Crop polypeptide enzymatic hydrolysate and preparation method thereof

Abstract

The invention relates to the technical field of polypeptide enzymatic hydrolysate, in particular to polypeptide enzymatic hydrolysate for crops and a preparation method thereof.The polypeptide enzymatic hydrolysate for the crops is prepared from, by weight, 30-40 parts of mixed enzymatic hydrolysate and 0.5-3 parts of stabilizer; the mixed enzymatic hydrolysate is soybean meal and diplopod mixed enzymatic hydrolysate, the mass ratio of the soybean meal to the diplopod is (5-15): 1, the soybean meal and the diplopod are used as raw materials of the polypeptide enzymatic hydrolysate provided by the invention, the diplopod has a good parasite expelling effect, and the diplopod polypeptide component subjected to enzymolysis has high permeability, so that the diplopod polypeptide component can be used for preparing the polypeptide enzymatic hydrolysate. The polypeptide can directly penetrate through plant cell walls to be rapidly absorbed by plants, and after being absorbed by the plants, the polypeptide enables the plants to have a certain insect pest resistance effect.

Description

Technical Field

[0001] The invention relates to the technical field of polypeptide enzymatic hydrolysate, and in particular to a polypeptide enzymatic hydrolysate of crops and a preparation method thereof. Background Art

[0002] Insect pests are a constant threat to food production at all stages. About 20-30 insect species are considered important pests of major crops, which reduce crop yields by about 30% before and after harvest, having a significant impact on agriculture and the economy.

[0003] The large-scale use of chemical pesticides in planting will not only kill insects but also harm their natural enemies, destroying the community and ecological balance in nature. It will also affect the microenvironment in the soil, change the soil quality, and affect the growth of crops.

[0004] Therefore, we proposed a polypeptide enzymatic hydrolysate of crops and a preparation method thereof to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a polypeptide enzymatic hydrolyzate of crops and a preparation method thereof.

[0006] A polypeptide enzymatic hydrolysate of crops, comprising the following raw materials in parts by weight: 30-40 parts of mixed enzymatic hydrolysate and 0.5-3 parts of stabilizer;

[0007] The mixed enzymatic hydrolysate is a mixed enzymatic hydrolysate of soybean meal powder and millipede, wherein the mass ratio of soybean meal powder to millipede is 5-15:1.

[0008] Preferably, the method for preparing the mixed enzymatic hydrolysate comprises the following steps:

[0009] A1. Wash and crush fresh millipedes, and then fully mix them with soybean meal powder. After mixing, freeze-dry them, and sieve the freeze-dried powder to separate the millipede powder from the soybean meal powder.

[0010] A2, the soybean meal powder obtained in step A1 and the alkaline phosphate buffer are mixed at a solid-liquid ratio of 1:10-15 to prepare a soybean meal powder slurry, the pH of the soybean meal powder slurry is adjusted to 9-10, and ultrasonic treatment is performed for 3-4 hours, the ultrasonic temperature is 45-55° C., and the ultrasonic power is 40-50kHz. After the treatment is completed, centrifugation is performed to obtain a supernatant, and then an acid phosphate buffer is added to adjust the pH of the supernatant to 4-5 and acid precipitation is performed for 1-1.5 hours. After the acid precipitation treatment is completed, the mixture is allowed to stand for 0.5-1 hour, and then centrifuged to obtain a lower precipitate, the lower precipitate is washed with water until it is neutral, and freeze-dried to obtain a soybean protein containing part of millipede protein, that is, a mixed protein;

[0011] A3, mixing the mixed protein and distilled water at a material-liquid ratio of 1:12-15, heating to 70-80°C, and heat preservation at a pressure of 0.08-0.1Mpa for 20-30min; continuing to heat to 90-100°C, and heat preservation at a pressure of 0.05-0.07Mpa for 10-12min to obtain a mixed protein slurry; adjusting the pH of the mixed protein slurry to 8-9, and adding subtilisin and hemicellulase for ultrasonic-assisted enzymolysis, the enzymolysis reaction temperature is 45-50°C, the enzymolysis reaction time is 2-3h, the ultrasonic power is 30-40kHz, the enzymolysis reaction is completed, and enzymolysis solution A is obtained;

