Low-yeast-flavor yeast protein and preparation method and application thereof

Abstract

This invention relates to the field of microbial application technology, specifically to a low-yeast-flavor yeast protein, its preparation method, and its applications. A method for preparing a low-yeast-flavor yeast protein includes the following steps: preparing a dispersion of high-protein yeast, adjusting the pH to 4-8, inactivating it, centrifuging to collect the heavy phase, and then adding water to obtain yeast milk; enzymatically hydrolyzing the obtained yeast milk using a complex enzyme and adding ethyl acetate, wherein the complex enzyme includes glucanase, mannanase, and lipase; inactivating the obtained enzymatic hydrolysate, centrifuging to collect the heavy phase, and obtaining a low-yeast-flavor yeast protein with a protein content of over 78%, a nucleic acid content of less than 1.5%, and almost no yeast odor or other unpleasant odors, meeting the needs of human nutrition and alternative protein fields.

Description

Technical Field

[0001] This invention relates to the field of microbial application technology, specifically to a low-yeast-flavor yeast protein, its preparation method, and its application. Background Technology

[0002] Protein is an essential component of human tissues and organs, participating in various systems that maintain tissue growth and metabolism. Therefore, adequate intake of high-quality protein is crucial for health. Finding sustainable alternative proteins has become a hot topic in the market. Yeast is the most widely used single-celled fungus among humans, and it is an excellent source of high-quality complete protein. The digestibility of yeast protein can reach 96%, with a net utilization rate of 59%.

[0003] In existing technologies, most methods do not involve screening yeast strains or optimizing fermentation processes to obtain raw materials with high protein content and low yeast flavor. Some methods also require further treatment with ethanol or supercritical carbon dioxide to increase protein content, which is not conducive to industrial production. Chinese patent CN109198156 discloses a method for preparing yeast protein, which includes enzymatically hydrolyzing nucleic acid yeast powder to remove the soluble portion, followed by homogenization, cell wall disruption, and drying. The yeast protein prepared by this invention has a protein content of over 75% and a protein yield of 30-35%. However, the crude fat content of this yeast protein is greater than 1%, which affects the flavor and texture of the protein. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the yeast protein prepared by the prior art has low protein content and contains off-flavors, which affects the sensory quality of the yeast protein.

[0005] To address the shortcomings of existing technologies, one objective of this invention is to provide a method for preparing low-yeast-flavor yeast protein; a second objective is to provide low-yeast-flavor yeast protein obtained by the above preparation method; and a third objective is to provide the application of the low-yeast-flavor yeast protein prepared by the above preparation method or the application of the above-mentioned low-yeast-flavor yeast protein in human nutrition and as a substitute protein.

[0006] The technical solution of this invention:

[0007] This invention provides a method for preparing low-yeast-flavor yeast protein, comprising the following steps:

[0008] (1) Prepare a dispersion of high-protein yeast, adjust the pH to 4-8, inactivate it, centrifuge to obtain the heavy phase, and then add water to obtain yeast milk;

[0009] (2) The yeast milk obtained in step (1) is enzymatically hydrolyzed by a compound enzyme and ethyl acetate, wherein the compound enzyme contains glucanase, mannanase and lipase.

[0010] (3) After inactivating the enzyme in the enzymatic hydrolysate obtained in step (2), centrifuge to obtain the heavy phase and obtain low yeast flavor yeast protein.

[0011] Preferably, the inactivation temperature in step (1) is 75-99℃, and the inactivation time is preferably 5-120 min.

[0012] Preferably, the weight percentage concentration of the dispersion in step (1) is 8-20%.

[0013] Preferably, the yeast milk in step (1) has a weight percentage concentration of 8-20%.

[0014] Preferably, the amount of the compound enzyme added in step (2) is 0.3-6% based on the dry matter of yeast milk. More preferably, the amount of the glucanase added is 0.1-2% based on the dry matter of yeast milk, the amount of the mannanase added is 0.1-2% and the amount of the lipase added is 0.1-2%.

[0015] Preferably, the amount of ethyl acetate added is 0.2-2% based on the dry matter of the yeast milk.

[0016] Preferably, the enzymatic hydrolysis temperature in step (2) is 40-70℃, more preferably, the enzymatic hydrolysis pH is 4-8, and even more preferably, the enzymatic hydrolysis time is 5-20h.

