Processing method of enzymolysis wool protein peptide powder for feed

Abstract

The invention relates to the technical field of wool protein peptide powder, and discloses a processing method of enzymolysis wool protein peptide powder for feed, which comprises the following steps: (1) wool treatment; selecting proper wool as a raw material, and performing pretreatment; (2) loading into a hydrolysis tank: loading the pretreated wool raw material into a pressure hydrolysis tank, adding water until the substrate concentration is 50%, and keeping the substrate concentration at 50%; (3) hydrolyzing; after the sealed tank opening in the step (2) is connected, the pressure of the inner cavity of the hydrolysis tank is increased to 0.30-0.45 Mpa, the pressure is maintained for 35-45 minutes, then the pressure is released, and the materials are cooled by a cooler and put into an enzymolysis tank; (4) performing enzymolysis; (3) adding 1.5% of a compound enzyme preparation according to the substrate concentration of the pre-treated wool in the enzymolysis tank being 50%, adjusting the pH value to 7.5-8.5 by using sodium carbonate, and carrying out enzymolysis at 55 DEG C for 6 hours; the processing method of the enzymolysis wool protein peptide powder for the feed is good in product effect, low in equipment investment, free of sewage and easy to popularize in a large area.

Description

Technical Field The invention relates to the technical field of wool protein peptide powder, in particular to a method for processing enzymatically hydrolyzed wool protein peptide powder for feeding. Background Art The shortage of feed protein resources and the low comprehensive utilization rate of resources have become bottlenecks restricting the healthy development of my country's feed and animal husbandry industries. It is particularly important to efficiently develop non-grain feed protein resources. my country's annual feather production exceeds 1 million tons, and the annual production of sheep wool reaches more than 400,000 tons. Although wool has important commercial value in the textile industry, the coarse and miscellaneous wool obtained from the wool combing factory cannot be used in the textile industry. If it is not processed into feed, it will become waste. The main components of coarse and miscellaneous wool are keratin (85%), and a small amount of fat (3%) and minerals (0.5%). Although it has a high protein content, it cannot be digested and utilized by animals. At present, the main processing of coarse wool is to process it into high-temperature and high-pressure hydrolyzed wool powder. Some companies use acid hydrolysis to extract amino acids and use rice bran and rice husk as carriers to produce a low-grade protein raw material. The preparation methods in public literature and patents generally have the defects of low production efficiency and high cost. There has never been a wool polypeptide protein product with good cost performance promoted in the market. Summary of the invention In view of the deficiencies of the prior art, the present invention provides a method for processing enzymatically hydrolyzed wool protein peptide powder for feed, which solves the problems of low production efficiency and high cost. The present invention provides the following technical solution: a method for processing enzymatically hydrolyzed wool protein peptide powder for feeding, comprising the following steps: (1) Wool processing: Select appropriate wool as raw material and perform pretreatment; (2) Loading into a hydrolysis tank: Loading the pretreated wool raw material into a pressure hydrolysis tank, adding water to a substrate concentration of 50%, and maintaining the substrate concentration at 50%; (3) hydrolysis; after the tank mouth is sealed in step (2), the pressure in the hydrolysis tank is increased to 0.30-0.45Mpa, maintained for 35-45 minutes and then released, and the material is cooled by a cooler and loaded into the enzymatic hydrolysis tank; (4) enzymolysis; the wool substrate concentration of the pre-treated wool in the enzymolysis tank is 50% as in step (3), 1.5% of the composite enzyme preparation is added according to the substrate, the pH value is adjusted to 7.5-8.5 with sodium carbonate, and the enzymolysis is performed at 55°C for 6 hours; (5) enzyme inactivation treatment; continuing from step (4), at the 7th hour, the temperature was raised to 80° C. and maintained for 20 minutes to inactivate the enzyme, thereby obtaining an enzymatic solution containing protein peptides and other solid particles; (6) centrifugal separation; adding the enzymatic hydrolyzate obtained in step (5) to a centrifuge for centrifugal separation, and then standing until stratification occurs to obtain an upper clear liquid and a lower precipitate; (7) Drying; the supernatant obtained in step (6) is directly transported to a grid tube bundle dryer for primary drying, and a disc or coil dryer for secondary drying, the drying temperature is 60-80° C., the moisture content of the material out of the machine is 7%, and a dry material is obtained; (8) crushing and packaging; after the dry material is cooled, it is packaged in a moisture-proof bag to obtain wool polypeptide protein powder. Preferably, the wool polypeptide protein powder obtained in step (8) has the following quality indicators: moisture ≤6%, ash ≤8%, crude protein ≥77%, acid-soluble