A method for preparing a low-fat, low-lactose buffalo milk protein base

Abstract

The application discloses a preparation method of low-fat and low-lactose buffalo milk protein base, and relates to the technical field of milk product processing. The preparation method comprises the following steps: (1) taking buffalo raw milk, preheating the buffalo raw milk, performing defatting treatment on the preheated buffalo raw milk by using a membrane, performing pasteurization, and cooling to obtain defatted milk; (2) adding Nurica lactase to the defatted milk, performing hydrolysis, killing the enzyme, and cooling to obtain first hydrolysis material; (3) adding Bonlacta lactase to the first hydrolysis material, performing hydrolysis, killing the enzyme, and cooling to obtain second hydrolysis material; (4) adding glucose oxidase to the second hydrolysis material, performing hydrolysis, killing the enzyme, cooling to room temperature, adding rice extract, uniformly mixing, sterilizing, and performing spray drying to obtain the buffalo milk protein base. The prepared buffalo milk protein base is low in browning degree, slightly sweet, low in fat and low in lactose.

Description

Technical Field

[0001] This invention relates to the field of dairy product processing technology, and in particular to a method for preparing a low-fat, low-lactose buffalo milk protein base. Background Technology

[0002] Buffalo milk contains dozens of times more fat, protein, minerals, and vitamins than Holstein milk and human milk. It is rich and creamy, low in cholesterol, and suitable for high-quality dairy processing. The main carbohydrate in buffalo milk is lactose, accounting for over 99% of the total carbohydrates. Lactose needs to be hydrolyzed into monosaccharides by lactase in the intestines before it can be absorbed by the body. For most people, lactase activity decreases to undetectable levels after weaning. In individuals lacking this enzyme, undigested lactose enters the large intestine directly after ingestion. Under the action of bacteria, it is fermented to produce short-chain fatty acids, carbon dioxide, hydrogen, and methane, causing gastrointestinal symptoms such as bloating, abdominal pain, and watery acidic diarrhea. This reduces the absorption of inorganic salts and proteins in the intestines, a condition known as lactose intolerance. Lactose intolerance significantly restricts the development of my country's dairy industry.

[0003] Low-lactose milk primarily uses standard lactase to hydrolyze lactose, reducing its content. While this enzymatic hydrolysis process is relatively simple, it has several drawbacks: First, it produces more glucose, resulting in a sweeter taste, especially buffalo milk, without reducing carbohydrate content, which doesn't meet current consumer demand for low-calorie, low-carbohydrate products. Second, enzymatic hydrolysis increases the reducing power of monosaccharides, making the milk protein base more susceptible to Maillard reactions during further high-temperature processing, leading to browning and off-flavors. Third, low-lactose milk base is more hygroscopic, with higher particle aggregation, making it prone to sticking to container walls when dried into powder, resulting in low recovery rates. Patent application number 202211639660.5 discloses a method for preparing milk rich in galactooligosaccharides. This method uses enzymatic hydrolysis to obtain low-lactose milk, but it does not solve the problem of browning. Patent application number 202310878642.0 discloses a method for inhibiting browning in low-lactose milk. This method uses the addition of anthocyanins to prevent browning, but anthocyanins have a bitter taste, and if the amount added is not properly controlled, it can easily affect the taste of the milk.

[0004] In conclusion, research on preventing browning in milk lactose-enzymatic hydrolysis products is of great significance. Summary of the Invention

[0005] To address the above shortcomings, this invention provides a method for preparing a low-fat, low-lactose buffalo milk protein base, which can obtain a non-browning, slightly sweet, low-fat, and low-lactose buffalo milk protein base. The specific technical solution is as follows:

[0006] A method for preparing a low-fat, low-lactose buffalo milk protein base includes the following steps:

[0007] (1) Take buffalo milk, preheat it, use a membrane to defatt it, pasteurize it, and cool it to obtain skim milk.

[0008] (2) Add Nurica lactase to the skim milk and hydrolyze for 0.5-1 h to inactivate the enzyme and cool to obtain the first hydrolysate.

