Application of lipase raw material for maintaining good stability and taste in viable bacteria product

Abstract

The invention relates to application of a lipase raw material for maintaining good stability and flavor in a liquid viable bacterium product, in particular to application of the lipase raw material for maintaining good tissue state and flavor of a product with active lactic acid bacteria in the shelf life. The method is especially used for maintaining the tissue state and flavor stability of the low-sugar active lactic acid bacteria product in the shelf life. The invention also relates to a corresponding viable bacterial product and to a method for producing a viable bacterial product.

Description

Technical Field

[0001] The present invention relates to the application of lipase raw materials for maintaining good stability and flavor in liquid live bacteria products, in particular to the application of lipase raw materials for maintaining good organizational state and flavor of products with active lactic acid bacteria during the shelf life, and in particular to the application of lipase raw materials for maintaining the organizational state and flavor stability of low-sugar active lactic acid bacteria products during the shelf life. Background Art

[0002] Fermented milk refers to a large category of dairy products made from cow's milk and other animal milk through a lactic acid fermentation process. For this type of product, the lactic acid bacteria must be present in large quantities and remain alive and active during the shelf life.

[0003] Lactic acid bacteria beverage is a kind of milk-containing beverage, which usually refers to a beverage made from milk or dairy products, with water, white sugar, or one or more ingredients such as sweeteners, acidulants, fruit juice, tea, etc. added to the emulsion made by lactic acid bacteria fermentation. Depending on whether it has been sterilized, it is divided into non-viable bacteria (sterilized) type and live bacteria (unsterilized) type. Non-viable bacteria lactic acid bacteria beverages can be stored at room temperature; the storage and transportation of live bacteria lactic acid bacteria beverages must usually be kept under cold chain conditions of 2-8°C, otherwise the number of live lactic acid bacteria will decrease and the taste of the beverage will be affected.

[0004] Therefore, how to ensure that products containing active lactic acid bacteria have a good texture and a good taste during the shelf life, thereby providing consumers with live bacteria products with a stable texture and good taste and flavor, has always been a problem in the industry.

[0005] Lipase (Lipase, glycerol ester hydrolase) belongs to the carboxyl ester hydrolase class, which can gradually hydrolyze triglycerides into glycerol and fatty acids. Lipase exists in animals, plant tissues and microorganisms (such as molds, bacteria, etc.) containing fat. Lipases include phosphatases, sterolases and carboxylesterases. Depending on the source of lipase, lipase can also be divided into animal lipase, plant lipase and microbial lipase. Lipase can be used in a variety of food processing fields such as oils, dairy products, ice cream, baking, etc., and can promote oil hydrolysis, enhance food flavor, etc.

[0006] At present, there is no report on using lipase raw materials to maintain good stability and taste in live bacteria products. Summary of the invention

[0007] One object of the present invention is to use lipase and / or lipase raw materials to maintain a good tissue state of live bacteria products, especially low-sugar live bacteria products during the shelf life.

[0008] In one embodiment, the lipase of the present invention is preferably an animal lipase.

[0009] The object of the present invention is to provide a new application of lipase and / or lipase raw materials. Lipase (Lipase, glycerol ester hydrolase) belongs to the carboxyl ester hydrolase class and can gradually hydrolyze triglycerides into glycerol and fatty acids. Lipase exists in animals, plant tissues and microorganisms (such as molds, bacteria, etc.) containing fat. Lipases include phosphatases, sterolases and carboxylesterases. Depending on the source of the lipase, lipase can also be divided into animal lipases, plant lipases and microbial lipases. Animal lipases are preferred in the present invention. The present invention is an application of using lipase raw materials to maintain a good tissue state during the shelf life of low-sugar live bacteria products.

[0010] According to a specific embodiment of the present invention, the amount of lipase raw material added has an important influence on the maintenance of the tissue state of the active lactic acid bacteria fermented product. The recommended amount of lipase material added is 0.01-1wt%, preferably 0.05-0.4wt%, which has the best effect on maintaining the product tissue state.

[0011] Unless otherwise specified, the proportions, contents, addition amounts, etc. involved in the present invention are all weight proportions, contents, addition amounts, etc.

