HK1192118B - Low calorie yogurt and method for producing same - Google Patents

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 same

Technical Field

The invention relates to low-calorie fermented milk and a preparation method thereof.

Background

Fermented milk is a health food which is widely and generally consumed, and the demand for low-calorie fermented milk has been increasing in recent years. However, a fermented milk with a small amount of milk fat tends to lose the original flavor and mouthfeel of the fermented milk. A method for improving the creaminess of a fermented milk with a low fat content by subjecting a raw milk to a deoxidation treatment has been disclosed (patent document 1).

On the other hand, problems in product quality arise due to dehydration (whey separation) of the fermented milk during cold storage or the like. Therefore, in order to suppress dehydration of fermented milk, a method of adding a stabilizer such as a gel, and in addition thereto, a method of adding a milk protein or a whey protein concentrate, and the like are known (patent documents 2 to 4). Patent document 5 discloses a method for producing fermented milk by subjecting to lactose decomposition treatment and deoxidation treatment, which is a method for stabilizing the flavor and the like of fermented milk, but does not describe suppression of dehydration of fermented milk.

Patent document 1 Japanese patent No. 3968108

Patent document 2 Japanese examined patent publication No. Hei 3-52940

Patent document 3 Japanese patent application laid-open No. 3-19838

Patent document 4 Japanese patent No. 2966330

Patent document 5 WO2010/098086 publication

In fermented milk with a small amount of milk fat, in particular, dehydration is likely to occur, and if a general milk protein or a Whey Protein Concentrate (WPC), Whey Protein Isolate (WPI)) is added, the flavor of the fermented milk or the like is reduced. Further, even if a stabilizer such as a gel is added, the original flavor and texture of the fermented milk are lost.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a low-calorie fermented milk and a method for producing the same, which solve the above-mentioned problems of the prior art and suppress dehydration without adding a stabilizer and have a good flavor, in a method for producing a fermented milk using a raw material milk having a small amount of milk fat.

In order to solve the above problems, the present inventors have made extensive studies and have found that dehydration of fermented milk with a small amount of milk fat can be significantly suppressed by reducing the dissolved oxygen concentration of raw milk to decompose lactose in the raw milk with a lactase. Further, it was found that a fermented milk with less dehydration and firm curd was obtained by blending α -lactalbumin (α -La) and/or β -lactoglobulin (β -Lg) at a predetermined ratio, and the results of the study were further advanced, and the present invention was completed.

That is, the present invention relates to the following low-calorie fermented milk and a method for producing the same.

[1] A method for producing a fermented milk with a low fat content, comprising: the dissolved oxygen concentration of the raw milk at the start of fermentation is reduced, and the lactase is added to the raw milk before the start of fermentation.

[2] The method according to [1], wherein the fermented milk with low fat content has a milk fat content of 0.01-2 wt%.

[3] The method according to [1] or [2], wherein the dissolved oxygen concentration of the starting milk at the time of starting fermentation is 5ppm 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 the α -lactalbumin or β -lactoglobulin in the raw milk is 0.5 to 1.5 wt%.

[6] The method according to any one of [1] to [5], wherein the raw milk has a total protein mass of 3 to 6% by weight and/or a total solid content of 8 to 11% by weight.

[7] And the method according to any one of [1] to [6], wherein lactose degradation 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 a stabilizer is not added.

[10] And a fermented milk produced by the method according to any one of [1] to [10 ].

[11] And a fermented milk containing no stabilizer, the fermented milk having a centrifugal dehydration rate of 10 to 50%, a hardness of 30 to 70g, and a total calorie of 50 kcal/100 g or less.

[12] The fermented milk according to [11], which has a milk fat content of 0.01 to 2 wt%, a total protein mass of 3 to 6 wt% and a total solid content of 8 to 11 wt%.

[13] The fermented milks according to [11] to [12], wherein the fermented milks have a lactose content of 0.01 to 1 wt%.

In the method for producing fermented milk of the present invention, even when raw milk having a small total solid content and a small milk fat content is used, dehydration of fermented milk can be suppressed without adding (blending) a stabilizer or the like. Further, by blending α -lactalbumin and/or β -lactoglobulin at a predetermined ratio, dehydration is suppressed from being reduced, and a fermented milk with firm curd is obtained. Therefore, the fermented milk of the present invention is excellent in preservability and also suitable for long-distance transportation.

