Preparation method and application of protein powder produced as a by-product of shrimp and crab processing

Abstract

The present invention belongs to the technical field of animal feed production, and specifically relates to a method for preparing protein powder of shrimp and crab processing byproducts and its application. The present invention proposes a method for preparing protein powder of shrimp and crab processing byproducts, which uses shrimp and crab processing byproducts as raw materials, undergoes endogenous enzymatic hydrolysis, and obtains shrimp and crab processing byproduct protein powder, which can be used to prepare aquatic feed, or nutritional additives or specific nutritional enhancers in pet feed. The present invention has a wide range of applications and low costs, realizes the effective utilization of shrimp and crab processing byproducts, reduces resource waste, and provides a practical basis for enterprises to realize the resource utilization of shrimp and crab processing byproducts, which is conducive to further improving the economic value of shrimp and crabs.

Description

Technical Field

[0001] The invention belongs to the technical field of animal feed production, and particularly relates to a method for preparing protein powder which is a by-product of shrimp and crab processing and application thereof. Background Art

[0002] The byproducts of shrimp and crab processing are rich in protein, chitin, astaxanthin, Ca2+ and other biological elements. Usually, the byproducts of shrimp and crab processing are mainly dried and crushed to make shrimp and crab meal and then added to feed (fish meal). However, after simple drying and crushing, the substances contained in them are still in a large molecular state. When added to animal feed or attractants and eaten by aquatic animals and mammals, their absorption rate, digestibility and bioavailability are not high.

[0003] Shrimp and crab (especially the viscera) contain a rich enzyme system, such as cathepsin, trypsin, lipase and peptidase, etc. Under the combined action of the above enzyme systems, the shrimp body and crab meat can undergo a certain degree of autolysis. However, in the simple shrimp and crab system, the enzyme system itself is not enough to cause a high degree of degradation of macromolecular substances.

[0004] Chinese patent number CN114732084A "A method for preparing stress-resistant animal feed using shrimp processing by-products bioprocessing" and Chinese patent number CN106615686B "A feed additive containing shrimp processing by-product protein powder and its preparation method and application" disclose methods for preparing feed or its additives using shrimp processing by-products. Although the feed is prepared by enzymatic hydrolysis, it still relies on the need for additional addition of protease, the method is cumbersome, the production cost is high, and it is difficult to invest in large-scale industrial production. Summary of the invention

[0005] In order to overcome the technical problems of the prior art methods being cumbersome, high production costs and difficulty in large-scale industrial production, the present invention proposes a method for preparing shrimp and crab processing byproduct protein powder and its application. The preparation method uses shrimp and crab processing byproducts as raw materials, and obtains shrimp and crab processing byproduct protein powder through endogenous enzymolysis treatment, which is applied to the preparation of aquatic feed, or the preparation of nutritional additives or nutritional enhancers in pet feed. The materials of the present invention are cheap and easy to obtain, the reaction conditions are mild, no exogenous protease needs to be added again, the effect of mutual enzymolysis of shrimp and crab processing byproducts by endogenous enzymes is good, and it has industrial advantages.

[0006] The specific technical solution of the present invention is:

[0007] In a first aspect, the present invention provides a method for preparing shrimp and crab processing by-product protein powder, comprising the following steps: crushing the shrimp and crab processing by-products and mixing them evenly, allowing endogenous enzymes in the shrimp and crab to interact with each other, and extracting the shrimp and crab processing by-product protein powder.

[0008] The invention uses shrimp and crab processing by-products as raw materials. The various enzymes contained in the shrimp and crab processing by-products have a certain degradation effect on the self-protein system, but they do not reach the degree and requirement of degradation into functional small molecules. The enzymes in the shrimp have a strong dissociation and degradation effect on the crab by-product protein; the enzymes in the crab have excellent effects on the dissociation of astaxanthin, protein dissociation and degradation in the shrimp by-products; and the endogenous enzymes of the two also have a good synergistic increase effect.

