Fermentation type sugar-free milk beverage as well as preparation method and application thereof

Abstract

The invention provides a fermented sugar-free milk beverage as well as a preparation method and application thereof, and relates to the field of milk beverages. The preparation method comprises the following steps: firstly, mixing lactase into a milk raw material for enzymolysis, then adding auxiliary materials such as a sweetening agent, a stabilizing agent and an acid regulating agent, and fermenting through a lactose fermentation strain to obtain the sugar-free milk beverage with the total sugar less than or equal to 0.5%, the ethanol less than or equal to 0.5%, the protein content of 0.7-1.0% and the acidity of 40-60 DEG T; the preparation method provided by the invention has the advantages of low requirement on the lactose fermentation capacity of the strain, short fermentation time and no need of acid regulation after fermentation, and can be used for producing sugar-free milk beverages or low-sugar milk products.

Description

Technical Field

[0001] The invention belongs to the field of milk beverages and relates to the preparation of sugar-free milk beverages, and specifically relates to a fermented sugar-free milk beverage and a preparation method and application thereof. Background Art

[0002] With the development of economic level, consumers are paying more and more attention to healthy lifestyle, and developing sugar-free (low-sugar) foods in diet has become a trend. GB13432-2004 stipulates that if the total amount of monosaccharides and disaccharides in solid or liquid foods is not higher than 0.5g / 100g (ml), they can be claimed as "sugar-free or sugar-free" on the product label; if the total amount of monosaccharides and disaccharides in solid or liquid foods is not higher than 5g / 100g (ml), they can be claimed as "low sugar" on the product label. The sugar content refers to the sum of monosaccharides and disaccharides. The World Health Organization (WHO) has proposed a new guideline, suggesting that the sugar content of adults' daily calorie intake should be less than 5%. The development of low-sugar (sugar-free) foods is very necessary to meet the needs of special groups of people. Studies have confirmed that for food raw materials with a sugar content of more than 5%, biotechnology can be used to decompose, utilize and transform sugar and carbohydrates to prepare sugar-free (low-sugar) foods. "Sugar-free" here is only a content claim standard, not that the sugar content in the drink is really 0. Therefore, even if it is called "sugar-free" beverages, most of them actually contain sugar. Among them, sugar-free foods / beverages may add some sweeteners to replace sugar, such as aspartame, acesulfame potassium, cyclamate, and natural sweeteners such as sugar alcohols. Sweeteners are a type of food additives and will be marked in the ingredient list on the food label.

[0003] Milk beverages are one of the most popular dairy products among consumers. GBT21732-2008 stipulates that milk beverages are beverage products made from milk or dairy products, with water and appropriate auxiliary materials added or fermented, with a milk protein content of 0.7-1.0%; the lactose content of most animal milks is around 5%, and the protein content is around 3%. According to the national standard technical requirements, even without adding sucrose, it is difficult to produce qualified milk beverages with no sugar and a milk protein content of 0.7-1.0% using conventional lactic acid bacteria in a one-step method.

[0004] With the continuous improvement of the production technology of fermented products and the research and screening of leavening agents, it has been found that milk beverages fermented through a specific process using microbial fermentation, enzyme preparations, lactic acid bacteria or yeast, can meet the product's total sugar content of less than 0.5% and alcohol content of less than 0.5%, meeting the quality standards and flavor requirements of sugar-free and non-alcoholic milk beverages.

[0005] Prior art CN107223709A provides a low-sugar or sucrose-free yogurt and a preparation method thereof. The raw materials of the yogurt are white sugar, sugar substitute, lactase, stabilizer, milk protein, starter and milk. The preparation method of the yogurt is: milk standardization, batching, degassing, homogenization and sterilization, enzymatic hydrolysis and fermentation, and filling. The present invention enhances the sweetness by selecting a suitable natural sweetener, and adds lactase to decompose lactose into glucose and galactose, further increasing the sweetness of the yogurt, and by adding a filling sweetener to make up for the loss of taste after not adding sucrose, and by reasonably adjusting the ratio of several sweeteners without adding a stabilizer, the existing low-sugar or sucrose-free yogurt products have poor taste, low viscosity, rough state and other problems. The disadvantage is that the lactase enzymatic hydrolysis and fermentation process are carried out simultaneously, and the fermentation time is only 4-7 hours, which makes it difficult to fully decompose lactose; there is no sterilization step after fermentation, which is easy to breed harmful microorganisms.

