Preparation method of drinking type fermented milk retaining original living protein
By using refrigeration and low-temperature ingredient to treat fresh raw milk in the preparation process, combining homogenization and steam sterilization technology to control fermentation conditions, the problems of denaturation and viscosity increase of active proteins caused by heat treatment are solved, and the effect of retaining the original active protein and reducing viscosity is achieved, and the taste and texture stability of fermented milk is improved.
Patent Information
- Application Number
- CN202311259989.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-27
- Publication Date
- 2025-03-28
AI Technical Summary
During the processing of existing fermented milk, heat treatment leads to denaturation of active proteins, reducing nutrients, increasing viscosity, and unstable texture, which cannot meet consumers' demand for low viscosity and stable texture beverages.
A preparation method is adopted, including refrigeration and storing fresh raw milk, homogenization and steam sterilization after low-temperature decomposition, inoculation of fermentation agent after cooling, controlling fermentation conditions, and finally conducting low-temperature homogenization and filling, retaining the original active protein and reducing viscosity.
It effectively retains a variety of active proteins in raw milk, reduces the viscosity of fermented milk, improves the smoothness of the taste and the stability of the texture, and provides a healthier drinking experience.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of fermented foods, and in particular to a method for preparing drinkable fermented milk retaining native active proteins. Background Art
[0002] Fermented milk is now loved by more and more consumers because of its delicious taste, rich nutrition and easier absorption. Generally, raw cow (sheep) milk or milk powder is used as raw material, sterilized and inoculated with lactic acid bacteria for fermentation, and fermented milk drinks with reduced lactose, increased acidity and thick texture can be obtained after a few hours. During the fermentation process, lactic acid bacteria convert lactose in raw milk into glucose and galactose, so that lactose-intolerant people who are allergic to milk can also eat it easily. However, in the processing of fermented milk, the heat treatment process currently uses 90-95℃ and 5-10min treatment methods at home and abroad. Although this treatment method can kill all microorganisms except a small number of spores, it will cause many active substances to be completely denatured, such as lactoferrin, β-lactoglobulin, α-lactalbumin and immunoglobulin. Active proteins will be denatured by heat, and the nutritional content will be greatly reduced. The texture becomes thicker, and the viscosity mostly reaches more than 300mPa·s. In addition, there are unstable texture problems such as water separation during the shelf life, which is quite different from the low-viscosity and stable texture beverages that consumers like now. Summary of the invention
[0003] In order to solve the problems in the prior art, more native active proteins contained in raw cow's milk are retained while reducing the viscosity of traditional yogurt, so that consumers can have a smoother yogurt drinking experience. The present invention provides a method for preparing fermented milk that can retain multiple active proteins in raw cow's milk, greatly reducing the denaturation loss of active proteins during the fermentation production process, and obtaining a drinkable fermented milk that contains more native active proteins, has reduced viscosity, improved smoothness of taste and stable texture.
[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows:
[0005] A method for preparing fermented milk retaining native active protein, comprising the following steps:
[0006] S1: Purify the fresh raw milk using a sterilizing centrifuge and store it in a refrigerator at 2-6°C for later use;
[0007] S2: adding sweeteners (such as white sugar, and artificial sweeteners such as sucralose and aspartame) into raw milk according to a proportion (the amount of white sugar added is 2-8%, and the amount of artificial sweetener added does not exceed the amount specified in the national standard GB 2760 food additives), and fermenting the material at 4-65°C to obtain an unfermented liquid.
[0008] S3: Optionally, homogenizing the above-mentioned liquid feed at a homogenization pressure of 100-200 bar and a temperature of 4-65° C.;
[0009] S4: After homogenization, the liquid is fed into the sterilizer and sterilized with steam at a temperature of 115-124°C for 0.1-2s;
[0010] S5: After sterilization, the material liquid is cooled to 42±1°C, and the fermentation is started by inoculating the fermentation agent (the fermentation agent includes one or a mixture of two or more of Lactobacillus bulgaricus, Streptococcus thermophilus, Streptococcus acidophilus or Bifidobacterium);
[0011] S6: When the pH of the fermented liquid drops to 4.3-4.6 or the fermentation is stopped after 4-8 hours, the emulsion is broken and cooled to 20±2℃;
[0012] S7: Perform downstream homogenization at a homogenization pressure of 160-200 bar, fill after cooling, and store in a refrigerator at 2-6°C to obtain drinkable fermented milk that retains the original active protein.