protein ≥25%, pepsin digestibility ≥90%, and volatile basic nitrogen ≤120 mg / 100 g. Preferably, the composite enzyme preparation in step (4) is composed of 0.8 parts by weight of alkaline protease with 200,000 activity units, 1.2 parts by weight of pancreatic enzyme with 4,000 activity units, and 1.5 parts by weight of serine keratinase with 100,000 activity units. Preferably, the pretreatment of wool in step (1) comprises the following steps: S101 washing: put the wool into clean water and wash it; S102 degreasing; weigh the wool washing and degreasing agent and mix it with water, add a small amount of sodium carbonate to adjust the pH value of the washing liquid to 7.5, the bath ratio of the washed wool to the washing liquid is 1:10, immerse the washed wool in the washing liquid at a temperature of 55°C for 1-3 hours, then take it out, wash it with water and dry it; S103 swelling: soak the degreased wool in a metal salt solution for 7-9 hours; S104 adds surfactant and reducing agent; S05, secondary washing: rinse repeatedly 3-5 times with clean water at a temperature of 40-60°C and then dry to obtain the pretreated wool. Preferably, the metal salt is a lithium bromide solution, and the concentration of the lithium bromide solution is 0.1 mol / L. LiBr can fully open the hydrogen bonds in wool fiber molecules, which is beneficial for the reducing agent to enter the wool molecules to open the disulfide bonds. The increase in its concentration is beneficial to the swelling of wool, and the dissolution rate and keratin recovery rate are maintained at a high level. Preferably, the reducing agent is a NaHSO3 solution, and the concentration of the NaHSO3 solution is 1 mol / L. The reaction principle of NaHSO3 and wool is: R1—s—S—R2+NaHSO3→R1-SSO3Na+R2—SHNaHSO3 The oxidized product R-SSO3Na (R is a keratin polypeptide chain) sodium thiosulfate has high solubility and no irritating odor. Preferably, the surfactant is sodium dodecyl sulfate, and the concentration of the sodium dodecyl sulfate is 0.02 mol / L. Preferably, the dried material after cooling in step (8) is crushed by Raymond mill, the fineness exceeds 40 mesh, and the moisture content is reduced to below 6% before packaging. The main function of surfactants is to produce giant micelles on the surface of the solvent system to prevent the opened disulfide bonds in the solution from being oxidized and reconnected when exposed to air. Compared with the prior art, the present invention provides a method for processing enzymatically hydrolyzed wool protein peptide powder for feed, which has the following beneficial effects: (1) The processing method of the enzymatic hydrolyzed wool protein peptide powder for feed combines the reduction method with the metal salt method, and dissolves the waste wool through the solvent system of NaHSO3 / LiBr / SDS to obtain a high wool dissolution rate (>90%), and the recovery rate of macromolecular keratin exceeds 50%. The entire solvent system has low cost, is non-toxic and has no odor, and meets environmental protection requirements. (2) The processing method of the enzymatically hydrolyzed wool protein peptide powder for feed uses a composite enzyme preparation to act on the keratin molecular structure without producing any toxic or harmful substances; the pepsin digestibility of the hydrolyzed wool polypeptide protein powder reaches 90%, which is 10 percentage points higher than the 80% pepsin digestibility standard of first-grade feather powder stipulated by the Ministry of Agriculture and Rural Affairs; the yield of 50% concentration enzymatic hydrolysis polypeptide reaches 22.74%, and adding 5% to replace 5-point meat powder in aquatic feed can reduce the feed coefficient by 0.16-0.19. The product has good effect, low equipment investment, no sewage generation, and is easy to promote on a large scale. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a logical schematic diagram of the present invention; Figure 2 This is a logical schematic diagram of wool pretreatment according to the present invention. DETAILED DESCRIPTION See also Figure 1-2 , a processing method of enzymatically hydrolyzed wool protein peptide powder for feed, the present invention provides the following technical solutions: Example 1, the present invention provides the following technical solution: a method for processing enzymatically hydrolyzed wool protein peptide powder for feed, The steps include: (1) Wool processing: Select appropriate wool as raw material and perform pretreatment; (2) Loading into a hydrolysis tank: Loading the pretreated wool raw material into a pressure hydrolysis tank, adding water to a substrate concentration of 50%, and maintaining the substrate concentration at 50%; The wool is put into the hydrolysis tank, and water is added to the substrate concentration of 50%. Steam is introduced into the hydrolysis tank. The raw material pretreatment process parameters described in this process are optimized and selected by the following experiments, as shown in Table 1, Table 2, and Table 3. Table 1. Test results of pepsin digestibility of wool powder at different hydrolysis times in experiment 1: Table 2. Pepsin digestibility (PD value) of wool powder at different hydrolysis pressures in test 2, maintained at pressure for 40 minutes: Test 3: hydrolysis pressure of 0.40Mpa and 0.5Mpa, maintaining pressure for 40 minutes. The destruction