[0012] The low-sugar live bacteria product with added lipase enzyme raw materials provided by the present invention maintains the stability of the tissue state and flavor during the shelf life. The low-sugar live bacteria product can be a liquid fermented dairy product or a low-temperature active lactic acid bacteria beverage product. The milk liquid used in the present invention mainly refers to fresh milk or reconstituted milk that should meet the purchase standards of fresh cow milk in my country. It can be whole milk, skim milk or low-fat milk. Preferably, the milk includes one or a combination of two or more of whole milk, partially skimmed milk and fully skimmed milk. When the milk content in the product is 80-90wt%, the physical and chemical indicators of the finished product include milk protein content ≥2.3wt%, fat content ≥2.5wt%, and total lactic acid bacteria ≥1*10 6 CFU / mL is usually called fermented milk. When the milk content in the product is 30-80wt%, the milk protein content is ≤2.3wt%, and the total number of lactic acid bacteria is ≥1*10 6 CFU / mL, and the milk protein content in the physical and chemical indicators of the finished product is ≥1.0wt%, which is usually called a live bacteria-containing milk beverage; the milk protein content in the physical and chemical indicators of the finished product is ≥0.7wt%, which is usually called an active lactic acid bacteria beverage.

[0013] In the above-mentioned fermented milk and lactobacillus beverage, preferably, the thickener selected to be added by the present invention includes one or more combinations of gellan gum, sodium carboxymethyl cellulose, propylene glycol alginate, locust bean gum, gelatin, agar, gum arabic, guar gum, xanthan gum, carrageenan, pectin, oxidized hydroxypropyl starch, etc., which work together with the product of the present invention to better achieve the stability of the product. The emulsifier selected to be added by the present invention can be selected from one or more combinations of glyceryl monostearate, glyceryl distearate, polyglycerol ester, sucrose ester, sodium stearoyl lactylate, monoglyceryl citrate, monoglyceryl tartarate, monoglyceryl succinate, monoglyceryl acetate, sodium tyroyl lactylate, etc. The stabilizer selected for addition in the present invention includes one or a combination of two or more of pectin, carboxymethyl cellulose, gellan gum, propylene glycol alginate, and soluble soybean polysaccharides; more preferably, the stabilizer is soluble soybean polysaccharide and / or pectin; further preferably, the added amount of the soluble soybean polysaccharide is less than 1% of the total weight of the fermented milk or lactic acid bacteria beverage raw materials, and the added amount of the pectin is less than 0.5% of the total weight of the fermented milk or lactic acid bacteria beverage raw materials. Regardless of whether it contains soluble soybean polysaccharides and pectin at the same time, or only contains one of the two, their contents are controlled within the above range.

[0014] The fermented milk or lactic acid bacteria beverage provided by the present invention can be white fermented milk, white lactic acid bacteria beverage, and can also be made into brown fermented milk, brown lactic acid bacteria beverage through Maillard reaction. When making brown fermented milk or brown lactic acid bacteria beverage milk base, generally one or a combination of two or more of glucose, fructose, galactose, fructose syrup, etc. are additionally added. The preferred amount of monosaccharide added is converted into 0.2%-8% of the total amount of yogurt raw materials (that is, the amount of sugar added accounts for 0.2%-8% of the total weight of the fermented milk or lactic acid bacteria beverage raw materials in terms of monosaccharide conversion). The browning treatment is carried out at 115°C for 5-10 minutes or in a water bath above 90°C for 2h-4h. Lactase can also be used to hydrolyze lactose in milk or reconstituted milk before the browning treatment is carried out.

[0015] According to a preferred specific embodiment of the present invention, the leavening agent comprises one or more of the mixing of Lactobacillus casei, Lactobacillus paracasei, Lactobacillus rhamnosus, Lactobacillus helveticus, Lactobacillus plantarum, Lactobacillus bulgaricus, Streptococcus thermophilus, etc. Lactobacillus paracasei is preferably used in lactobacillus beverage. The inoculum amount of the leavening agent is 0.0001-0.008wt%, and the preferred addition amount is 0.001-0.006wt%. Fermented plant milk and fermented milk preferably use Lactobacillus bulgaricus and Streptococcus thermophilus, and the inoculum amount of the leavening agent is 0.0001-0.01wt%, and the preferred addition amount is 0.001-0.006wt%.

[0016] Preferably, the raw materials containing active fermented products may also include one or a combination of two or more of carbohydrates, edible flavors, acidity regulators, conventional auxiliary materials and water. When adding sweetening auxiliary materials, the amount of sugar alcohol added should be reduced accordingly. Conventional auxiliary materials can be used to adjust the taste of the modulated milk or the solid content index of the material. The acidity regulator is selected from one or more of lactic acid, citric acid and malic acid, tartaric acid and phosphoric acid, and its content is 0.001wt%-1wt% based on 100 parts by weight of the raw materials.

[0017] The lipase of the present invention can catalyze the hydrolysis, alcoholysis, esterification, transesterification and reverse synthesis of triacylglycerol and other water-insoluble esters. The recommended dosage in the live bacteria product is 0.01-1wt%, preferably 0.05-0.4wt%.

