Fermented cheese added with acid whey and preparation method of fermented cheese

Abstract

The invention provides fermented cheese added with acid whey and a preparation method of the fermented cheese. The first aspect of the invention provides fermented cheese added with acid whey. The fermented cheese is prepared from the following raw materials: 250-300 parts by mass of acid whey, 80-100 parts by mass of cheese powder, 10-20 parts by mass of single cream, 60-80 parts by mass of a sweetening agent, 4.8-6 parts by mass of carbohydrate, 3-7.2 parts by mass of dietary fibers and probiotics with 1 * 107-1 * 108 viable count. The fermented cheese is prepared by taking the acid whey as a raw material, and the obtained fermented cheese not only has relatively good water-holding capacity and stability, but also has relatively good tissue state, taste and flavor, and is a fermented cheese product with relatively high quality.

Description

Technical Field

[0001] The present invention relates to a fermented buttermilk added with acid whey and a preparation method thereof, and belongs to the technical field of dairy products. Background Art

[0002] Whey is the liquid separated from casein and fat in milk during the production of dairy products such as cheese. Whey includes two major categories: acid whey and sweet whey. Among them, the by-product of fresh cheese produced by the separated whey method belongs to acid whey. At present, in the dairy industry, the treatment process and equipment for sweet whey are relatively mature, and sweet whey is effectively recovered and processed into different types of whey raw materials, increasing the profits of dairy enterprises; while acid whey has high contents of lactic acid and ash, etc., and is difficult to treat. The current main treatment methods are directly used as animal feed or directly treated as wastewater, which not only causes huge waste but also exerts great pressure on the environment.

[0003] Currently, acid whey can be fermented to obtain dairy products to solve the problem of low utilization rate of acid whey. However, there is still a large room for improvement in the water holding capacity and stability of the existing dairy products prepared from acid whey. Summary of the Invention

[0004] The present invention provides a fermented buttermilk added with acid whey and a preparation method thereof, which are used to solve the problem of poor water holding capacity and stability of the existing dairy products prepared from acid whey.

[0005] In the first aspect of the present invention, a fermented buttermilk added with acid whey is provided. The raw materials required for preparing the fermented buttermilk include 250 - 300 parts by mass of acid whey, 80 - 100 parts by mass of buttermilk powder, 10 - 20 parts by mass of light cream, 60 - 80 parts by mass of sweetener, 4.8 - 6 parts by mass of carbohydrate, 3 - 7.2 parts by mass of dietary fiber, and probiotics with a viable count of 1×10 7 ~1×10 8 ;

[0006] The fermented buttermilk is obtained by successively performing homogenization, sterilization, fermentation, and refinement on a second mixed material, and the second mixed material includes a first enzymolysis material, a sweetener, a carbohydrate, and a dietary fiber;

[0007] The first enzymolysis material is obtained by enzymolyzing a first mixed material with lipase. The first mixed material includes a nanofiltration retentate, buttermilk powder, and light cream, and the nanofiltration retentate is obtained by subjecting acid whey to nanofiltration treatment.

[0008] In the present invention, acid whey refers to the liquid by-product generated during the production of cheese or casein, with a pH lower than 4.6; buttermilk powder is a solid powder made from buttermilk through processes such as sterilization and spray drying; cream is the component obtained by centrifugally separating milk; the sweetener includes one or more of steviol glycoside, erythritol, and maltitol; the carbohydrate includes starch; the dietary fiber includes citrus fiber; the probiotic can be a conventional strain such as lactic acid bacteria for buttermilk fermentation.

[0009] Weigh a certain mass fraction of each of the above components. Specifically, the content of acid whey should not be too much, otherwise it will cause instability in the product system and problems such as water separation. The mass fraction of acid whey is 250 - 300 parts. As the basic component for preparing fermented buttermilk, the mass fraction of buttermilk powder is 80 - 100 parts. The mass fraction of cream is 10 - 20 parts. The sweetener is used to improve the taste of fermented buttermilk, and its mass fraction is 60 - 80 parts. Starch and citrus fiber, as stabilizers, help to improve the problem of water separation, and their mass fractions are 4.8 - 6 parts and 3 - 7.2 parts respectively.

