk of the present invention is desirably 3% or less, preferably 2% or less, more preferably 1% or less, and most preferably less than 0.5%. The preferred range is 0.01 to 2%, more preferably 0.05 to 1%, and still more preferably 0.1 to 0.5%.
The total solid content of the fermented milk of the present invention is desirably 11% or less, preferably 10.5% or less, more preferably 10.2% or less, and most preferably 10% or less. The preferred range is 8 to 11%, more preferably 8.5 to 10.5%, and still more preferably 9 to 10.2%.
The total protein content of the fermented milk of the present invention is desirably 3 to 6%, more preferably 3.5 to 5.5%, and further preferably 4 to 5%.
The lactose content of the fermented milk of the present invention is desirably 0.01 to 1%, more preferably 0.05 to 0.8%, and still more preferably 0.1 to 0.5%.
The pH of the fermented milk of the present invention is desirably 4 to 5, more preferably 4.3 to 4.8, and still more preferably 4.5 to 4.7.

The fermented milk of the present invention preferably has a high α-lactalbumin content or β-lactoglobulin content, and the content of these proteins regulates the α-lactalbumin content and / or β-lactoglobulin content in the raw milk. Can be obtained.

It is desirable that α-lactalbumin is contained in the total protein of fermented milk at a ratio of 7% or more, preferably 12 to 40%, more preferably 17 to 25%. Further, it is desirable that the whole fermented milk is contained at a ratio of 0.3% or more, preferably 0.5 to 1.5%, and more preferably 0.7 to 1%.
It is desirable that β-lactoglobulin is contained in the total protein of the fermented milk in a proportion of 10% or more, preferably 12 to 40%, more preferably 15 to 25%. Further, it is desirable that the whole fermented milk is contained at a ratio of 0.4% or more, preferably 0.5 to 1.5%, and more preferably 0.6 to 1%.

The fermented milk of the present invention preferably does not contain a stabilizer. Moreover, it is preferable not to add a sweetener etc., However, You may add as needed before fermentation or after fermentation.

The present invention will be described in detail by the following examples, but the present invention is not limited to the examples.

The raw materials used are shown below.
Non-fat dry milk (manufactured by Meiji Co., Ltd.), WPC34 (manufactured by Leprino Foods), and β-Lgrich WPC75 (manufactured by Leprino Foods) were used. In β-Lg rich WPC75, the main component of protein is β-Lg, and β-Lg is contained in about 80% in the protein, and whey protein such as α-La is contained in about 20%.
As the lactose-degrading enzyme, lactase (GODO-YNL, 10,000 U / g, manufactured by Godo Shusei Co., Ltd.) was used.
Lactobacillus bulgaricus bacteria and Streptococcus thermophilus bacteria isolated from Meiji Bulgaria yogurt were used as lactic acid bacteria starters (manufactured by Meiji Co., Ltd.).
The card tension was measured using a Neo Card Meter ME305 (manufactured by iTechno Engineering).

Example 1
Non-fat dry milk: 90.7 g, WPC34: 13.5 g, tap water: 895.8 g were mixed to prepare raw material milk used for producing fermented milk.
The obtained raw milk was heated (sterilized) at 95 ° C. for 5 minutes and then cooled to about 38 ° C. After the raw milk is cooled, lactase (GODO-YNL, manufactured by Godo Sakesei Co., Ltd.) is added at 0.1% by weight, and lactic acid bacteria starter (produced by Meiji Co., Ltd., separated from Meiji Bulgaria yogurt) is added at 2% by weight. Vaccinated. Thereafter, nitrogen gas was blown through the pipe to adjust the dissolved oxygen to 4 ppm or less. In addition, before sterilizing raw material milk, lactase can be added and it is made to carry out an enzymatic reaction, lactose can be decomposed | disassembled, and lactic acid fermentation can also be performed.

Next, the raw material milk containing lactase and lactic acid bacteria starter is filled into a cup container (capacity: 100 g, made of plastic) and left to stand in the fermentation chamber (38 ° C.) until the lactic acid acidity reaches 0.7%. Fermented. Then, it cooled in the refrigerator compartment (10 degrees C or less), and the set type yogurt (fermented milk) was manufactured.
The obtained fermented milk (total solid content: 10.0 wt%, fat content: 0.1 wt%, 40 kcal / 100 g) has a hardness (card tension) of 35 g and a centrifugal water separation rate (3000 rpm (2150 × g) 10 minutes, room temperature) was 35%.

Example 2
Non-fat dry milk: 86.3 g, β-Lg rich WPC75: 4.4 g, WPC34: 13.5 g, tap water: 874.8 g were mixed to prepare raw material milk used for producing fermented milk.
The obtained raw milk was heated (sterilized) at 95 ° C. for 5 minutes and then cooled to about 38 ° C. After the raw milk is cooled, lactase (GODO-YNL, manufactured by Godo Sakesei Co., Ltd.) is added at 0.1% by weight, and lactic acid bacteria starter (produced by Meiji Co., Ltd., separated from Meiji Bulgaria yogurt) is added at 2% by weight. Vaccinated. Thereafter, nitrogen gas was blown through the pipe to adjust the dissolved oxygen to 4 ppm or less. In addition, before sterilizing raw material milk, lactase can be added and it is made to carry out an enzymatic reaction, lactose can be decomposed | disassembled, and lactic acid fermentation can also be performed.