[0006] Prior art CN115886068A The present invention provides a natural sweet milk containing galacto-oligosaccharides and a low-sugar or zero-sugar lactobacillus beverage. Nurica lactase is added during the preparation of natural sweet milk containing galacto-oligosaccharides and a low-sugar or zero-sugar lactobacillus beverage containing galacto-oligosaccharides, and the preparation method controls a lower hydrolysis temperature and a suitable ratio of ingredients. By adding Nurica lactase, the product can naturally contain galacto-oligosaccharides; in addition, for products that require browning, there is no need to add additional glucose, and the browning of the product can be achieved by using the glucose produced by the decomposition of lactose; for non-browning or neutral products, dairy products with natural sweetness can be prepared; not only that, the consumption of glucose in the generated galacto-oligosaccharides and the browning process can further realize the preparation of low-sugar or zero-sugar products. The disadvantage is that the fermentation time is long (68 to 72 hours), and acid solution needs to be added after fermentation for acid adjustment, and the process is cumbersome.

[0007] The present invention aims to develop sugar-free milk beverages and low-sugar dairy products containing whole milk protein through fermentation, which can meet the needs of more consumers who like dairy products and control sugar, provide a new idea for the development of new sugar-free (low-sugar) specialty fermented dairy products and other types of sugar-free (low-sugar) foods, and is of great significance to promoting the scientific and technological innovation and development of sugar-free (low-sugar) foods. Summary of the invention

[0008] The present invention aims at the problems existing in the prior art and provides a fermented sugar-free milk beverage and a preparation method and application thereof. The present invention adopts a two-stage method of first using lactase for enzymatic hydrolysis and then fermenting to prepare a sugar-free milk beverage with a total sugar content of ≤0.5%, ethanol ≤0.5%, a protein content of 0.7-1.0%, and an acidity of 40-60°T; the preparation method of the present invention has the advantages of low requirements on the lactose fermentation ability of the strain, short fermentation time, and no need for acid adjustment after fermentation.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0010] In one aspect, the present invention provides a method for preparing a fermented sugar-free milk beverage, comprising the following steps:

[0011] S1: adding lactase to the milk raw material for enzymatic hydrolysis to obtain hydrolyzed milk;

[0012] S2: adding a sweetener, a stabilizer and an acidifier to the hydrolyzed milk and mixing them evenly to obtain a fermentation base;

[0013] S3: adding lactose fermentation bacteria to the fermentation base for fermentation;

[0014] S4: After fermentation, the finished product is obtained through sterilization, cooling and filling.

[0015] Preferably, the lactose fermentation bacteria include commercially available lactic acid bacteria or commercially available yeast, the commercially available lactic acid bacteria include Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, Bifidobacterium lactis, Bifidobacterium longum, Lactococcus lactis, Lactobacillus helveticus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus rhamnosus or Leuconostoc pseudomesenteroides, and the commercially available yeast includes Kluyveromyces marxianus or Saccharomyces cerevisiae.

[0016] Preferably, the lactose fermenting bacteria comprises any one of Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus salivarius subsp. thermophilus or Saccharomyces cerevisiae.

[0017] In some embodiments, the brewer's yeast is Angel brewer's dry yeast.

[0018] Preferably, the dairy raw materials in step S1 include natural dairy substances and processed dairy substances, which provide major nutrients.

[0019] Preferably, the natural dairy substance comprises animal milk, and the processed dairy substance comprises milk powder.

[0020] Preferably, the animal milk comprises camel milk, mare milk or cow milk, and the milk powder comprises whole milk powder, skim milk powder or whey powder.