[0013] Preferably, before high-temperature steam sterilization, a 100-120 mesh filter is used to remove dust and other impurities, and then a centrifuge is used to remove non-milk cells and other impurities in the raw milk by low-temperature centrifugation, and the conditions of the low-temperature centrifugation are 4-10°C, 4000-8000rpm, preferably 4-6°C, 4000-6000rpm, and more preferably 4°C, 5000rpm. Finally, a centrifuge is used at 10-65°C, 4000-8000rpm, preferably 15-30°C, 4000-6000rpm, and more preferably 25°C, 5000rpm to peel off microorganisms such as spores, which can remove foreign matter and undesirable microorganisms in milk to a greater extent and reduce safety risks.
[0014] Preferably, during the chemical process, a low temperature of 4°C is used to further reduce the damage of temperature to active proteins.
[0015] The present invention provides fermented milk with retained native active protein, which is prepared by any of the above-mentioned preparation methods.
[0016] The fermented milk contains lactoferrin, β-lactoglobulin, α-lactalbumin and immunoglobulin.
[0017] Preferably, the lactoferrin content is 35-40 mg / kg, the β-lactoglobulin content is 2100-2300 mg / kg, the α-lactalbumin content is 1200-1400 mg / kg and the immunoglobulin content is about 40-45 mg / kg.
[0018] More preferably, the lactoferrin content is 36-37 mg / kg, the β-lactoglobulin content is 2150-2250 mg / kg, the α-lactalbumin content is 1211-1389 mg / kg and the immunoglobulin content is about 41.2-44 mg / kg.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] The fermented milk retains more original active protein in milk; the viscosity of the fermented milk is reduced, making it smoother for consumers to drink; a better texture is achieved, and the water separation phenomenon is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 The water separation of the fermented milk prepared in the examples and comparative examples after being stored at 30° C. for 14 days is shown. DETAILED DESCRIPTION
[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.
[0023] Unless otherwise specified, the raw materials of the kit used in the present invention are commercially available.
[0024] The addition amounts of all components in the present invention exceed the range specified by national standards.
[0025] Embodiment 1
[0026] This embodiment provides a method for preparing a drinkable fermented milk that retains native active protein, the method comprising the following steps:
[0027] S1 uses healthy dairy cows from large-scale ranch breeding bases and extracts fresh milk from the udders of healthy cows using mechanized milking equipment.
[0028] S2 tests the protein, fat, non-fat milk solids, density and acidity contained in fresh milk. The acceptance criteria comply with the national food safety standard GB19301. Qualified fresh milk is stored in a cold chain at 4°C.
[0029] S3 passes the raw milk through a 100-120 mesh filter to remove dust and other impurities, and then purifies the raw milk through a centrifuge, controls the temperature to 4°C, and centrifuges at a speed of 5000rpm to remove non-milk cells and other impurities in the milk.
[0030] S4 uses a sterilizing centrifuge at 25°C and 5000rpm to physically remove microorganisms from raw milk.
[0031] S5 tested the protein and fat content of the raw milk after being treated in a sterilizing centrifuge. The protein content was measured to be 3.3g / 100g and the fat content was 3.2g / 100g. The raw milk was refrigerated and stored at 4°C for future use.
[0032] S6: Add 5wt% of granulated sugar to the filtered milk and dissolve the mixture at 4°C.
[0033] S7 steam sterilizes the milk after the material is dissolved, and the sterilization condition is 124℃, 0.1s.
[0034] S8: Cool down to 42°C and inoculate the fermentation agent to start fermentation.
[0035] S9 stops fermentation when the pH of the material drops to 4.6, demulsifies and cools to 20°C, homogenizes at a pressure of 160 bar and then fills, and stores in a refrigerator at 4°C to obtain drinkable fermented milk that retains the original active protein and has low viscosity and stable texture.