Next, the raw material milk containing lactase and lactic acid bacteria starter is filled into a cup container (capacity: 100 g, made of plastic) and left to stand in the fermentation chamber (38 ° C.) until the lactic acid acidity reaches 0.7%. Fermented. Then, it cooled in the refrigerator compartment (10 degrees C or less), and the set type yogurt (fermented milk) was manufactured.
The obtained fermented milk (total solid content: 10.0 wt%, fat content: 0.1 wt%, 40 kcal / 100 g) has a hardness (card tension) of 50 g and a centrifugal water separation rate (3000 rpm (2150 × g) 10 minutes, room temperature) was 25%.

Furthermore, this fermented milk (total solid content: 10.0% by weight, fat content: 0.1% by weight, 40 kcal / 100 g) is manufactured in an actual manufacturing process (factory), and a cup container (capacity: 450 g, made of paper) When 700 pcs were filled and 1300 km was transported by a refrigerated car (truck), the card did not collapse, the water separation (whey-off) was small, and a commercial product (total solid content: 12.5% by weight, fat content: 3.0% by weight) or less.

From the above results, it was shown that the fermented milk of the present invention not only suppresses water separation but also does not collapse even when impacted by long-distance transportation, and the quality of the fermented milk is stable. It was also shown that the centrifugal water separation rate was further improved by adjusting the concentration of β-lactoglobulin.

Comparative Example 1
Non-fat dry milk: 90.7 g, WPC34: 13.5 g, tap water: 895.8 g were mixed to prepare raw material milk used for producing fermented milk.
The obtained raw milk was heated (sterilized) at 95 ° C. for 5 minutes and then cooled to about 43 ° C. Then, after the raw milk was cooled, lactic acid bacteria starter (manufactured by Meiji Co., Ltd., separated from Meiji Bulgaria yogurt) was inoculated at 2% by weight.

Next, the raw milk containing the lactic acid bacteria starter was filled into a cup container (capacity: 100 g, made of plastic), and allowed to stand and fermented in the fermentation chamber (43 ° C.) until the lactic acid acidity reached 0.7%. . Then, it cooled in the refrigerator compartment (10 degrees C or less), and the set type yoghurt (fermented milk) (control article) was manufactured.
The obtained fermented milk (total solid content: 10.0 wt%, fat content: 0.1 wt%, 40 kcal / 100 g) has a hardness (card tension) of 50 g and a centrifugal water separation rate (3000 rpm (2150 × g)). 10 minutes, room temperature) was 65%.

From the above results, the method for producing fermented milk of the present invention greatly improves the water separation rate of fermented milk with a low fat content at 45% or more without adding a stabilizer, and adjusts the concentration of β-lactoglobulin. It was shown that the improvement was further improved by 60% or more.

The present invention relates to a low-calorie fermented milk and a method for producing the same, and can provide fermented milk in which the curd is not broken even by impact during transportation and the occurrence of water separation is suppressed.

Claims

A method for producing low-fat fermented milk, which comprises reducing the dissolved oxygen concentration of raw milk at the start of fermentation and adding lactose-degrading enzyme into the raw milk before the start of fermentation.
The method according to claim 1, wherein the low-fat fermented milk has a milk fat content of 0.01 to 2% by weight.
The method according to claim 1 or 2, wherein the dissolved oxygen concentration of the raw material milk at the start of fermentation is 5 ppm or less.
The method according to any one of claims 1 to 3, wherein the raw milk contains a high concentration of α-lactalbumin or β-lactoglobulin.
The method according to claim 4, wherein the concentration of α-lactalbumin or β-lactoglobulin is 0.5 to 1.5% by weight in the raw material milk.
The method according to any one of claims 1 to 5, wherein the raw milk has a total protein content of 3 to 6% by weight and / or a total solid content of 8 to 11% by weight.
The method according to any one of claims 1 to 6, wherein lactose decomposition is performed during fermentation.
The method according to any one of claims 1 to 7, wherein the lactose decomposition rate is 75 to 90%.
The method according to any one of claims 1 to 8, wherein no stabilizer is added.
10. Fermented milk produced by the method according to any one of claims 1 to 9.
Fermented milk without stabilizers, having a centrifugal water separation of 50-10%, a hardness of 30-70 g, and a total calorie of 50 kcal / 100 g or less.
The fermented milk according to claim 11, having a milk fat content of 0.01-2% by weight, a total protein content of 3-6% by weight, and a total solid content of 8-11% by weight.
The fermented milk according to claim 11 or 12, which has a lactose content of 0.01 to 1% by weight.