Preparation method and application of high-protein-content concentrated whey protein powder

Abstract

The invention discloses a preparation method and application of high-protein-content concentrated whey protein powder, and belongs to the technical field of dairy products. The preparation method comprises the following steps: carrying out intermittent mode ultrasonic treatment on raw milk, centrifuging, collecting filtrate, carrying out curdling treatment at a specific temperature, carrying out ultrafiltration on whey, collecting trapped fluid, concentrating, and drying; the content of protein in the concentrated whey protein powder can be effectively improved, and the solubility of the concentrated whey protein powder in water can be effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of dairy product technology, and in particular relates to a method for preparing concentrated whey protein powder with high protein content and its application. Background Technology

[0002] Whey protein concentrate, rich in essential amino acids, easily absorbed, and possessing excellent emulsifying and solubilizing properties, is widely used in protein supplements, special diets, and infant formula. However, traditional production processes, especially heat treatment, can easily lead to irreversible denaturation of whey proteins (particularly heat-sensitive immunoglobulins and lactoferrin). While the nutritional value of denatured proteins remains largely unchanged, their functional properties (such as solubility, foaming ability, and emulsifying properties) are significantly reduced, impacting their application in high-end food systems. Furthermore, some processes employ multiple low-temperature concentrations, which prolong production cycles and increase energy consumption. Additionally, the protein content of existing whey protein concentrates is generally between 30-35%, which cannot effectively meet the requirements of high-end diets for high-protein whey protein concentrates. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing high-protein concentrated whey protein powder with high protein content and excellent solubility, as well as its application.

[0004] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing high-protein-content concentrated whey protein powder, the method comprising the following steps: (1) Ultrasound the raw milk, centrifuge it after ultrasounding, and collect the filtrate; (2) After heating the filtrate to 35-45℃, add rennet to perform coagulation treatment. After the coagulation treatment is completed, separate the solid and liquid, collect the filtrate, and obtain whey. (3) The whey liquid is subjected to ultrafiltration, the retentate of ultrafiltration is collected, the retentate is concentrated and dried to obtain concentrated whey protein powder with high protein content; In step (1), the ultrasound is performed in an intermittent mode, wherein in each work-stop cycle, the ratio of working time to stop time is 1:(0.5-1.5), the individual working time is 1-2 min, and the total ultrasound time is ≥30 min.

[0005] This invention involves intermittently sonicating and centrifuging raw milk, then collecting the filtrate and coagulating it at a specific temperature, followed by ultrafiltration of the whey, collection of the retentate, and concentration. This effectively increases the protein content of the concentrated whey protein powder and also improves its solubility in water. Furthermore, the preparation method provided by this invention has high production efficiency.

[0006] Specifically, firstly, this invention enhances the surface hydrophobicity of protein molecules by subjecting raw milk to ultrasonic treatment using a specific intermittent model, thereby increasing surface activity and improving the solubility of the prepared concentrated whey protein powder in water. Secondly, this invention uses rennet within a specific temperature range for coagulation treatment. Casein forms paracasein under the action of rennet, causing the paracasein particles to aggregate and form a gel, thus separating casein from the raw milk and separating whey protein, lactose, and minerals from casein. Simultaneously, the use of rennet for coagulation also reduces the product production cycle. Thirdly, this invention performs ultrafiltration on the coagulated whey liquid, effectively removing lactose and mineral components from the whey protein, resulting in concentrated whey protein powder with high protein content and high product purity.

[0007] For example, the ratio of working time to rest time can be any point value between 1: (0.5-1.5) or a range value between any two points, such as 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, etc.

[0008] Preferably, the ratio of working time to rest time is 1:1.

[0009] For example, each individual working time can be an independent value between 0.8 and 2 minutes, or a range between any two points, such as 0.8 min, 1 min, 1.2 min, 1.5 min, 1.8 min, 2 min, etc.

[0010] Preferably, the single working time is 1 minute.

[0011] Preferably, the total ultrasound time is 30-40 minutes.

