阅读说明：本技术 一种无乳糖微发酵牛乳及其制备方法 (Lactose-free micro-fermented milk and preparation method thereof ) 是由 孙颜君 苏米亚 徐致远 刘振民 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种无乳糖微发酵牛乳及其制备方法,该微发酵牛乳包括以下质量百分比的原料：原料乳99.925～99.971％、酵母0.008～0.012％、植物乳杆菌0.001～0.003％和乳糖酶0.02～0.06％。无乳糖微发酵牛乳的制备方法包括：S1：将原料乳预热后脱脂,得到脱脂乳和稀奶油；S2：将S1中的脱脂乳杀菌,加入酵母和乳糖酶,加热,再加入植物乳杆菌,进行发酵水解,得到发酵水解料液；S3：将S1中的稀奶油杀菌,将其加入S2中的发酵水解料液,预热、无菌均质后冷却灌装,即得。本发明的微发酵牛乳不含乳糖,适合乳糖不耐症消费群体,且产品风味、口感好。(The invention discloses lactose-free micro-fermented milk and a preparation method thereof, wherein the micro-fermented milk comprises the following raw materials in percentage by mass: 99.925-99.971% of raw milk, 0.008-0.012% of yeast, 0.001-0.003% of lactobacillus plantarum and 0.02-0.06% of lactase. The preparation method of the lactose-free micro-fermented milk comprises the following steps: s1: preheating raw milk and then degreasing to obtain skim milk and cream; s2: sterilizing skim milk in S1, adding yeast and lactase, heating, adding lactobacillus plantarum, and performing fermentation hydrolysis to obtain fermentation hydrolysis feed liquid; s3: and (3) sterilizing the cream in the S1, adding the cream into the fermentation hydrolysis feed liquid in the S2, preheating, carrying out aseptic homogenization, cooling and filling to obtain the cream. The micro-fermented milk does not contain lactose, is suitable for lactose intolerance consumer groups, and has good flavor and mouthfeel.)

1. The lactose-free micro-fermented milk is characterized by comprising the following raw materials in percentage by mass: 99.925-99.971% of raw milk, 0.008-0.012% of yeast, 0.001-0.003% of lactobacillus plantarum and 0.02-0.06% of lactase.

2. The lactose-free micro-fermented milk according to claim 1, wherein the protein content in the raw milk is not less than 3.0 wt%, the lactose content is not less than 3.0 wt%, the solid content of the non-fat milk is not less than 8.1 wt%, the pH value is 6.7-6.8, and the titrating acidity is not more than 18T.

3. The lactose-free micro-fermented milk according to claim 1, wherein the viable yeast count is 10⁶～10⁸cfu/ml。

4. A method for preparing lactose-free micro-fermented milk according to any of claims 1 to 3, which comprises the following steps:

s1: preheating raw milk and then degreasing to obtain skim milk and cream;

s2: sterilizing skim milk in S1, adding yeast and lactase, heating, adding lactobacillus plantarum, and performing fermentation hydrolysis to obtain fermentation hydrolysis feed liquid;

s3: and (3) sterilizing the cream in the S1, adding the cream into the fermentation hydrolysis feed liquid in the S2, preheating, carrying out aseptic homogenization, cooling and filling to obtain the cream.

5. The method for preparing lactose-free micro-fermented milk according to claim 4, wherein in the S1, the fat content in the skim milk is less than 0.5%; preheating raw milk to 60-65 ℃.

6. The method for preparing lactose-free micro-fermented milk according to claim 4, wherein in S2, the sterilization temperature of the skim milk is 90-95 ℃ and the sterilization time is 3-7 min.

7. The method for preparing lactose-free micro-fermented milk according to claim 4, wherein in S2, the fermentation temperature is 25-30 ℃, the fermentation time is 8-12 h, and the pH value is 6.38-6.43 when the fermentation is finished.

8. The method for preparing lactose-free micro-fermented milk according to claim 4, wherein in S2, the hydrolysis is carried out at 25-30 ℃ for 8-12 h, and then at 35-37 ℃ for 3-4 h, and the lactose content is 0.14-0.35% after the hydrolysis is finished.