[0021] Specifically, the camel milk is inspected and purchased in accordance with the Xinjiang Uygur Autonomous Region local standard "Raw Camel Milk-DBS65010-2023" raw milk purchase standard, and meets the following requirements:

[0022] (1) Acidity (°T): The raw camel milk used to prepare fermented camel milk products must be fresh, with a natural acidity of 16-24, determined using the phenolphthalein indicator method in GB5009.239 National Food Safety Standard Determination of Acidity of Foods;

[0023] (2) Relative density (20℃ / 4℃): ≥1.028, measured using the method in GB5009.2 National Food Safety Standard - Determination of Density of Food;

[0024] (3) Protein content (g / 100g): ≥3.5%, determined by the Kjeldahl nitrogen method in GB 5009.5 National Food Safety Standard Determination of Protein in Foods;

[0025] (4) Fat content (g / 100g): ≥4.0, determined using the method in GB 5009.6 National Food Safety Standard Determination of Fat in Foods;

[0026] (5) Non-fat milk solids content (g / 100g): ≥8.5, determined using the method in GB 5413.39 National Food Safety Standard Determination of Non-fat Milk Solids in Foods;

[0027] (6) Lactose content (g / 100g): 5.3-5.4, determined by the method in GB 5413.5 National Food Safety Standard Determination of Lactose in Foods;

[0028] (7) Total sugar content (g / 100ml): 5.4-5.6, determined by the method in GB 5009.8 National Food Safety Standard Determination of Total Sugars in Foods;

[0029] (8) The limits of pollutants and mycotoxins meet the national requirements for dairy products.

[0030] It is worth mentioning that total sugar in food production generally refers to reducing sugars (such as glucose, fructose, sucrose, lactose, etc.), and the reducing sugars in common animal milk (such as mare's milk, cow's milk, goat's milk, camel's milk, etc.) are mainly lactose, so the lactose content here is not much different from the total sugar content.

[0031] Preferably, in step S1, the amount of lactase added is 0.05-0.15%, and after being mixed with the milk raw material, it is kept at 35-40°C for 3-5 hours, and then kept at 75-80°C for 5-30 minutes for inactivation. Lactase, also known as β-galactosidase, is a digestive enzyme in the human body. It is the most important digestive enzyme in infants and young children whose main source of nutrition is breast milk / milk powder. The main function of lactase is to digest lactose, hydrolyze lactose into galactose and glucose, and provide energy for microorganisms that cannot directly utilize lactose.

[0032] Specifically, the lactase is Danisco Bonlacta TM Lactase.

[0033] Preferably, the sweetener comprises natural sweetener and artificial sweetener. Sweetener refers to a food additive that can give food sweetness, bringing sweetness and unique flavor to food, and can be divided into natural sweetener and synthetic sweetener according to its source.

[0034] Preferably, the natural sweetener comprises steviol glycoside, mogroside or monk fruit extract, and the artificial sweetener comprises erythritol, maltitol, sorbitol, xylitol, crystalline fructose, sucralose or acesulfame potassium.

[0035] Preferably, the sweetener comprises erythritol, xylitol, crystalline fructose and sucralose, with a total addition amount of 5-10%; the stabilizer comprises sodium carboxymethyl cellulose, sodium citrate and pectin, with a total addition amount of 0.5-1.0%; and the acidifier is citric acid, with an addition amount of 0.05-0.15%.

[0036] Preferably, the sweetener comprises 20-40 parts of erythritol, 10-30 parts of xylitol, 5-10 parts of crystalline fructose and 0.5-1.0 parts of sucralose by weight; and the mass ratio of sodium carboxymethyl cellulose, sodium citrate and pectin in the stabilizer is 1:1:1.

[0037] Preferably, the stabilizer comprises soybean polysaccharide, pectin, sodium citrate or sodium carboxymethyl cellulose. Stabilizer refers to an additive that can improve the stability of food and prevent food from spoiling. Stabilizer can change the physical properties of food, such as texture, taste, tissue structure, etc., provide food with better texture and taste, and extend the shelf life of food.

[0038] Preferably, the acidifier comprises citric acid, malic acid or lactic acid. Acidity regulation can enhance many functional properties of food, such as changing and maintaining the acidity of food and improving its flavor; enhancing antioxidant effects and preventing food from becoming rancid; and complexing with heavy metal ions to prevent oxidation or fading reactions, stabilize color, reduce turbidity, and enhance gelling properties. Acids all have certain antimicrobial effects. Although acid alone is used to inhibit bacteria, the concentration required for preservation is too high, which affects the sensory properties of food and is difficult to apply in practice. However, when used in sufficient concentration, a certain acidifier is selected and used in combination with other preservation methods such as refrigeration and heating, the shelf life of food can be effectively extended. As for the choice of different acids, it depends on the properties of the acid and its cost. The regulations allow the use of 17 types of acidity regulators, including citric acid, potassium citrate, lactic acid, tartaric acid, etc., among which citric acid is a widely used acidifier.