[0012] A4, the millipede powder obtained in step A1 is mixed with distilled water at a solid-liquid ratio of 1:12-15, and heated to 70-80°C, and heat-treated at a pressure of 0.08-0.1 MPa for 20-30 min; continue to heat to 90-100°C, and heat-treated at a pressure of 0.05-0.07 MPa for 10-12 min to obtain a millipede powder slurry; adjust the pH of the millipede powder slurry to 4-5, and add pepsin and pancreatin for ultrasonic enzymolysis, the enzymolysis reaction temperature is 45-50°C, the enzymolysis reaction time is 2-3 h, the ultrasonic power is 30-40 kHz, the enzymolysis reaction is completed, and an enzymolysis solution B is obtained;

[0013] A5, mixing enzymatic hydrolysate A and enzymatic hydrolysate B to obtain a mixed solution, adjusting the pH to 6.5-7.5, and adding papain for ultrasonic enzymolysis, the enzymatic hydrolysis reaction temperature is 45-50°C, the enzymatic hydrolysis reaction time is 2-3h, the ultrasonic power is 30-40kHz, the enzymatic hydrolysis reaction is completed, and a mixed enzymatic hydrolysate crude product is obtained;

[0014] A6. The crude mixed enzymatic hydrolysate is subjected to microwave inactivation treatment to obtain an inactivated enzymatic hydrolysate, which is then cooled, centrifuged, the supernatant is collected, ultrafiltered, and the filtrate is collected to obtain a mixed enzymatic hydrolysate.

[0015] Preferably, in step A1, the mesh size of the soybean meal powder is 10-20 meshes, and the mesh size of the millipede powder is 60-80 meshes.

[0016] Preferably, the concentration of the alkaline phosphate buffer is 0.1 to 0.15 mol / L, and the concentration of the acidic phosphate buffer is 0.1 to 0.15 mol / L.

[0017] Preferably, in the step A3, the amount of subtilisin and hemicellulase added is 2 to 2.5 ug / g of the mixed protein slurry, wherein the mass ratio of subtilisin to hemicellulase is 1:2 to 3; in the step A4, the amount of pepsin and pancreatic enzyme added is 2 to 2.5 ug / g of the millipede powder slurry, wherein the mass ratio of pepsin to pancreatic enzyme is 1:2 to 3; in the step A5, the amount of papain added is 1 to 1.5 ug / g of the mixed solution.

[0018] Preferably, in step A6, when the enzymatic hydrolysate is subjected to microwave inactivation treatment, the microwave power is 500-800 W, the microwave inactivation temperature is 80-90° C., the microwave inactivation time is 2-3 min, and after the microwave inactivation is completed, an enzyme-inactivation enzymatic hydrolysate is obtained.

[0019] Preferably, in step A6, during the ultrafiltration process, the supernatant is ultrafiltered using an ultrafiltration membrane with a molecular weight of 5000Da to 20000Da.

[0020] Preferably, the stabilizer is one of sodium thiosulfate, vitamin C, vitamin E, lipoic acid and sodium metabisulfite, or a mixture of two or more thereof.

[0021] Preferably, a method for preparing a polypeptide enzymatic hydrolysate of crops comprises fully mixing the mixed enzymatic hydrolysate with a stabilizer to obtain the polypeptide enzymatic hydrolysate of crops.

[0022] The beneficial effects of the present invention are:

[0023] 1. The polypeptide enzymatic hydrolyzate proposed by the present invention uses soybean meal and millipede as raw materials, wherein the millipede itself has a good insect repellent effect, and the millipede polypeptide component after enzymatic hydrolysis has high permeability and can directly penetrate the plant cell wall and be quickly absorbed by the plant. After the polypeptide is absorbed by the plant, the plant has a certain insect pest resistance effect.

[0024] 2. The polypeptide enzymatic hydrolysate proposed by the present invention, after being added to the soil, can promote the reproduction of probiotics, improve soil quality, have a certain inhibitory effect on some fungi in the soil that are harmful to crops, and can improve the disease resistance of crops.

[0025] 3. In the polypeptide enzymatic hydrolysate proposed by the present invention, during the enzymatic hydrolysis process, fresh millipedes are washed and crushed, and then fully mixed with soybean meal powder. After the mixing is completed, freeze-drying is performed, and the freeze-dried powder is sieved to separate the millipede powder from the soybean meal powder, so that most of the liquid active ingredients in the millipede are absorbed into the soybean meal powder. The active ingredients are mainly acidic, and the enzymatic hydrolysis effect is better when enzymatic hydrolysis is performed in an alkaline environment.