[0018] The fermented product containing live bacteria of the present invention may also be selectively added with one or more of dietary fiber, compound nutrients, fruit and vegetable juice, sweeteners (sugars or sweeteners), edible flavors, salt or other seasoning substances or additives as needed to give the product more abundant nutrition or further improve the flavor of the product and increase the variety of the product. The selection and addition amount of these substances can be determined by those skilled in the art according to actual needs.

[0019] In the above-mentioned dairy products containing active lactic acid bacteria, preferably, the conventional auxiliary materials include one or a combination of two or more of sweetened condensed milk, concentrated whey protein, and concentrated milk protein. The amount of protein raw materials added can be determined according to the needs of the product.

[0020] The equipment used in the production process of the present invention, such as steam fumigation equipment, homogenizer for homogenization, mixing tank for mixing, fermentation tank for fermentation, and sterilization equipment, can all adopt well-known equipment in the art. The filling of the liquid dairy product of the present invention can also be carried out according to the existing filling technology of liquid products in the art. The specific production equipment and filling process will not be described in detail here.

[0021] In the product containing active lactic acid bacteria of the present invention, there is no precipitation or stratification during the shelf life of the product, the product texture is uniform and the color is stable.

[0022] The method for preparing fermented milk or fermented vegetable milk containing lipase raw materials provided by the present invention may comprise the following steps:

[0023] (1) Material preparation: Heat the purified water to 35-50° C., start stirring, then directly add the qualified milk or whole milk powder, add one or more of the lipase raw materials, white sugar, stabilizer, conventional auxiliary materials, etc., and stir for 60 minutes to prepare the material;

[0024] (2) Homogenization: The liquid is homogenized at a pressure of 15-30 MPa and preheated to about 60-70°C before homogenization;

[0025] (3) Sterilization: The homogenized liquid is sterilized at 93-97°C for 5-10 minutes;

[0026] (4) Cooling and inoculation: Cooling the sterilized liquid to an inoculation temperature of 37°C-42°C and inoculating;

[0027] (5) Fermentation: When the acidity of the feed reaches 70-80°T or the pH is less than 4.5, the fermentation is terminated (the temperature and fermentation time range is applicable to most freeze-dried direct-injection fermentation agents). The fermentation can be terminated when either the acidity index or the pH index reaches the requirement;

[0028] If a solidified product is produced: the inoculated liquid can be filled into unit packaging, and then the temperature is maintained at 41-43°C for 4-5 hours. When the acidity reaches 70-75°T, the product is cooled to 2-6°C and refrigerated for about 12-24 hours to obtain a solidified finished product.

[0029] If producing stirred products: demulsify the fermented liquid and immediately cool it to 20-25℃, fill it, and then refrigerate it at 2-6℃ for about 12-24 hours to obtain the stirred finished product;

[0030] If producing drinking products: after the fermentation of the liquid is completed, it is homogenized twice, and the homogenization pressure is 0-10MPa before filling to obtain a drinking product.

[0031] The fermented product obtained by the present invention has good flavor and taste, and the bacterial count of the product is constant or decreases slightly during the shelf life, the state is stable, no unacceptable stratification, precipitation and fat floating occurs, and no obvious odor is generated.

[0032] The method for preparing a lactic acid bacteria beverage containing a lipase raw material provided by the present invention may comprise the following steps:

[0033] (1) Chemical synthesis and hydration: Heat the whole-fat reconstituted milk or milk to 35°C-50°C, then add one or a combination of two or more of sugars, lipase raw materials, stabilizers, conventional auxiliary materials, etc., and stir for 60 minutes to chemically synthesize;

[0034] (2) Homogenization: The liquid is homogenized at a pressure of 15-30 MPa and preheated to about 65°C before homogenization;

[0035] (3) Sterilization: The homogenized liquid is sterilized at 93-97°C for 5-10 minutes;

[0036] (4) Cooling and inoculation: Cooling the liquid to the inoculation temperature of 37°C-42°C and inoculating;

[0037] (5) Fermentation: When the acidity of the white milk lactic acid bacteria base reaches 70-80°T, the fermentation is terminated, and the fermentation time is 4-6 hours; the acidity of the brown milk base needs to reach above 160°T, and the general fermentation time is 48-90h. When the pH of the fermented plant milk is less than 4.0, the fermentation is terminated, and the general fermentation time is 6-10 hours. The range of fermentation temperature and fermentation time is applicable to most freeze-dried direct-injection starter cultures;

[0038] (6) homogenizing and cooling: cooling the fermented liquid to room temperature and homogenizing under sterile conditions at a homogenization pressure of 15-30 MPa to obtain a yogurt base;

[0039] (7) preparing a yogurt base diluent: adding one or a combination of two or more of white sugar, stabilizer, sweetener, etc. to prepare a diluent, stirring for 30 to 40 minutes to dissolve the material, and then pasteurizing at 95° C. / 300 seconds, and cooling to below 30° C. for later use;

[0040] (8) Preparation of beverage: The amount of yogurt base added is 20%-75% of the total weight of the active lactic acid bacteria beverage, and the above-mentioned yogurt base diluent is added at the same time, and then the mixed solution is low-temperature homogenized at a homogenization pressure of 15-30 MPa to obtain a lactic acid bacteria beverage.