[0017] Preferably, the enzyme inactivation temperature in step (2) is 75-90℃, and more preferably, the enzyme inactivation time is 0.5-3h.

[0018] Preferably, the above preparation method further includes the step of drying the heavy phase obtained in step (3): the heavy phase is prepared into a solution with a weight percentage of 8-20%, and dried to obtain powdered low-yeast-flavor yeast protein. Preferably, the drying is one of microwave drying, spray drying or vacuum drying.

[0019] The present invention also provides a low-yeast-flavor yeast protein prepared by the above preparation method, wherein the protein content is ≥78%, and preferably, the nucleic acid content is ≤1.5%.

[0020] The present invention also provides the preparation of low-yeast-flavor yeast protein by the above preparation method or the application of the above-mentioned low-yeast-flavor yeast protein in human nutrition and alternative proteins.

[0021] The beneficial effects of this invention are:

[0022] This invention uses high-protein yeast as raw material, which is inactivated and hydrolyzed by compound enzymes to obtain yeast protein with low yeast odor. Its protein content reaches more than 78%, and the nucleic acid content is less than 1.5%. It has almost no yeast odor or other unpleasant odors, and can meet the needs of human nutrition and alternative protein fields. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0024] This invention provides a method for preparing low-yeast-flavor yeast protein, comprising the following steps:

[0025] (1) Prepare a dispersion of high-protein yeast, adjust the pH to 4-8, inactivate it, centrifuge to obtain the heavy phase, and then add water to obtain yeast milk;

[0026] (2) The yeast milk obtained in step (1) is enzymatically hydrolyzed by a compound enzyme and ethyl acetate, wherein the compound enzyme contains glucanase, mannanase and lipase.

[0027] (3) After inactivating the enzyme in the enzymatic hydrolysate obtained in step (2), centrifuge to obtain the heavy phase and obtain low yeast flavor yeast protein.

[0028] The high-protein yeast of this invention is a yeast strain obtained through batch or continuous fermentation using molasses and / or hydrolyzed sugar as raw materials, with a yeast protein content ≥50.0%. The yeast strain is *Saccharomyces cerevisiae* FX-2. This strain was deposited at the China Center for Type Culture Collection (CCTCC) on August 1, 2016, with accession number CCTCC NO: M2016418. This strain has been described in the patent publication text with publication number CN108220175A.

[0029] This invention employs the method of inactivating high-protein yeast, causing yeast denaturation, inactivation of endogenous enzymes, and permeability of the cell membrane, thereby releasing the soluble portion. This reduces the production of odorous substances such as amino acids due to yeast autolysis. Simultaneously, adjusting the pH to 4-8 is beneficial for the release of yeast endogenous substances, especially yeast nucleic acids, which reduces the nucleic acid content in yeast protein, thus avoiding excessive uric acid levels in the human body after consumption. Furthermore, glucanase and mannanase are used to enzymatically remove the glucan and mannan from the yeast, and lipase is used to remove a small amount of fat from the yeast, increasing the protein content.

[0030] In a preferred embodiment of the present invention, the inactivation temperature in step (1) is 75-99°C, and the preferred inactivation time is 5-120 min.

[0031] In a preferred embodiment of the present invention, the weight percentage concentration of the dispersion in step (1) is 8-20%.

[0032] In another preferred embodiment of the present invention, the yeast milk in step (1) has a weight percentage concentration of 8-20%.

[0033] In another preferred embodiment of the present invention, the amount of the compound enzyme added in step (2) is 0.3-6% based on the dry matter of yeast milk. Preferably, the amount of the glucanase added is 0.1-2% based on the dry matter of yeast milk, the amount of the mannanase added is 0.1-2% and the amount of the lipase added is 0.1-2%.

[0034] In another preferred embodiment of the present invention, the amount of ethyl acetate added is 0.2-2% based on the dry matter of yeast milk. Adding ethyl acetate can, on the one hand, regulate the osmotic function of cells, which is beneficial for enzymatic hydrolysis; on the other hand, the fat dissolves into the ethyl acetate, which is beneficial for fat removal.