[0026] 4. In the polypeptide hydrolysate proposed in the present invention, during the enzymatic hydrolysis process, the mixed protein is firstly hydrolyzed in an alkaline environment, and then the millipede powder is hydrolyzed in an acidic environment. Finally, the two hydrolysates are mixed and then hydrolyzed in a neutral environment. This can effectively improve the efficiency of the enzymatic hydrolysis and save some raw materials during the neutralization process.

[0027] 5. The polypeptide enzymatic hydrolysate proposed in the present invention has high permeability, and the polypeptide active substances produced by enzymatic hydrolysis can directly penetrate the plant cell wall and be quickly absorbed by the plant, and are used to synthesize the plant's own nutrients. It has high absorption efficiency and significant growth-promoting effect. The polypeptide provided by soybean meal mainly promotes plant growth and improves plant disease resistance. DETAILED DESCRIPTION

[0028] The present invention will be further explained below in conjunction with specific embodiments.

[0029] In the following examples, the experimental methods or test methods, unless otherwise specified, are conventional methods; reagents and materials, unless otherwise specified, are obtained from conventional commercial channels or prepared by conventional methods, among which: subtilisin, hemicellulase, pepsin, pancreatin and papain were purchased from Shanghai Yuanye Biotechnology Co., Ltd.; soybean meal was purchased from Jinan Haicheng Chemical Co., Ltd.

[0030] In Example 1, a polypeptide enzymatic hydrolyzate of crops is composed of the following raw materials in parts by weight: 30 parts of mixed enzymatic hydrolyzate and 0.5 parts of stabilizer;

[0031] The mixed enzymatic hydrolysate is a mixed enzymatic hydrolysate of soybean meal powder and millipede, wherein the mass ratio of soybean meal powder to millipede is 5:1.

[0032] The preparation method of the mixed enzymatic hydrolysate comprises the following steps:

[0033] A1. Wash and crush fresh millipedes, and then fully mix them with soybean meal powder. After mixing, freeze-dry them, and sieve the freeze-dried powder to separate the millipede powder from the soybean meal powder.

[0034] A2, the soybean meal powder obtained in step A1 and the alkaline phosphate buffer are mixed at a solid-liquid ratio of 1:10 to prepare a soybean meal powder slurry, the pH of the soybean meal powder slurry is adjusted to 9, and ultrasonic treatment is performed for 3 hours, the ultrasonic temperature is 45° C., and the ultrasonic power is 40 kHz. After the treatment is completed, centrifugation is performed to obtain a supernatant, and then an acidic phosphate buffer is added to adjust the pH of the supernatant to 4 and acid precipitation is performed for 1 hour. After the acid precipitation treatment is completed, the mixture is allowed to stand for 0.5 hours, and then centrifuged to obtain a lower precipitate, the lower precipitate is washed with water to neutrality, and freeze-dried to obtain a soybean protein containing part of millipede protein, that is, a mixed protein;

[0035] A3, the mixed protein and distilled water were mixed at a material-liquid ratio of 1:12, and heated to 70°C, and kept warm for 20 minutes at a pressure of 0.08 MPa; the mixed protein slurry was further heated to 90°C, and kept warm for 10 minutes at a pressure of 0.05-0.07 MPa to obtain a mixed protein slurry; the pH of the mixed protein slurry was adjusted to 8, and subtilisin and hemicellulase were added for ultrasonic-assisted enzymolysis, the enzymolysis reaction temperature was 45°C, the enzymolysis reaction time was 2 hours, the ultrasonic power was 30 kHz, and the enzymolysis reaction was completed to obtain enzymolysis solution A;

[0036] A4, the millipede powder obtained in step A1 was mixed with distilled water at a solid-liquid ratio of 1:12, and heated to 70°C, and kept warm for 20 minutes at a pressure of 0.08 MPa; the millipede powder slurry was obtained by further heating to 90°C, and kept warm for 10 minutes at a pressure of 0.05 MPa, and the millipede powder slurry was obtained; the pH of the millipede powder slurry was adjusted to 4, and pepsin and pancreatin were added for ultrasonic enzymolysis, the enzymolysis reaction temperature was 45°C, the enzymolysis reaction time was 2 hours, the ultrasonic power was 30-40 kHz, and the enzymolysis reaction was completed to obtain enzymolysis solution B;