of heat-sensitive amino acids in wool powder is shown in Table 3. Table 3 Analysis values ​​of thermosensitive amino acids: As can be seen from Table 3, when the pressure is higher than 0.5 MPa, the heat-sensitive amino acids can be greatly destroyed within 40 minutes. In summary, the suitable conditions for raw material pretreatment are: moisture 50%, pressure 0.30-0.45Mpa, pressure holding time 35-45 minutes, disulfide bond cleavage rate 74.94-81.00% (3) hydrolysis; after the tank mouth is sealed in step (2), the pressure in the hydrolysis tank is increased to 0.30-0.45Mpa, maintained for 35-45 minutes and then released, and the material is cooled by a cooler and loaded into the enzymatic hydrolysis tank; The material is fed into a spiral heat exchanger to cool down to 55°C and sent to the enzymatic hydrolysis tank; (4) enzymolysis; the wool substrate concentration of the pre-treated wool in the enzymolysis tank is 50% as in step (3), 1.5% of the composite enzyme preparation is added according to the substrate, the pH value is adjusted to 7.5-8.5 with sodium carbonate, and the enzymolysis is performed at 55°C for 6 hours; The compound enzyme preparation is composed of 0.8 parts by weight of alkaline protease with 200,000 activity units, 1.2 parts by weight of pancreatic enzyme with 4,000 activity units, and 1.5 parts by weight of serine keratinase with 100,000 activity units. The enzyme preparation formulation and production process parameters are screened by the following tests: Screening test for enzyme preparation formulation Single enzyme test: The pretreated wool was used to prepare a substrate concentration of 10%, pH 8.0, temperature 55°C, and enzymatic hydrolysis time of 6 hours. Alkaline protease (A), neutral protease (B), trypsin (C), papain (D), bromelain (E), and F keratinase were selected from the endonucleases and added at 0.4% of the substrate for enzymatic hydrolysis comparison tests to determine the hydrolysis degree and acid-soluble protein after 6 hours of enzymatic hydrolysis. Table 4 Single enzyme test data From Table 4, it can be seen that C, A, and F have better effects on enzymatic hydrolysis of wool protein. Two-enzyme combination test: The pretreated wool was used to prepare a substrate concentration of 10%, pH 8.0, temperature 55°C, and enzymatic hydrolysis for 6 hours. According to the acid-soluble protein index, an orthogonal test was performed at two factors and four levels to determine the composite ratio of endonucleases C and A. See Tables 5 and 6. Table 5 Orthogonal test table Table 6 Orthogonal test results Table 6: Pancreatic enzyme is the first hydrolase for hydrolyzing wool keratin, alkaline enzyme is the second hydrolase, alkaline enzyme: pancreatic enzyme = 2:3 combination, the highest value of phosphate soluble protein / crude protein = 61%, which is 14 percentage points higher than the highest value of single enzyme. Three-enzyme combination test Alkaline protease and pancreatin were prepared in a mass ratio of 2:3, and added at 0.5%, 1.0%, 1.5%, and 2.0% of the substrate weight. Keratinase was also added in this ratio, and the combination test was performed as shown in Table 7 and Table 8. Test conditions: Heat-denatured wool was used to prepare a liquid with a substrate concentration of 10%, the temperature was 55°C, the pH was 8.0, and the enzymatic hydrolysis was performed for 6 hours, and the degree of hydrolysis and acid-soluble protein were measured. Table 7 Three enzyme combination test design: Table 8 Three enzyme combination test data: Table 8: Keratinase 1.5% + (alkali + pancreatin) 2.0% acid-soluble protein / crude protein = 83.31%, hydrolysis degree 33.33% is the best combination. The mass ratio of the three enzymes, alkaline enzyme: pancreatin: keratinase = 0.8:1.2:1.5, among which alkaline protease has 200,000 activity units, pancreatin has 4,000 activity units, and keratinase has 100,000 activity units. Optimization and screening test of enzymatic hydrolysis process parameters Enzymatic hydrolysis is affected by temperature, pH value, time, enzyme amount (complex enzyme), water content, etc. The three factors of temperature, time and enzyme amount were selected, and acid-soluble protein / crude protein was used as an indicator. An orthogonal test was performed at a substrate concentration of 10%. The results are shown in Tables 9 and 10: Table 9 Orthogonal test table Table 10 Orthogonal test results The range analysis shows that when the substrate concentration is 10%, the degree of influence is temperature > enzyme amount > time. The suitable conditions for wool powder hydrolysis with composite protease are temperature 55°C, 6 hours, and enzyme amount 1.0-2.0%. Considering the cost factor, 1.5% of the composite enzyme is added. At a reaction temperature of 55°C, a reaction time of 6 hours, an enzyme dosage of 1.5%, substrate concentration and pH value factors were selected, and acid-soluble protein / crude protein and PD (pepsin digestibility)% were used as indicators to perform an enzymatic hydrolysis orthogonal test. The results are shown in Tables 7 and 8: Table 11 Orthogonal test table Table 12 Orthogonal test results The range analysis shows that the influence degree is: substrate concentration > pH value, (a) The substrate concentration is 20%, the pH value is 8.0, the acid-soluble protein / crude protein is 0.63, and the PD is 92%. The enzymatic