[0010] During the preparation process, first, subject the acid whey to nanofiltration treatment and collect the nanofiltration retentate to remove inorganic salts and small - molecule organic substances in the acid whey; then, fully mix and homogenize the nanofiltration retentate with buttermilk powder and cream to obtain the first mixed material, and add lipase for enzymatic hydrolysis to hydrolyze the fat in the first mixed material into small - molecule fatty acids, improve the mixture system, ensure the stability of the mixture system, and avoid the influence of macromolecular fat on the stability and water - holding capacity of fermented buttermilk. After the enzymatic hydrolysis ends, obtain the first enzymatically hydrolyzed material.

[0011] Subsequently, fully mix and homogenize the first enzymatically hydrolyzed material, sweetener, carbohydrate, and dietary fiber to obtain the second mixed material, and then successively perform homogenization, sterilization, fermentation, and refinement on the second mixed material to obtain the fermented buttermilk.

[0012] The fermented buttermilk provided by the present invention has a water - holding capacity of not less than 80% and a viscosity of not less than 650 Pa·s at 20 - 25°C; and after being stored for 21 days, the reduction rate of pH is not higher than 8.5%, and the growth rate of acidity is not higher than 45.0%.

[0013] The second aspect of the present invention provides a preparation method of the fermented buttermilk added with acid whey as described in any one of the above, including the following steps:

[0014] Step 1: Subject the acid whey to nanofiltration treatment and collect the nanofiltration retentate;

[0015] Step 2: Mix and homogenize the nanofiltration retentate, buttermilk powder, and cream to obtain the first mixed material; adjust the pH of the first mixed material to 6.3 - 6.5, add lipase for enzymatic hydrolysis to obtain the first enzymatically hydrolyzed material; perform homogenization treatment on the first enzymatically hydrolyzed material;

[0016] Step 3, adding sweetener, carbohydrate and dietary fiber to the homogenized first enzymatic material, stirring evenly to obtain a second mixed material; homogenizing and sterilizing the second mixed material in sequence; inoculating probiotics into the sterilized second mixed material for fermentation, and refining after the fermentation to obtain fermented buttermilk with added acid whey.

[0017] In a specific embodiment, Figure 1 A schematic diagram of a method for preparing fermented buttermilk according to an embodiment of the present invention is shown in FIG. Figure 1 As shown, the method specifically comprises the following steps:

[0018] Step 1: Perform nanofiltration on the acid whey and collect the nanofiltration interception liquid.

[0019] Nanofiltration (NF), also known as low-pressure reverse osmosis, allows some inorganic salts and certain solvents to pass through the membrane, thereby achieving a separation effect, and can separate substances with relatively small molecular weight in acid whey, such as inorganic salts, or small molecular organic substances such as glucose and sucrose from the solvent. Furthermore, nanofiltration treatment is carried out using a nanofiltration membrane, and the pore size of the nanofiltration membrane is 0.001-0.002μm.

[0020] Step 2: Evenly mix the nanofiltration intercepted liquid, buttermilk powder and cream to obtain a first mixed material; adjust the pH of the first mixed material to 6.3-6.5, add lipase for enzymolysis to obtain a first enzymolysis material; and perform a first homogenization treatment on the first enzymolysis material.

[0021] The nanofiltration retentate collected after the nanofiltration treatment, the buttermilk powder and the cream are mixed evenly according to the above-mentioned mass parts to obtain a first mixed material. After adjusting the pH of the first mixed material to 6.3-6.5, lipase is added to enzymolyze the first mixed material.

[0022] Furthermore, the lipase activity is 13-15 LU / g, the enzymatic hydrolysis temperature is 35-40° C., and the enzymatic hydrolysis time is 20-45 min. Otherwise, the enzymatic hydrolysis effect is poor and cannot achieve the desired effect.

[0023] After the enzymolysis is completed, a first enzymolysis material is obtained, and the first enzymolysis material is homogenized. Specifically, in the homogenization process, the first-level homogenization pressure is 15 to 25 bar, and the second-level homogenization pressure is 160 to 180 bar.

[0024] Step 3: Add sweeteners, carbohydrates, and dietary fiber to the first enzymatically hydrolyzed material after homogenization, stir evenly to obtain a second mixed material; perform homogenization and sterilization treatments on the second mixed material in sequence; inoculate probiotics in the second mixed material after sterilization for fermentation, and perform refinement after fermentation to obtain fermented buttermilk added with acid whey.