[0037] A5, the enzymatic hydrolysate A and the enzymatic hydrolysate B were mixed to obtain a mixed solution, the pH was adjusted to 6.5, and papain was added for ultrasonic enzymolysis. The enzymatic hydrolysis reaction temperature was 45°C, the enzymatic hydrolysis reaction time was 2h, the ultrasonic power was 30kHz, and the enzymatic hydrolysis reaction was completed to obtain a mixed enzymatic hydrolysate crude product;

[0038] A6. The crude mixed enzymatic hydrolysate is subjected to microwave inactivation treatment to obtain an inactivated enzymatic hydrolysate, which is then cooled, centrifuged, the supernatant is collected, ultrafiltered, and the filtrate is collected to obtain a mixed enzymatic hydrolysate.

[0039] In step A1, the mesh size of the soybean meal powder is 10 mesh, and the mesh size of the millipede powder is 60 mesh.

[0040] The concentration of the alkaline phosphate buffer was 0.1 mol / L, and the concentration of the acidic phosphate buffer was 0.1 mol / L.

[0041] In step A3, the amount of subtilisin and hemicellulase added is 2ug / g of the mixed protein slurry, wherein the mass ratio of subtilisin and hemicellulase is 1:2; in step A4, the amount of pepsin and pancreatic enzyme added is 2ug / g of the millipede powder slurry, wherein the mass ratio of pepsin and pancreatic enzyme is 1:2; in step A5, the amount of papain added is 1ug / g of the mixed liquid.

[0042] In step A6, when the enzymatic hydrolysate is subjected to microwave inactivation treatment, the microwave power is 500 W, the microwave inactivation temperature is 80° C., the microwave inactivation time is 2 min, and after the microwave inactivation is completed, an enzyme-inactivation enzymatic hydrolysate is obtained.

[0043] In step A6, during the ultrafiltration process, the supernatant is ultrafiltered using an ultrafiltration membrane with a molecular weight of 5000Da.

[0044] The stabilizer is sodium thiosulfate.

[0045] A method for preparing a polypeptide enzymolyzate of crops comprises fully mixing a mixed enzymolyzate with a stabilizer to obtain the polypeptide enzymolyzate of crops.

[0046] In Example 2, a polypeptide enzymatic hydrolyzate of a crop is composed of the following raw materials in parts by weight: 40 parts of mixed enzymatic hydrolyzate and 3 parts of stabilizer;

[0047] The mixed enzymatic hydrolysate is a mixed enzymatic hydrolysate of soybean meal powder and millipede, wherein the mass ratio of soybean meal powder to millipede is 15:1.

[0048] The preparation method of the mixed enzymatic hydrolysate comprises the following steps:

[0049] A1. Wash and crush fresh millipedes, and then fully mix them with soybean meal powder. After mixing, freeze-dry them, and sieve the freeze-dried powder to separate the millipede powder from the soybean meal powder.

[0050] A2, the soybean meal powder obtained in step A1 and the alkaline phosphate buffer are mixed at a solid-liquid ratio of 1:15 to prepare a soybean meal powder slurry, the pH of the soybean meal powder slurry is adjusted to 10, and ultrasonic treatment is performed for 4 hours, the ultrasonic temperature is 55° C., and the ultrasonic power is 50 kHz. After the treatment is completed, centrifugation is performed to obtain a supernatant, and then an acid phosphate buffer is added to adjust the pH of the supernatant to 5 and acid precipitation is performed for 1.5 hours. After the acid precipitation treatment is completed, the mixture is allowed to stand for 1 hour, and then centrifuged to obtain a lower precipitate, the lower precipitate is washed with water until it is neutral, and freeze-dried to obtain a soybean protein containing part of millipede protein, that is, a mixed protein;