[0009] Preferably, the method comprises the following steps: washing, draining and crushing shrimp and crab processing by-products into a semi-dry mixture of processing by-products with particles of different sizes; mixing the semi-dry mixture of shrimp and crab processing by-products at a mass ratio of 9:1 to 7:3, adding distilled water, stirring and mixing, and obtaining a mixed system; and heating the mixed system after ultrasonic treatment under stirring conditions, so that endogenous enzymes in shrimp and crab can perform complementary and synergistic enzymolysis, and extracting to obtain shrimp and crab processing by-product protein powder.

[0010] After draining in step (1), the byproduct is still in a wet state containing a large amount of water, which is beneficial for the enzyme system to maintain stability and exert enzymatic hydrolysis in the later stage.

[0011] Preferably, the endogenous enzymes in the shrimp include trypsin and cathepsin B.

[0012] Preferably, the endogenous enzymes in the crab include serine protease and lipase.

[0013] The enzymes contained in shrimp and crab processing by-products have a certain degradation effect on their own protein system, but they have not yet reached the degree and requirements of degradation into functional small molecules. The trypsin and cathepsin B in shrimp have a strong effect on the dissociation and degradation of crab by-product proteins; the serine protease and lipase in crab have excellent effects on the dissociation of astaxanthin, protein dissociation and degradation in shrimp by-products; and the endogenous trypsin, cathepsin B, serine protease and lipase of the two also have a good synergistic effect.

[0014] Preferably, the shrimp is Chinese tube whip shrimp, and the crab is fine-spotted round-toed crab.

[0015] The content of endogenous enzymes trypsin and cathepsin B in Chinese tube shrimp is relatively high, so they have strong effects on the dissociation and degradation of proteins in the by-products of round-toed crabs; while the content of endogenous enzymes serine protease and lipase in round-toed crabs is relatively high, so they have excellent effects on the dissociation of astaxanthin, protein dissociation and degradation in Chinese tube shrimp; when the processing by-products of Chinese tube shrimp and round-toed crab are used as raw materials, the content of endogenous enzymes is relatively high, the enzymatic hydrolysis efficiency is improved, and these endogenous enzymes also have a good synergistic effect.

[0016] Preferably, the particle size of the semi-dry mixture of shrimp processing by-products is 0.048-0.075 mm, and the particle size of the semi-dry mixture of crab processing by-products is 0.058-0.080 mm.

[0017] Shrimp and crab contain different enzyme compositions and types. Crushing them into particles of different sizes is beneficial to the release of various enzymes in shrimp and crab by-products, and to better exert enzymatic effects in the later stage.

[0018] Preferably, the mass of the added distilled water is 12-18% (w / w) of the total mass of the mixed system.

[0019] Adding a small amount of water is conducive to the degradation effect of enzymes, and the low addition ratio is also conducive to the subsequent drying to obtain the product.

[0020] Preferably, the temperature of the heated mixing system is 42-48° C., the time of heating the mixing system is 60-75 min, and the stirring speed of the mixing system is 50-80 r / min.

[0021] Preferably, the ultrasonic treatment method is low power and frequency ultrasonic treatment.

[0022] Ultrasonic treatment mainly helps dissolve endogenous enzymes in crushed particles (inside cells) into the solution, thereby improving the efficiency of enzymatic hydrolysis.

[0023] In a second aspect, the present invention provides the use of the shrimp and crab processing by-product protein powder in the preparation of aquatic feed or a nutritional additive or nutritional fortifier in the preparation of pet feed.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] (1) The method for preparing the shrimp and crab processing by-product protein powder provided by the present invention has simple process steps, a stable and controllable process, energy saving, high efficiency, and green environmental protection, and can reduce the pollution of shrimp and crab processing by-products to the environment.

[0026] (2) The shrimp and crab processing by-product protein powder provided by the present invention has simple components, good preservation and dispersibility, contains 48-65 g / 100 g crude protein (including 10.5-13.5 g / 100 g carotene protein complex) and 22-38 μg / g astaxanthin, wherein more than 95% of the protein peptides have a molecular weight of <40 KDa, has high nutritional value, is very suitable for promotion and application in feed, and can be used to prepare aquatic feed, or as a nutritional additive or specific nutritional enhancer in pet feed.