[0009] (3) Add Bonlacta lactase to the primary hydrolysate and hydrolyze for 0.5-1 h, inactivate the enzyme, cool, and obtain secondary hydrolysate;

[0010] (4) Add rice extract to the secondary hydrolysate, mix well, sterilize, and spray dry to obtain the buffalo milk protein base.

[0011] Further, in step (1), the preheating temperature is 40-55℃, and the cooling temperature is 40-50℃.

[0012] Furthermore, in step (1), the membrane is a ceramic membrane with a pore size of 1.4-2.0 μm, and the fat content in the skimmed milk is less than 0.3%.

[0013] Further, in step (2), the enzyme activity of the Nurica lactase is 500-600 U / g, the amount added is 0.1-0.3%, and the temperature after cooling is 40-50℃.

[0014] Further, in step (3), the activity of the Bonlacta lactase is 400-500 U / g, the amount added is 0.2-0.5%, and the cooling is cooling to room temperature.

[0015] Furthermore, in step (4), the amount of rice extract added is 1-4% of the weight of the secondary hydrolysate.

[0016] Further, in step (4), the method for preparing the rice extract is as follows: cooked rice is fermented for 2-3 days to obtain saccharified material, the saccharified material is added to 50-80 times its weight of water and mixed, the pH is adjusted to neutral, then 1-3% alkaline protease is added, and the mixture is continuously stirred at 50-55℃ for 10-15 hours, and the enzyme is inactivated at 70-85℃ for 10-20 minutes. The solid and liquid are separated, activated carbon is added to the filtrate and stirred for 10-20 minutes, the activated carbon is removed, and the mixture is dried to obtain the rice extract.

[0017] Further, in step (4), the sterilization is performed at 110-135°C for 3-4 seconds.

[0018] Furthermore, the preparation method further includes the steps of adding glucose oxidase for hydrolysis for 20-30 minutes, enzyme inactivation, and cooling, wherein the steps are performed before adding the rice extract; the amount of glucose oxidase added is 0.1-0.5% of the weight of the secondary hydrolysate.

[0019] Furthermore, the enzyme inactivation temperature is 60-70℃, and the time is 10-20s.

[0020] Nurica lactase can convert lactose into galactooligosaccharides.

[0021] Bonlactat lactase breaks down lactose into glucose and galactose.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. This invention first uses Nurica lactase to convert part of the lactose into galacto-oligosaccharides, and then uses Bonlacta lactase to break down the remaining lactose into glucose and galactose. This avoids the problem of incomplete hydrolysis caused by the inhibition of the hydrolysis reaction by the product when using Bonlacta lactase alone, resulting in more complete lactose hydrolysis. The lactose content of the obtained product is 0-1.5g / 100g, which can avoid the occurrence of lactose intolerance.

[0024] 2. The rice extract of this invention contains small peptides with antioxidant activity, which can inhibit the Maillard reaction, effectively preventing browning of the product. Furthermore, the rice extract is colorless, odorless, and non-toxic, ensuring high safety and not affecting the taste. Meanwhile, glucose oxidase can convert some glucose into gluconic acid, which inhibits the Maillard reaction. The combination of rice extract and glucose oxidase treatment effectively slows down the browning process of the product.

[0025] 3. The glucose oxidase of this invention can hydrolyze some glucose, reducing the glucose content and sweetness. In addition, some lactose has been converted into galactooligosaccharides, resulting in even less carbohydrate content, which meets the current consumer demand for low-calorie and low-carbohydrate products.

[0026] 4. This invention uses methods such as adding glucose oxidase and Nurica lactase to reduce the glucose content, thereby reducing the hygroscopicity of the powder, making the particles less granular and less prone to adhering to the container wall, resulting in a high recovery rate. Compared with traditional enzymatic hydrolysis methods (recovery rate of 30-50%), the recovery rate of the powder is as high as 80% or more.