[0039] Preferably, the lactose fermentation bacteria are made into a starter and added to the fermentation base at a volume ratio of 4-6% and mixed, and the fermentation is carried out at a temperature of 30-38°C. The fermentation is stopped when the acidity is within the range of 40-60°T and the total sugar content is less than 0.5%.

[0040] Preferably, after the fermentation is completed, the temperature is maintained at 85-90°C for 10-15 minutes for sterilization, and then cooled to 4-6°C before filling.

[0041] Preferably, in step S4, it is not necessary to add an acidifier to adjust the acidity after the fermentation is completed, so the preparation process is simplified.

[0042] On the other hand, the present invention provides application of the above preparation method in producing sugar-free milk beverages or low-sugar dairy products.

[0043] Preferably, a proper amount of fruit and vegetable juice or cereal extract is added to the fermentation base material without limiting the protein content after fermentation, and a flavored low-sugar dairy product can be prepared.

[0044] Preferably, the preparation method can be used to produce sugar-free or low-sugar yogurt.

[0045] On the other hand, the present invention provides a sugar-free milk beverage prepared by the above preparation method.

[0046] Preferably, the sugar-free milk beverage has a total sugar content of ≤0.5%, an ethanol content of ≤0.5%, a protein content of ≤1.0%, and an acidity of 40-60°T.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. The present invention obtains a sugar-free milk beverage with a total sugar content of ≤0.5%, an ethanol content of ≤0.5%, a protein content of 0.7-1.0%, and an acidity of 40-60°T by a method of enzymolysis followed by fermentation. The fermentation time is short and no acidification process is required after fermentation.

[0049] 2. The present invention can prepare sugar-free milk beverages by using lactase and fermenting with common commercially available lactose fermentation strains, and has low requirements for fermentation strains;

[0050] 3. The preparation method provided by the present invention can be extended to the production of other sugar-free or low-sugar dairy products. DETAILED DESCRIPTION

[0051] It is worth noting that, unless otherwise specified, the raw materials used in the present invention are all common commercially available products, and their sources are not specifically limited. Table 1 illustrates the sources of key materials.

[0052] Table 1 Material Description

[0053] Materials / Equipment Manufacturer / Source Article number / Batch number / Model Lactase Danisco <![CDATA[Bonlacta TM ]]> Skim camel milk powder Xinjiang Wangyuan Camel Milk Industry Co., Ltd. 20240503 Lactobacillus delbrueckii subsp.bulgaricus French production Tianjin Technology Company agent N072401237KDC Streptococcus salivarius subsp. thermophilus French production Tianjin Technology Company agent N072401237KDC Angel brewing dry yeast Angel Yeast Co., Ltd. 20230702M45 Lactobacillus paracasei Xinjiang Wangyuan Camel Milk Industry Co., Ltd. Deposit number: CGMCC No.20803, deposit date: 2020-09-22 Lactobacillus rhamnosus Xinjiang Wangyuan Camel Milk Industry Co., Ltd. Deposit number: CGMCC No.26601, deposit date: 2023-02-21 Kluyveromyces marxianus Xinjiang Wangyuan Camel Milk Industry Co., Ltd. Deposit number: CGMCC No.19778, deposit date: 2020-05-06

[0054] The above Lactobacillus paracasei, Lactobacillus rhamnosus and Kluyveromyces marxianus are all deposited in the General Microbiology Center of China National Committee for the Preservation and Administration of Microbiological Cultures. Preparation Example 1: Acceptance, testing and pretreatment of raw milk

[0055] 1. Raw camel milk acceptance: Raw camel milk is inspected and purchased in accordance with the Xinjiang Uygur Autonomous Region local standard "Raw Camel Milk-DBS65010-2023" raw milk purchase standard. The raw milk indicators meet the following requirements:

[0056] (1) Acidity (°T): The raw camel milk used to prepare fermented camel milk products must be fresh, with a natural acidity of 16-24, determined using the phenolphthalein indicator method in GB 5009.239 National Food Safety Standard Determination of Acidity of Foods;

[0057] (2) Relative density (20℃ / 4℃): ≥1.028, measured using the method in GB 5009.2 National Food Safety Standard - Determination of Density of Food;