[0041] When applying lipase raw materials to live bacteria beverages, they need to be used in the milk base of the beverage.

[0042] The active lactic acid bacteria beverage obtained according to the present invention has good flavor and taste, and the bacterial count of the product is constant or decreases slightly during the shelf life, the state is stable, no unacceptable stratification, precipitation and fat floating occurs, and no obvious odor is generated.

[0043] Therefore, in one aspect, the present invention relates to the use of lipase as a stabilizer in the preparation of live bacterial preparations.

[0044] In one embodiment, the amount of lipase added to the raw material as a stabilizer is 0.01-1 wt %, preferably 0.05-0.4 wt % of the total amount of the raw material.

[0045] In another embodiment, the live bacteria product is an active lactic acid bacteria product; preferably, the live bacteria product is flavored fermented milk or a lactic acid bacteria beverage; more preferably, the live bacteria product is low-sugar or sugar-free flavored fermented milk or a low-sugar or sugar-free lactic acid bacteria beverage.

[0046] In another aspect, the present invention provides a live bacteria product, wherein the raw materials of the live bacteria product include lipase as a stabilizer.

[0047] In one embodiment, the amount of lipase added to the raw material as a stabilizer is 0.01-1 wt %, preferably 0.05-0.4 wt % of the total amount of the raw material.

[0048] In another embodiment, the live bacteria product is an active lactic acid bacteria product; preferably, the live bacteria product is flavored fermented milk or a lactic acid bacteria beverage; more preferably, the live bacteria product is low-sugar or sugar-free flavored fermented milk or a low-sugar or sugar-free lactic acid bacteria beverage.

[0049] In yet another aspect, the present invention provides a method for maintaining the stability of the tissue state and / or the taste of a live bacteria product during the shelf life, which comprises including lipase as a stabilizer in the raw materials of the live bacteria product.

[0050] In one embodiment, the amount of lipase added to the raw material as a stabilizer is 0.01-1 wt %, preferably 0.05-0.4 wt % of the total amount of the raw material.

[0051] In another embodiment, the live bacteria product is an active lactic acid bacteria product; preferably, the live bacteria product is flavored fermented milk or a lactic acid bacteria beverage; more preferably, the live bacteria product is low-sugar or sugar-free flavored fermented milk or a low-sugar or sugar-free lactic acid bacteria beverage.

[0052] In a further aspect, the present invention also provides a method for preparing a live bacteria product, comprising:

[0053] providing a feedstock comprising lipase as a stabilizer;

[0054] Inoculate the starter and ferment.

[0055] Optionally, the amount of lipase added as a stabilizer in the raw material is 0.01-1wt% of the total amount of the raw material, preferably 0.05-0.4wt%.

[0056] Optionally, the live bacteria product is an active lactic acid bacteria product; preferably, the live bacteria product is flavored fermented milk or a lactic acid bacteria beverage; more preferably, the live bacteria product is low-sugar or sugar-free flavored fermented milk or a low-sugar or sugar-free lactic acid bacteria beverage.

[0057] Also optionally, the fermentation agent is selected from Lactobacillus casei, Lactobacillus paracasei, Bacillus rhamnosus, Lactobacillus helveticus, Lactobacillus plantarum, Lactobacillus bulgaricus, Streptococcus thermophilus or a combination thereof; preferably, the fermentation agent is selected from Lactobacillus bulgaricus, Streptococcus thermophilus or a combination thereof.

[0058] The beneficial effects of the present invention are as follows:

[0059] The present invention proposes for the first time to use lipase raw materials as stabilizers for maintaining good tissue state and flavor of liquid active fermented dairy products.

[0060] The invention provides a live bacteria product with good flavor, taste and texture through a reasonable formula and appropriate process.

[0061] The present invention controls the fat content of the product by the dosage range of the lipase raw material, thereby controlling the material composition and thus affecting the product stability. The present invention is the first to use the lipase raw material as a stabilizer to maintain a good stable state and flavor of the active fermented product during the shelf life, which is a new application of lipase. DETAILED DESCRIPTION

[0062] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0063] Example 1-7: A low-sugar flavored fermented milk containing lipase

[0064] 1. Raw material formula (based on 1000kg total raw material):

[0065] Lipase 0.1-10kg

[0066] Mixed bacteria (mainly thermophilic Streptococcus and bulgaricus Lactobacillus) 100g

[0067] Milk residue kg.