[0035] In another preferred embodiment of the present invention, the enzymatic hydrolysis temperature in step (2) is 40-70°C, preferably, the enzymatic hydrolysis pH is 4-8, and even more preferably, the enzymatic hydrolysis time is 5-20h.

[0036] In another preferred embodiment of the present invention, the enzyme inactivation temperature in step (3) is 75-90°C, and preferably, the enzyme inactivation time is 0.5-3h.

[0037] In another preferred embodiment of the present invention, the method further includes a step of drying the heavy phase obtained in step (3): the heavy phase is prepared into a solution with a weight percentage of 8-20%, and dried to obtain powdered low-yeast-flavor yeast protein. Preferably, the drying is one of microwave drying, spray drying or vacuum drying.

[0038] The present invention also provides a low-yeast-flavor yeast protein prepared by the above preparation method, wherein the protein content is ≥78%, and preferably, the nucleic acid content is ≤1.5%.

[0039] The present invention also provides the preparation of low-yeast-flavor yeast protein by the above preparation method or the application of the above-mentioned low-yeast-flavor yeast protein in human nutrition and alternative proteins.

[0040] The beneficial effects of the present invention will be further illustrated below through specific embodiments.

[0041] The sources of raw materials and equipment used in the embodiments and comparative examples of this invention are shown in Table 1.

[0042] Table 1. Sources of raw materials and equipment used in the embodiments and comparative examples of this invention.

[0043]

[0044] Example 1

[0045] (1) The culture medium contains carbon, nitrogen, and phosphorus sources. The carbon source is 7000g of 30% molasses, the nitrogen source is 400g of ammonium sulfate, and the phosphorus source is 600g of potassium dihydrogen phosphate. The culture medium is sterilized at 121℃ for 10min, inoculated with Saccharomyces cerevisiae FX-2 for fermentation culture at 29℃ for 18h at a pH of 5.0, to obtain high-protein yeast milk with a protein content of 58%.

[0046] (2) Prepare a 10wt% dispersion of the high-protein yeast milk from step (1), adjust the pH to 6.0 with sodium hydroxide or citric acid, inactivate it at 85℃ for 1h, and then centrifuge at 5000r / min for 10 minutes to collect the heavy phase.

[0047] (3) Prepare a 10wt% yeast milk by mixing the above-mentioned heavy phase, adjust the pH to 6.5, add 0.2% (based on the dry matter mass of yeast milk) ethyl acetate, 0.5% (based on the dry matter mass of yeast milk) glucanase, 0.5% (based on the dry matter mass of yeast milk) mannanase, and 0.5% (based on the dry matter mass of yeast milk) lipase, and enzymatically hydrolyze at 55℃ for 15h;

[0048] (4) After the enzymatic hydrolysis is completed, the temperature is raised to 80℃ and the enzyme is inactivated for 2 hours. The hydrolysate is centrifuged at 5000 r / min for 10 minutes to collect the heavy phase.

[0049] (5) Prepare a 15wt% dispersion of the above heavy phase, and then spray dry it to obtain powdered low-yeast-flavor yeast protein with a moisture content of <8%.

[0050] The protein content, fat content, nucleic acid content, glucan content, and mannose content in high-protein yeast and low-flavor yeast were determined using the following methods. The results are shown in Table 4.

[0051] 1) Determination of protein content

[0052] The protein content was determined according to GB 5009.5-2016, the method for determining protein in food. The specific procedure is as follows: Take 1g of sample, add 20mL of concentrated sulfuric acid for digestion under the action of a mixed catalyst (0.4g copper sulfate pentahydrate + 6g potassium sulfate), then distill, absorb the nitrogen in the product with boric acid, and titrate with 0.1mol / L hydrochloric acid. Read the data, calculate the nitrogen content, and use N (nitrogen content) × 6.25 as the protein coefficient to calculate the protein content.

[0053] 2) Determination of fat content

[0054] The fat content was determined according to GB 5009.6-2016, the method for determining fat in food. The specific procedure is as follows: weigh 2-5g of sample and place it in a filter paper tube. Place the filter paper tube in a Soxhlet extractor and extract with ether or petroleum ether. Then, recover the ether or petroleum ether in the receiving bottle, dry it, weigh it, and calculate the fat content.

