In this paper, the preparation of soybean peptide with good flavor from soybean waste residue was studied. The conventional acid method, alkali method and general enzymatic hydrolysis method were abandoned, and the soybean polypeptide with high hydrolysis degree and good flavor was prepared by using self-selected microbial protease combined with papain and trypsin. A strain MY 10 was screened based on the traditional fermented food tofu in China, which can produce microbial protease with certain degradation ability to soybean protein, and at the same time can eliminate the bad flavor of soybean protein after being hydrolyzed by endonuclease. MY 10 was preliminarily identified as Mucor. The relationship between bacterial growth and enzyme production characteristics was studied. It was found that the strain reached the maximum value in liquid culture medium for 84 hours, and the pH value of the culture medium continued to decrease from 0 to 48 hours, reaching 4.2 at 48 hours, and then the pH value began to increase, reaching above 7.0 after 84 hours. Through the determination of protease activity, it was found that the protease activity produced by MY 10 reached the maximum at 84 h; Separating and purifying the crude enzyme solution. Firstly, 60% saturated (NH4)2SO 4 was used for precipitation, and then Sephadex G75 was used. Through the determination of protease activity, it is found that it may contain neutral protease and alkaline protease. The properties of crude enzyme solution were studied, and it was found that the optimum pH value of the enzyme system was 9.2, and the optimum temperatures of neutral and alkaline protease were 60℃ and 50℃ respectively. Because the protease activity of this enzyme system is not very high, in order to improve the hydrolysis degree of soybean meal and obtain soybean peptides with high hydrolysis degree, papaya eggs are selected in this paper ...

Abstract: In this paper, the problem of producing colorful peptides from bean dregs was discussed. The conventional methods such as acid, alkali and ordinary enzymolysis were abandoned, and the soybean polypeptide with high hydrolysis degree and good flavor was prepared by the synergistic effect of microbial protease, papain and trypsin. A fungus that can produce protease, which has the ability to decompose soybean protein and eliminate odor. ...

Table of Contents: 1 Literature Review 10-2 1

Composition and structure of soybean protein1.111

1.2 Biological Activities and Main Uses of Soybean Polypeptide 1 1- 12

1.3 soybean protein modification 12- 14

1.4 formation mechanism and debittering method of bitter peptide 14- 18

Formation mechanism of bitter bark 1.4 1. 16

1.4.2 Debit method 16- 18

1.5 Effect of Mucor Sufu on Soybean Protein 18-20

Study on anti-nutritional factors in soybean meal 1.6 20-2 1

The research hypothesis of this paper is 2 1-22.

3 Materials and Methods 22-30

3. 1 material 22-23

3. 1. 1 experimental raw materials and main reagents 22

3. 1.2 Medium 22-23

3. 1.3 instruments and equipment 23

3.2 Method 23-30

3.2. 1 Screening and identification of microbial protease-producing bacteria and study on their fermentation conditions 23-26

3.2.2 Double Enzymes Hydrolyze Soybean Protein 26-27

3.2.3 Preparation of Soybean Skin with Good Flavor 27-30

4 Results and Analysis 30-53

4. 1 Screening and identification of microbial protease-producing bacteria and its fermentation conditions 30-40

4. Screening of1.1microbial protease-producing strain 30-3 1

4. Identification of1.2 Strain 3 1-33

4. Study on the growth and enzyme production characteristics of1.3my10 bacteria 33-35.

4. Isolation and purification of1.4 enzyme 35-37

4. 1.5 Study on the Properties of Crude Enzyme Liquid 37-40

4.2 Double Enzymes Hydrolyze Soybean Protein 40-48

4.2. Endoenzyme Hydrolysis of1Soybean Meal 40-48

4.3 Preparation of Soybean Skin with Good Flavor 48-49

4.4 Analysis of changes in nutritional components of soybean meal before and after enzymolysis 49-53

4.4. 1 amino acid content determination result 49

4.4.2 protein degradation analysis 49-50

4.4.3 Analysis of changes of anti-nutritional factors before and after enzymolysis 50-53

5 Discussion 53-57

5. 1 Screening and identification of microbial protease-producing bacteria and study on their fermentation conditions 53-54

5. 1. 1 Screening of microbial protease-producing bacteria 53

5. Isolation and purification of1.2 enzyme 53

5. Study on the Properties of Protease 53-54 of1.3my10

5.2 Double Enzymes Hydrolyze Soybean Protein 54-56

5.2. 1 Pretreatment of Soybean Meal 54

5.2.2 Control of reaction conditions during enzymolysis 54-55

5.2.3 Removing beany smell 55

5.2.4 Study on Enzymatic Hydrolysis Process 55-56

5.2.5 Bitterness Study 56

5.3 Preparation of Soybean Skin with Good Flavor 56-57

5.4 Analysis of changes in nutritional components of soybean meal before and after enzymolysis 57

6 Conclusion 57-59

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