In the method for producing fermented milk of the present invention, lactose in the raw milk is decomposed by the lactase, and therefore, not only sweetness can be imparted to the fermented milk, but also the fermentation step can be stabilized. Therefore, a low-calorie fermented milk with less dehydration can be stably provided while maintaining the flavor and stable quality of the fermented milk. Further, according to the production method in which the raw milk is fermented while reducing the dissolved oxygen concentration, the original milk-fat-derived flavor and texture of the fermented milk can be obtained even when the raw milk having a low fat content is used.

In the method for producing fermented milk of the present invention, since the raw milk has a high content of α -lactoglobulin or β -lactoglobulin in the total protein, the method has little effect on the flavor of fermented milk that provides an off-flavor, unlike the case of adding ordinary milk protein or whey protein concentrate (WPC, WPI). By using WPC having a higher α -lactalbumin content or β -lactoglobulin content than the content of ordinary whey protein concentrates (WPC, WPI), for example, if WPC having a protein content of 80% or less is added to the starting milk, it is possible to label the product with a whey protein concentrate as a milk component and stably produce a fermented milk having a firm curd.

Therefore, in the method for producing fermented milk of the present invention, the quality of fermented milk with a small amount of milk fat can be effectively improved, and low-calorie fermented milk with good flavor, low total solid content, and low fat content can be provided.

Detailed Description

The method for producing fermented milk of the present invention includes a step of reducing the dissolved oxygen concentration in a raw milk (deoxidation step) and a step of decomposing lactose in the raw milk with a lactase (lactose decomposition step), and preferably includes α -lactalbumin (α -La) and/or β -lactoglobulin (β -Lg) at a predetermined ratio in the raw milk.

In the present specification, "fermented milk" includes "fermented milk" defined by provincial regulations (provincial regulations such as milk) relating to milk and dairy product ingredient standards and the like. For example, the fermented milk refers to fermented milk obtained by fermenting milk such as raw milk, cow milk, special cow milk, raw goat milk, sterilized goat milk, fresh goat milk, component-adjusted cow milk, low-fat cow milk, fat-free cow milk, and processed milk, or milk containing a fat-free milk solid content equal to or higher than that of the above milk, with lactic acid bacteria or yeast, or frozen fermented milk obtained by freezing the above milk. They comprise many types of yogurt, typical set yogurt in the present specification.

Usually, set yogurt such as plain yogurt is produced by filling a container with raw milk and then fermenting (post-fermentation). On the other hand, soft yogurt or yogurt drink is produced by micronizing fermented milk after fermentation, homogenizing the milk, and then filling the milk into a container (pre-fermentation).

Raw milk

The "raw milk" is a raw material of fermented milk such as yogurt, and is also called mixed yogurt or mixed fermented milk. In the present invention, well-known raw milk can be suitably used. The raw milk includes raw milk before sterilization and raw milk after sterilization. The raw milk may also comprise water, raw milk, sterilized milk, skimmed milk, whole milk powder, skimmed milk powder, buttermilk, butter, and butter.

The production method of the present invention is applicable to the production of usual fermented milk, and is particularly suitable for the production of low-calorie fermented milk, and the raw milk used in this case is preferably low-fat milk and preferably has a predetermined total protein amount in order to obtain an appropriate firmness (curd tension). The low-calorie fermented milk of the present invention is mainly produced from raw milk having a low total solid content and a low fat content.

The raw milk used in the production method of the present invention is not particularly limited, but preferably contains the following components. In the present specification,% represents weight% (w/w).

The amount of the milk fat 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 still more preferably 9 to 10.2%.

The total protein mass in the raw milk is desirably 3 to 6%, more preferably 3.5 to 5.5%, and 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 still more preferably 6 to 7%.

The raw milk used in the production method of the present invention may be added (blended) with whey protein, and preferably a concentrate of whey protein having a high α -lactalbumin content or β -lactoglobulin content is used.