[0012] For example, the total ultrasound time can be any point value between 30 and 40 minutes or a range between any two points, such as 32-38 minutes, or 30 minutes, 32 minutes, 35 minutes, 38 minutes, 40 minutes, etc.

[0013] In a preferred embodiment of the preparation method described in this invention, the ultrasonic power in step (1) is 600-1000W.

[0014] For example, in step (1), the power of the ultrasound can be any point value between 600-1000W or a range between any two points, such as 600W, 800W, 1000W, etc.

[0015] The present invention has found that by further selecting the ultrasonic power within the above range, the obtained concentrated whey protein powder has a higher protein content and greater solubility in water.

[0016] As a preferred embodiment of the preparation method of the present invention, in step (1), the centrifugation speed is 3500-4000 rpm and the centrifugation time is 10-15 min.

[0017] As a preferred embodiment of the preparation method of the present invention, in step (2), the solid-liquid separation includes filtration, and the filter cloth of the filter has a pore size of 150-250 mesh.

[0018] In a preferred embodiment of the preparation method described in this invention, the enzyme activity of the rennet is ≥2000 U / g.

[0019] In a preferred embodiment of the preparation method described in this invention, in step (2), the mass percentage of rennet is 0.1-0.5% based on the mass of raw milk.

[0020] For example, the mass percentage of rennet, based on the mass of raw milk, can be any point value or a range between any two points between 0.1% and 0.5%, such as 0.1%-0.3%, 0.15%-0.3%, 0.2%-0.3%, 0.15%-0.2%, 0.15%-0.3%, etc., or 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc.

[0021] In a preferred embodiment of the preparation method described in this invention, the curdling treatment time in step (2) is 20-30 min.

[0022] For example, the curd treatment time can be any point value between 20 and 30 minutes or a range between any two points, such as 24-30 minutes, 25-30 minutes, 26-30 minutes, etc., or 20 minutes, 22 minutes, 25 minutes, 28 minutes, 30 minutes, etc.

[0023] As a preferred embodiment of the preparation method described in this invention, in step (3), the ultrafiltration treatment is performed using an ultrafiltration membrane with a molecular weight cutoff of 20kDa-50kDa.

[0024] For example, the molecular weight cutoff of the ultrafiltration membrane can be any point value or any range between 20kDa and 50kDa, such as 20kDa-30kDa, 30kDa-50kDa, or 20 kDa, 25 kDa, 30 kDa, 35 kDa, 40 kDa, 45 kDa, 50 kDa, etc.

[0025] In a preferred embodiment of the preparation method described in this invention, in step (3), the concentration temperature is 40-60°C, and the concentration endpoint is when the solid content of the retentate is 10-25%.

[0026] As a preferred embodiment of the preparation method of the present invention, in step (3), the drying is spray drying, and the inlet temperature of the spray drying is 160-220℃ and the outlet temperature is 70-80℃.

[0027] In a second aspect, the present invention provides a high-protein-content concentrated whey protein powder, prepared using the preparation method described in the present invention.

[0028] As a preferred embodiment of the high-protein-content concentrated whey protein powder of the present invention, the high-protein-content concentrated whey protein powder has a protein mass content of ≥80%.

[0029] As a preferred embodiment of the high-protein-content concentrated whey protein powder of the present invention, the high-protein-content concentrated whey protein powder has a solubility of ≥99% in water at 30°C.

[0030] A third aspect of the present invention provides the application of the high-protein-content concentrated whey protein powder in the preparation of protein supplements, special diets, and infant formula.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention involves intermittently ultrasonicating and centrifuging raw milk, then collecting the filtrate and coagulating it at a specific temperature, followed by ultrafiltration of the whey, collection of the retentate, and concentration. This effectively increases the protein content of the concentrated whey protein powder and also improves its solubility in water. Furthermore, the preparation method provided by this invention has high production efficiency.

[0032] 2. The preparation method provided by this invention uses water as the solvent throughout the process, and the reaction conditions are mild, safe, environmentally friendly, and pollution-free, which is in line with the concept and requirements of green development. Therefore, it can be widely used in the preparation of protein supplements, special diets, and infant formula foods. Detailed Implementation

[0033] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0034] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in the field; and unless otherwise specified, the raw materials used in parallel experiments are from the same batch.