[0036] Embodiment 2
[0037] This embodiment provides a method for preparing a drinkable fermented milk that retains native active protein, the method comprising the following steps:
[0038] S1 uses healthy dairy cows from large-scale ranch breeding bases and extracts fresh milk from the udders of healthy cows using mechanized milking equipment.
[0039] S2 tests the protein, fat, non-fat milk solids, density and acidity contained in fresh milk. The acceptance criteria comply with the national food safety standard GB19301. Qualified fresh milk is stored in a cold chain at 4°C.
[0040] S3 tested the protein and fat content of the raw milk and found that the protein content was 3.4g / 100g and the fat content was 3.4g / 100g. The raw milk was refrigerated and stored at 4°C for future use.
[0041] S4 Add 5% white sugar to the filtered milk and melt at 65°C.
[0042] S5 homogenizes the milk after the mixing at 160 bar, and the homogenization temperature is 65°C.
[0043] S6 is homogenized and then sterilized by steam at high temperature at 115°C for 2s.
[0044] After S7 is cooled to 42°C, the fermentation agent is inoculated to start fermentation.
[0045] S8 stops fermentation when the pH value of the material drops to 4.6, demulsifies and cools to 20°C, homogenizes at a pressure of 200 bar and then fills. After filling, refrigerates and stores at 4°C to obtain drinkable fermented milk that retains the original active protein, has low viscosity and stable texture.
[0046] Embodiment 3
[0047] This embodiment provides a method for preparing a drinkable fermented milk that retains native active protein, the method comprising the following steps:
[0048] S1 uses healthy dairy cows from large-scale ranch breeding bases and extracts fresh milk from the udders of healthy cows using mechanized milking equipment.
[0049] S2 tests the protein, fat, non-fat milk solids, density and acidity contained in fresh milk. The acceptance criteria comply with the national food safety standard GB19301. Qualified fresh milk is stored in a cold chain at 4°C.
[0050] S3 tested the protein and fat content of the raw milk and found that the protein content was 3.4g / 100g and the fat content was 3.4g / 100g. The raw milk was refrigerated and stored at 4°C for future use.
[0051] S4: adding 5wt% of white sugar to the filtered milk and melting the mixture at 65°C.
[0052] S5 sterilizes the milk after the material is dissolved by steam at high temperature, and the sterilization conditions are 120℃ and 0.136s.
[0053] After S6 is cooled to 42°C, the fermentation agent is inoculated to start fermentation.
[0054] S7 stops fermentation when the pH value of the material drops to 4.6, demulsifies and cools to 20°C, homogenizes at a pressure of 160 bar and then fills, and stores in a refrigerator at 4°C to obtain drinkable fermented milk with low viscosity and stable texture and retains the original active protein.
[0055] Comparative Example 1
[0056] This comparative example provides a method for preparing fermented milk, which comprises the following steps:
[0057] S1 uses healthy dairy cows from large-scale ranch breeding bases and extracts fresh milk from the udders of healthy cows using mechanized milking equipment.
[0058] S2 tests the protein, fat, non-fat milk solids, density and acidity contained in fresh milk. The acceptance criteria comply with the national food safety standard GB19301. Qualified fresh milk is stored in a cold chain at 4°C.
[0059] S3 passes the raw milk through a 100-120 mesh filter to remove dust and other impurities, and then purifies the raw milk through a centrifuge, controls the temperature to 4°C, and centrifuges at a speed of 5000rpm to remove non-milk cells and other impurities in the milk.
[0060] S4 uses a sterilizing centrifuge at 25°C and 5000rpm to physically remove microorganisms from raw milk.
[0061] S5 tested the protein and fat content of the raw milk after being treated in a sterilizing centrifuge. The protein content was measured to be 3.3g / 100g and the fat content was 3.2g / 100g. The raw milk was refrigerated and stored at 4°C for future use.
[0062] S6: adding 5wt% of white sugar to the filtered milk, and cooling the material at 4°C.
[0063] S7 homogenizes the milk after the material is mixed, with a homogenization pressure of 200 bar and a temperature of 20°C.
[0064] S8 sterilizes the homogenized milk at high temperature at 95°C for 300s.