[0025] Fully mix the first enzymatically hydrolyzed material after homogenization with sweeteners, carbohydrates, and dietary fiber evenly to obtain a second mixed material; the types and mass parts of the sweeteners, carbohydrates, and dietary fiber are as described above.

[0026] Perform homogenization treatment on the second mixed material. Specifically, during the homogenization treatment, the primary homogenization pressure is 30 - 40 bar, and the secondary homogenization pressure is 160 - 180 bar. Perform sterilization treatment on the second mixed material after homogenization. Specifically, the sterilization temperature is 90 - 95 °C, and the sterilization time is 280 - 300 s. After sterilization treatment, probiotics can be inoculated for fermentation treatment. Specifically, the fermentation temperature is 35 - 50 °C, and stop fermentation when the pH of the fermented buttermilk is not higher than 4.6.

[0027] After fermentation ends, refine the fermentation product to improve the state of the product and make the product smoother and more delicate; specifically, the refinement treatment is carried out using a Y - tron refinement pump, and the frequency of the Y - tron refinement pump is 10 - 15 Hz, which helps to improve the fineness of the product.

[0028] The present invention prepares a fermented buttermilk using acid whey as a raw material. The obtained fermented buttermilk not only has good water - holding capacity and stability, but also has good tissue state, taste, and flavor, and is a fermented buttermilk product with high quality. Brief Description of the Drawings

[0029] Figure 1 It is a schematic flow chart of the preparation method of the fermented buttermilk provided by an embodiment of the present invention. Detailed Embodiments

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0031] Example 1

[0032] This embodiment provides a fermented buttermilk added with acid whey. The raw materials used include 270 parts by mass of acid whey, 100 parts by mass of buttermilk powder, 15 parts by mass of light cream, 60 parts by mass of sweetener (steviol glycoside: erythritol = 50:0.04), 4.5 parts by mass of citrus fiber, 5.5 parts by mass of starch, and lactic acid bacteria with a viable count of 1×10 7 CFU.

[0033] The preparation method includes the following steps:

[0034] (1) Nanofiltration treatment: Pass the acid whey through an NF membrane, and collect the nanofiltration retentate; the pore size of the NF membrane is 0.002 μm.

[0035] (2) Ingredients preparation: Mix 270 parts of the treated acid whey, 100 parts of buttermilk powder, and 15 parts of light cream, adjust the acidity to 6.4, add lipase for enzymatic hydrolysis, the enzyme activity of the lipase is 13.5 LU / g, the enzymatic hydrolysis temperature is 35 - 40 °C, after enzymatic hydrolysis for 30 min, obtain the first enzymatically hydrolyzed material;

[0036] (3) Homogenization: Homogenize the first enzymatically hydrolyzed material at 20 / 160 bar;

[0037] (4) Ingredients preparation: Add steviol glycoside, erythritol, citrus fiber, and starch, and mix and stir for 20 min to obtain the second mixed material;

[0038] (5) Homogenization and sterilization: Homogenize the second mixed material at a homogenization pressure of 30 - 40 / 160 - 180 bar; the sterilization temperature is between 90 - 95 °C, and the sterilization time is controlled within 280 - 300 s;

[0039] (6) Fermentation: Cool the yogurt fermentation base obtained in step (5) to 43 °C, inoculate the starter at 0.2%, and carry out constant-temperature fermentation at 43 ± 2 °C. Stop fermentation when pH ≤ 4.6.

[0040] (7) Refinement: Immediately demulsify and refine the yogurt obtained after fermentation in step (6). The frequency of the Y-tron refinement pump is 10 Hz, and then cool it to 15 - 18 °C to terminate fermentation;

[0041] (8) Filling: Carry out filling;

[0042] (9) Cold storage and after-ripening: After filling in step (8), the obtained yogurt is subjected to after-ripening and needs to be refrigerated at 2 - 6 °C.

[0043] Example 2

[0044] This embodiment provides a fermented buttermilk added with acid whey. The raw materials used include 250 parts by mass of acid whey, 80 parts by mass of buttermilk powder, 20 parts by mass of light cream, 60 parts by mass of sweetener (stevioside: maltitol = 45:0.03), 6 parts by mass of citrus fiber, 6 parts by mass of starch, and 1×10 7 CFU viable count of lactic acid bacteria.