[0027] (3) The enzymes contained in the by-products of shrimp and crab processing have a certain degradation effect on their own protein system, but they have not reached the degree and requirements of degradation into functional small molecules. The trypsin and cathepsin B in shrimp have a strong dissociation and degradation effect on the protein of crab by-products; the serine protease and lipase in crab have excellent effects on the dissociation of astaxanthin, protein dissociation and degradation in shrimp by-products; in particular, the content of endogenous enzymes trypsin and cathepsin B in Chinese whip shrimp is relatively high, and the content of endogenous enzymes serine protease and lipase in round-toed crab is relatively high; when the by-products of Chinese whip shrimp processing and round-toed crab processing are used as raw materials, the content of endogenous enzymes is relatively high, the enzymatic hydrolysis efficiency is improved, and they have a good synergistic effect. The present invention makes full use of the synergistic enzymatic hydrolysis of the two, and can achieve the degradation of functional molecules without adding exogenous enzymes.

[0028] (4) The present invention has a wide range of applications and low cost, and can achieve effective utilization of shrimp and crab processing by-products, reduce resource waste, and provide a practical basis for enterprises to achieve resource utilization of shrimp and crab processing by-products, which is conducive to further improving the economic value of shrimp and crabs. DETAILED DESCRIPTION

[0029] The present invention is further described below with reference to the embodiments, but is not intended to be limiting of the present invention.

[0030] Overall embodiment

[0031] A method for preparing shrimp and crab processing byproduct protein powder comprises the following steps: crushing shrimp and crab processing byproducts and mixing them evenly, allowing endogenous enzymes in the shrimp and crab to interact with each other, and extracting the shrimp and crab processing byproduct protein powder.

[0032] Preferably, the method comprises the following steps: washing, draining and crushing shrimp and crab processing by-products into a semi-dry mixture of processing by-products with particles of different sizes; mixing the semi-dry mixture of shrimp and crab processing by-products at a mass ratio of 9:1 to 7:3, adding distilled water, stirring and mixing, and obtaining a mixed system; and heating the mixed system after ultrasonic treatment under stirring conditions, so that endogenous enzymes in shrimp and crab can perform complementary and synergistic enzymolysis, and extracting to obtain shrimp and crab processing by-product protein powder.

[0033] Preferably, the endogenous enzymes in the shrimp include trypsin and cathepsin B.

[0034] Preferably, the endogenous enzymes in the crab include serine protease and lipase.

[0035] Preferably, the shrimp is Chinese tube whip shrimp, and the crab is fine-spotted round-toed crab.

[0036] Preferably, the particle size of the semi-dry mixture of shrimp processing by-products is 0.048-0.075 mm, and the particle size of the semi-dry mixture of crab processing by-products is 0.058-0.080 mm.

[0037] Preferably, the mass of the added distilled water is 12-18% (w / w) of the total mass of the mixed system.

[0038] Preferably, the temperature of the heated mixing system is 42-48° C., the time of heating the mixing system is 60-75 min, and the stirring speed of the mixing system is 50-80 r / min.

[0039] Preferably, the ultrasonic treatment method is low power and frequency ultrasonic treatment.

[0040] The shrimp and crab processing by-product protein powder is used in preparing aquatic feed or preparing nutritional additives or nutritional enhancers in pet feed.

[0041] Example 1

[0042] (1) The byproducts of the processing of Chinese whip shrimp and the byproducts of the processing of round crab are simply rinsed to remove impurities such as mud and sand, and then simply drained and kept for 5 minutes; then they are ultrafinely ground to prepare a semi-dry mixture of shrimp processing byproducts with a particle size of 0.048 mm and a semi-dry mixture of crab processing byproducts with a particle size of 0.080 mm;

[0043] (2) mixing the above-mentioned semi-dry mixture of shrimp and crab processing byproducts at a weight ratio (wet weight) of 9:1, adding 12% (w / w) distilled water based on the total mass of the mixed system, and stirring to mix thoroughly;

[0044] (3) The above mixed system was subjected to ultrasonic treatment at a power of 120 W and a frequency of 20 kHz for 5 min while maintaining a stirring speed of 80 r / min; the ultrasonic treatment was stopped, and the mixed system was heated to 45° C. for 60 min while maintaining a stirring speed of 60 r / min to perform complementary and synergistic enzymolysis of endogenous enzymes in shrimps and crabs;

[0045] (4) After the enzymatic hydrolysis is completed, the mixed system is filtered at 0.40 mm to obtain a filtrate and a filter residue, which are then dried at 60° C. to obtain a dried filtrate and a dried filter residue. The dried filtrate contains 55.5 g / 100 g crude protein (of which 11.5 g / 100 g is carotene-protein complex) and 32 μg / g astaxanthin, and more than 95% of the protein peptides have a molecular weight of <40 KDa, and have high nutritional value, and can be used as a nutritional supplement for pet feed or a specific nutritional enhancer.