[0065] After S9 is cooled to 42°C, the fermentation agent is inoculated to start fermentation.
[0066] S10: When the pH value of the material drops to 4.6, the fermentation is stopped, the emulsion is broken and cooled to 20°C, and filling is started. After filling, the material is refrigerated and stored at 4°C.
[0067] Comparative Example 2
[0068] This comparative example provides a method for preparing fermented milk, which comprises the following steps:
[0069] S1 uses healthy dairy cows from large-scale ranch breeding bases and extracts fresh milk from the udders of healthy cows using mechanized milking equipment.
[0070] S2 tests the protein, fat, non-fat milk solids, density and acidity contained in fresh milk. The acceptance criteria comply with the national food safety standard GB19301. Qualified fresh milk is stored in a cold chain at 4°C.
[0071] S3 tested the protein and fat content of the raw milk and found that the protein content was 3.4g / 100g and the fat content was 3.4g / 100g. The raw milk was refrigerated and stored at 4°C for future use.
[0072] S4: adding 5wt% of white sugar to the filtered milk, and heating the material at 65°C.
[0073] S5 steam sterilizes the milk after the material is dissolved, and the sterilization condition is 95°C for 300s.
[0074] After S6 is cooled to 42°C, the fermentation agent is inoculated to start fermentation.
[0075] S7: When the pH value of the material drops to 4.6, the fermentation is stopped, the emulsion is broken and cooled to 20°C, and the filling is started after homogenization at a pressure of 200 bar. After filling, the material is refrigerated and stored at 4°C.
[0076] Comparative Example 3
[0077] This comparative example provides a method for preparing fermented milk, which comprises the following steps:
[0078] S1 uses healthy dairy cows from large-scale ranch breeding bases and extracts fresh milk from the udders of healthy cows using mechanized milking equipment.
[0079] S2 tests the protein, fat, non-fat milk solids, density and acidity in fresh milk. The acceptance criteria meet the national food safety standard GB19301. Qualified fresh milk is stored in a cold chain at 4°C. The protein content is 3.4g / 100g and the fat content is 3.4g / 100g. It is stored in a refrigerated state at 4°C for future use.
[0080] S3 adds 5wt% white sugar into milk, and heats the material at 65°C.
[0081] S4 steam sterilizes the milk after the material is dissolved, and the sterilization condition is 115℃, 0.5s.
[0082] After S5 is cooled to 42°C, the fermentation agent is inoculated to start fermentation.
[0083] S6: When the pH value of the material drops to 4.6, the fermentation is stopped, the emulsion is broken and cooled to 20°C, homogenized at a pressure of 160 bar, and then filled and stored in a refrigerator at 4°C.
[0084] Effect Example
[0085] The products obtained in the above embodiments and comparative examples were measured for relevant indicators, and the detection basis was BJC-FDD-FB1906 "Determination of whey protein in milk and dairy products-Liquid chromatography", BJC-FDD-FB1801 "Determination of lactoferrin in food", BJC-FDD-FB2102 "Determination of immunoglobulin IgG in milk and dairy products-High performance liquid chromatography", etc. The results are summarized in the following Table 1.
[0086] Table 1 Test results of various indicators of fermented milk obtained in all cases
[0087]
[0088]
[0089] As shown in Table 1, except for Comparative Example 3 which contains microbial risks, the contents of lactoferrin, β-lactoglobulin, α-lactalbumin and immunoglobulin in the three embodiments are significantly increased, and the contents are increased by about 2-50 times compared with Comparative Examples 1 and 2. This means that the fermented milk prepared by the present invention retains more native active proteins. In addition, the viscosity of the three embodiments is also significantly lower than that of the comparative example, and the viscosity decreases by about 100-300 mPa·s.
[0090] The stability of the six samples in the above examples and comparative examples was further tested. 45 g of each of the six samples was placed in a 50 mL centrifuge tube and stored at 30°C for 14 days to observe the water separation. Figure 1 , the three on the left are embodiments, and the three on the right are comparative examples. It can be seen that the bottom of the comparative example has obvious water separation and stratification, while the three embodiments on the left have basically no water separation. Table 2 shows the results of water separation rate. The water separation rate of the embodiments is 1-11.6% lower than that of the comparative example, which means that the fermented milk prepared according to the three embodiments has better stability.