[0058] (3) Protein content (g / 100g): ≥3.5%, determined by the Kjeldahl nitrogen method in GB 5009.5 National Food Safety Standard Determination of Protein in Foods;

[0059] (4) Fat content (g / 100g): ≥4.0, determined using the method in GB 5009.6 National Food Safety Standard Determination of Fat in Foods;

[0060] (5) Non-fat milk solids content (g / 100g): ≥8.5, determined using the method in GB 5413.39 National Food Safety Standard Determination of Non-fat Milk Solids in Foods;

[0061] (6) Lactose content (g / 100g): 5.3-5.4, determined by the method in GB 5413.5 National Food Safety Standard Determination of Lactose in Foods;

[0062] (7) Total sugar content (g / 100g): 5.4-5.6, determined by the method in GB 5009.8 National Food Safety Standard Determination of Total Sugars in Foods;

[0063] (8) The limits of pollutants and mycotoxins meet the national requirements for dairy products.

[0064] 2. Milk purification: Use appropriate milk purification equipment to remove spore bacteria, macromolecular fungi and impurities in milk;

[0065] 3. Ingredients: Sweeteners and other auxiliary materials can be added according to product needs, and hydration and ingredients can be carried out in a certain proportion;

[0066] 4. Homogenization: Heat the prepared liquid to 75°C and homogenize under a pressure of 20Mpa;

[0067] 5. Sterilization: Heat the homogenized liquid to 95°C and keep it warm for 5 minutes for sterilization;

[0068] The acceptance of other types of dairy products is carried out according to their respective standards, and the pre-treatment methods remain unified.

[0069] Preparation Example 2: Preparation of starter culture

[0070] The sources of the strains are shown in Table 1, and the method for preparing the starter is as follows:

[0071] (1) Preparation of liquid culture medium: 90% fresh camel milk, 1% galactose, 5% purified water; adjust the pH to 4.5 with citric acid, and sterilize at 95°C for 30 min before use;

[0072] (2) Take out the pure strains stored in the refrigerator, select an appropriate amount and add it to the test tube or triangular flask containing the sterilized liquid to activate it according to the strain requirements until the number of viable bacteria reaches 5.0×10 8 -1.0×10 9 CFU / mL, expanded culture according to 5% inoculum;

[0073] (3) The cultured liquid bacterial solution was centrifuged at 0-4°C, concentrated, and washed with sterile distilled water, and then made into a protective agent using 14.5% skim camel milk powder, 2% galactose, and 83.5% distilled water. It was sterilized at 95°C for 30 minutes before use. The protective agent and bacterial solution were embedded in a volume ratio of 1:1, and the solution was kept at -45°C-40°C for 1 hour and sublimated to 35°C. The number of viable bacteria reached 6×10 8 CFU / g dry powder bacteria.

[0074] The high-efficiency lactose fermentation agent is made from a mixed strain of bacteria provided by Xinjiang Wangyuan Camel Milk Industrial Co., Ltd. Specifically, the three strains of Lactobacillus paracasei, Lactobacillus rhamnosus, and Kluyveromyces marxianus are cultured separately to make bacterial powder and then mixed in a live bacteria ratio of 1:1:1.

[0075] Example 1: Preparation of sugar-free camel milk beverage

[0076] The camel milk sterilized in Preparation Example 1 was cooled to 35° C., 0.05% lactase was added, kept warm for 5 hours, and then kept warm at 80° C. for 5 minutes to inactivate the lactose-free camel milk.

[0077] To prepare 1L of camel milk base material, the following materials are required: 300 ml of low-lactose camel milk, compound sweetener (30 g of erythritol, 20 g of xylitol, 10 g of crystalline fructose, 0.5 g of sucralose), 7.5 g of compound stabilizer (the mass ratio of sodium carboxymethyl cellulose, sodium citrate, and pectin is 1:1:1), and 1 g of citric acid; according to the above proportions, the required amount for production is weighed, the sweetener and stabilizer are mixed and dissolved in the low-lactose camel milk, and the volume is fixed to 90% with purified water, and the citric acid is dissolved in 10% purified water and then slowly added to the camel milk mixture to obtain the camel milk base material;

[0078] The starter prepared by Lactobacillus delbrueckii subspecies bulgaricus in Preparation Example 2 was added to the camel milk base material at a volume ratio of 4% for fermentation, the culture temperature was maintained at 35°C, the acidity and total sugar content were detected after 20 hours of fermentation, and the fermentation was stopped when the acidity reached 40-60°T and the total sugar content was lower than 0.5%, or the fermentation time reached 50 hours and the fermentation was stopped (the fermentation time did not exceed 50 hours). The fermented milk beverage was kept at 85°C for 10 minutes for sterilization, cooled to 4-6°C, and filled to obtain the product.