As used herein, "whey protein concentrate" includes: whey Protein Concentrate (WPC) obtained by concentrating the major proteins of whey by Ultrafiltration (UF) and drying the concentrate; defatted WPC (low-fat and high-protein) obtained by removing the fat from whey by Microfiltration (MF) or centrifugation, concentrating by UF, and drying; whey Protein Isolate (WPI) obtained by subjecting whey major protein or the like to selective separation treatment by ion exchange resin method, gel filtration method or the like and then drying the resulting product; desalted whey desalted by a Nanofiltration (NF) method, an electrodialysis method or the like and then dried, and mineral-concentrated whey obtained by precipitating a mineral component derived from whey and then concentrating by a centrifugal separation method or the like. The main "whey protein" includes α -lactalbumin (α -La) and β -lactoglobulin (β -Lg).

In the present invention, it is preferable to use a Whey Protein Concentrate (WPC) or a Whey Protein Isolate (WPI) having a high α -lactalbumin content or β -lactoglobulin content, and it is more preferable to use a Whey Protein Concentrate (WPC) having a high α -lactalbumin content or β -lactoglobulin content. They may also use multiple species simultaneously.

The whey protein having a high content of α -lactalbumin, the β -lactoglobulin, and the whey protein having a high content of β -lactoglobulin are obtained by, for example, a method of selective separation from whey. The separation methods include ion exchange chromatography, hydrophobic chromatography, gel filtration, ultrafiltration, isoelectric point separation, co-precipitation with polyelectrolytes, salting out, and temperature treatment. The above-mentioned methods are also disclosed in Japanese patent laid-open Nos. 7-203863, 61-268138, 63-39545, and the like.

Further, α -lactalbumin (α -La) and β -lactoglobulin (β -Lg) are commercially available as such, and WPC and WPI having such high contents are also commercially available or manufactured. For example, WPC rich in α -La (manufactured by Domo corporation), WPC rich in β -Lg (manufactured by Domo corporation), WPC rich in α -La (manufactured by Davisco corporation), WPC rich in β -Lg (manufactured by Davisco corporation), WPC rich in α -La (manufactured by LeprinoFoods corporation), WPC rich in β -Lg (manufactured by LeprinoFoods corporation), ALACENWPI895 (manufactured by Fonterra corporation) and the like can be used. In the total protein of WPC and WPI such as WPC rich in α -La or WPC rich in β -Lg, the α -lactalbumin content of 60 to 100%, preferably 80 to 95%, preferably 65 to 100%, and more preferably 80 to 95% may be used as appropriate. Furthermore, α -lactalbumin and β -lactoglobulin themselves, or a combination of these WPC and WPI may also be used.

In addition, the protein content of WPC and WPI such as WPC rich in α -La or WPC rich in β -Lg may be preferably 30 to 95%, more preferably 35 to 80%, and still more preferably 65 to 75%, based on the total solid content.

In the method for producing fermented milk of the present invention, the raw milk preferably contains α -lactalbumin or β -lactoglobulin at a high concentration.

The α -lactalbumin is desirably contained in the total protein of the raw milk at a ratio of 7% or more, preferably 12 to 40%, and more preferably 17 to 25%. The content of the total raw milk is preferably 0.3% or more, more preferably 0.5 to 1.5%, and still more preferably 0.7 to 1%.

The beta-lactoglobulin is desirably contained in the total protein of the raw milk at a ratio of 10% or more, preferably 12 to 40%, and more preferably 15 to 25%. The content of the milk is preferably 0.4% or more, more preferably 0.5 to 1.5%, and still more preferably 0.6 to 1% of the total amount of the raw milk.

In the method for producing fermented milk of the present invention, it is preferable that the starting milk contains WPC rich in α -La or WPC rich in β -Lg.

The amount of the α -La-rich WPC in the raw milk varies depending on the α -La content in the α -La-rich WPC, and is desirably contained in a proportion of 0.5% or more, preferably 0.6 to 2%, and more preferably 0.75 to 1.5% in the whole raw milk.

The amount of the WPC rich in β -Lg in the raw milk varies depending on the β -Lg content of the WPC rich in β -Lg, and the raw milk desirably contains 0.55% or more, preferably 0.65 to 2%, and more preferably 0.8 to 1.5% of the total raw milk.

When the concentration of α -lactalbumin or β -lactoglobulin is in the preferred range, the dehydration-inhibiting effect can be obtained. As their concentration increases, the hardness also tends to become high. Further, in their preferred ranges, off-flavors are difficult to generate.

The term "dehydration" used in the present specification includes a phenomenon of separation of whey liquid, and can be measured, for example, by a centrifugal dehydration rate obtained by centrifugal separation or the like.