[0027] 5. The milk of this invention is degreased using a ceramic membrane, resulting in milk with a fat content of less than 0.3%, which better meets the current demand for reducing fat intake. Detailed Implementation

[0028] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0029] Example 1

[0030] A method for preparing a low-fat, low-lactose buffalo milk protein base includes the following steps:

[0031] (1) Take buffalo milk, preheat it to 40°C, then use a ceramic membrane with a pore size of 1.4 μm to degrease it, pasteurize it, and cool it to 40°C to obtain skimmed milk.

[0032] (2) Add 0.1% of the weight of skim milk of Nurica lactase with an enzyme activity of 500 U / g to skim milk and hydrolyze for 0.5 h. Inactivate the enzyme at 60 ℃ for 10 s and cool to 40 ℃ to obtain the first hydrolysate.

[0033] (3) Add 0.2% of the weight of the primary hydrolysate with Bonlacta lactase (400 U / g) to the primary hydrolysate and hydrolyze for 0.5 h. Inactivate the enzyme at 60 °C for 10 s and cool to room temperature to obtain the secondary hydrolysate.

[0034] (4) Add 1% of rice extract by weight of the secondary hydrolysate to the secondary hydrolysate, mix well, sterilize at 110°C for 3 seconds, and spray dry to obtain the buffalo milk protein base.

[0035] The method for preparing rice extract is as follows: cooked rice is fermented for 2 days to obtain saccharified material. The saccharified material is added to 50 times its weight of water and mixed. The pH is adjusted to neutral. Then, 1% alkaline protease is added. The mixture is stirred continuously at 50°C for 10 hours and then the enzyme is inactivated at 70°C for 10 minutes. The solid and liquid are separated. Activated carbon is added to the filtrate and stirred for 10 minutes. The activated carbon is removed and the mixture is dried to obtain the rice extract.

[0036] Example 2

[0037] A method for preparing a low-fat, low-lactose buffalo milk protein base includes the following steps:

[0038] (1) Take buffalo milk, preheat it to 55°C, then use a ceramic membrane with a pore size of 2.0 μm to defatt it, pasteurize it, and cool it to 50°C to obtain skim milk.

[0039] (2) Add 0.3% of the weight of skim milk of Nurica lactase with an enzyme activity of 600 U / g to skim milk for 1 hour, inactivate the enzyme at 70°C for 20 seconds, and cool to 50°C to obtain the first hydrolysate.

[0040] (3) Add 0.5% of the weight of the primary hydrolysate with Bonlacta lactase (500 U / g) to the primary hydrolysate and hydrolyze for 1 hour. Inactivate the enzyme at 70°C for 20 seconds and cool to room temperature to obtain the secondary hydrolysate.

[0041] (4) Add 4% of the weight of rice extract to the secondary hydrolysate and mix well. Sterilize at 135°C for 4 seconds and spray dry to obtain the buffalo milk protein base.

[0042] The method for preparing rice extract is as follows: cooked rice is fermented for 3 days to obtain saccharified material. The saccharified material is added to 80 times its weight of water and mixed. The pH is adjusted to neutral. Then, 3% alkaline protease is added. The mixture is stirred continuously at 55°C for 15 hours and then the enzyme is inactivated at 85°C for 20 minutes. The solid and liquid are separated. Activated carbon is added to the filtrate and stirred for 20 minutes. The activated carbon is removed and the mixture is dried to obtain the rice extract.

[0043] Example 3

[0044] A method for preparing a low-fat, low-lactose buffalo milk protein base includes the following steps:

[0045] (1) Take buffalo milk, preheat it to 50°C, then use a ceramic membrane with a pore size of 1.5 μm to degrease it, pasteurize it, and cool it to 45°C to obtain skimmed milk.

[0046] (2) Add 0.2% of the weight of skim milk of Nurica lactase with an enzyme activity of 550 U / g to skim milk and hydrolyze for 0.8 h. Inactivate the enzyme at 65 ℃ for 15 s and cool to 45 ℃ to obtain the first hydrolysate.