[0079] Example 2: Preparation of sugar-free mare's milk beverage

[0080] After the raw mare's milk was inspected, it was pretreated according to the method of Preparation Example 1, the sterilized mare's milk was cooled to 38°C, 1.50% lactase was added, and the temperature was kept for 3 hours, and then kept at 78°C for 15 minutes to inactivate the lactose-low mare's milk;

[0081] To prepare 1L of mare's milk base, the following materials are required: 400 ml of low-lactose mare's milk, a compound sweetener (30 g of erythritol, 20 g of xylitol, 10 g of crystalline fructose, and 0.5 g of sucralose), 10 g of a compound stabilizer (sodium carboxymethyl cellulose, sodium citrate, and pectin in a mass ratio of 1:1:1), and 0.5 g of citric acid; according to the above ratio, the required amount for production is weighed, the sweetener and the stabilizer are mixed and dissolved in the low-lactose mare's milk, and the volume is fixed to 90% with purified water, and the citric acid is dissolved in 10% purified water and then slowly added to the mare's milk mixture to obtain the mare's milk base;

[0082] The starter prepared by the thermophilic subspecies of Streptococcus salivarius in Preparation Example 2 was added to the mare's milk base at a volume ratio of 6% for fermentation. The culture temperature was maintained at 35°C. The acidity and total sugar content were detected after 20 hours of fermentation. The fermentation was stopped when the acidity reached 40-60°T and the total sugar content was lower than 0.5%, or the fermentation time reached 50 hours (the fermentation time did not exceed 50 hours). The fermented milk beverage was sterilized at 85°C for 10 minutes, cooled to 4-6°C, and filled to obtain the product.

[0083] Example 3: Preparation of sugar-free milk beverage

[0084] After the raw milk is inspected, it is pretreated according to the method of Preparation Example 1, the sterilized milk is cooled to 40°C, 1.00% lactase is added, and the mixture is kept warm for 4 hours, and then kept warm at 75°C for 30 minutes to inactivate the mixture to obtain low-lactose milk;

[0085] To prepare 1L of milk base, the following materials are required: 350 ml of low-lactose milk, compound sweetener (30 g of erythritol, 20 g of xylitol, 10 g of crystalline fructose, 0.5 g of sucralose), 5 g of compound stabilizer (sodium carboxymethyl cellulose, sodium citrate, and pectin in a mass ratio of 1:1:1), and 1.5 g of citric acid; according to the above ratio, the required amount for production is weighed, the sweetener and stabilizer are mixed and dissolved in the low-lactose milk, and the volume is fixed to 90% with purified water, and the citric acid is dissolved in 10% purified water and then slowly added to the milk mixture to obtain the milk base;

[0086] The starter prepared by Angel brewing dry yeast in Preparation Example 2 was added to the camel milk base at a volume ratio of 5% for fermentation. The culture temperature was maintained at 35°C. The acidity and total sugar content were detected after 20 hours of fermentation. The fermentation was stopped when the acidity reached 40-60°T and the total sugar content was lower than 0.5%, or the fermentation time reached 50 hours and the fermentation was stopped (the fermentation time did not exceed 50 hours). The fermented camel milk beverage was sterilized at 85°C for 10 minutes, cooled to 4-6°C, and filled to obtain the product.

[0087] Comparative Example 1: Preparation of sugar-free camel milk beverage

[0088] The preparation was carried out according to the method of Example 1, except that the starter was replaced with the high-efficiency lactose starter in Preparation Example 2.

[0089] Comparative Example 2: Preparation of Sugar-free Mare's Milk Beverage

[0090] The preparation was carried out according to the method of Example 2, except that the starter was replaced with the high-efficiency lactose starter in Preparation Example 2.