The raw milk is homogenized and sterilized, and then cooled to a predetermined temperature (around fermentation temperature). Then, a fermentation agent is injected, and in the case of the former fermentation, the fermentation is started by filling the fermentation tank or the like, and in the case of the latter fermentation, the fermentation is started by filling the fermentation tank or the like with a single food container or the like commonly used for the distribution.

In addition, a stabilizer or the like may be added, but in the method for producing fermented milk of the present invention, since fermented milk whose curd is strong and whose dehydration is difficult to occur can be obtained without adding a stabilizer or the like, it is preferable not to add a stabilizer. In the present specification, the term "stabilizer" refers to a stabilizer used in common fermented milk such as gelatin, pectin, agar, starch, carboxymethyl cellulose, carrageenan, and a thickening polysaccharide such as xanthan gum.

Deoxidation treatment Process

The deoxidation treatment step is a step for removing oxygen present in the raw milk. As a method for reducing the dissolved oxygen concentration in the raw milk, for example, a method of performing gas substitution treatment with an inert gas, a membrane separation method using a deoxygenation membrane, a method of degassing by vacuum or low pressure, or the like can be used. In the deoxidation treatment step, for example, the amount of oxygen dissolved in the raw material milk (dissolved oxygen concentration, DO) may be reduced to about 5ppm or less, preferably 3ppm or less, and more preferably 2ppm or less.

The dissolved oxygen concentration of the starting milk at the time of starting fermentation is preferably as low as possible. For example, when the temperature of the raw milk is about 40 ℃, it is preferably 5ppm or less, and more preferably 3ppm or less. By reducing the dissolved oxygen concentration, the fermentation time can be shortened, and the fermentation can be performed in a short time range of 3 to 7 hours even when the fermentation temperature is reduced. These deoxidation treatment steps are also described in japanese patent No. 3666871, japanese patent No. 3644505, and japanese patent No. 3968108.

The deoxidation treatment step may be performed at the stage of blending the raw milk, after homogenization and sterilization, or before starting fermentation after addition of a starter. However, from the viewpoint of importance in maintaining the dissolved oxygen concentration in a reduced state at the start of fermentation, it is desirable that the deoxidation treatment step is performed immediately before or after the addition of the fermentation agent, or simultaneously.

In the case of performing the gas replacement treatment (inert gas replacement) by an inert gas, typically, nitrogen gas is generally used as the inert gas generally used in food. In addition to nitrogen gas and the like, a rare gas such as helium, neon, argon, xenon, or the like can be used. As a method for replacing the dissolved oxygen with the inert gas, a known method such as a method of directly bubbling the inert gas during mixing, a method using a static mixer, or a method of adding a gas to a mixer while mixing and stirring can be used. The inert gas substitution can be performed after the addition of the fermentation agent, and the process is less limited than the method such as membrane separation.

In the case of a membrane separation method (deoxygenation membrane gas replacement) using a deoxygenation membrane, a hollow fiber membrane (mitsubishi yang corporation, MHF304 KM) or the like can be used as the deoxygenation membrane. The method of using the deoxygenation membrane can be referred to the existing method of using the deoxygenation membrane, and the gas replacement of the deoxygenation membrane is suitable for raw milk and can be performed before a leaven is added.

Instead of the mixing of the inert gas or the deoxidation film, oxygen dissolved in the raw milk may be removed by degassing. Such a degasser is also disclosed in Japanese patent laid-open publication Nos. 2002-370006 and 2005-304390.

Fermentation step

In order to perform lactic acid fermentation of a raw milk having a reduced dissolved oxygen concentration, a starter is added (mixed) to the raw milk to perform fermentation. As these fermentation agents, known ones can be suitably used, and lactic acid bacteria fermentation agents are preferably used. Further, as the lactic acid bacteria starter, in addition to lactobacillus bulgaricus (l.bulgaricus), streptococcus thermophilus (s.thermophilus), lactobacillus (l.lactis), lactobacillus gasseri (l.gasseri) and Bifidobacterium (Bifidobacterium), one or more of lactic acid bacteria, Bifidobacterium and yeast which are generally used for producing fermented milk may be used.