[0055] 3) Determination of nucleic acid content

[0056] Total phosphorus was determined according to GB / T 6437 "Determination of Total Phosphorus in Feed" and calculated using the following formula: Nucleic acid content = Total phosphorus × 340 / 32. The specific procedure is as follows: Phosphorus in the nucleic acid of yeast hydrolysate is digested to generate water-soluble inorganic phosphorus, which reacts with ammonium molybdate to form ammonium phosphomolybdate. Under acidic conditions, a reducing agent is used to generate molybdenum blue, the intensity of which is directly proportional to the P2O5 content, conforming to the Lambert-Beer law. The absorbance at 700 nm is measured using a spectrophotometer.

[0057] 4) Determination of mannan and dextran

[0058] 4.1 Detection Principle

[0059] Based on the different partition coefficients of dextran and mannose between the mobile phase and the stationary phase of the liquid chromatography column, the hydrolyzed sample was injected into the liquid chromatograph using pure water as the mobile phase. After the sugar molecules elute, they were detected by a differential detector and quantified using the external standard method. During the hydrolysis of β-glucan and mannose, incomplete hydrolysis of the sample and partial side reactions of the glucose and mannose produced by hydrolysis due to high temperatures can lead to detection results that are lower than the actual β-glucan and mannose content in the product. A dextran reference standard was used to correct for the errors caused by the hydrolysis process.

[0060] 4.2 Instruments

[0061] a) Water bath;

[0062] b) Vortex mixer;

[0063] c) Electric furnace;

[0064] d) Pressure steam sterilizer;

[0065] e) High performance liquid chromatograph: with differential detector and sugar column (6.5mm × 300mm waters sugar pak-1).

[0066] 4.3 Reagents

[0067] a) Pure water;

[0068] b) Hydrochloric acid: approximately 37%;

[0069] c) Glucose: AR;

[0070] d) Mannose: AR;

[0071] e) Sodium hydroxide: AR;

[0072] f) Mixed standard solution of glucose and mannose (2g / L): Weigh 0.2000g of glucose and mannose respectively, and dilute to 100ml with pure water.

[0073] g) Dextran reference standard (curdlan from Alcaligenes faecalis): Sigma product, catalog number

[0074] h) Sodium hydroxide solution: 300 g / L.

[0075] 4.4 Sample Preparation

[0076] Accurately weigh 400 mg (accurate to 0.1 mg) of the sample into a 20 ml heat-resistant glass test tube with a screw cap. Add 6.0 ml of hydrochloric acid (37%), carefully seal the tube, and mix using a vortex mixer to obtain a homogeneous suspension. Place the tube in a 30°C water bath for 45 min, vortexing every 15 min. Then, quantitatively transfer the suspension to a 200 ml Durham flask. Wash the test tube several times with approximately 100 ml–120 ml of water, adding the washings to the Durham flask. Place the Durham flask in an autoclave and autoclave at 121°C for 60 min. After cooling, adjust the pH of the solution to 6–7 with sodium hydroxide solution, and then bring the volume to 200 ml. Filter using a 0.45 μm cellulose acetate membrane for later use. Simultaneously, accurately weigh 200 mg of dextran reference standard (see 1.3(g)) and treat it using the same method as the sample.

[0077] 4.5 Chromatographic conditions

[0078] Pure water was used as the mobile phase at a flow rate of 0.5 ml / min and a column temperature of 80 °C. The sample was injected only after the instrument baseline had stabilized.

[0079] 4.6 Plotting the Standard Curve

[0080] Pipettes of 1, 2, 3, 4, and 5 ml of mannose / glucose standard solution (see 1.3(f)) into 10 ml volumetric flasks, respectively, and diluted to the mark with high-purity water to obtain mixed standards of 200, 400, 600, 800, and 1000 mg / L of mannose and glucose. Under the above chromatographic conditions, accurately inject 20 μL of each standard solution, obtain the regression equation between the peak area and the concentration of the standard, and plot the standard curve.

[0081] 4.7 Determination of Samples and Reference Standards

[0082] Under the same chromatographic conditions, the treated sample and dextran reference standard were injected separately into the chromatograph, and the retention time and peak area of ​​each chromatographic peak were recorded. Qualitative analysis was performed using the retention time of the sugar standard peak, and quantitative analysis was performed using the peak area of ​​the sugar standard peak.