[0091] Comparative Example 3: Preparation of Sugar-Free Milk Beverage

[0092] The preparation was carried out according to the method of Example 3, except that the starter was replaced with the high-efficiency lactose starter in Preparation Example 2.

[0093] Comparative Example 4: Preparation of sugar-free camel milk beverage

[0094] The preparation was carried out according to the method of Example 1, except that no lactase was added to decompose the raw camel milk after pretreatment, and the subsequent camel milk base material was directly prepared.

[0095] Comparative Example 5: Preparation of Sugar-free Mare's Milk Beverage

[0096] The preparation was carried out according to the method of Example 2, except that no lactase was added to decompose the raw mare's milk after pretreatment, and the subsequent preparation of the mare's milk base was carried out directly.

[0097] Comparative Example 6: Preparation of Sugar-Free Milk Beverage

[0098] The preparation was carried out according to the method of Example 3, except that no lactase was added to decompose the raw milk after pretreatment, and the subsequent milk base was prepared directly.

[0099] Comparative Example 7: Preparation of sugar-free camel milk beverage

[0100] The preparation was carried out according to the method of Example 1, except that no lactase was added to decompose the raw camel milk after pretreatment, and the subsequent camel milk base was prepared directly, and the starter was replaced with the high-efficiency lactose starter in Preparation Example 2.

[0101] Comparative Example 8: Preparation of Sugar-Free Mare's Milk Beverage

[0102] The preparation was carried out according to the method of Example 2, except that no lactase was added to decompose the raw mare's milk after pretreatment, and the subsequent mare's milk base was prepared directly, and the starter was replaced with the high-efficiency lactose starter in Preparation Example 2.

[0103] Comparative Example 9: Preparation of Sugar-Free Milk Beverage

[0104] The preparation was carried out according to the method of Example 3, except that no lactase was added to decompose the raw milk after pretreatment, and the subsequent milk base was prepared directly, and the starter was replaced with the high-efficiency lactose starter in Preparation Example 2.

[0105] Effect Example 1: Determination of total sugar, acidity, ethanol and protein content

[0106] According to the method in Preparation Example 1, the total sugar, acidity, and protein contents of the products in Examples 1-3 and Comparative Examples 1-9 were determined, and the fermentation time was calculated. The ethanol content of the products was determined by the distillation method in "GB / T4928-2001 Beer Analysis Method", and the results are shown in Table 2.

[0107] It can be seen from Table 2 that in the one-stage method, the commercially available lactose fermentation strains used in Comparative Examples 4-6 have a long fermentation time, low efficiency, high fermentation cost, and it is difficult to reduce the total sugar to 0.5%; while Comparative Examples 7-9 use a high-efficiency lactose fermentation agent, and the fermentation time is greatly shortened when the total sugar is reduced to below 0.5%, indicating that it is difficult for commercially available lactose fermentation strains to produce sugar-free milk beverages through the one-stage method; in the two-stage method, the fermentation time of commercially available lactose fermentation strains used in Examples 1-3 is significantly shortened, which is similar to the fermentation time of the high-efficiency lactose fermentation agent in Comparative Examples 1-3, and the total sugar content (≤0.5%) and acidity (40-60°T) also meet the requirements, indicating that the fermentation efficiency of commercially available lactose fermentation strains is greatly improved in the two-stage method, the fermentation cycle is shortened, the requirements for fermentation strains are reduced, and the fermentation cost is reduced, which can meet the requirements for fermentation production of sugar-free milk beverages with total sugar ≤0.5%, ethanol ≤0.5%, protein content 0.7-1.0%, and acidity 40-60°T, and no acidification step is required after fermentation.

[0108] Table 2 Comparison of effects of different implementation methods

[0109]

[0110]

[0111] Effect Example 2: Sensory and Taste Evaluation

[0112] Table 3 shows the sensory taste evaluation results of 300 people on the products in Examples 1-3 and Comparative Examples 1-9. As can be seen from Table 3, the products in Examples 1-3 and Comparative Examples 1-3 are well received by consumers, and all indicators have received high evaluations, indicating that the commercially available lactose fermentation strains can produce a good taste similar to that of a high-efficiency lactose fermentation agent in the two-stage method, and the evaluation is high; in contrast, the evaluations of Comparative Examples 4-6 are relatively low, indicating that the milk beverages produced by the commercially available lactose fermentation strains in the one-stage method have a poor taste and a low evaluation, reflecting the advantage of the two-stage method provided by the present invention that has low requirements for the lactose fermentation ability of the fermentation strains.