[0051] A3, the mixed protein and distilled water were mixed at a material-liquid ratio of 1:15, and heated to 80°C, and kept warm for 30 minutes at a pressure of 0.1 MPa; continued to heat to 100°C, and kept warm for 12 minutes at a pressure of 0.07 MPa to obtain a mixed protein slurry; the pH of the mixed protein slurry was adjusted to 9, and subtilisin and hemicellulase were added for ultrasonic-assisted enzymolysis, the enzymolysis reaction temperature was 50°C, the enzymolysis reaction time was 3 hours, the ultrasonic power was 40 kHz, the enzymolysis reaction was completed, and enzymolysis solution A was obtained;

[0052] A4, the millipede powder obtained in step A1 was mixed with distilled water at a solid-liquid ratio of 1:15, and heated to 80°C, and kept warm for 30 minutes at a pressure of 0.1 MPa; the millipede powder slurry was obtained by further heating to 100°C, and kept warm for 12 minutes at a pressure of 0.07 MPa, to obtain a millipede powder slurry; the pH of the millipede powder slurry was adjusted to 5, and pepsin and pancreatin were added for ultrasonic enzymolysis, the enzymolysis reaction temperature was 50°C, the enzymolysis reaction time was 3 hours, the ultrasonic power was 40 kHz, and the enzymolysis reaction was completed to obtain an enzymolysis solution B;

[0053] A5, the enzymatic hydrolysate A and the enzymatic hydrolysate B were mixed to obtain a mixed solution, the pH was adjusted to 7.5, and papain was added for ultrasonic enzymolysis. The enzymatic hydrolysis reaction temperature was 50°C, the enzymatic hydrolysis reaction time was 3h, the ultrasonic power was 40kHz, and the enzymatic hydrolysis reaction was completed to obtain a crude mixed enzymatic hydrolysate;

[0054] A6. The crude mixed enzymatic hydrolysate is subjected to microwave inactivation treatment to obtain an inactivated enzymatic hydrolysate, which is then cooled, centrifuged, the supernatant is collected, ultrafiltered, and the filtrate is collected to obtain a mixed enzymatic hydrolysate.

[0055] In step A1, the mesh size of the soybean meal powder is 20 mesh, and the mesh size of the millipede powder is 80 mesh.

[0056] The concentration of the alkaline phosphate buffer was 0.15 mol / L, and the concentration of the acidic phosphate buffer was 0.15 mol / L.

[0057] In step A3, the amount of subtilisin and hemicellulase added is 2.5ug / g of the mixed protein slurry, wherein the mass ratio of subtilisin to hemicellulase is 1:3; in step A4, the amount of pepsin and pancreatic enzyme added is 2.5ug / g of the millipede powder slurry, wherein the mass ratio of pepsin to pancreatic enzyme is 1:3; in step A5, the amount of papain added is 1.5ug / g of the mixed liquid.

[0058] In step A6, when the enzymatic hydrolysate is subjected to microwave inactivation treatment, the microwave power is 800 W, the microwave inactivation temperature is 90° C., the microwave inactivation time is 3 min, and after the microwave inactivation is completed, an enzyme-inactivation enzymatic hydrolysate is obtained.

[0059] In step A6, during the ultrafiltration process, the supernatant is ultrafiltered using an ultrafiltration membrane with a molecular weight of 20,000 Da.

[0060] The stabilizer is a mixture of vitamin C and vitamin E in a mass ratio of 1:1.

[0061] A method for preparing a polypeptide enzymolyzate of crops comprises fully mixing a mixed enzymolyzate with a stabilizer to obtain the polypeptide enzymolyzate of crops.

[0062] In Example 3, a polypeptide enzymatic hydrolyzate of a crop is composed of the following raw materials in parts by weight: 35 parts of mixed enzymatic hydrolyzate and 2 parts of stabilizer;

[0063] The mixed enzymatic hydrolysate is a mixed enzymatic hydrolysate of soybean meal powder and millipede, wherein the mass ratio of soybean meal powder to millipede is 10:1.

[0064] The preparation method of the mixed enzymatic hydrolysate comprises the following steps:

[0065] A1. Wash and crush fresh millipedes, and then fully mix them with soybean meal powder. After mixing, freeze-dry them, and sieve the freeze-dried powder to separate the millipede powder from the soybean meal powder.