Among these leavening agents, a leavening agent comprising a mixed leavening agent of lactobacillus bulgaricus (l.bulgaricus) and streptococcus thermophilus (s.thermophilus) standardized as a starter for yogurt in the food code standard is more preferable. Other lactic acid bacteria or bifidobacteria such as lactobacillus gasseri (l.gasseri) and Bifidobacterium (Bifidobacterium) may be added (blended) to the yogurt starter as a base material according to the actual desired fermented milk. The amount of the fermentation agent to be added may be any amount as appropriate for the production method of known fermented milk. The method of adding (injecting) the fermentation agent may be performed by any known method generally used for the production of fermented milk.

In the present invention, the fermentation can be carried out using an amount smaller than the amount of the conventional fermentation agent. The amount of the fermentation agent used in the case of fermenting raw milk (mixed yogurt) without a deoxidation step (treatment for reducing the dissolved oxygen concentration) at a fermentation temperature of 43 ℃ for 3 hours with a lactic acid acidity of 0.7% is 100% based on the amount of the fermentation agent. Specifically, in the normal fermentation condition, the addition amount of the leavening agent is about 2% of the total amount of the raw milk, while the addition amount of the leavening agent in the present invention is about 0.5-1.0% of the total amount of the raw milk and about 25-50% of the addition amount of the normal leavening agent.

Lactose decomposition step

The lactose decomposition step is a step of decomposing lactose by lactase (lactase). The lactase may be added in principle at any stage of the production process. For example, from the viewpoint of reducing the risk of bacterial contamination, the raw milk may be left in a low-temperature state, subjected to heat sterilization after decomposing lactose, and subjected to fermentation after the enzyme has lost its activity. On the other hand, the raw milk may be sterilized by heating, mixed (blended) with a starter and a lactase, and fermented in a state where the enzyme is active. Further, the raw milk is fermented, and lactose is decomposed into lactic acid to generate acid, and as the pH value is lowered, the enzyme may be inactivated. By such treatment, the lactose decomposition rate can be effectively improved.

In addition, when the starting milk is mixed with a starter and a lactase to ferment, the enzyme reaction is not required before the starting milk is heated and sterilized, so that the production process of the fermented milk can be simplified and the original flavor of the fermented milk can be maximally maintained. Further, since the lactose degradation rate can be effectively increased by performing such treatment, it is not necessary to continuously control the lactose degradation rate and the degree of fermentation (change in acidity) independently, and the product management is extremely easy.

Therefore, in the present invention, the lactase is preferably added (blended) to the raw milk at the same time as the starter, but is not particularly limited, and may be added to the raw milk at the same time as the starter is added or after the starter is added, even if it is added to the raw milk before the starter is added. When a raw milk containing a lactose-decomposing enzyme and a fermentation agent is used, lactose in the raw milk is decomposed while undergoing a fermentation step. The lactase may be added to the raw milk before the deoxidation treatment step, or may be added to the raw milk after the deoxidation treatment step. Such a lactose degradation step is also disclosed in WO 2010/098086.

The optimum pH for the activity of the lactose-degrading enzyme of the present invention is in the neutral region, and is an enzyme that loses activity in the acidic region, and preferably can degrade lactose in the active state. Examples of the lactase include enzymes derived from bacteria and yeast. The optimum pH for activity is 6.3 to 7.5 or less and the pH for inactivation is 4 to 6. Furthermore, the lactase is preferably a lactase derived from Kluyveromyces lactis (Kluyveromyces lactis) or a lactase derived from Kluyveromyces fragilis (Kluyveromyces fragilis). The lactose-degrading enzyme derived from Kluyveromyces lactis includes, in addition to Kluyveromyces lactis itself, lactose-degrading enzymes derived from Kluyveromyces lactis. Further, lactolytic enzymes are commercially available, and examples of commercially available lactolytic enzymes include lactase F (manufactured by Amano enzyme Co., Ltd.), lactonesL-3 (manufactured by Daihuazai Kaishi Co., Ltd.), lactonesL-10 (manufactured by Daihuazai Kaishi Co., Ltd.), and lactase (GODO-YNL, manufactured by contract alcohol Co., Ltd.).

The lactose decomposition rate is not limited, and may be 65% or more, preferably 75 to 90%, and more preferably 80 to 90%. In addition, the lactonase may be added to the raw milk in an amount of 5U/g or more, preferably 7 to 20U/g, and more preferably 10 to 15U/g. When the lactose decomposition rate is low, the dehydration rate improving effect of the present invention tends to be sufficiently obtained.