[0068] The bacteria used to prepare flavored fermented milk were mainly thermophilic Streptococcus and bulgaricus Lactobacillus, which were purchased from Chr. Hansen (Beijing) Trading Co., Ltd. Lipase was purchased from DSM Trading (Shanghai) Co., Ltd.

[0069] 2. The production of the flavored fermented milk containing lipase in this embodiment is mainly carried out according to the following operations:

[0070] (1) Chemical synthesis and hydration: Heat the milk to 45°C, then add lipase and stir for 60 minutes;

[0071] (2) Homogenization: Homogenize the liquid feed at a homogenization pressure of 15 MPa and preheat to about 65°C before homogenization;

[0072] (3) Sterilization: sterilization reaction at 95°C for 300 seconds;

[0073] (4) Cooling and inoculation: Cooling the liquid to the inoculation temperature of 42°C and inoculating;

[0074] (5) Fermentation: Starting from 3.5 hours, the pH is measured every 30 minutes, and the fermentation is terminated when the pH is <4.5. After demulsification, stirred flavored fermented milk is obtained;

[0075] Comparative Example 1: The addition of lipase was omitted, and the other steps were the same as those in Example 1.

[0076] All samples were stored at 20°C.

[0077] 3. Results

[0078] 3.1 Effect of lipase on the number of viable bacteria in the product

[0079] The specific results are shown in Table 1. The present invention uses the method specified in the National Food Safety Standard Food Microbiology Test Lactic Acid Bacteria Test (GB4789.35-2010) to determine the total number of lactic acid bacteria in the product.

[0080] Table 1: Effect of different amounts of lipase added on the number of viable bacteria during the shelf life of the product

[0081]

[0082] *This refers to the total number of thermophilic Streptococcus and bulgaricus Lactobacillus

[0083] As shown in Table 1, within the addition range of the lipase raw material of the present invention, under the same action time, the product with the addition of lipase will not affect the number of viable bacteria in the product. When the addition amount of lipase is less than 0.05%, the addition of lipase raw material will not affect the fermentation time. However, when the addition amount of lipase is greater than 0.05%, the greater the addition amount of lipase, the more free fatty acids are hydrolyzed in fat, resulting in an increase in the acidity of the feed liquid, and the longer the time required for the product to ferment to the same pH.

[0084] 3.2 Effect of lipase on product acidity

[0085] The present invention adopts the method specified in the national food safety standard for determination of food acidity (GB 5009.239-2016), and uses a Mettler G10S-acidity titrator to determine the acidity of the product. Two parallel samples are measured each time, and the average value of the two samples is finally taken. The measurement result retains one decimal place. The specific results are shown in Table 2.

[0086] Table 2: Effect of different amounts of lipase added on the acidity of flavored fermented milk during shelf life

[0087]

[0088] It can be seen from Table 2 that within the addition range of the lipase raw material of the present invention, the addition of the lipase raw material has a significant effect on the initial acidity of the product, but has little effect on the acidity of the product after fermentation.

[0089] 3.3 Effect of lipase on product stability

[0090] The test samples were divided into 250ml blue-capped bottles, and the liquid in each bottle was at the 200ml scale line. Use a transparent soft ruler to measure the water separation height along the wall. Water separation height ≤ 2mm-no water separation. 2mm≤water separation height ≤ 4mm-slight water separation, 4mm≤water separation height ≤ 8mm is slight water separation, 8mm≤water separation height-partial water separation. Partial water separation is unacceptable. See Table 3 for details.

[0091] Table 3: Effect of different amounts of lipase added on the shelf stability of flavored fermented milk - tissue state during shelf life

[0092]

[0093] According to the results of the stability test, the greater the amount of lipase raw material added, the better the stability of the product. However, when the added amount reaches 0.4% or above, the increase in the amount of lipase added has little effect on the stability of the product.

[0094] 3.4 Effect of lipase on taste

[0095] The product stored at 20°C for 6 days was tasted. The tasting results are shown in Table 4.

[0096] Table 4: Tasting results of samples with lipase and control samples

[0097] Lipase addition amount‰ Tasting results Compared with the control Comparative Example 1 Moderate sweetness and sourness, no peculiar smell —— Example 1-0.1 Moderate sweetness and sourness, no peculiar smell Equivalence Example 2-0.5 Moderate sweetness and sourness, no peculiar smell Equivalence Example 3-1 Moderate sweetness and sourness, no peculiar smell like Example 4-2 Moderate sweetness and sourness, no peculiar smell like Example 5-4 Moderate sweetness and sourness, no peculiar smell like Embodiment 6-8 Moderate sweet and sour, with a strange smell dislike Examples 7-10 Moderate sweet and sour, with a strange smell dislike

[0098] The products stored at 4-6°C for 24 days were tasted. The tasting results are shown in Table 5.