[0113] Table 3 Sensory taste evaluation of different products

[0114]

[0115] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a fermented sugar-free milk beverage, characterized in that: The following steps are involved: S1: adding lactase to the milk raw material for enzymatic hydrolysis to obtain hydrolyzed milk; S2: adding a sweetener, a stabilizer and an acidifier to the hydrolyzed milk and mixing them evenly to obtain a fermentation base; S3: adding lactose fermentation bacteria to the fermentation base for fermentation; S4: After fermentation, the finished product is obtained through sterilization, cooling and filling.

2. The preparation method according to claim 1, characterized in that: The lactose fermentation bacteria include commercially available lactic acid bacteria or commercially available yeasts, the commercially available lactic acid bacteria include Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, Bifidobacterium lactis, Bifidobacterium longum, Lactococcus lactis, Lactobacillus helveticus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus rhamnosus or Leuconostoc pseudomesenteroides, and the commercially available yeast includes Kluyveromyces marxianus or Saccharomyces cerevisiae.

3. The preparation method according to claim 2, characterized in that: The lactose fermenting bacteria include any one of Lactobacillus delbrueckii subspecies bulgaricus, Streptococcus salivarius subspecies thermophilic or Saccharomyces cerevisiae.

4. The preparation method according to claim 1, characterized in that: The dairy raw materials include natural dairy substances and processed dairy substances, the natural dairy substances include animal milk, and the processed dairy substances include milk powder.

5. The preparation method according to claim 4, characterized in that: The animal milk includes camel milk, mare milk or cow milk, and the milk powder includes whole milk powder, skim milk powder or skim whey powder.

6. The preparation method according to claim 1, characterized in that: In step S1, the lactase is added in an amount of 0.05-0.15%, and after being mixed with the milk raw material, the mixture is kept at 35-40° C. for 3-5 hours, and then kept at 75-80° C. for 5-30 minutes to be inactivated.

7. The preparation method according to claim 1, characterized in that: The sweeteners include natural sweeteners and artificial sweeteners.

8. The preparation method according to claim 7, characterized in that: The natural sweetener comprises steviol glycoside, mogroside or mogroside extract, and the artificial sweetener comprises erythritol, maltitol, sorbitol, xylitol, crystalline fructose, sucralose or acesulfame potassium.

9. The preparation method according to claim 1, characterized in that: The stabilizer comprises soybean polysaccharide, pectin, sodium citrate or sodium carboxymethyl cellulose.

10. The preparation method according to claim 1, characterized in that: The acid regulator comprises citric acid, malic acid or lactic acid.

11. The preparation method according to claim 1, characterized in that: The sweetener comprises erythritol, xylitol, crystalline fructose and sucralose, and the total addition amount is 5-10%; the stabilizer comprises sodium carboxymethyl cellulose, sodium citrate and pectin, and the total addition amount is 0.5-1.0%; the acidifier is citric acid, and the addition amount is 0.05-0.15%.

12. The preparation method according to claim 11, characterized in that: The sweetener comprises 20-40 parts of erythritol, 10-30 parts of xylitol, 5-10 parts of crystalline fructose and 0.5-1.0 parts of sucralose by weight; the mass ratio of sodium carboxymethyl cellulose, sodium citrate and pectin in the stabilizer is 1:1:

1.

13. The preparation method according to claim 1, characterized in that: In step S3, the lactose fermentation bacteria are prepared into a starter and then added into the fermentation base material at a volume ratio of 4-6% and mixed evenly, and the fermentation is carried out at a temperature of 30-38°C. The fermentation is stopped when the acidity is within the range of 40-60°T and the total sugar content is less than 0.5%.

14. The preparation method according to claim 1, characterized in that: After the fermentation in step S4 is completed, the temperature is maintained at 85-90° C. for 10-15 minutes for sterilization, and the mixture is cooled to 4-6° C. before filling.

15. Use of the preparation method according to any one of claims 1 to 14 in the production of sugar-free milk beverages or low-sugar dairy products.

16. A sugar-free milk beverage prepared by the preparation method according to any one of claims 1 to 14.

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