[0047] (3) Add 0.4% of the weight of the primary hydrolysate with Bonlacta lactase (450 U / g) to the primary hydrolysate and hydrolyze for 0.8 h. Inactivate the enzyme at 65 °C for 15 s and cool to room temperature to obtain the secondary hydrolysate.

[0048] (4) Add 0.4% of glucose oxidase by weight of the secondary hydrolysate to the secondary hydrolysate for 25 min, inactivate the enzyme at 65°C for 15 s, cool to room temperature, add 2% of rice extract by weight of the secondary hydrolysate and mix well, sterilize at 125°C for 4 s, and spray dry to obtain the buffalo milk protein base.

[0049] The method for preparing rice extract is as follows: cooked rice is fermented for 2.5 days to obtain saccharified material. The saccharified material is added to 70 times its weight of water and mixed. The pH is adjusted to neutral. Then, 2% alkaline protease is added. The mixture is stirred continuously at 53°C for 12 hours and then the enzyme is inactivated at 75°C for 15 minutes. The solid and liquid are separated. Activated carbon is added to the filtrate and stirred for 15 minutes. The activated carbon is removed and the mixture is dried to obtain the rice extract.

[0050] Example 4

[0051] A method for preparing a low-fat, low-lactose buffalo milk protein base includes the following steps:

[0052] (1) Take buffalo milk, preheat it to 55°C, then use a ceramic membrane with a pore size of 2.0 μm to defatt it, pasteurize it, and cool it to 40°C to obtain skimmed milk.

[0053] (2) Add 0.3% of the weight of skim milk of Nurica lactase with an enzyme activity of 500 U / g to skim milk for 1 hour, inactivate the enzyme at 70°C for 10 seconds, and cool to 50°C to obtain the first hydrolysate.

[0054] (3) Add 0.5% of the weight of the primary hydrolysate with Bonlacta lactase (400 U / g) to the primary hydrolysate and hydrolyze for 1 hour. Inactivate the enzyme at 70°C for 20 seconds and cool to room temperature to obtain the secondary hydrolysate.

[0055] (4) Add 0.3% of glucose oxidase by weight of the secondary hydrolysate to the secondary hydrolysate for 25 min, inactivate the enzyme at 65°C for 15 s, cool to room temperature, add 1% of rice extract by weight of the secondary hydrolysate and mix well, sterilize at 135°C for 4 s, and spray dry to obtain the buffalo milk protein base.

[0056] The method for preparing rice extract is as follows: cooked rice is fermented for 3 days to obtain saccharified material. The saccharified material is added to 80 times its weight of water and mixed. The pH is adjusted to neutral. Then, 3% alkaline protease is added. The mixture is stirred continuously at 55°C for 15 hours and then the enzyme is inactivated at 70-85°C for 20 minutes. The solid and liquid are separated. Activated carbon is added to the filtrate and stirred for 20 minutes. The activated carbon is removed and the mixture is dried to obtain the rice extract.

[0057] I. Test on the degree of lactose hydrolysis :

[0058] To demonstrate the high degree of lactose hydrolysis in this invention, the applicant conducted the following experiments, which were divided into four groups:

[0059] Group 1: Low-fat, low-lactose buffalo milk protein base was prepared using the method described in Example 1;

[0060] Group 2: Perform step (3) first, then step (2), that is, first hydrolyze with Bonlacta lactase, then hydrolyze with Nurica lactase, and the remaining steps are the same as in Example 1;

[0061] Group 3: No step (3), that is, no Bonlacta lactase is used, only Nurica lactase is used for hydrolysis, and the amount of Nurica lactase in step (2) is increased to 0.4% of the weight of skim milk, the hydrolysis time is increased to 1 hour, and the rest of the steps are the same as in Example 1.

[0062] Group 4: No step (2), that is, no Nurica lactase is used, only Bonlacta lactase is used for hydrolysis, and the amount of enzyme used in step (3) is increased to 0.4% of the weight of skim milk, and the hydrolysis time is increased to 1 hour. The remaining steps are the same as in Example 1.