[0083] 4.8 Result Calculation

[0084] The content of β-glucan or mannan is calculated using the following formula:

[0085] X=(A1×0.2×100)÷(m1×1000)×0.9×F……………………(1)

[0086] F=P×(100-W)÷[(A2×0.2×100)÷(m2×1000)×0.9]…(2)

[0087] In the formula:

[0088] X --- The content of β-glucan or mannan in the sample, %;

[0089] A1---The content of glucose or mannose in the sample solution, in mg / L, obtained from the standard curve based on the peak area of ​​the sample solution;

[0090] A2---The glucose content of the sample solution, in mg / L, obtained from the standard curve based on the peak area of ​​the dextran reference solution;

[0091] m1---Mass of the sample taken, in g;

[0092] m2 --- The mass of dextran reference standard weighed, in grams;

[0093] 0.2 --- The volume of the sample / dextran standard after treatment and final volume adjustment, in L;

[0094] 0.9 --- The coefficient for converting glucose or mannose to β-glucan or mannose;

[0095] F---Empirical compensation coefficient for the lower results caused by the destruction of glucose and mannose during sample acid hydrolysis;

[0096] P---Purity of dextran reference standard (based on the test report provided by the reagent manufacturer);

[0097] W---Moisture content of dextran reference standard (based on the test report provided by the reagent manufacturer).

[0098] Note: Within the same laboratory, the F-value is generally tested every 1-2 months. The F-value is around 1.25, and the laboratory periodically corrects the F-value.

[0099] Sensory evaluation was used to assess the flavor and mouthfeel of yeast protein. Nine sensory evaluators were selected to conduct the sensory evaluation. The procedure was as follows: 2g of low-yeast-flavor yeast protein was weighed and added to 98mL of water to prepare a 2% solution. Then, the subjects rated the aroma, mouthfeel, and acceptability, with each item ranging from 0 to 6 points. The evaluation criteria are shown in Table 2, and the results are shown in Table 4.

[0100] Table 2 Sensory Analysis Evaluation Criteria

[0101]

[0102]

[0103] Examples 2-7

[0104] The process parameters were tested according to the parameters shown in Table 3, and the other parameters were the same as in Example 1.

[0105] Example 8

[0106] The difference from Example 1 is that there is no drying process in step (4), and the heavy phase collected in step (3) is the low yeast flavor yeast protein. The process parameters are tested according to the table in Table 3.

[0107] Comparative Example 1

[0108] The difference from Example 8 is that the pH of the dispersion in step (1) is adjusted to 9.0, and the process parameters are tested according to the table in Table 4.

[0109] Comparative Example 2

[0110] The difference from Example 8 is that in step (1), the pH of the dispersion was adjusted to 3.0, and the process parameters were tested according to the table in Table 4.

[0111] Comparative Example 3

[0112] The difference from Example 8 is that the compound enzyme used in step (2) is 0.5% (based on the dry matter weight of yeast milk) glucanase and 0.5% (based on the dry matter weight of yeast milk) mannanase, and the process parameters are tested according to the table in Table 4.

[0113] Comparative Example 4

[0114] The difference from Example 8 is that ethyl acetate is not added during enzymatic hydrolysis in step (2), and the process parameters are tested according to the parameters shown in Table 4.

[0115] Comparative Example 5

[0116] Wine yeast RV002 was used instead of high-protein yeast, and everything else was the same as in Example 8.

[0117] Table 3 Process conditions for Examples 2-8

[0118]

[0119] Table 4. Process parameters for Comparative Examples 1-4

[0120]

[0121] Table 5. Measurement results of Examples 1-8 and Comparative Examples 1-5

[0122] Protein content, % Fat,% Nucleic acid, % Glucan, % Mannan, % Example 1 85.6 2.6 1.5 2.1 2.5 Example 2 79.4 3.8 1.1 2.2 2.1 Example 3 80.8 3.6 0.9 2.3 2.4 Example 4 81.6 3.1 0.6 2.6 2.8 Example 5 82.5 2.1 0.5 2.8 2.9 Example 6 83.2 2.5 0.7 2.7 2.8 Example 7 86.3 2.3 0.5 2.3 2.5 Example 8 85.6 2.6 1.5 2.1 2.5 Comparative Example 1 85.2 2.5 0.4 2.9 3.1 Comparative Example 2 76.5 4.9 3.5 3.5 3.8 Comparative Example 3 73.2 7.9 1.2 2.4 2.6 Comparative Example 4 74.4 6.8 1.3 2.3 2.6 Comparative Example 5 69.3 9.8 2.8 6.8 7.2