[0035] Rennet: Nanning Pangbo Biotechnology Co., Ltd., enzyme activity is 2000U / g.

[0036] Example 1 This invention provides a concentrated whey protein powder, the preparation method of which includes the following steps: (1) 100 kg of raw milk was subjected to intermittent ultrasonication at a power of 800 W. In each work-stop cycle, the ratio of working time to stop time was 1:1, the single working time was 1 min, and the total ultrasonic time was 38 min. After ultrasonication, the milk was centrifuged at 4000 rpm for 10 min and the filtrate was collected. (2) After heating the filtrate to 40°C, add rennet (0.1% by mass based on the mass of raw milk) for 30 min of coagulation treatment. After the coagulation treatment is completed, filter through a 200-mesh filter cloth and collect the filtrate to obtain whey. (3) The whey liquid was subjected to ultrafiltration using an organic membrane with a molecular weight cutoff of 30 kDa. The retentate from the ultrafiltration was collected and concentrated at 55°C to a solid content of 15%, and then spray-dried (inlet temperature 180°C, outlet temperature 75°C) to obtain concentrated whey protein powder.

[0037] Example 2 This invention provides a concentrated whey protein powder, the preparation method of which includes the following steps: (1) 100 kg of raw milk was subjected to intermittent sonication at a power of 800 W. In each work-stop cycle, the ratio of working time to stop time was 1:1, the single working time was 1 min, and the total sonication time was 35 min. After sonication, the milk was centrifuged at 3800 rpm for 12 min and the filtrate was collected. (2) After heating the filtrate to 40°C, add rennet (0.2% by mass based on the mass of raw milk) for 25 min of coagulation treatment. After the coagulation treatment is completed, filter the filtrate through a 200-mesh filter cloth and collect the filtrate to obtain whey. (3) The whey liquid was subjected to ultrafiltration using an organic membrane with a molecular weight cutoff of 20 kDa. The retentate from the ultrafiltration was collected and concentrated at 50°C to a solid content of 18%, and then spray-dried (inlet temperature 180°C, outlet temperature 75°C) to obtain concentrated whey protein powder.

[0038] Example 3 This invention provides a concentrated whey protein powder, the preparation method of which includes the following steps: (1) 100 kg of raw milk was subjected to intermittent sonication at a power of 800 W. In each work-stop cycle, the ratio of working time to stop time was 1:1, the single working time was 1 min, and the total sonication time was 35 min. After sonication, the milk was centrifuged at 3500 rpm for 15 min and the filtrate was collected. (2) After heating the filtrate to 40°C, add rennet (0.15% by mass based on the mass of raw milk) for coagulation treatment for 26 min. After the coagulation treatment is completed, filter through a 200-mesh filter cloth and collect the filtrate to obtain whey. (3) The whey liquid was subjected to ultrafiltration using an organic membrane with a molecular weight cutoff of 50 kDa. The retentate from the ultrafiltration was collected and concentrated at 52°C to a solid content of 13%, and then spray-dried (inlet temperature 180°C, outlet temperature 75°C) to obtain concentrated whey protein powder.

[0039] Example 4 This invention provides a concentrated whey protein powder, the preparation method of which includes the following steps: (1) 100 kg of raw milk was subjected to intermittent sonication at a power of 800 W. In each work-stop cycle, the ratio of working time to stop time was 1:1, the single working time was 1 min, and the total sonication time was 32 min. After sonication, the milk was centrifuged at 3800 rpm for 12 min and the filtrate was collected. (2) After heating the filtrate to 40°C, add rennet (0.3% by mass based on the mass of raw milk) for 24 min of coagulation treatment. After the coagulation treatment is completed, filter the filtrate through a 200-mesh filter cloth and collect the filtrate to obtain whey. (3) The whey liquid was subjected to ultrafiltration using an organic membrane with a molecular weight cutoff of 30 kDa. The retentate from the ultrafiltration was collected and concentrated at 50°C to a solid content of 17%, and then spray-dried (inlet temperature 180°C, outlet temperature 75°C) to obtain high protein content concentrated whey protein powder.