[0066] A2, the soybean meal powder obtained in step A1 and the alkaline phosphate buffer are mixed at a solid-liquid ratio of 1:12 to prepare a soybean meal powder slurry, the pH of the soybean meal powder slurry is adjusted to 9.5, and ultrasonic treatment is performed for 3.5 hours, the ultrasonic temperature is 50° C., and the ultrasonic power is 45 kHz. After the treatment is completed, centrifugation is performed to obtain a supernatant, and then an acidic phosphate buffer is added to adjust the pH of the supernatant to 4.5 and acid precipitation is performed for 1.2 hours. After the acid precipitation treatment is completed, the mixture is allowed to stand for 0.7 hours, and then centrifuged to obtain a lower precipitate, the lower precipitate is washed with water until it is neutral, and freeze-dried to obtain a soybean protein containing part of millipede protein, that is, a mixed protein;

[0067] A3. Mix the mixed protein and distilled water at a material-liquid ratio of 1:14, heat to 75°C, and keep warm for 25 minutes at a pressure of 0.09 MPa; continue to heat to 95°C, and keep warm for 11 minutes at a pressure of 0.06 MPa to obtain a mixed protein slurry; adjust the pH of the mixed protein slurry to 8.5, and add subtilisin and hemicellulase for ultrasonic-assisted enzymolysis, the enzymolysis reaction temperature is 48°C, the enzymolysis reaction time is 2.8 hours, the ultrasonic power is 35 kHz, the enzymolysis reaction is completed, and enzymolysis solution A is obtained;

[0068] A4, the millipede powder obtained in step A1 was mixed with distilled water at a solid-liquid ratio of 1:13, and heated to 75°C, and kept warm for 25 minutes at a pressure of 0.09 MPa; the millipede powder slurry was obtained by further heating to 95°C, and kept warm for 11 minutes at a pressure of 0.06 MPa to obtain a millipede powder slurry; the pH of the millipede powder slurry was adjusted to 4.5, and pepsin and pancreatin were added for ultrasonic enzymolysis, the enzymolysis reaction temperature was 48°C, the enzymolysis reaction time was 2.5 hours, the ultrasonic power was 35 kHz, and the enzymolysis reaction was completed to obtain an enzymolysis solution B;

[0069] A5, the enzymatic hydrolysate A and the enzymatic hydrolysate B were mixed to obtain a mixed solution, the pH was adjusted to 7, and papain was added for ultrasonic enzymolysis. The enzymatic hydrolysis reaction temperature was 48°C, the enzymatic hydrolysis reaction time was 2.5h, the ultrasonic power was 35kHz, and the enzymatic hydrolysis reaction was completed to obtain a mixed enzymatic hydrolysate crude product;

[0070] A6. The crude mixed enzymatic hydrolysate is subjected to microwave inactivation treatment to obtain an inactivated enzymatic hydrolysate, which is then cooled, centrifuged, the supernatant is collected, ultrafiltered, and the filtrate is collected to obtain a mixed enzymatic hydrolysate.

[0071] In step A1, the mesh size of the soybean meal powder is 15 mesh, and the mesh size of the millipede powder is 70 mesh.

[0072] The concentration of the alkaline phosphate buffer is 0.12 mol / L, and the concentration of the acidic phosphate buffer is 0.12 mol / L.

[0073] In step A3, the amount of subtilisin and hemicellulase added is 2.2ug / g of the mixed protein slurry, wherein the mass ratio of subtilisin to hemicellulase is 1:2.5; in step A4, the amount of pepsin and pancreatic enzyme added is 2.2ug / g of the millipede powder slurry, wherein the mass ratio of pepsin to pancreatic enzyme is 1:2.5; in step A5, the amount of papain added is 1.2ug / g of the mixed liquid.

[0074] In step A6, when the enzymatic hydrolysate is subjected to microwave inactivation treatment, the microwave power is 700 W, the microwave inactivation temperature is 85° C., the microwave inactivation time is 2.5 min, and after the microwave inactivation is completed, an enzyme-inactivation enzymatic hydrolysate is obtained.

[0075] In step A6, during the ultrafiltration process, the supernatant is ultrafiltered using an ultrafiltration membrane with a molecular weight of 10,000 Da.

[0076] The stabilizer is a mixture of lipoic acid and sodium pyrosulfite in a mass ratio of 1:1.

[0077] A method for preparing a polypeptide enzymolyzate of crops comprises fully mixing a mixed enzymolyzate with a stabilizer to obtain the polypeptide enzymolyzate of crops.