[0123] Table 6 Sensory evaluation results of Examples 1-8 and Comparative Examples 1-5

[0124]

[0125]

[0126] As shown in Table 5, the low-yeast-flavor yeast proteins prepared in Examples 1-8 all had a protein content ≥78%. Compared with Example 8, the pH of yeast inactivation in Comparative Example 1 was 9.0. Although the nucleic acid content was slightly lower than that in Example 8, the sensory score was also lower. From a sensory perspective, an excessively high pH is not conducive to the good aroma and taste of yeast protein, and will produce a certain unpleasant alkaline taste. The pH of yeast inactivation in Comparative Example 2 was 3.0, and the nucleic acid content was significantly higher than that in Example 8. In Comparative Example 3, no lipase was added during enzymatic hydrolysis, and the fat content was much higher than that in Example 8. In Comparative Example 4, no ethyl acetate was added during enzymatic hydrolysis, and the fat content was higher than that in Example 8. In Comparative Example 5, ordinary yeast was used instead of high-protein yeast, and the protein content was significantly lower than that in Example 8, while the fat content, glucan, and mannose content were higher.

[0127] As shown in Table 6, the sensory scores of Comparative Examples 1-5 in terms of odor, taste and acceptability were all less than 5 points, while the sensory scores of Examples 1-8 in terms of odor, taste and acceptability were all above 5 points. The yeast protein prepared by this invention has a low yeast flavor, almost no yeast odor or other unpleasant odors, and no unpleasant taste. It can be used in the fields of human nutrition and alternative proteins.

[0128] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a low-yeast-flavor yeast protein, characterized by, Includes the following steps: (1) Prepare a dispersion of high-protein yeast, adjust the pH to 4-8, inactivate it, centrifuge to collect the heavy phase, and then add water to obtain yeast milk; the high-protein yeast has a protein content ≥50.0%; (2) The yeast milk obtained in step (1) is enzymatically hydrolyzed using a compound enzyme and ethyl acetate, wherein the compound enzyme comprises glucanase, mannanase and lipase; the amount of glucanase added is 0.1-2% based on the dry matter of the yeast milk, the amount of mannanase added is 0.1-2% based on the dry matter of the yeast milk, and the amount of lipase added is 0.1-2%; the amount of ethyl acetate added is 0.2-2% based on the dry matter of the yeast milk. (3) After inactivating the enzyme in the enzymatic hydrolysate obtained in step (2), centrifuge to obtain the heavy phase and obtain low yeast flavor yeast protein.

2. The method for preparing low-yeast-flavor yeast protein according to claim 1, characterized in that, In step (1), the inactivation temperature is 75-99℃.

3. The method for preparing low-yeast-flavor yeast protein according to claim 2, characterized in that, In step (1), the inactivation time is 5-120 min.

4. The method for preparing low-yeast-flavor yeast protein according to claim 1, characterized in that, In step (1), the weight percentage concentration of the dispersion is 8-20%.

5. The method for preparing low-yeast-flavor yeast protein according to claim 2, characterized in that, In step (1), the weight percentage concentration of the dispersion is 8-20%.

6. The method for preparing low-yeast-flavor yeast protein according to claim 1, characterized in that, In step (1), the yeast milk has a weight percentage concentration of 8-20%.

7. The method for preparing low-yeast-flavor yeast protein according to claim 2, characterized in that, In step (1), the yeast milk has a weight percentage concentration of 8-20%.

8. The method for preparing low-yeast-flavor yeast protein according to claim 4, characterized in that, In step (1), the yeast milk has a weight percentage concentration of 8-20%.

9. The method for preparing low-yeast-flavor yeast protein according to claim 1, characterized in that, Based on the dry matter of yeast milk, in step (2), the amount of the compound enzyme added is 0.3-6%.