[0099] Table 5: Tasting results of samples with lipase and control samples

[0100] Lipase addition amount‰ Tasting results Compared with the control Comparative Example 1 Moderate sweetness and sourness, no peculiar smell —— Example 1-0.1 Moderate sweetness and sourness, no peculiar smell Equivalence Example 2-0.5 Moderate sweetness and sourness, no peculiar smell Equivalence Example 3-1 Moderate sweetness and sourness, no peculiar smell like Example 4-2 Moderate sweetness and sourness, no peculiar smell like Example 5-4 Moderate sweetness and sourness, no peculiar smell like Embodiment 6-8 Moderate sweetness and sourness, no peculiar smell Equivalence Examples 7-10 Moderate sweet and sour, with a strange smell dislike

[0101] According to the tasting results, under the same action time, when the amount of lipase raw materials added is ≤0.4%, storage at 20℃ for 6 days and refrigerated storage at 4-6℃ for 24 days will not bring unpleasant taste. However, when the amount of lipase raw materials added is greater than or equal to 1%, the liquid will have an odor, affecting the flavor of the product. When the amount of lipase raw materials added is between 0.4% and 1%, the liquid will have an odor when stored at 20℃ for 6 days, but will not produce an odor when stored at 4-6℃ for 24 days.

[0102] The flavored fermented milk produced by the embodiment of the present invention has good flavor and taste, a refreshing taste, can be stored at 20°C for 6 days and 4-6°C for 24 days, does not have unacceptable stratification or precipitation, has no obvious odor, and has a good number of live bacteria.

[0103] Example 8-14: A low-sugar lactic acid bacteria beverage containing lipase

[0104] 1. Raw material formula (based on 1000kg total raw material):

[0105]

[0106] The strains of the yogurt base for the fermented active lactic acid bacteria beverage were mainly Lactobacillus paracasei, which was purchased from Chr. Hansen (Beijing) Trading Co., Ltd. Lipase was purchased from DSM Trading (Shanghai) Co., Ltd.

[0107] 2. The production of the active lactic acid bacteria beverage containing lipase in this embodiment is mainly carried out according to the following operations:

[0108] (1) Chemical preparation and hydration: Heat part of the pure water to 45°C, then add whole milk powder, glucose, and lipase, and start stirring for 30 to 40 minutes to prepare the mixture for chemical preparation and hydration;

[0109] (2) Homogenization: Homogenize the liquid feed at a homogenization pressure of 15 MPa and preheat to about 65°C before homogenization;

[0110] (3) Sterilization: sterilization reaction at 95°C for 300 seconds;

[0111] (4) Cooling and inoculation: Cooling the liquid to the inoculation temperature of 37°C and inoculating;

[0112] (5) Fermentation: Fermentation is terminated when the acidity reaches 180°T;

[0113] (6) homogenizing and cooling: cooling the fermented liquid to room temperature and homogenizing under sterile conditions at a homogenization pressure of 15 MPa to obtain a yogurt base;

[0114] (7) preparing a yogurt base diluent: preparing sugar water with white sugar and soluble soybean polysaccharide, pasteurizing the sugar water at 95° C. for 300 seconds, and cooling the sugar water to below 30° C. for later use;

[0115] (8) Preparation of beverage: The amount of yogurt base added is 30% of the total weight of the active lactic acid bacteria beverage, and the balance is supplemented with the prepared sugar water. The mixed solution is then homogenized at low temperature with a homogenization pressure of 18 MPa.

[0116] Comparative Example 2: The addition of lipase was omitted, and the other steps were the same as those in Example 8.

[0117] Comparative Example 3: The addition of lipase was cancelled, and the whole milk powder was replaced with skim milk powder with the same protein content. The rest was the same as Example 8.

[0118] Comparative Example 4: The addition of lipase was cancelled, and 0.2 kg of high-fat pectin was supplemented. The rest was the same as Example 8.

[0119] 3. Results

[0120] 3.1 Effect of lipase on the number of viable bacteria in the product

[0121] The specific results are shown in Table 6. The present invention uses the method specified in the National Food Safety Standard Food Microbiology Test Lactic Acid Bacteria Test (GB4789.35-2010) to determine the total number of lactic acid bacteria in the product.