9. The method for preparing lactose-free micro-fermented milk according to claim 4, wherein in S3, the sterilization temperature of the cream is 108-115 ℃, and the sterilization time is 20-30S.

10. The method for preparing lactose-free micro-fermented milk according to claim 4, wherein the S3 is preheated to 40-50 ℃ and the homogenization pressure is 150-250 bar.

Technical Field

The invention belongs to the technical field of fermented foods, and particularly relates to lactose-free micro-fermented milk and a preparation method thereof.

Background

The milk and its products contain all the nutrients necessary for human body, including milk protein, milk fat, lactose, minerals, vitamins, nucleosides, nucleotides, growth factors, etc. Dairy products have become an important component of the consumer's nutritional diet, especially pure milk products. The proportion of lactose intolerance symptoms of Asian consumer groups is high, and aiming at the problem, pure milk products without lactose are developed by various large dairy enterprises and are mainly realized by hydrolyzing lactose by lactase. Today, innovative products continuously compete for consumers' eyes, traditional products cannot meet consumers, and products with unique bright spots are needed to be favored by consumers and markets.

About the innovation of the prior pure milk, the method is mainly started from the aspects of enriching the flavor and improving the nutritional value. The yeast, as a novel probiotic, plays an important role in the industries of cheese, fermented dairy products and the like, and is mainly shown to participate in the fermentation of carbohydrates in the dairy products to generate aromatic compounds, and possibly stimulate the growth of lactic acid bacteria. According to the national standard, the lactose content in the dairy product is less than or equal to 0.5g/100g (ml), namely that no lactose is contained.

In order to further improve the nutritional value and sensory experience of the lactose-free pure milk, the invention adds the yeast and the lactobacillus for fermentation, and prepares the fermented pure milk product with unique taste and flavor and high nutrition by controlling the fermentation process and the processing technology, thereby being convenient for industrial production and providing more healthy new choices for consumers.

Disclosure of Invention

The invention aims to solve the technical problem of providing a novel fermented pure milk product for lactose intolerance consumer groups aiming at the development of pure milk products which declare '0 lactose' and 'contain probiotics' at present. The invention combines the actual pure milk processing, optimizes the formula and the process of the production, innovatively adds the yeast and the lactobacillus to ferment in the enzymolysis process of the pure milk, and can realize 0 lactose in the product, the special flavor of the yeast and the lactobacillus and the special taste containing bubbles through a large number of tests. The preparation method is simple and can be used for industrial production.

On one hand, the invention provides lactose-free micro-fermented milk which comprises the following raw materials in percentage by mass: 99.925-99.971% of raw milk, 0.008-0.012% of yeast, 0.001-0.003% of lactobacillus plantarum and 0.02-0.06% of lactase.

Further, the content of protein in the raw milk is more than or equal to 3.0 wt%, the content of lactose is more than or equal to 3.0 wt%, the content of non-fat milk solid is more than or equal to 8.1 wt%, the pH value is 6.7-6.8, and the titration acidity is less than or equal to 18 DEG T.

Further, the viable count of yeast is 10⁶～10⁸cfu/ml。

On the other hand, the invention also provides a preparation method of the lactose-free micro-fermented milk, which comprises the following steps:

s1: preheating raw milk and then degreasing to obtain skim milk and cream;

s2: sterilizing skim milk in S1, adding yeast and lactase, heating, adding lactobacillus plantarum, and performing fermentation hydrolysis to obtain fermentation hydrolysis feed liquid;

s3: and (3) sterilizing the cream in the S1, adding the cream into the fermentation hydrolysis feed liquid in the S2, preheating, carrying out aseptic homogenization, cooling and filling to obtain the cream.

Further, in the S1, the fat content in the skim milk is lower than 0.5%; preheating raw milk to 60-65 ℃.

Further, in the step S2, the sterilization temperature of the skim milk is 90-95 ℃, and the sterilization time is 3-7 min.

Further, in the S2, the fermentation temperature is 25-30 ℃, the fermentation time is 8-12 hours, and the pH value is 6.38-6.43 after the fermentation is finished.

Further, in the S2, the hydrolysis is carried out for 8-12 h at 25-30 ℃, the reaction is carried out for 3-4 h at 35-37 ℃, and the lactose content is 0.14-0.35% after the hydrolysis is finished.