10. The method for preparing low-yeast-flavor yeast protein according to claim 4, characterized in that, Based on the dry matter of yeast milk, in step (2), the amount of the compound enzyme added is 0.3-6%.

11. The method for preparing low-yeast-flavor yeast protein according to claim 6, characterized in that, Based on the dry matter of yeast milk, in step (2), the amount of the compound enzyme added is 0.3-6%.

12. The method for preparing low-yeast-flavor yeast protein according to any one of claims 1-11, characterized in that, In step (2), the enzymatic hydrolysis temperature is 40-70℃.

13. The method for preparing low-yeast-flavor yeast protein according to any one of claims 1-11, characterized in that, In step (2), the enzymatic hydrolysis pH is 4-8.

14. The method for preparing low-yeast-flavor yeast protein according to claim 12, characterized in that, In step (2), the enzymatic hydrolysis pH is 4-8.

15. The method for preparing low-yeast-flavor yeast protein according to any one of claims 1-11, characterized in that, In step (2), the enzymatic hydrolysis time is 5-20 hours.

16. The method for preparing low-yeast-flavor yeast protein according to claim 12, characterized in that, In step (2), the enzymatic hydrolysis time is 5-20 hours.

17. The method for preparing low-yeast-flavor yeast protein according to claim 13, characterized in that, In step (2), the enzymatic hydrolysis time is 5-20 hours.

18. The method for preparing low-yeast-flavor yeast protein according to claim 14, characterized in that, In step (2), the enzymatic hydrolysis time is 5-20 hours.

19. The method for preparing low-yeast-flavor yeast protein according to any one of claims 1-11, characterized in that, In step (3), the enzyme inactivation temperature is 75-90℃.

20. The method for preparing low-yeast-flavor yeast protein according to claim 12, characterized in that, In step (3), the enzyme inactivation temperature is 75-90℃.

21. The method for preparing low-yeast-flavor yeast protein according to claim 13, characterized in that, In step (3), the enzyme inactivation temperature is 75-90℃.

22. The method for preparing low-yeast-flavor yeast protein according to claim 15, characterized in that, In step (3), the enzyme inactivation temperature is 75-90℃.

23. The method for preparing low-yeast-flavor yeast protein according to any one of claims 1-11, characterized in that, In step (3), the enzyme inactivation time is 0.5-3h.

24. The method for preparing low-yeast-flavor yeast protein according to claim 19, characterized in that, In step (3), the enzyme inactivation time is 0.5-3h.

25. The method for preparing low-yeast-flavor yeast protein according to any one of claims 1-11, characterized in that, It also includes the step of drying the heavy phase obtained in step (3): the heavy phase is prepared into a solution with a weight percentage of 8-20%, and dried to obtain powdered low-yeast-flavor yeast protein.

26. The method for preparing low-yeast-flavor yeast protein according to claim 12, characterized in that, It also includes the step of drying the heavy phase obtained in step (3): the heavy phase is prepared into a solution with a weight percentage of 8-20%, and dried to obtain powdered low-yeast-flavor yeast protein.

27. The method for preparing low-yeast-flavor yeast protein according to claim 13, characterized in that, It also includes the step of drying the heavy phase obtained in step (3): the heavy phase is prepared into a solution with a weight percentage of 8-20%, and dried to obtain powdered low-yeast-flavor yeast protein.

28. The method for preparing low-yeast-flavor yeast protein according to claim 15, characterized in that, It also includes the step of drying the heavy phase obtained in step (3): the heavy phase is prepared into a solution with a weight percentage of 8-20%, and dried to obtain powdered low-yeast-flavor yeast protein.

29. The method for preparing low-yeast-flavor yeast protein according to claim 25, characterized in that, The drying process is one of microwave drying, spray drying, or vacuum drying.

30. A low-yeast-flavor yeast protein prepared by the method described in any one of claims 1-29, characterized in that, Its protein content is ≥78%.

31. The low-yeast-flavor yeast protein according to claim 30, wherein, Nucleic acid content ≤1.5%.

32. The method for preparing low-yeast-flavor yeast protein according to any one of claims 1-29, or the use of the low-yeast-flavor yeast protein according to claim 30 or 31 in alternative protein products.

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