Fermentation conditions and lactose decomposition conditions

In general, fermentation conditions such as fermentation temperature and fermentation time are adjusted in consideration of the kind of lactic acid bacteria added to the raw milk, the flavor of the fermented milk actually required, and the like, but the temperature in the fermentation chamber (fermentation temperature) is maintained at about 30 to 50 ℃.

In the method for producing fermented milk of the present invention, fermentation may be performed at a relatively low temperature, preferably 30 to 39 ℃, more preferably 32 to 38 ℃, and even more preferably 34 to 37 ℃.

On the other hand, when a fermentation agent of about 25 to 50% of the amount of a usual fermentation agent (i.e., 0.5 to 1.0% of the total amount of raw milk) is used, fermentation may be performed at 38 to 46 ℃, preferably 38 to 45 ℃, and more preferably 39 to 43 ℃ which is about the same as the usual fermentation temperature.

In the case of this method, since fermentation can be carried out at a fermentation temperature which is generally used, the temperature in the fermentation chamber can be easily controlled as in the case of a normal product, and there is an advantage that the risk of the propagation of undesired bacteria and the like can be reduced.

The fermentation time may be a time at which the acidity of the fermented milk reaches about 0.7%. In the production method of the present invention, the fermentation time is preferably 3 to 7 hours, and more preferably 3 to 5 hours. In this case, the acidity of lactic acid can be calculated by titration with NaOH or phenolphthalein indicator, or the like.

In addition, even when lactose in the raw milk is decomposed before fermentation, the lactose decomposition is carried out at 0 to 55 ℃ at which the lactase-decomposing enzyme maintains the activity, preferably 30 to 50 ℃, and more preferably 35 to 45 ℃. The lactose decomposition condition can be achieved if the proper temperature of common lactose decomposing enzyme is 35-45 ℃ and is kept for more than 1 hour.

Fermented milk

The fermented milk obtained by the production method of the present invention has a firm curd and is not easily dehydrated even if it has a low total solid content and a low fat content. The adjustment of the components such as the amount of milk fat and the amount of protein in the fermented milk can be achieved by adjusting the ratio of skim milk powder or whey protein in the starting milk. The fermented milk of the present invention is not particularly limited, and preferably has the following characteristics.

The centrifugal dehydration rate of the fermented milk of the present invention is desirably 60% or less, preferably 10 to 50%, and more preferably 15 to 40%.

The hardness of the fermented milk of the present invention is preferably 30g or more, preferably 30 to 70g, and more preferably 40 to 60 g.

The total calorie (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 in the present specification includes less than 50 kcal/100 g. Therefore, the low-calorie fermented milk of the present invention may be 50 kcal/100 g or less, 45 kcal/100 g or less, or 40 kcal/100 g or less.

The centrifugal dehydration rate can be determined by measuring the proportion (% by weight) of the supernatant (whey) separated by centrifuging the fermented milk. For example, it can be obtained by centrifugation at 3000rpm (2150 Xg) for 10 minutes at room temperature. Furthermore, the firmness (curd tension: CT) can be measured by a general apparatus such as NEO curd tension meter ME305 (product of ITECNOENGINEERING Co., Ltd.), and the total calorie can be calculated from the values of the respective nutrients by a general method.

The amount of milk fat in the fermented milk of the present invention is desirably 3% or less, preferably 2% or less, more preferably 1% or less, and most preferably 0.5% or less. In addition, the preferable range is 0.01 to 2%, the more preferable range is 0.05 to 1%, and the even more preferable range is 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. In addition, the preferable range is 8 to 11%, the more preferable range is 8.5 to 10.5%, and the still more preferable range is 9 to 10.2%.

The total protein mass of the fermented milk of the present invention is desirably 3 to 6%, more preferably 3.5 to 5.5%, and still more 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 is preferably a milk having a high α -lactalbumin content or β -lactoglobulin content, and the protein content is obtained by adjusting the α -lactalbumin content and/or β -lactoglobulin content in the starting milk.

The α -lactalbumin is desirably contained in the total protein of the fermented milk at a ratio of 7% or more, preferably 12 to 40%, and more preferably 17 to 25%. The content of the fermented milk is preferably 0.3% or more, more preferably 0.5 to 1.5%, and still more preferably 0.7 to 1%.