[0040] Example 5 This invention provides a concentrated whey protein powder. The difference between the concentrated whey protein powder and that in Example 1 is that in step (2), the mass percentage of rennet is 0.5% based on the mass of raw milk.

[0041] Example 6 This invention provides a concentrated whey protein powder, which differs from Example 1 in that in step (2), a curdling process is performed for 20 minutes.

[0042] Comparative Example 1 The present invention provides a concentrated whey protein powder as a comparative example. The difference between the concentrated whey protein powder and Example 1 is that in step (3), the whey liquid is subjected to ultrafiltration treatment using an organic membrane with a molecular weight cutoff of 5 kDa.

[0043] Comparative Example 2 The present invention provides a concentrated whey protein powder as a comparative example. The difference between the concentrated whey protein powder and Example 1 is that in step (1), there is no centrifugation after the ultrasonic treatment.

[0044] Comparative Example 3 The present invention provides a concentrated whey protein powder as a comparative example. The difference between the concentrated whey protein powder and Example 1 is that in step (1), there is no ultrasonic process, that is: 100 kg of raw milk is centrifuged at 4000 rpm for 10 min and the filtrate is collected.

[0045] Comparative Example 4 The present invention provides a concentrated whey protein powder as a comparative example. The difference between the concentrated whey protein powder and Example 1 is that in step (2), the mass percentage of rennet is 0.05% based on the mass of raw milk, and the coagulation time is 30 min.

[0046] Comparative Example 5 The present invention provides a concentrated whey protein powder as a comparative example. The difference between the concentrated whey protein powder and Example 1 is that in step (1), the single working time is 0.5 min.

[0047] Comparative Example 6 The present invention provides a concentrated whey protein powder as a comparative example. The difference between the concentrated whey protein powder and Example 1 is that in step (1), the total ultrasonic time is 20 min.

[0048] Comparative Example 7 The present invention provides a concentrated whey protein powder as a comparative example. The difference between the concentrated whey protein powder and Example 1 is that in step (1), the ratio of working time to rest time is 1:0.2.

[0049] Comparative Example 8 The present invention provides a concentrated whey protein powder as a comparative example. The difference between the concentrated whey protein powder and Example 1 is that in step (2), the curdling time is 40 min.

[0050] Comparative Example 9 The present invention provides a concentrated whey protein powder as a comparative example. The difference between the concentrated whey protein powder and Example 1 is that in step (3), the whey liquid is subjected to ultrafiltration treatment using an organic membrane with a molecular weight cutoff of 60 kDa.

[0051] Comparative Example 10 The present invention provides a concentrated whey protein powder as a comparative example. The difference between the concentrated whey protein powder and Example 1 is that in step (2), the filtrate is heated to 30°C.

[0052] Comparative Example 11 The present invention provides a concentrated whey protein powder as a comparative example. The difference between the concentrated whey protein powder and Example 1 is that in step (2), the filtrate is heated to 50°C.