[0122] Table 6: Effect of different amounts of lipase added on the number of viable bacteria in lactic acid beverage products during shelf life

[0123]

[0124] *This refers to the total number of Lactobacillus paracasei

[0125] As can be seen from Table 6, within the addition range of the lipase raw material of the present invention, under the same action time, the product with the addition of lipase will not affect the number of live bacteria in the product. When the addition amount of lipase is less than 0.05%, the addition of lipase raw material will not affect the fermentation time; when the addition amount of lipase is greater than 0.05% and ≤ 0.4%, the greater the addition amount of lipase, the more free fatty acids are hydrolyzed in fat, resulting in an increase in the acidity of the feed liquid, and the longer the time required for the product to ferment to the same pH. However, it does not affect the number of live bacteria in the product; when the addition amount of lipase is greater than 0.4%, the number of live bacteria in the product will be affected, and the higher the addition amount, the lower the number of live bacteria in the product.

[0126] 3.2 Effect of lipase on product acidity

[0127] The present invention adopts the method specified in the national food safety standard for determination of food acidity (GB 5009.239-2016), and uses a Mettler G10S-acidity titrator to determine the acidity of the product. Two parallel samples are measured each time, and the average value of the two samples is finally taken. The measurement result retains one decimal place. The specific results are shown in Table 7.

[0128] Table 7: Effect of different amounts of lipase added on the acidity of active lactic acid bacteria beverages during shelf life

[0129]

[0130] As shown in Table 7, within the addition range of the lipase raw material of the present invention, when the addition amount of the lipase raw material is greater than 0.4%, both the initial fermentation acidity and the acidity during the shelf life of the product are affected. And the higher the addition amount of the lipase, the smaller the change in acidity during the shelf life of the product. When the addition amount of the lipase raw material is ≤0.4%, the addition of the lipase has little effect on the acidity of the fermented product.

[0131] 3.3 Effect of lipase on product stability

[0132] Centrifugal sedimentation rate: Weigh 30g (accurate to 0.01g) of sample into a 50mL centrifuge tube, weigh the mass of the centrifuge tube, record it as M0, and the mass of the sample as M1; centrifuge the weighed sample at 20℃ and 3500r / min for 15 minutes, pour out the liquid after centrifugation, invert the centrifuge tube for 10 minutes, weigh the centrifuge tube and the sediment, record it as M2. The mathematical model of centrifugal sedimentation rate is shown in the formula:

[0133]

[0134] Each sample was tested three times in parallel and the results were averaged. The experimental results are recorded in Table 8 below. The lower the centrifugal sedimentation rate, the better the product stability.

[0135] Table 8: Effect of different amounts of lipase added on the shelf stability of lactic acid bacteria beverages - centrifugal sedimentation rate

[0136] Lipase addition amount‰ Centrifugal sedimentation rate Comparative Example 2 2.5％ Example 8-0.1 2.3％ Example 9-0.5 2.0％ Example 10-1 2.0％ Example 11-2 1.9％ Example 12-4 1.8％ Example 13-8 2.8％ Example 14-10 3.0％ Comparative Example 3 2.3％ Comparative Example 4 1.7％

[0137] The test samples were divided into 250ml blue-capped bottles, with the liquid in each bottle at the 200ml mark. Use a transparent soft ruler to measure the water separation height along the wall. Water separation height ≤ 2mm - no water separation. 2mm ≤ water separation height ≤ 4mm - slight water separation, 4mm ≤ water separation height ≤ 8mm - slight water separation, 8mm ≤ water separation height - partial water separation. Partial water separation is unacceptable. See Table 9 for details.

[0138] Table 9: Effect of different amounts of lipase added on the shelf stability of active lactic acid bacteria beverages - tissue state during shelf life

[0139]

[0140] According to the results of the stability test, when the amount of lipase raw material added is ≥0.05% and ≤0.4%, the greater the amount added, the better the stability of the product. However, when the amount added reaches 0.4% and above, the increase in the amount of lipase added will have a bad effect on the stability of the product. This is because lipase affects the milk-based fermentation of lactic acid bacteria beverages, thereby affecting the stability of the product.

[0141] 3.4 Effect of lipase on taste

[0142] The products stored at 20°C for 6 days were tasted. The tasting results are shown in Table 10.

[0143] Table 10: Tasting results of samples with lipase and control samples

[0144] Lipase addition amount‰ Tasting results Compared with the control Comparative Example 2 Moderate sweetness and sourness, no peculiar smell —— Example 8-0.1 Moderate sweetness and sourness, no peculiar smell Equivalence Example 9-0.5 Moderate sweetness and sourness, no peculiar smell Equivalence Example 10-1 Moderate sweetness and sourness, no peculiar smell like Example 11-2 Moderate sweetness and sourness, no peculiar smell like Example 12-4 Moderate sweetness and sourness, no peculiar smell like Example 13-8 Moderate sweet and sour, with a strange smell dislike Example 14-10 Moderate sweet and sour, with a strange smell dislike Comparative Example 3 Moderate sweetness and sourness, no peculiar smell Equivalence Comparative Example 4 Moderate sweetness and sourness, no peculiar smell Equivalence

[0145] According to the tasting results, within the same action time, when the amount of lipase raw materials added is ≤0.4%, it will not bring unpleasant taste. However, when the amount of lipase raw materials added is ≥0.4%, the liquid will have an odor, affecting the flavor of the product.