The beta-lactoglobulin is desirably contained in the total protein of the fermented milk at a ratio of 10% or more, preferably 12 to 40%, and more preferably 15 to 25%. The content of the fermented milk is preferably 0.4% or more, more preferably 0.5 to 1.5%, and still more preferably 0.6 to 1%.

The fermented milk of the present invention preferably does not contain a stabilizer. Furthermore, it is preferable not to add a sweetener or the like, and if necessary, it may be added before or after fermentation.

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

Examples

The raw materials used are as follows.

Skimmed milk powder (manufactured by Mingmy), WPC34 (manufactured by LeprinoFoods), and WPC75 (manufactured by LeprinoFoods) rich in β -Lg were used. The WPC75 rich in beta-Lg mainly contains beta-Lg, wherein the protein contains about 80% of beta-Lg and about 20% of whey protein such as alpha-La.

Lactase (GODO-YNL, 10000U/g, manufactured by contract alcohol Co., Ltd.) was used as the lactase.

Lactobacillus bulgaricus and Streptococcus thermophilus (manufactured by Mingzhi Co.) isolated from Mingzhi Bulgarian yogurt were used as the lactic acid bacteria starter.

The curd tension was measured by using a NEO curd tension meter ME305 (product of ITECNOENGINEERING Co., Ltd.).

Example 1

90.7g of skim milk powder, 13.5g of WPC34, and 895.8g of tap water were mixed to prepare a starting milk for producing fermented milk.

The resulting raw milk was heated (sterilized) at 95 ℃ for 5 minutes, and then cooled to about 38 ℃. Further, after cooling the raw milk, lactase (GODO-YNL, manufactured by contract alcohol Co.) was added at 0.1 wt% and a lactic acid bacteria starter (separated from Kochia gazette, manufactured by Kokai) was injected at 2 wt%. Thereafter, nitrogen gas was blown through the pipe, and dissolved oxygen was adjusted to 4ppm or less. Alternatively, lactase may be added to the raw milk before sterilization to perform an enzymatic reaction, and lactic acid fermentation may be performed after decomposition of lactose.

Next, the raw material milk containing lactase and a lactic acid bacteria starter was filled in a cup container (capacity: 100g, made of plastic), and left to stand in a fermentation chamber (38 ℃ C.) and fermented until the acidity of lactic acid reached 0.7%. Thereafter, the yogurt was cooled in a refrigerator (10 ℃ C. or lower) to produce set yogurt (fermented milk).

The hardness (curd tension) of the resulting fermented milk (total solid content: 10.0% by weight, fat content: 0.1% by weight, 40 kcal/100 g) was 35g, and the centrifugal dehydration rate (3000 rpm (2150 Xg), 10 minutes, room temperature) was 35%.

Example 2

The starting milk used for the production of fermented milk was prepared by mixing 86.3g of skimmed milk powder, 4.4g of WPC75 rich in β -Lg, 13.5g of WPC34, and 874.8g of tap water.

The resulting raw milk was heated (sterilized) at 95 ℃ and then cooled to about 38 ℃. Further, after cooling the raw milk, lactase (GODO-YNL, manufactured by contract alcohol Co., Ltd.) was added at 0.1 wt%, and a lactic acid bacteria starter (manufactured by Mingzhi, separated from Mingzhu yogurt) was injected at 2 wt%. Thereafter, nitrogen gas was blown through the pipe, and dissolved oxygen was adjusted to 4ppm or less. Alternatively, lactase may be added to the raw milk before sterilization to perform an enzymatic reaction, and lactic acid fermentation may be performed after decomposition of lactose.

Next, the raw material milk containing lactase and a lactic acid bacteria starter was filled in a cup container (capacity: 100g, made of plastic), and left to stand in a fermentation chamber (38 ℃ C.) and fermented until the acidity of lactic acid reached 0.7%. Thereafter, the yogurt was cooled in a refrigerator (10 ℃ C. or lower) to produce set yogurt (fermented milk).

The hardness (curd tension) of the resulting fermented milk (total solid content: 10.0% by weight, fat content: 0.1% by weight, 40 kcal/100 g) was 50g, and the centrifugal dehydration rate (3000 rpm (2150 Xg), 10 minutes, room temperature) was 25%.