[0053] Example of effect The performance of the concentrated whey protein powder prepared by the examples and comparative examples of this invention is recorded, including the following aspects: 1. Yield: The yield is obtained by dividing the mass of the weighed concentrated whey protein powder by the mass of the raw milk, i.e., yield = (mass of concentrated whey protein powder / mass of raw milk) × 100%; 2. Protein content: The detection method refers to GB5009.5 (Kjeldahl method); 3. Fat content: The detection method refers to Method III of GB5009.6; 4. Lactose content: The detection method refers to Method I of GB5009.8; 5. Solubility: The concentrated whey protein powder prepared in the examples and comparative examples was added to ultrapure water at 30℃ and dissolved to form a protein solution of 1 mg / mL. The absorbance value at 280 nm was measured. The dissolved sample was placed in a refrigerator at 4℃ overnight and then centrifuged at 4000 rpm for 10 min. The absorbance value of the supernatant at 280 nm was measured, and the solubility of the product was calculated using the following formula: M = R1 / R0 × 100% In the formula: M is the precipitation rate; R0 is the absorbance value of the protein solution at 280 nm; R1 is the absorbance value of the supernatant at 280 nm; the results are shown in Table 1. Table 1 As can be seen from Table 1, when the technical solution provided by the present invention is adopted, the yield of the concentrated whey protein powder is relatively high, above 0.52%, and the protein content is relatively high, while the fat and lactose content is relatively low. Specifically, the obtained protein content is above 83.2%, the fat content is below 0.87%, and the lactose content is below 2.21%. At the same time, the obtained concentrated whey protein powder has excellent solubility in water, with a solubility of above 99.29%. As can be seen from Examples 1 and Comparative Examples 3 and 5-7, when ultrasonic treatment was not used during production, or when ultrasonic treatment was used but not within the requirements of this invention, the solubility of the resulting product was significantly lower than that of Example 1, with other processes remaining unchanged. As can be seen from Examples 1 and Comparative Example 2, when centrifugation was not used during production, the resulting product had a lower protein content, a higher fat content, and poorer solubility. As can be seen from Examples 1 and Comparative Examples 4, 8, 10, and 11, the amount of rennet added and the rennet treatment parameters had a significant impact on the product during production. When the amount of rennet added or the rennet parameters were outside the scope of this invention, the overall performance of the resulting product was significantly lower when other processes remained unchanged. As can be seen from Examples 1 and Comparative Examples 1 and 9, when organic membrane parameters were used during production but not within the scope of this invention, the overall performance of the resulting product was also significantly lower.

[0054] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a high-protein-content concentrated whey protein powder, characterized in that, The preparation method includes the following steps: (1) Ultrasound the raw milk, centrifuge it after ultrasounding, and collect the filtrate; (2) After heating the filtrate to 35-45℃, add rennet to perform coagulation treatment. After the coagulation treatment is completed, perform solid-liquid separation, collect the filtrate, and obtain whey. (3) The whey liquid is subjected to ultrafiltration, the retentate of the ultrafiltration is collected, the retentate is concentrated and dried to obtain concentrated whey protein powder with high protein content; In step (1), the ultrasound is performed in an intermittent mode, wherein in each work-stop cycle, the ratio of working time to stop time is 1:(0.5-1.5), the individual working time is 0.8-2 min, and the total ultrasound time is ≥30 min.

2. The preparation method according to claim 1, characterized in that, In step (1), the power of the ultrasound is 600-1000W.

3. The preparation method according to claim 1, characterized in that, In step (1), the centrifugation speed is 3500-4000 rpm and the centrifugation time is 10-15 min.

4. The preparation method according to claim 1, characterized in that, In step (2), the solid-liquid separation includes filtration, and the filter cloth of the filter has a pore size of 150-250 mesh; And / or, in step (2), the mass percentage of rennet is 0.1-0.5% based on the mass of raw milk; And / or, in step (2), the curd treatment time is 20-30 min.

5. The preparation method according to claim 1, characterized in that, The enzyme activity of the protease with curdling activity is ≥2000 U / g.

6. The preparation method according to claim 1, characterized in that, In step (3), the ultrafiltration treatment is performed using an ultrafiltration membrane with a molecular weight cutoff of 20kDa-50kDa; And / or, in step (3), the concentration temperature is 40-60℃, and the concentration endpoint is when the solid content of the retentate is 10-25%; And / or, in step (3), the drying is spray drying, the inlet temperature of the spray drying is 160-220℃, and the outlet temperature is 70-80℃.

7. A high-protein-content concentrated whey protein powder, characterized in that, The high-protein concentrated whey protein powder is prepared using the preparation method described in any one of claims 1-6.

8. The high-protein-content concentrated whey protein powder according to claim 7, characterized in that, The high-protein concentrated whey protein powder contains ≥80% protein by mass. And / or, the high-protein-content concentrated whey protein powder has a solubility of ≥99% in water at 30°C.

9. The application of the high-protein-content concentrated whey protein powder as described in claim 7 or 8 in the preparation of protein supplements, special diets, and infant formula.

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