Further, in the S3, the sterilization temperature of the cream is 108-115 ℃, and the sterilization time is 20-30S.

Further, in the step S3, the mixture is preheated to 40-50 ℃ and the homogenizing pressure is 150-250 bar.

The positive progress effects of the invention are as follows:

1. the staged yeast and lactobacillus plantarum are respectively fermented to provide better product flavor and mouthfeel;

2. the formula and the process can be used for industrialized production, provide the development of pure milk products which simultaneously claim '0 lactose' and 'contain probiotics' for consumers, and provide a novel fermentation type pure milk product for lactose intolerance consumer groups.

Detailed Description

In order to more clearly illustrate the technical solution of the present invention, the technical solution of the present invention will be further illustrated with reference to the following specific embodiments:

one of the technical schemes provided by the invention is as follows:

the invention provides lactose-free micro-fermented milk which comprises the following raw materials in percentage by mass: 99.925-99.971% of raw milk, 0.008-0.012% of yeast, 0.001-0.003% of lactobacillus plantarum and 0.02-0.06% of lactase.

Specifically, the content of protein in the raw milk is more than or equal to 3.0 wt%, the content of lactose is more than or equal to 3.0 wt%, the content of non-fat milk Solids (SNF) is more than or equal to 8.1 wt%, the pH value is 6.7-6.8, and the titration acidity is less than or equal to 18 DEG T.

Specifically, the number of viable yeast cells is 10⁶～10⁸cfu/ml。

One of the technical schemes provided by the invention is as follows:

the invention also provides a preparation method of the lactose-free micro-fermented milk, which comprises the following steps:

s1: preheating raw milk and then degreasing to obtain skim milk and cream;

s2: sterilizing skim milk in S1, adding yeast and lactase, heating, adding lactobacillus plantarum, and performing fermentation hydrolysis to obtain fermentation hydrolysis feed liquid;

s3: and (3) sterilizing the cream in the S1, adding the cream into the fermentation hydrolysis feed liquid in the S2, preheating, carrying out aseptic homogenization, cooling and filling to obtain the cream.

Specifically, in the step S1, fat separation is performed on the raw milk, and the fat content of the obtained skim milk is lower than 0.5%; preheating raw milk to 60-65 ℃.

In the S2, the sterilization temperature of the skim milk is 90-95 ℃, and the sterilization time is 3-7 min.

In the S2, the fermentation temperature is 25-30 ℃, the fermentation time is 8-12 h, and the pH value is 6.38-6.43 after the fermentation is finished.

In the S2, the hydrolysis reaction is carried out for 8-12 h at 25-30 ℃, the reaction is carried out for 3-4 h at 35-37 ℃, and the lactose content is 0.14-0.35% after the hydrolysis is finished;

heating to 35-37 ℃, wherein the pH value of the skim milk is 5.98-6.04 after fermentation.

In the S3, the sterilization temperature of the cream is 108-115 ℃, and the sterilization time is 20-30S.

In the step S3, the mixture is preheated to 40-50 ℃, and the homogenizing pressure is 150-250 bar.

The lactose-free micro-fermented milk product prepared by the method has the pH value of 6.03-6.21, the lactose content of 0.14-0.35%, and good fermentation flavor and taste.

The reagents and starting materials used in the present invention are commercially available.

On the basis of the common knowledge in the field, the preferred conditions can be combined randomly to obtain the preferred embodiments of the invention. On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention. On the basis of the common knowledge in the field, the preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.

The performance indexes of the raw materials meet the requirements of relevant quality standards. Other materials and equipment not specifically described are commercially available.