[0091] Table 2 Water separation rate (weight ratio) of fermented milk obtained in the examples and comparative examples stored at 30°C for 14 days
[0092] sample Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Water separation rate 2.2％ 3.3％ 3.3％ 4.3％ 8.7％ 13.8％
[0093] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A method for preparing fermented milk retaining native active proteins, wherein the fermented milk preferably contains lactoferrin, β-lactoglobulin, α-lactalbumin and immunoglobulin, more preferably, the lactoferrin content is 35-40 mg / kg, the β-lactoglobulin content is 2100-2300 mg / kg, the α-lactalbumin content is 1200-1400 mg / kg and the immunoglobulin content is about 40-45 mg / kg, and most preferably, the lactoferrin content is 36-37 mg / kg, the β-lactoglobulin content is 2150-2250 mg / kg, the α-lactalbumin content is 1211-1389 mg / kg and the immunoglobulin content is about 41.2-44 mg / kg, comprising the following steps: S1: Purify the raw milk using a sterilizing centrifuge and store it at low temperature for later use; S2: adding a sweetener to raw milk, and performing fermentation at low temperature to obtain an unfermented liquid; S3: The feed liquid is input into the sterilizer and sterilized by steam at a temperature of 115-124°C for 0.1-2s, preferably 115-120°C, 0.136-2s or 120-124°C, 0.1-0.136s; S4: After sterilization, cool the liquid to 42±1°C and inoculate the fermentation agent to start fermentation; S5: When the pH of the fermented liquid drops to 4.3-4.6 or the fermentation is stopped after 4-8 hours, the emulsion is broken and cooled to 20±2℃; S6: Perform downstream homogenization with a homogenization pressure of 160-200 bar, fill after cooling, and store in a refrigerator at 2-6°C to obtain drinkable fermented milk that retains the original active protein.
2. The method according to claim 1, characterized in that The low temperature in step S1 is 2-6°C.
3. The method according to claim 1, characterized in that: The low temperature in step S2 is 2-6°C, preferably 4°C.
4. The method according to claim 1, characterized in that: The fermentation agent is one or a combination of two or more of Lactobacillus bulgaricus, Streptococcus thermophilus, Streptococcus acidophilus or Bifidobacterium.
5. The method according to any one of claims 1 to 4, characterized in that After step S2, the method further comprises the following steps: homogenizing the unfermented liquid material, wherein the homogenization pressure is 100-200 bar and the temperature is 4-65°C.
6. The method according to any one of claims 1 to 4, characterized in that In step S1, the following steps are also included: first, use a filter to remove dust and other impurities, then use a centrifuge to remove non-milk cells in the raw milk by low-temperature centrifugation, and finally use a centrifuge to physically remove microorganisms in the raw milk.
7. The method according to claim 6, characterized in that The pore size of the filter is 100-120 meshes.
8. The method according to claim 6, characterized in that The conditions of the low-temperature centrifugation are 4-10°C, 4000-8000rpm, preferably 4°C-6°C, 4000-6000rpm.
9. The method according to claim 6, characterized in that The conditions for physically stripping the microorganisms in the raw milk by using a centrifuge are 10-65° C., 4000-8000 rpm, preferably 15-30° C., 4000-6000 rpm.
10. A fermented milk retaining native active protein prepared by the preparation method according to any one of claims 1 to 9.
11. The fermented milk according to claim 10, characterized in that The fermented milk contains lactoferrin, β-lactoglobulin, α-lactalbumin and immunoglobulin. Preferably, the lactoferrin content is 35-40 mg / kg, the β-lactoglobulin content is 2100-2300 mg / kg, the α-lactalbumin content is 1200-1400 mg / kg and the immunoglobulin content is about 40-45 mg / kg. More preferably, the lactoferrin content is 36-37 mg / kg, the β-lactoglobulin content is 2150-2250 mg / kg, the α-lactalbumin content is 1211-1389 mg / kg and the immunoglobulin content is about 41.2-44 mg / kg.