[0046] Comparative Example 1

[0047] (1) The byproducts of Chinese whip shrimp processing were simply rinsed to remove impurities such as mud and sand, and then simply drained and kept for 5 minutes; and then ultrafinely crushed to prepare a semi-dry mixture of shrimp processing byproducts with a particle size of 0.048 mm;

[0048] (2) adding 12% (w / w) distilled water to the above crushed shrimp processing byproducts, and stirring to mix thoroughly;

[0049] (3) The above mixed system was subjected to ultrasonic treatment at a power of 120 W and a frequency of 20 kHz for 5 min while maintaining a stirring speed of 80 r / min; the ultrasonic treatment was stopped, and the mixed system was heated to 45° C. for 60 min while maintaining a stirring speed of 60 r / min to hydrolyze the endogenous enzymes in the shrimp;

[0050] (4) After the enzymatic hydrolysis is completed, the mixed system is filtered at 0.40 mm to obtain a filtrate and a filter residue, which are then dried at 60° C. to obtain a filtrate dry product and a filter residue dry product. The filtrate dry product contains 8.5 g / 100 g crude protein (including 1.3 g / 100 g carotene-protein complex) and 6.5 μg / g astaxanthin.

[0051] Comparative Example 1 shows that when the raw materials used are only the byproducts of the processing of Chinese tube whip shrimp, compared with the mixed synergistic enzymatic hydrolysis of shrimp and crab processing byproducts, the molecular weight of the protein peptide in the filtrate dry product is larger, and the content of easily absorbed nutrients contained in the filtrate dry product is lower. Based on theoretical research and experiments, the team of the present invention found that the enzymes contained in the byproducts of shrimp and crab processing have a certain degradation effect on their own protein system, but they have not yet reached the degree and requirements of degradation into functional small molecules, while the trypsin and cathepsin B in the Chinese tube whip shrimp have a strong dissociation and degradation effect on the protein of the byproduct of the fine-pointed round toe crab; the serine protease and lipase in the fine-pointed round toe crab have excellent effects on the dissociation of astaxanthin in the Chinese tube whip shrimp, protein dissociation and degradation; the endogenous trypsin, cathepsin B, serine protease, and lipase of the two also have a good synergistic increase. The present application makes full use of the synergistic enzymatic hydrolysis of the two, and the degradation of functional molecules can be achieved without adding exogenous enzymes.

[0052] Comparative Example 2

[0053] (1) The byproducts of the processing of the round-toed crab are simply rinsed to remove impurities such as mud and sand, and then simply drained and kept for 5 minutes; then they are ultrafinely crushed to prepare a semi-dry mixture of the byproducts of the processing of the crab with a particle size of 0.080 mm;

[0054] (2) Add 12% (w / w) distilled water to the above crushed semi-dry mixture of crab processing byproducts, based on the total mass of the mixed system, and stir to mix thoroughly;

[0055] (3) The above mixed system was subjected to ultrasonic treatment at a power of 120 W and a frequency of 20 kHz for 5 min while maintaining a stirring speed of 80 r / min; the ultrasonic treatment was stopped, and the mixed system was heated to 45° C. for 60 min while maintaining a stirring speed of 60 r / min for enzymatic hydrolysis of endogenous enzymes in crabs;

[0056] (4) After the enzymatic hydrolysis is completed, the mixed system is filtered at 0.40 mm to obtain a filtrate and a filter residue, which are then dried at 60° C. to obtain a filtrate dry product and a filter residue dry product. The filtrate dry product contains 4.5 g / 100 g crude protein (including 1.3 g / 100 g carotene-protein complex) and 1.9 μg / g astaxanthin.