Example 1

(1) Preheating raw milk (with the addition of 99.971%) to 60 ℃ for fat separation to obtain skim milk and cream, wherein the fat content in the skim milk is less than 0.5%;

(2) and (2) respectively sterilizing the skim milk and the cream obtained in the step (1), wherein the sterilization condition of the skim milk is 90 ℃/3min, and the sterilization condition of the cream is 108 ℃/30 s. And cooling the sterilized cream to 10 ℃ for later use. Cooling the sterilized skim milk to 25 ℃ (pH 6.7), adding 0.008% of yeast starter and 0.02% of lactase, and fermenting for 12h, wherein the pH of cow milk is 6.38; heating yeast to ferment the cow milk to 35 ℃, inoculating lactobacillus plantarum 0.001%, continuing fermenting for 4h, and stopping fermenting when the pH value reaches 5.98;

(3) and (3) respectively preheating the fermented milk and the cream of the lactobacillus plantarum in the step (2) to 40 ℃, mixing, homogenizing at the temperature, wherein the homogenizing pressure is 150bar, cooling and filling.

The product prepared by the method has the lactose content of 0.35 percent, the viable count of the yeast and the viable count of the lactobacillus plantarum are 106cfu/ml respectively, the taste is unique, the bubble feeling is realized, and the flavor is rich and mellow.

Example 2

(1) Preheating raw milk (with the addition of 99.925%) to 62 ℃ for fat separation to obtain skim milk and cream, wherein the fat content in the skim milk is less than 0.5%;

(2) and (2) respectively sterilizing the skim milk and the cream obtained in the step (1), wherein the sterilization condition of the skim milk is 93 ℃/5min, and the sterilization condition of the cream is 110 ℃/25 s. And cooling the sterilized cream to 10 ℃ for later use. Cooling the sterilized skim milk to 30 ℃ (pH 6.7), adding 0.012% of yeast starter and 0.06% of lactase, and fermenting for 8h, wherein the pH of cow milk is 6.43; heating the yeast to ferment the cow milk to 37 ℃, inoculating 0.003 percent of lactobacillus plantarum, continuing to ferment for 3 hours, and stopping fermentation when the pH value reaches 6;

(3) and (3) respectively preheating the fermented cow milk and the sterilized cream of the lactobacillus plantarum in the step (2) to 45 ℃, mixing, homogenizing at the temperature, wherein the homogenizing pressure is 200bar, cooling and filling.

The product prepared by the method contains lactose 0.14%, and viable count of yeast and Lactobacillus plantarum is 10⁷cfu/ml, unique taste, bubble feeling and rich and mellow flavor.

Example 3

(1) Preheating raw milk (with the addition of 99.948%) to 65 ℃ for fat separation to obtain skim milk and cream, wherein the fat content in the skim milk is less than 0.5%;

(2) and (2) respectively sterilizing the skim milk and the cream obtained in the step (1), wherein the sterilization condition of the skim milk is 95 ℃/7min, and the sterilization condition of the cream is 115 ℃/20 s. And cooling the sterilized cream to 10 ℃ for later use. Cooling the sterilized skim milk to 27 ℃ (pH 6.7), adding yeast starter 0.01% and lactase 0.04% for fermenting for 10h, wherein the pH of cow milk is 6.40; heating yeast to ferment the cow milk to 36 ℃, inoculating lactobacillus plantarum 0.002 percent, continuing to ferment for 3.5 hours, and stopping fermentation when the pH value reaches 6.04;

(3) and (3) respectively preheating the fermented cow milk and the sterilized cream of the lactobacillus plantarum in the step (2) to 50 ℃, mixing, homogenizing at the temperature, wherein the homogenizing pressure is 250bar, cooling and filling.

The product prepared by the method contains lactose 0.23%, and viable count of yeast and Lactobacillus plantarum is 10⁸cfu/ml, unique taste, bubble feeling and rich and mellow flavor.

Effect example 1

The products prepared in examples 1 to 3 were refrigerated at 4 ℃ and subjected to shelf life tests, and the survival rates, pH and lactose contents of yeast and Lactobacillus plantarum were measured at shelf lives of 7d, 14d and 30d, respectively, and the results are shown in Table 1 below:

table 1 comparison of effects

As can be seen from the table above, the number of yeast, the number of lactobacillus plantarum, the pH of the product and the lactose content are not significantly different from the shelf life of 0d when the product is refrigerated for 7 d; after refrigeration for 14d and 30d, the yeast quantity, the lactobacillus plantarum quantity and the lactose content are obviously reduced, the pH value of the product is not obviously different, but at 30d, the product still has stronger bubble mouthfeel.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.