hydrolysate is separated, concentrated, and dried to obtain a polypeptide protein product; (b) The substrate concentration is 35% and 50%, the pH value is 8.0, the acid-soluble protein / crude protein is 0.35 and 0.25 (35% and 25%), the PD is 91%, and the enzymatic hydrolyzed material is directly dried without separation and concentration to obtain a polypeptide protein product. (5) enzyme inactivation treatment; continuing from step (4), at the 7th hour, the temperature was raised to 80° C. and maintained for 20 minutes to inactivate the enzyme, thereby obtaining an enzymatic solution containing protein peptides and other solid particles; (6) centrifugal separation; adding the enzymatic hydrolyzate obtained in step (5) to a centrifuge for centrifugal separation, and then standing until stratification occurs to obtain an upper clear liquid and a lower precipitate; (7) Drying; the supernatant obtained in step (6) is directly transported to a grid tube bundle dryer for primary drying, and a disc or coil dryer for secondary drying, the drying temperature is 60-80° C., the moisture content of the material out of the machine is 7%, and a dry material is obtained; Since wool enzymatic hydrolysate is hot and sticky, the material is easy to stick to the heat transfer equipment, affecting the heat transfer efficiency and product quality. A 304 stainless steel mesh with a mesh size of 5-20mm is wrapped around the outer periphery of the 3-meter portion extending from the feed end to the discharge end of the heat transfer tube of the tube bundle dryer to prevent the material from directly contacting the heating tube. The hot air passes through the mesh from the inside to the outside, changing the original conduction heating to convection heating. The sticky and wet material condenses on the mesh wall and falls off in blocks without sticking to the heating tube wall. This improved tube bundle dryer is connected in series with a disc or coil dryer. Each device is applied at a different temperature. It is suitable for drying protein active peptide paste products that are heat-sensitive, heat-sticky, and highly viscous. The surface temperature of the material in the first-stage dryer is 60-70℃, and the surface temperature of the material in the second-stage dryer is 70-80℃. The moisture content of the material out of the machine is 7%; (8) crushing and packaging; after the dry material is cooled, it is packaged in a moisture-proof bag to obtain wool polypeptide protein powder. Because the product has thermal viscosity, if the hammer mill or claw mill is used, friction heat is generated during crushing, and the material is heated and sticks to the screen holes, and cannot operate normally. If the material is crushed by Raymond mill, the temperature of the material is low and cannot reach the critical temperature of thermal viscosity. The moisture content of the finished product is ≤6%, and the packaging bag should be added with an inner film bag to prevent moisture absorption and caking. Preferably, the wool polypeptide protein powder obtained in step (8) has the following quality indicators: moisture ≤6%, ash ≤8%, crude protein ≥77%, acid-soluble protein ≥25%, pepsin digestibility ≥90%, and volatile basic nitrogen ≤120 mg / 100 g. Preferably, the pretreatment of wool in step (1) comprises the following steps: S101 washing: put the wool into clean water and wash it; S102 degreasing; weigh the wool washing and degreasing agent and mix it with water, add a small amount of sodium carbonate to adjust the pH value of the washing liquid to 7.5, the bath ratio of the washed wool to the washing liquid is 1:10, immerse the washed wool in the washing liquid at a temperature of 55°C for 1-3 hours, then take it out, wash it with water and dry it; S103 swelling: soak the degreased wool in a metal salt solution for 7-9 hours; S104 adds surfactant and reducing agent; S05, secondary washing: rinse repeatedly 3-5 times with clean water at a temperature of 40-60°C and then dry to obtain the pretreated wool. Preferably, the metal salt is a lithium bromide solution, and the concentration of the lithium bromide solution is 0.1 mol / L. LiBr can fully open the hydrogen bonds in wool fiber molecules, which is beneficial for the reducing agent to enter the wool molecules to open the disulfide bonds. The increase in its concentration is beneficial to the swelling of wool, and the dissolution rate and keratin recovery rate are maintained at a high level. Preferably, the reducing agent is a NaHSO3 solution, and the concentration of the NaHSO3 solution is 1 mol / L. The reaction principle of NaHSO3 and wool is: R1—s—S—R2+NaHSO3→R1-SSO3Na+R2—SHNaHSO3 The oxidized product R-SSO3Na (R is a keratin polypeptide chain) sodium thiosulfate has high solubility and no irritating odor. Preferably, the surfactant is sodium dodecyl sulfate, and the concentration of the sodium dodecyl sulfate is 0.02 mol / L. Preferably, the dried material after cooling in step (8) is crushed by Raymond mill, the fineness exceeds 40 mesh, and the moisture content is reduced to below 6% before packaging. The main function of surfactants is to produce giant micelles on the surface of the solvent system to prevent the opened disulfide bonds in the solution from being oxidized and reconnected when exposed to air. Embodiment 2, The obtained product is wool polypeptide protein powder, and the steps are:

[0035] (1) Open the air inlet valve of the hydrolysis tank, preheat the tank body, add 1000 kg of tap water into the tank, add 1750 kg of coarse wool residue, then close the feed valve and continue to increase the pressure. When the inner cavity pressure rises to 0.35Mpa, close the air inlet valve. When the inner cavity pressure gauge is higher than 0.45Mpa, open the pressure relief valve to 0.40Mpa on the pressure gauge for 40 minutes, release the pressure, start the vacuum pump, extract the hot steam in the tank, and open the discharge valve.

[0037] (3) The hydrolyzed wool pulp is cooled by a heat exchanger and fed into an enzymolysis tank. 26 kg of composite protease and 53 kg of sodium carbonate are added at 1.5% of the substrate. The enzymolysis temperature is 55° C., the pH value is 8.0, and the enzymolysis time is 6 hours.

[0038] (4) After the enzymatic hydrolysis is completed, the temperature is raised to 80°C and maintained for 20 minutes to inactivate the enzyme.

[0039] (5) The enzymatic hydrolyzate is dried after leaving the tank. The surface temperature of the material in the first tube bundle is controlled at 60-65°C, and the surface temperature of the material in the second disc dryer is controlled at 65-75°C. The moisture content of the material is 7%.

[0040] (6) Crushing and packaging: crush with Raymond mill, fineness should be over 40 mesh, moisture should be ≤6%, and packed in 50 kg polyethylene bags (with inner film bags). Sampling and testing should be conducted to check the physical and chemical indexes and nutritional indexes of the products.

[0041] Table 2 Physical and chemical index test results of the obtained products

[0042] Table 3 Amino acid analysis values ​​of the obtained products

[0043] Table 4 Molecular weight distribution of the acid-soluble protein obtained

[0044] Table 5 Peptide content analysis values ​​of the obtained products

[0045] (7) Experimental results of adding wool protein powder and meat powder to carp feed

[0046] Table 6. Carp feed formula Raw material name Wool protein powder group% Meat meal group% Fishmeal 5 5 Enzymatic Wool Powder 5 0 Meat powder 5 12 Soybean meal 22 22 Canola Meal 25 23 Cottonseed meal 5 5 flour 24.2 25 Premix 4 4 Fat 4.8 3.8 MHA 0.08 0.06 Lysine 0.1 0.07

[0047] Table 7. Carp bait coefficient

[0048] Result analysis: The test was conducted under the same conditions of nitrogen and energy, various nutritional indicators and environmental conditions, and the feed coefficient was used as an important indicator for comprehensive evaluation of the effect. The feed coefficient of the wool polypeptide protein powder group in this test was 0.19 and 0.16 lower than that of the meat powder, respectively, indicating that the feed conversion rate of wool polypeptide protein powder is better than that of commercially available meat powder.

[0049] Safety of wool protein powder: The complex enzyme preparation acts on the molecular structure of keratin and does not produce any toxic or harmful substances.

[0050] Effectiveness of wool protein powder: The hydrolyzed wool polypeptide protein powder produced by this method has a pepsin digestibility of 90%, which is 10 percentage points higher than the 80% pepsin digestibility standard of first-grade feather powder stipulated by the Ministry of Agriculture and Rural Affairs; the yield of 50% enzymatic polypeptides reaches 22.74%, and adding 5% to aquatic feed to replace 5-point meat meal can reduce the feed coefficient by 0.16-0.19.

[0051] Energy saving analysis

[0052] Comparison of energy consumption of products obtained from different enzymatic hydrolysis concentrations:

[0053] The comparison of heat energy cost of different production processes for processing 1750 kg of wool is shown in Table 8 Calculation basis: The thermal efficiency of the tube bundle dryer is 70%, and 1430kg of steam is consumed to evaporate 1000kg of water. The double-effect concentration evaporates 1000kg of water and consumes 650kg of gas. The moisture content of the dry material is 7% In summary, the preferred substrate concentration for enzymatic hydrolysis of wool keratin is 50%, and the resulting unit acid-soluble protein has low energy consumption, good product effect, low equipment investment, no sewage generation, and is easy to promote on a large scale. Example 3, a method for processing enzymatically hydrolyzed wool protein peptide powder for feeding, The steps include: (1) Wool processing: Select appropriate wool as raw material and perform pretreatment; (2) Loading into a hydrolysis tank: Loading the pretreated wool raw material into a pressure hydrolysis tank, adding water to a substrate concentration of 50%, and maintaining the substrate concentration at 50%; (3) hydrolysis; after the tank mouth is sealed in step (2), the pressure in the hydrolysis tank is increased to 0.30 MPa, maintained for 35 minutes and then released, and the material is cooled by a cooler and loaded into the enzymatic hydrolysis tank; (4) enzymolysis; the wool substrate concentration of the pre-treated wool in the enzymolysis tank is 50% as in step (3), 1.5% of the composite enzyme preparation is added according to the substrate, the pH value is adjusted to 7.5 with sodium carbonate, and the enzymolysis is carried out at 55° C. for 6 hours; (5) enzyme inactivation treatment; continuing from step (4), at the 7th hour, the temperature was raised to 80° C. and maintained for 20 minutes to inactivate the enzyme, thereby obtaining an enzymatic solution containing protein peptides and other solid particles; (6) centrifugal separation; adding the enzymatic hydrolyzate obtained in step (5) to a centrifuge for centrifugal separation, and then standing until stratification occurs to obtain an upper clear liquid and a lower precipitate; (7) Drying; the supernatant obtained in step (6) is directly transported to a grid tube bundle dryer for primary drying, and a disc or coil dryer for secondary drying, the drying temperature is 60° C., the moisture content of the material out of the machine is 7%, and a dry material is obtained; (8) crushing and packaging; after the dry material is cooled, it is packaged in a moisture-proof bag to obtain wool polypeptide protein powder. Preferably, the wool polypeptide protein powder obtained in step (8) has the following quality indicators: moisture ≤6%, ash ≤8%, crude protein ≥77%, acid-soluble protein ≥25%, pepsin digestibility ≥90%, and volatile basic nitrogen ≤120 mg / 100 g. Preferably, the composite enzyme preparation in step (4) is composed of 0.8 parts by weight of alkaline protease with 200,000 activity units, 1.2 parts by weight of pancreatic enzyme with 4,000 activity units, and 1.5 parts by weight of serine keratinase with 100,000 activity units. Preferably, the pretreatment of wool in step (1) comprises the following steps: S101 washing: put the wool into clean water and wash it; S102 degreasing; weigh the wool washing and degreasing agent and mix it with water, add a small amount of sodium carbonate to adjust the pH value of the washing liquid to 7.5, the bath ratio of the washed wool to the washing liquid is 1:10, immerse the washed wool in the washing liquid at a temperature of 55°C for 1 hour, then take it out, wash it with water and dry it; S103 swelling; soak the degreased wool in a metal salt solution for 7 hours; S104 adds surfactant and reducing agent; S05, secondary washing: rinse repeatedly three times with clean water at a temperature of 40°C and then dry to obtain the pretreated wool. Preferably, the metal salt is a lithium bromide solution, and the concentration of the lithium bromide solution is 0.1 mol / L. Preferably, the reducing agent is a NaHSO3 solution, and the concentration of the NaHSO3 solution is 1 mol / L. Preferably, the surfactant is sodium dodecyl sulfate, and the concentration of the sodium dodecyl sulfate is 0.02 mol / L. Preferably, the dried material after cooling in step (8) is crushed by Raymond mill, the fineness exceeds 40 mesh, and the moisture content is reduced to below 6% before packaging. Embodiment 4: This embodiment differs from Embodiment 1 in that it includes the following steps: (1) Wool processing: Select appropriate wool as raw material and perform pretreatment; (2) Loading into a hydrolysis tank: Loading the pretreated wool raw material into a pressure hydrolysis tank, adding water to a substrate concentration of 50%, and maintaining the substrate concentration at 50%; (3) hydrolysis; after the tank mouth is sealed in step (2), the pressure in the hydrolysis tank is increased to 0.40 MPa, maintained for 40 minutes and then released, and the material is cooled by a cooler and loaded into the enzymatic hydrolysis tank; (4) enzymolysis; the wool substrate concentration of the pre-treated wool in the enzymolysis tank is 50% as in step (3), 1.5% of the composite enzyme preparation is added according to the substrate, the pH value is adjusted to 8 with sodium carbonate, and the enzymolysis is carried out at 55° C. for 6 hours; (5) enzyme inactivation treatment; continuing from step (4), at the 7th hour, the temperature was raised to 80° C. and maintained for 20 minutes to inactivate the enzyme, thereby obtaining an enzymatic solution containing protein peptides and other solid particles; (6) centrifugal separation; adding the enzymatic hydrolyzate obtained in step (5) to a centrifuge for centrifugal separation, and then standing until stratification occurs to obtain an upper clear liquid and a lower precipitate; (7) Drying; the supernatant obtained in step (6) is directly transported to a screen-type tube bundle dryer for primary drying, and a disc or coil dryer for secondary drying, the drying temperature is 70° C., the moisture content of the material out of the machine is 7%, and a dry material is obtained; (8) crushing and packaging; after the dry material is cooled, it is packaged in a moisture-proof bag to obtain wool polypeptide protein powder. Preferably, the wool polypeptide protein powder obtained in step (8) has the following quality indicators: moisture ≤6%, ash ≤8%, crude protein ≥77%, acid-soluble protein ≥25%, pepsin digestibility ≥90%, and volatile basic nitrogen ≤120 mg / 100 g. Preferably, the composite enzyme preparation