[0063] Control group: Buffalo milk powder that has not undergone any enzymatic hydrolysis.

[0064] The experiment used fresh milk from the same buffalo at Guangxi Nongken Xijiang Dairy Co., Ltd. as the research subject. After the experiment, the lactose content of the buffalo milk protein base prepared in each group was measured. The results are shown in Table 1.

[0065] Table 1. Lactose content of each group of buffalo milk protein base

[0066] Group Lactose content (%) Group 1 (Example 1) 0.5 Group 2 3.0 Group 3 3.9 Group 4 3.2 Reference group 5.4

[0067] Note: According to the health department, lactose content ≤0.5g / 100g is lactose-free, and lactose content ≤2g / 100g is low-lactose.

[0068] The table above shows that the present invention can obtain low-lactose or lactose-free base materials by first using Nurica lactase and then Bonlacta lactase for hydrolysis.

[0069] II. Maillard Reaction Degree Test :

[0070] To demonstrate that the method of this invention can alleviate browning of the finished product, the applicant conducted the following experiments, which were divided into 4 groups:

[0071] Group 1: Prepared using the method of Example 4;

[0072] Group 2: Step (4) is a step without glucose oxidase hydrolysis; the other steps are the same as in Example 4.

[0073] Group 3: Step (4) without adding rice extract, other steps are the same as in Example 4;

[0074] Group 4: Step (4) replaces rice extract with anthocyanins, and the other steps are the same as in Example 4.

[0075] The experiment also included a control group, which did not include the glucose oxidase hydrolysis step, nor did it add rice extract; the other steps were the same as in Example 4.

[0076] The experiment used fresh milk from the same buffalo at Guangxi Nongken Xijiang Dairy Co., Ltd. as the research object. After the experiment, the amount of 5-hydroxymethylfurfural (Maillard reaction product) generated in the buffalo milk protein base prepared in each group was detected. Specifically, the amount of 5-hydroxymethylfurfural generated was detected at 100℃ for different heating times (30 min, 60 min, 90 min, 120 min, 150 min, and 180 min). The detection method was as follows: 1.0 g of the sample to be tested was weighed, 3 mL of acetonitrile was added, and the mixture was vortexed at 5300 rpm for 7 min. Then, 0.1 g of sodium chloride and 0.01 g of anhydrous sodium acetate were added, and the mixture was vortexed thoroughly at 2800 rpm for 5 min. After sonication for 30 min, 0.6 g of anhydrous magnesium sulfate was added, and the mixture was centrifuged at 5800 rpm for 10 min. 1 mL of the supernatant was taken, and 10 mg of C was added. 18 20 mg of anhydrous magnesium sulfate and 10 mg of PSA were added. The purified solution was centrifuged at 5200 rpm for 5 min. The supernatant was passed through a PTF membrane, and the filtrate was collected and analyzed by GC-MS. The results are shown in Table 2.

[0077] Table 2. Production of 5-hydroxymethylfurfural in each group of buffalo milk protein base

[0078]

[0079] The table above shows that the addition of rice extract and glucose oxidase can inhibit the Maillard reaction, reduce the content of the reaction product 5-hydroxymethylfurfural, and effectively alleviate the browning time of the product.

[0080] three, Product glucose content testing :

[0081] To demonstrate that the base material obtained by the method of this invention is a low-carbohydrate product, the applicant conducted the following experiments, which were divided into 3 groups:

[0082] Group 1: Prepared using the method of Example 4;

[0083] Group 2: Step (2) hydrolyze with an equal amount of Bonlacta lactase instead of Nurica lactase, and the other steps are the same as in Example 4;

[0084] Group 3: Step (4) is a step without glucose oxidase hydrolysis, and the other steps are the same as in Example 4.

[0085] Reference group: Step (2) hydrolysis was performed using an equal amount of Bonlacta lactase instead of Nurica lactase, and step (4) hydrolysis was performed without glucose oxidase. Other steps were the same as in Example 4.