Subsequently, the fermented milk (total solid content: 10.0 wt%, fat content: 0.1 wt%, 40 kcal/100 g) was produced in an actual production process (plant), filled into 700 cup containers (capacity: 450g, paper), and transported 1300km by a refrigerator car (truck), it was confirmed that the curd was not broken and a small amount of dehydration (whey separation) occurred, and it was equal to or less than that of a commercially available product (total solid content: 12.5 wt%, fat content: 3.0 wt%).

According to the above results, the fermented milk of the present invention exhibits stable quality of fermented milk in which not only dehydration can be suppressed, but also curd is not broken even if impact occurs during long-distance transportation. Furthermore, it was shown that by adjusting the concentration of β -lactoglobulin, the centrifugal dehydration rate can be further improved.

Comparative example 1

90.7g of skim milk powder, 13.5g of WPC34, and 895.8g of tap water were mixed to prepare a starting milk for fermented milk production.

The resulting raw milk was heated (sterilized) at 95 ℃ for 5 minutes, and then cooled to about 43 ℃. Further, after cooling the raw milk, 2 wt% of a lactic acid bacteria starter (manufactured by Mingzhi corporation, isolated from Mingzhi Bulgarian yogurt) was injected.

Next, the raw material milk containing the lactic acid bacteria starter was filled in a cup container (capacity: 100g, made of plastic), and left to stand in a fermentation chamber (43 ℃ C.) and fermented until the acidity of lactic acid reached 0.7%. Thereafter, the yogurt was cooled in a refrigerator (10 ℃ C. or lower) to produce set yogurt (fermented milk) (control).

The hardness (curd tension) of the resulting fermented milk (total solid content: 10.0% by weight, fat content: 0.1% by weight, 40 kcal/100 g) was 50g, and the centrifugal dehydration rate (3000 rpm (2150 Xg), 10 minutes, room temperature) was 65%.

The above results show that the dehydration ratio of the fermented milk with a low fat content can be improved by 45% or more without adding a stabilizer, and that the dehydration ratio can be further improved by 60% or more by adjusting the concentration of β -lactoglobulin in the method for producing fermented milk of the present invention.

Industrial applicability

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

Claims (16)

1. A method for producing a fermented milk having a low fat content and a centrifugal dehydration rate of 60% or less, comprising: the dissolved oxygen concentration of the raw milk at the start of fermentation is reduced, and the lactase is added to the raw milk before the start of fermentation.

2. The method according to claim 1, wherein the amount of milk fat in the raw milk is 3% or less.

3. The method according to claim 1 or 2, wherein the dissolved oxygen concentration of the starting milk at the start of fermentation is 5ppm or less.

4. A process according to any one of claims 1 to 3, wherein the raw milk comprises a high concentration of alpha-lactalbumin or beta-lactoglobulin.

5. A process according to claim 4, wherein the concentration of α -lactalbumin or β -lactoglobulin in the starting milk is 0.5 to 1.5% by weight.

6. A process according to any one of claims 1 to 5, wherein the starting milk has a total protein mass of 3 to 6 wt% and/or a total solids content of 8 to 11 wt%.

7. A process according to any one of claims 1 to 6, wherein lactose breakdown is carried out in a fermentation.

8. A process according to any one of claims 1 to 7, wherein the lactose breakdown rate is 75 to 90%.

9. The method of any one of claims 1-8, wherein no stabilizer is added.

10. A fermented milk having a low fat content and a centrifuge dehydration rate of 60% or less, produced by the method according to any one of claims 1 to 9.

11. The fermented milk according to claim 10, wherein the fermented milk is a set-type fermented milk.

12. The fermented milk according to claim 10 or 11, wherein the centrifugal dehydration rate is 10 to 50%.

13. The fermented milk according to any one of claims 10 to 12, wherein the fermented milk has a centrifuge dehydration rate of 10 to 50%, a hardness of 30 to 70g, and a total calorie of 50 kcal/100 g or less.

14. Fermented milk according to claim 13, wherein the fermented milk has a milk fat content of 3% or less, a total protein mass of 3-6 wt% and/or a total solids content of 8-11 wt%.

15. Fermented milk according to claim 13 or 14, wherein the lactose content of the fermented milk is 0.01-1 wt%.

16. A method for producing a fermented milk with a reduced fat content, which comprises: in the production of a low-fat fermented milk, the dissolved oxygen concentration of the starting milk at the start of fermentation is reduced, and a lactolytic enzyme is added to the starting milk before the start of fermentation.