in step (4) is composed of 0.8 parts by weight of alkaline protease with 200,000 activity units, 1.2 parts by weight of pancreatic enzyme with 4,000 activity units, and 1.5 parts by weight of serine keratinase with 100,000 activity units. Preferably, the pretreatment of wool in step (1) comprises the following steps: S101 washing: put the wool into clean water and wash it; S102 degreasing; weigh the wool washing and degreasing agent and mix it with water, add a small amount of sodium carbonate to adjust the pH value of the washing liquid to 7.5, the bath ratio of the washed wool to the washing liquid is 1:10, immerse the washed wool in the washing liquid at a temperature of 55°C for 1-3 hours, then take it out, wash it with water and dry it; S103 swelling; soak the degreased wool in the metal salt solution for 8 hours; S104 adds surfactant and reducing agent; S05, secondary washing: rinse repeatedly 4 times with clean water at a temperature of 50°C and then dry to obtain the pretreated wool. Preferably, the metal salt is a lithium bromide solution, and the concentration of the lithium bromide solution is 0.1 mol / L. Preferably, the reducing agent is a NaHSO3 solution, and the concentration of the NaHSO3 solution is 1 mol / L. Preferably, the surfactant is sodium dodecyl sulfate, and the concentration of the sodium dodecyl sulfate is 0.02 mol / L. Preferably, the dried material after cooling in step (8) is crushed by Raymond mill, the fineness exceeds 40 mesh, and the moisture content is reduced to below 6% before packaging. Embodiment 5: This embodiment differs from Embodiment 1 in that it includes the following steps: (1) Wool processing: Select appropriate wool as raw material and perform pretreatment; (2) Loading into a hydrolysis tank: Loading the pretreated wool raw material into a pressure hydrolysis tank, adding water to a substrate concentration of 50%, and maintaining the substrate concentration at 50%; (3) hydrolysis; after the tank mouth is sealed in step (2), the pressure in the hydrolysis tank is increased to 0.45 MPa, maintained for 45 minutes and then released, and the material is cooled by a cooler and loaded into the enzymatic hydrolysis tank; (4) enzymolysis; the wool substrate concentration of the pre-treated wool in the enzymolysis tank is 50% as in step (3), 1.5% of the composite enzyme preparation is added according to the substrate, the pH value is adjusted to 8.5 with sodium carbonate, and the enzymolysis is carried out at 55°C for 6 hours; (5) enzyme inactivation treatment; continuing from step (4), at the 7th hour, the temperature was raised to 80° C. and maintained for 20 minutes to inactivate the enzyme, thereby obtaining an enzymatic solution containing protein peptides and other solid particles; (6) centrifugal separation; adding the enzymatic hydrolyzate obtained in step (5) to a centrifuge for centrifugal separation, and then standing until stratification occurs to obtain an upper clear liquid and a lower precipitate; (7) Drying; the supernatant obtained in step (6) is directly transported to a grid tube bundle dryer for primary drying, and a disc or coil dryer for secondary drying, the drying temperature is 80° C., the moisture content of the material out of the machine is 7%, and a dry material is obtained; (8) crushing and packaging; after the dry material is cooled, it is packaged in a moisture-proof bag to obtain wool polypeptide protein powder. Preferably, the wool polypeptide protein powder obtained in step (8) has the following quality indicators: moisture ≤6%, ash ≤8%, crude protein ≥77%, acid-soluble protein ≥25%, pepsin digestibility ≥90%, and volatile basic nitrogen ≤120 mg / 100 g. Preferably, the composite enzyme preparation in step (4) is composed of 0.8 parts by weight of alkaline protease with 200,000 activity units, 1.2 parts by weight of pancreatic enzyme with 4,000 activity units, and 1.5 parts by weight of serine keratinase with 100,000 activity units. Preferably, the pretreatment of wool in step (1) comprises the following steps: S101 washing: put the wool into clean water and wash it; S102 degreasing; weigh the wool washing and degreasing agent and mix it with water, add a small amount of sodium carbonate to adjust the pH value of the washing liquid to 7.5, the bath ratio of the washed wool to the washing liquid is 1:10, immerse the washed wool in the washing liquid at a soaking temperature of 55°C for 3 hours, then take it out, wash it with water and dry it; S103 swelling: soak the degreased wool in a metal salt solution for 9 hours; S104 adds surfactant and reducing agent; S05, secondary washing: rinse repeatedly 5 times with clean water at a temperature of 40-60°C and then dry to obtain the pretreated wool. Preferably, the metal salt is a lithium bromide solution, and the concentration of the lithium bromide solution is 0.1 mol / L. Preferably, the reducing agent is a NaHSO3 solution, and the concentration of the NaHSO3 solution is 1 mol / L. Preferably, the surfactant is sodium dodecyl sulfate, and the concentration of the sodium dodecyl sulfate is 0.02 mol / L. Preferably, the dried material after cooling in step (8) is crushed by Raymond mill, the fineness exceeds 40 mesh, and the moisture content is reduced to below 6% before packaging. In summary, the processing method of the enzymatically hydrolyzed wool protein peptide powder for feed, the processing method of the enzymatically hydrolyzed wool protein peptide powder for feed, combines the reduction method with the metal salt method, and dissolves the waste wool through the NaHSO3 / LiBr / SDS solvent system to obtain a higher wool dissolution rate (>90%), and the recovery rate of macromolecular keratin exceeds 50%. The entire solvent system has low cost, is non-toxic and odorless, and meets environmental protection requirements. The processing method of the enzymatically hydrolyzed wool protein peptide powder for feed uses a composite enzyme preparation to act on the keratin molecular structure without producing any toxic or harmful substances; the pepsin digestibility of the wool polypeptide protein powder reaches 90%, which is 10 percentage points higher than the standard of 80% pepsin digestibility of first-class feather powder stipulated by the Ministry of Agriculture and Rural Affairs; the yield of 50% concentration enzymatic hydrolysis polypeptide reaches 22.74%, and adding 5% to replace 5-point meat powder in aquatic feed can reduce the feed coefficient by 0.16-0.19, the product has good effect, low equipment investment, does not produce sewage, and is easy to promote on a large scale.