[0045] The preparation method of the fermented buttermilk provided in this embodiment can refer to Embodiment 1, the difference being that the parts by mass of the raw materials are different.

[0046] Embodiment 3

[0047] This embodiment provides a fermented buttermilk added with acid whey. The raw materials used include 300 parts by mass of acid whey, 95 parts by mass of buttermilk powder, 15 parts by mass of light cream, 80 parts by mass of sweetener (stevioside: erythritol = 55:0.06), 3.6 parts by mass of citrus fiber, 5.4 parts by mass of starch, and 1×10 8 CFU viable count of lactic acid bacteria.

[0048] The preparation method of the fermented buttermilk provided in this embodiment can refer to Embodiment 1, the difference being that the parts by mass of the raw materials are different and the first mixed material is acidified to 6.5.

[0049] Comparative Example 1

[0050] This comparative example provides a fermented buttermilk added with acid whey. The raw materials used include 290 parts by mass of acid whey, 100 parts by mass of buttermilk powder, 20 parts by mass of light cream, 80 parts by mass of sweetener (stevioside: maltitol = 55:0.06), 3.6 parts by mass of citrus fiber, 5.4 parts by mass of starch, and 1×10 7 CFU viable count of lactic acid bacteria.

[0051] The preparation method of the fermented buttermilk provided in this comparative example includes the following steps:

[0052] (1) Ingredient preparation: Mix 290 parts by mass of acid whey, 100 parts by mass of buttermilk powder, and 20 parts by mass of light cream, acidify to 6.4, add lipase for enzymatic hydrolysis, the enzyme activity of the lipase is 14 LU / g, the enzymatic hydrolysis temperature is 35 - 40 °C, and after enzymatic hydrolysis for 30 min, obtain the first enzymatically hydrolyzed material;

[0053] (2) Homogenization: Homogenize the first enzymatically hydrolyzed material at 20 / 160 bar;

[0054] (4) Ingredient preparation: Add stevioside, maltitol, citrus fiber, and starch and mix and stir for 20 min to obtain the second mixed material;

[0055] (5) Homogenization and sterilization: The second mixed material is homogenized at a homogenization pressure of 30 - 40 / 160 - 180 bar; the sterilization temperature is between 90 and 95 °C, and the sterilization time is controlled within 280 - 300 s;

[0056] (6) Fermentation: Cool the yogurt fermentation base obtained in step (5) to 43 °C, inoculate with a starter at 0.2%, and carry out constant-temperature fermentation at 43 ± 2 °C. Stop fermentation when pH ≤ 4.6;

[0057] (7) Refinement: Immediately demulsify and refine the yogurt obtained after fermentation in step (6). The frequency of the Y-tron refining pump is 15 Hz, and then cool it to 15 - 18 °C to terminate fermentation;

[0058] (8) Filling: Carry out filling;

[0059] (9) Cold storage and after-ripening: The yogurt obtained after filling in step (8) is post-ripened and needs to be refrigerated at 2 - 6 °C.

[0060] Comparative Example 2

[0061] This comparative example provides a fermented buttermilk added with acid whey. The raw materials used include 250 parts by mass of acid whey, 80 parts by mass of buttermilk powder, 20 parts by mass of light cream, 60 parts by mass of sweetener (stevioside: maltitol = 45:0.03), 6 parts by mass of citrus fiber, 6 parts by mass of starch, and lactic acid bacteria with a viable count of 1×10 7 CFU.

[0062] The preparation method of the fermented buttermilk provided in this comparative example can refer to Example 1, except that the parts by mass of the raw materials are different, and the first mixed material is not subjected to lipase enzymatic hydrolysis treatment.

[0063] Comparative Example 3

[0064] This comparative example provides a fermented buttermilk added with acid whey. The raw materials used include 270 parts by mass of acid whey, 90 parts by mass of buttermilk powder, 20 parts by mass of light cream, 80 parts by mass of sweetener (stevioside: maltitol = 60:0.06), 3.6 parts by mass of citrus fiber, 5.4 parts by mass of starch, and lactic acid bacteria with a viable count of 1×10 8 CFU.