[0086] The experiment used fresh milk from the same buffalo at Guangxi Nongken Xijiang Dairy Co., Ltd. as the research object. After the experiment, the glucose content of the buffalo milk protein base prepared in each group was measured, and the dry powder recovery rate of the finished product (the amount of dry powder recovered / the total amount of dry powder, where the total amount of dry powder is the calculated theoretical amount of dry powder) was calculated. The results are shown in Table 3:

[0087] Table 3. Glucose content of buffalo milk protein base in each group

[0088] Group Glucose content (g / 100g) Finished product dry powder recovery rate (%) Group 1 (Example 4) 3.5 88.5 Group 2 4.6 66.7 Group 3 4.9 62.4 Reference group 5.8 38.1

[0089] Table 3 shows that the base material prepared by the method of the present invention has a reduced glucose content and lower sweetness, which meets the current consumer demand for low-calorie and low-carbohydrate products. At the same time, the reduced glucose content results in lower hygroscopicity of the resulting dry powder, a lower particle size distribution, and less adhesion to container walls, leading to a higher recovery rate compared to traditional methods.

[0090] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing a low-fat, low-lactose buffalo milk protein base, characterized in that, Includes the following steps: (1) Take buffalo milk, preheat it, use a membrane to defatt it, pasteurize it and cool it to obtain skim milk; (2) Add Nurica lactase to the skim milk and hydrolyze for 0.5-1h, inactivate the enzyme, cool, and obtain the first hydrolysate; (3) Add Bonlacta lactase to the primary hydrolysate and hydrolyze for 0.5-1 h, inactivate the enzyme, cool, and obtain secondary hydrolysate; (4) Add 0.1-0.5% of glucose oxidase by weight of the secondary hydrolysate to the secondary hydrolysate for 20-30 minutes to hydrolyze, inactivate the enzyme, cool, then add rice extract, mix well, sterilize, and spray dry to obtain the buffalo milk protein base. The method for preparing the rice extract is as follows: cooked rice is fermented for 2-3 days to obtain saccharified material. The saccharified material is added to 50-80 times its weight of water and mixed. The pH is adjusted to neutral. Then, 1-3% alkaline protease is added. The mixture is stirred continuously at 50-55℃ for 10-15 hours and then the enzyme is inactivated at 70-85℃ for 10-20 minutes. The solid and liquid are separated. Activated carbon is added to the filtrate and stirred for 10-20 minutes. The activated carbon is removed and the mixture is dried to obtain the rice extract.

2. The method for preparing a low-fat, low-lactose buffalo milk protein base according to claim 1, characterized in that, In step (1), the preheating temperature is 40-55℃ and the cooling temperature is 40-50℃.

3. The method for preparing a low-fat, low-lactose buffalo milk protein base according to claim 1, characterized in that, In step (1), the membrane is a ceramic membrane with a pore size of 1.4-2.0 μm, and the fat content in the skimmed milk is less than 0.3%.

4. The method for preparing a low-fat, low-lactose buffalo milk protein base according to claim 1, characterized in that, In step (2), the Nurica lactase has an enzyme activity of 500-600 U / g, is added at a rate of 0.1-0.3%, and is cooled to a temperature of 40-50°C.

5. The method for preparing a low-fat, low-lactose buffalo milk protein base according to claim 1, characterized in that, In step (3), the activity of the Bonlacta lactase is 400-500 U / g, the amount added is 0.2-0.5%, and the cooling is cooling to room temperature.

6. The method for preparing a low-fat, low-lactose buffalo milk protein base according to claim 1, characterized in that, In step (4), the amount of rice extract added is 1-4% of the weight of the secondary hydrolysate.

7. The method for preparing a low-fat, low-lactose buffalo milk protein base according to claim 1, characterized in that, In step (4), the sterilization is performed at 110-135℃ for 3-4 seconds.

8. The method for preparing a low-fat, low-lactose buffalo milk protein base according to claim 1, characterized in that, The enzyme inactivation temperature is 60-70℃, and the time is 10-20s.

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