[0146] The products stored at 4-6°C for 24 days were tasted. The tasting results are shown in Table 11.

[0147] Table 11: Tasting results of samples with lipase and control samples

[0148] Lipase addition amount‰ Tasting results Compared with the control Comparative Example 2 Moderate sweetness and sourness, no peculiar smell —— Example 8-0.1 Moderate sweetness and sourness, no peculiar smell Equivalence Example 9-0.5 Moderate sweetness and sourness, no peculiar smell Equivalence Example 10-1 Moderate sweetness and sourness, no peculiar smell like Example 11-2 Moderate sweetness and sourness, no peculiar smell like Example 12-4 Moderate sweetness and sourness, no peculiar smell like Example 13-8 Moderate sweet and sour, with a strange smell Equivalence Example 14-10 Moderate sweet and sour, with a strange smell dislike Comparative Example 3 Moderate sweetness and sourness, no peculiar smell Equivalence Comparative Example 4 Moderate sweetness and sourness, no peculiar smell Equivalence

[0149] The lactic acid bacteria beverage produced by the embodiment of the present invention has good product flavor and taste, a refreshing taste, can be stored at 20°C for 6 days, and refrigerated at 4-6°C for 24 days, without unacceptable stratification or precipitation, no obvious odor, and has a good number of live bacteria.

[0150] The embodiments of the present invention described above are intended to be exemplary only; many variations and modifications will be apparent to those skilled in the art. All such variations and modifications are intended to be within the scope of the present invention as defined in any appended claims.

Claims

1. Use of lipase as a stabilizer in the preparation of live bacterial products.

2. The use according to claim 1, wherein the amount of lipase added as a stabilizer in the raw material is 0.01-1wt%, preferably 0.05-0.4wt% of the total amount of the raw material.

3. The use according to claim 1 or 2, wherein the live bacteria product is an active lactic acid bacteria product; preferably, the live bacteria product is a flavored fermented milk or a lactic acid bacteria beverage; more preferably, the live bacteria product is a low-sugar or sugar-free flavored fermented milk or a low-sugar or sugar-free lactic acid bacteria beverage.

4. Live bacteria products, wherein the raw materials of the live bacteria products include lipase as a stabilizer.

5. The live bacteria product according to claim 4, wherein the amount of lipase added to the raw material as a stabilizer is 0.01-1wt% of the total amount of the raw material, preferably 0.05-0.4wt%.

6. The use according to claim 4 or 5, wherein the live bacteria product is an active lactic acid bacteria product; preferably, the live bacteria product is flavored fermented milk or a lactic acid bacteria beverage; more preferably, the live bacteria product is low-sugar or sugar-free flavored fermented milk or a low-sugar or sugar-free lactic acid bacteria beverage.

7. A method for maintaining the stability of the tissue state and / or the taste stability of a live bacteria product during the shelf life, comprising including lipase as a stabilizer in the raw materials of the live bacteria product.

8. The method according to claim 7, wherein the amount of lipase added to the raw material as a stabilizer is 0.01-1 wt%, preferably 0.05-0.4 wt%, of the total amount of the raw material.

9. The method according to claim 7 or 8, wherein the live bacteria product is an active lactic acid bacteria product; preferably, the live bacteria product is flavored fermented milk or a lactic acid bacteria beverage; more preferably, the live bacteria product is low-sugar or sugar-free flavored fermented milk or a low-sugar or sugar-free lactic acid bacteria beverage.

10. A method for preparing a live bacteria product, wherein include: providing a feedstock comprising lipase as a stabilizer; Inoculate the starter and ferment. Optionally, the amount of lipase added as a stabilizer in the raw material is 0.01-1wt% of the total amount of the raw material, preferably 0.05-0.4wt%. Optionally, the live bacteria product is an active lactic acid bacteria product; preferably, the live bacteria product is flavored fermented milk or a lactic acid bacteria beverage; more preferably, the live bacteria product is low-sugar or sugar-free flavored fermented milk or a low-sugar or sugar-free lactic acid bacteria beverage. Also optionally, the fermentation agent is selected from Lactobacillus casei, Lactobacillus paracasei, Lactobacillus rhamnosus, Lactobacillus helveticus, Lactobacillus plantarum, Lactobacillus bulgaricus, Streptococcus thermophilus or a combination thereof; preferably, the fermentation agent is selected from Lactobacillus bulgaricus, Streptococcus thermophilus or a combination thereof.

Images