[0065] The preparation method of the fermented buttermilk provided in this comparative example can refer to Example 1, except that the parts by mass of the raw materials are different, and the first mixed material is not subjected to lipase enzymatic hydrolysis treatment.

[0066] Comparative Example 4

[0067] This comparative example provides a fermented buttermilk added with acid whey. The raw materials used include 300 parts by mass of acid whey, 95 parts by mass of buttermilk powder, 15 parts by mass of light cream, 55 parts by mass of sweetener (stevioside: maltitol = 40:0.02), 3.8 parts by mass of citrus fiber, 3.2 parts by mass of starch, and 1×10 7 CFU viable count of lactic acid bacteria.

[0068] The preparation method of the fermented buttermilk provided in this comparative example can refer to Example 1, with the difference being different parts by mass of raw materials.

[0069] Comparative Example 5

[0070] This comparative example provides a fermented buttermilk added with acid whey. The raw materials used include 270 parts by mass of acid whey, 100 parts by mass of whole milk powder, 15 parts by mass of coconut oil, 60 parts by mass of sweetener added (stevioside: maltitol = 50:0.04), 4.5 parts by mass of citrus fiber, 5.5 parts by mass of starch, and 1×10 8 CFU viable count of lactic acid bacteria.

[0071] The preparation method of the fermented buttermilk provided in this comparative example can refer to Example 1, with the difference being that some raw materials are replaced by other raw materials.

[0072] Product Experiment

[0073] 1. Conduct a sensory evaluation of the fermented buttermilk prepared in Examples 1 to 3 and Comparative Examples 1 to 5 in terms of taste and flavor. The main evaluation items include: tissue state (presence or absence of separation, viscosity, fineness, texture, etc.), color, flavor, taste, etc. A total of 40 people participated in the experiment and conducted sensory evaluations on Examples 1 to 3 and Comparative Examples 1 to 5 respectively. The sensory scoring criteria are shown in Table 1, and the experimental record results are shown in Table 2.

[0074] Table 1

[0075]

[0076] Table 2

[0077]

[0078]

[0079] It can be seen from the results in Table 2 that the fermented buttermilk provided in Examples 1 to 3 has good tissue state, taste and flavor. The product has no whey separation, a strong buttery flavor, a harmonious aroma, a delicate taste, a moderate sourness and sweetness, a uniform taste, and meets the expected state compared with Comparative Examples 1 to 5.

[0080] 2. Evaluation of viscosity and water holding capacity. The evaluation method is as follows, and the results are shown in Table 3.

[0081] 1) The test method for viscosity is as follows: Using a rheometer, let the fermented buttermilk stand at room temperature (20 - 25 °C) for 15 min and then pour it into the sample cell. The CC25DIN fixture is used for testing, the test distance is 500 microns, and the shear rate is 0.01 - 150 S -1 , take 15 data points for detection, and take the shear rate of 90 S -1 as the viscosity value.

[0082] 2) Use the water - holding capacity of the sample to judge the influence of the hydration time on the product state. Record the weight of the centrifuge tube as W0 (g). Take about 20 ml of the fermented buttermilk sample in the centrifuge tube, and weigh the total weight as W (g). Centrifuge at 5000 r / min for 15 min, discard the supernatant, and record the remaining total weight as W1 (g). The measurement method for the water - holding capacity is: Water - holding capacity (%) = ((W1 - W0) / (W - W0)) × 100%.

[0083] Table 3

[0084]

[0085]

[0086] As shown in Table 3, after acid whey is mixed with buttermilk powder and cream, the lipase enzymatic hydrolysis treatment and non - treatment have an impact on the final product state. In the non - enzymatic hydrolysis treatment, the product viscosity decreases, the water - holding capacity decreases, the product state is not good, which will cause the product to exude water and affect the product quality. At the same time, the raw materials used in the fermented buttermilk and whether nanofiltration treatment is carried out will both affect the water - holding capacity and viscosity of the fermented buttermilk.

[0087] 3. Evaluation of product stability

[0088] Place the fermented buttermilk provided in Examples 1 - 3 and Comparative Examples 1 - 5 at room temperature for 21 days, and test the pH and acidity of the fermented buttermilk on the 1st, 7th, 14th, and 21st days. Calculate the pH change rate according to pH change rate = (pH value on the 21st day - pH value on the 1st day) / pH value on the 1st day * 100%, and calculate the acidity change rate according to acidity change rate = (acidity value on the 21st day - acidity value on the 1st day) / acidity value on the 1st day * 100%. The test results are shown in Table 4.