[0078] In Comparative Example 1, compared with Example 3, the polypeptide hydrolyzate in Comparative Example 1 is a mixture of millipede hydrolyzate and a stabilizer, and the rest is the same as Example 3.

[0079] In Comparative Example 2, compared with Example 3, the polypeptide enzymatic hydrolyzate in Comparative Example 2 is a mixture of soybean meal enzymatic hydrolyzate and a stabilizer, and the rest is the same as Example 3.

[0080] In Comparative Example 3, compared with Example 3, when preparing the mixed enzymatic hydrolysate in Comparative Example 4, step A1 was not performed, and compared with Example 3, the rest of the steps were the same as Example 3.

[0081] In comparative example 4, in step A5, the pH of enzymatic hydrolysate A and enzymatic hydrolysate B are adjusted to 7 separately, and ultrasonic hydrolyzed with papain are performed separately. After the reaction is completed, the two groups of enzymatic hydrolysates are mixed. The rest is the same as in example 3.

[0082] The polypeptide hydrolysates prepared in Examples 1-3 and Comparative Examples 1-4 were used for tobacco floating seedling cultivation, and the main growth indicators are shown in Table 1.

[0083] Table 1

[0084] Seedling rate% Days to seedlings Average plant height cm Average crown width cm Example 1 92.3 40～45 18.4 12.5 Example 2 93.5 40～45 18.1 12.7 Example 3 94.1 40～45 19.2 13.3 Comparative Example 1 89.6 50～55 15.2 9.6 Comparative Example 2 75.2 45～50 16.8 10.5 Comparative Example 3 86.9 45～50 17.2 11.1 Comparative Example 4 92.5 40～45 18.5 12.6

[0085] As can be seen from Table 1, the growth indexes of Examples 1-3 are better than those of Comparative Examples 1-3; in Comparative Example 1, the polypeptide hydrolysate is a mixture of millipede hydrolysate and a stabilizer, which is not easily affected by pests and diseases, has a high germination rate, but a relatively slow growth rate; in Comparative Example 2, the polypeptide hydrolysate is a mixture of soybean meal hydrolysate and a stabilizer, and the ability to resist pests and diseases is reduced, but the surviving seedlings have a good growth momentum; in Comparative Example 3, its growth index is slightly lower than that of Examples 1-3; in Example 4, its growth index is close to that of Examples 1-3.

[0086] In Examples 1-3, the incidence of pests at the seedling stage can be reduced by about 60 to 90%.

[0087] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A polypeptide enzymatic hydrolyzate of crops, characterized in that: The method comprises the following raw materials in parts by weight: 30 to 40 parts of mixed enzymatic hydrolysate and 0.5 to 3 parts of stabilizer; The mixed enzymatic hydrolysate is a mixed enzymatic hydrolysate of soybean meal powder and millipede, wherein the mass ratio of soybean meal powder to millipede is 5-15:

1.