Claims

1. A method for processing enzymatically hydrolyzed wool protein peptide powder for feed, characterized in that: The steps include: (1) Wool processing: Select appropriate wool as raw material and perform pretreatment; (2) Loading into a hydrolysis tank: Loading the pretreated wool raw material into a pressure hydrolysis tank, adding water to a substrate concentration of 50%, and maintaining the substrate concentration at 50%; (3) hydrolysis; after the tank mouth is sealed in step (2), the pressure in the hydrolysis tank is increased to 0.30-0.45Mpa, maintained for 35-45 minutes and then released, and the material is cooled by a cooler and loaded into the enzymatic hydrolysis tank; (4) enzymolysis; the wool substrate concentration of the pre-treated wool in the enzymolysis tank is 50% as in step (3), 1.5% of the composite enzyme preparation is added according to the substrate, the pH value is adjusted to 7.5-8.5 with sodium carbonate, and the enzymolysis is performed at 55°C for 6 hours; (5) enzyme inactivation treatment; continuing from step (4), at the 7th hour, the temperature was raised to 80° C. and maintained for 20 minutes to inactivate the enzyme, thereby obtaining an enzymatic solution containing protein peptides and other solid particles; (6) centrifugal separation; adding the enzymatic hydrolyzate obtained in step (5) to a centrifuge for centrifugal separation, and then standing until stratification occurs to obtain an upper clear liquid and a lower precipitate; (7) Drying; the supernatant obtained in step (6) is directly transported to a grid tube bundle dryer for primary drying, and a disc or coil dryer for secondary drying, the drying temperature is 60-80° C., the moisture content of the material out of the machine is 7%, and a dry material is obtained; (8) crushing and packaging; after the dry material is cooled, it is packaged in a moisture-proof bag to obtain wool polypeptide protein powder.

2. The method for processing enzymatically hydrolyzed wool protein peptide powder for feed according to claim 1, characterized in that: The quality indicators of the wool polypeptide protein powder obtained in step (8) are: moisture ≤6%, ash ≤8%, crude protein ≥77%, acid-soluble protein ≥25%, pepsin digestibility ≥90%, and volatile basic nitrogen ≤120mg / 100g.

3. The method for processing enzymatically hydrolyzed wool protein peptide powder for feed according to claim 1, characterized in that: The composite enzyme preparation in step (4) is composed of 0.8 parts by weight of alkaline protease with 200,000 activity units, 1.2 parts by weight of pancreatic enzyme with 4,000 activity units, and 1.5 parts by weight of serine keratinase with 100,000 activity units.

4. The method for processing enzymatically hydrolyzed wool protein peptide powder for feed according to claim 1, characterized in that: The pretreatment of wool in step (1) comprises the following steps: S101 washing: put the wool into clean water and wash it; S102 degreasing; weigh the wool washing and degreasing agent and mix it with water, add a small amount of sodium carbonate to adjust the pH value of the washing liquid to 7.5, the bath ratio of the washed wool to the washing liquid is 1:10, immerse the washed wool in the washing liquid at a temperature of 55°C for 1-3 hours, then take it out, wash it with water and dry it; S103 swelling: soak the degreased wool in a metal salt solution for 7-9 hours; S104 adds surfactant and reducing agent; S05, secondary washing: rinse repeatedly 3-5 times with clean water at a temperature of 40-60°C and then dry to obtain the pretreated wool.

5. The method for processing enzymatically hydrolyzed wool protein peptide powder for feed according to claim 4, characterized in that: The metal salt is a lithium bromide solution, and the concentration of the lithium bromide solution is 0.1 mol / L.

6. The method for processing enzymatically hydrolyzed wool protein peptide powder for feed according to claim 4, characterized in that: The reducing agent is NaHSO3 solution, and the concentration of the NaHSO3 solution is 1 mol / L.

7. The method for processing enzymatically hydrolyzed wool protein peptide powder for feed according to claim 4, characterized in that: The surfactant is sodium dodecyl sulfate, and the concentration of the sodium dodecyl sulfate is 0.02 mol / L.

8. The method for processing enzymatically hydrolyzed wool protein peptide powder for feed according to claim 1, characterized in that: The dried material after cooling in the step (8) is crushed by Raymond mill to a fineness of more than 40 meshes, and then packaged after the moisture content is reduced to less than 6%.

9. Application of the processing method of enzymatically hydrolyzed wool protein peptide powder for feed according to any one of claims 1 to 8 in the preparation of wool protein peptide.

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