[0089] Table 4

[0090]

[0091]

[0092] As can be seen from the results in Table 4, with the extension of the storage time, the pH and the change rate of acidity of the fermented buttermilk provided in Comparative Examples 1 to 5 are relatively high, while the fermented buttermilk provided in Examples 1 to 3 can reach the expected effects in terms of pH and acidity within 21 days and has strong stability.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fermented buttermilk added with acid whey, characterized in that, The raw materials required for preparing the fermented buttermilk include 250-300 parts by mass of acid whey, 80-100 parts by mass of buttermilk powder, 10-20 parts by mass of cream, 60-80 parts by mass of sweetener, 4.8-6 parts by mass of carbohydrates, 3-7.2 parts by mass of dietary fiber and 1*10 7 ~1*10 8 Probiotics with viable counts; the fermented buttermilk is obtained by successively performing homogenization, sterilization, fermentation, and refinement on a second mixed material, and the second mixed material includes a first enzymatically hydrolyzed material, a sweetener, a carbohydrate, and a dietary fiber; the first enzymatically hydrolyzed material is obtained by enzymatically hydrolyzing a first mixed material with lipase, the first mixed material includes a nanofiltration retentate, buttermilk powder, and cream, and the nanofiltration retentate is obtained by subjecting acid whey to nanofiltration treatment.

2. The fermented buttermilk according to claim 1, characterized in that, the lipase has an enzyme activity of 13 - 15 LU / g, the temperature of the enzymatic hydrolysis treatment is 35 - 40 °C, and the enzymatic hydrolysis time is 20 - 45 min.

3. The fermented buttermilk according to claim 1, characterized in that, the sweetener includes one or more of stevioside, erythritol, and maltitol; and / or, the carbohydrate includes starch; and / or, the dietary fiber includes citrus fiber.

4. The fermented buttermilk according to any one of claims 1 - 3, characterized in that, at 20 - 25 °C, the water holding capacity of the fermented buttermilk is not less than 80%, and the viscosity is not less than 650 pa·s.

5. The fermented buttermilk according to any one of claims 1 - 3, characterized in that, after the fermented buttermilk is stored for 21 days, the reduction rate of pH is not higher than 8.5%, and the growth rate of acidity is not higher than 45.0%.

6. A preparation method of the fermented buttermilk added with acid whey according to any one of claims 1 - 5, characterized in that, it includes the following steps: Step 1, subject acid whey to nanofiltration treatment and collect the nanofiltration retentate; Step 2, mix the nanofiltration retentate, buttermilk powder, and cream evenly to obtain a first mixed material; adjust the pH of the first mixed material to 6.3 - 6.5, add lipase for enzymatic hydrolysis to obtain a first enzymatically hydrolyzed material; perform homogenization treatment on the first enzymatically hydrolyzed material; Step 3, add a sweetener, a carbohydrate, and a dietary fiber to the homogenized first enzymatically hydrolyzed material, stir evenly to obtain a second mixed material; perform homogenization and sterilization treatments on the second mixed material in sequence; inoculate probiotics in the sterilized second mixed material for fermentation, and perform refinement after fermentation to obtain the fermented buttermilk added with acid whey.

7. The preparation method according to claim 6, characterized in that, the lipase has an enzyme activity of 13 - 15 LU / g, the temperature of the enzymatic hydrolysis treatment is 35 - 40 °C, and the enzymatic hydrolysis time is 20 - 45 min.

8. The preparation method according to claim 6, characterized in that, in Step 2, in the homogenization treatment, the primary homogenization pressure is 15 - 25 bar, and the secondary homogenization pressure is 160 - 180 bar; and / or, in Step 3, in the homogenization treatment, the primary homogenization pressure is 30 - 40 bar, and the secondary homogenization pressure is 160 - 180 bar.

9. The preparation method according to claim 6, characterized in that, the fermentation temperature is 35 - 50 °C, and when the pH of the fermented buttermilk is not higher than 4.6, stop the fermentation.

10. The preparation method according to claim 6, characterized in that, the frequency of the refinement treatment is 10 to 15 Hz.

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