2. The polypeptide enzymatic hydrolyzate of crops according to claim 1, characterized in that: The preparation method of the mixed enzymatic hydrolysate comprises the following steps: A1. Wash and crush fresh millipedes, and then fully mix them with soybean meal powder. After mixing, freeze-dry them, and sieve the freeze-dried powder to separate the millipede powder from the soybean meal powder. A2, the soybean meal powder obtained in step A1 and the alkaline phosphate buffer are mixed at a solid-liquid ratio of 1:10-15 to prepare a soybean meal powder slurry, the pH of the soybean meal powder slurry is adjusted to 9-10, and ultrasonic treatment is performed for 3-4 hours, the ultrasonic temperature is 45-55° C., and the ultrasonic power is 40-50kHz. After the treatment is completed, centrifugation is performed to obtain a supernatant, and then an acid phosphate buffer is added to adjust the pH of the supernatant to 4-5 and acid precipitation is performed for 1-1.5 hours. After the acid precipitation treatment is completed, the mixture is allowed to stand for 0.5-1 hour, and then centrifuged to obtain a lower precipitate, the lower precipitate is washed with water until it is neutral, and freeze-dried to obtain a soybean protein containing part of millipede protein, that is, a mixed protein; A3, mixing the mixed protein and distilled water at a material-liquid ratio of 1:12-15, heating to 70-80°C, and heat preservation at a pressure of 0.08-0.1Mpa for 20-30min; continuing to heat to 90-100°C, and heat preservation at a pressure of 0.05-0.07Mpa for 10-12min to obtain a mixed protein slurry; adjusting the pH of the mixed protein slurry to 8-9, and adding subtilisin and hemicellulase for ultrasonic-assisted enzymolysis, the enzymolysis reaction temperature is 45-50°C, the enzymolysis reaction time is 2-3h, the ultrasonic power is 30-40kHz, the enzymolysis reaction is completed, and enzymolysis solution A is obtained; A4, the millipede powder obtained in step A1 is mixed with distilled water at a solid-liquid ratio of 1:12-15, and heated to 70-80°C, and heat-treated at a pressure of 0.08-0.1 MPa for 20-30 min; continue to heat to 90-100°C, and heat-treated at a pressure of 0.05-0.07 MPa for 10-12 min to obtain a millipede powder slurry; adjust the pH of the millipede powder slurry to 4-5, and add pepsin and pancreatin for ultrasonic enzymolysis, the enzymolysis reaction temperature is 45-50°C, the enzymolysis reaction time is 2-3 h, the ultrasonic power is 30-40 kHz, the enzymolysis reaction is completed, and an enzymolysis solution B is obtained; A5, mixing enzymatic hydrolysate A and enzymatic hydrolysate B to obtain a mixed solution, adjusting the pH to 6.5-7.5, and adding papain for ultrasonic enzymolysis, the enzymatic hydrolysis reaction temperature is 45-50°C, the enzymatic hydrolysis reaction time is 2-3h, the ultrasonic power is 30-40kHz, the enzymatic hydrolysis reaction is completed, and a mixed enzymatic hydrolysate crude product is obtained; A6. The crude mixed enzymatic hydrolysate is subjected to microwave inactivation treatment to obtain an inactivated enzymatic hydrolysate, which is then cooled, centrifuged, the supernatant is collected, ultrafiltered, and the filtrate is collected to obtain a mixed enzymatic hydrolysate.

3. The polypeptide enzymatic hydrolyzate of crops according to claim 2, characterized in that: In the step A1, the mesh size of the soybean meal powder is 10-20 meshes, and the mesh size of the millipede powder is 60-80 meshes.

4. The polypeptide enzymatic hydrolyzate of crops according to claim 2, characterized in that: The concentration of the alkaline phosphate buffer is 0.1-0.15 mol / L, and the concentration of the acidic phosphate buffer is 0.1-0.15 mol / L.

5. The polypeptide enzymatic hydrolyzate of crops according to claim 2, characterized in that: In the step A3, the amount of subtilisin and hemicellulase added is 2-2.5 ug / g of the mixed protein slurry, wherein the mass ratio of subtilisin to hemicellulase is 1:2-3; in the step A4, the amount of pepsin and pancreatic enzyme added is 2-2.5 ug / g of the millipede powder slurry, wherein the mass ratio of pepsin to pancreatic enzyme is 1:2-3; in the step A5, the amount of papain added is 1-1.5 ug / g of the mixed solution.

6. The polypeptide enzymatic hydrolyzate of crops according to claim 2, characterized in that: In step A6, when the enzymatic hydrolysate is subjected to microwave inactivation treatment, the microwave power is 500-800 W, the microwave inactivation temperature is 80-90° C., and the microwave inactivation time is 2-3 min. After the microwave inactivation is completed, an enzyme-inactivation enzymatic hydrolysate is obtained.

7. The polypeptide enzymatic hydrolyzate of crops according to claim 2, characterized in that: In the step A6, during the ultrafiltration process, the supernatant is ultrafiltered using an ultrafiltration membrane with a molecular weight of 5000Da to 20000Da.

8. The polypeptide enzymatic hydrolyzate of crops according to claim 1, characterized in that: The stabilizer is one of sodium thiosulfate, vitamin C, vitamin E, lipoic acid and sodium pyrosulfite, or a mixture of two or more thereof.

9. The method for preparing a polypeptide enzymatic hydrolyzate of crops according to any one of claims 1 to 8, characterized in that: The mixed enzymatic hydrolysate is fully mixed with the stabilizer to obtain the polypeptide enzymatic hydrolysate of crops.