[0057] Comparing Example 1, it can be seen that when the raw materials used are only the byproducts of the processing of round-toed crabs, compared with the mixed synergistic enzymatic hydrolysis of shrimp and crab processing byproducts, the molecular weight of the protein peptides in the filtrate dry product is larger, and the content of easily absorbed nutrients contained in the filtrate dry product is lower. Based on theoretical research and experiments, the team of the present invention found that the various enzymes contained in the byproducts of shrimp and crab processing have a certain degradation effect on their own protein system, but they have not yet reached the degree and requirements of degradation into functional small molecules, while the trypsin and cathepsin B in the Chinese tube whip shrimp have a strong dissociation and degradation effect on the protein of the byproducts of round-toed crabs; the serine protease and lipase in the round-toed crab have excellent effects on the dissociation of astaxanthin, protein dissociation and degradation in the Chinese tube whip shrimp; the endogenous trypsin, cathepsin B, serine protease, and lipase of the two also have a good synergistic increase. The present application makes full use of the synergistic enzymatic hydrolysis of the two, and the degradation of functional molecules can be achieved without adding exogenous enzymes.

[0058] Comparative Example 3

[0059] (1) simply rinsing the byproducts of whiteleg shrimp processing and the byproducts of round-toed crab processing to remove impurities such as mud and sand, and then simply draining and keeping for 5 minutes; then ultrafine grinding them respectively to prepare a semi-dry mixture of whiteleg shrimp processing byproducts with a particle size of 0.048 mm and a semi-dry mixture of crab processing byproducts with a particle size of 0.080 mm;

[0060] (2) mixing the above-mentioned semi-dry mixture of shrimp and crab processing byproducts at a weight ratio (wet weight) of 9:1, adding 12% (w / w) distilled water based on the total mass of the mixed system, and stirring to mix thoroughly;

[0061] (3) The above mixed system was subjected to ultrasonic treatment at a power of 120 W and a frequency of 20 kHz for 5 min while maintaining a stirring speed of 80 r / min; the ultrasonic treatment was stopped, and the mixed system was heated to 45° C. for 60 min while the stirring speed of the mixed system was 60 r / min to perform complementary synergistic enzymolysis of endogenous enzymes in white shrimp and round-toed crab;

[0062] (4) After the enzymatic hydrolysis is completed, the mixed system is filtered at 0.40 mm to obtain a filtrate and a filter residue, which are then dried at 60° C. to obtain a dried filtrate and a dried filter residue. The dried filtrate contains 22.3 g / 100 g crude protein (of which 6.5 g / 100 g carotene-protein complex) and 21.2 μg / g astaxanthin, and more than 70% of the protein peptides have a molecular weight of <40 KDa.

[0063] Comparative Example 1 shows that when the raw materials used are byproducts of white shrimp and round-toed crab processing, the effect of the mixed synergistic enzymatic treatment of the two is not good. The molecular weight of the protein peptide in the filtrate dried product of Comparative Example 3 is relatively large, and the content of easily absorbed nutrients contained in the filtrate dried product is relatively low. Based on theoretical research and experiments, the team of the present invention found that the serine protease and lipase in the round-toed crab have the effects of astaxanthin dissociation, protein dissociation and degradation in the Chinese whip shrimp. Although the types of enzymes in the Chinese whip shrimp and the white shrimp are roughly the same, the activity size, specific activity and content of trypsin and cathepsin-like enzymes in the two are significantly different. Therefore, the dissociation and degradation of the protein of the round-toed crab byproduct by the white shrimp is weakened, which also directly affects the complementary and synergistic enzymatic hydrolysis effect between the enzyme systems in the white shrimp and the round-toed crab in the later stage.

[0064] Comparative Example 4

[0065] (1) The byproducts of the processing of Chinese whip shrimp and the byproducts of the processing of round crab are simply rinsed to remove impurities such as mud and sand, and then simply drained and kept for 5 minutes; then they are ultrafinely ground to prepare a semi-dry mixture of shrimp processing byproducts with a particle size of 0.048 mm and a semi-dry mixture of crab processing byproducts with a particle size of 0.080 mm;

[0066] (2) mixing the above-mentioned semi-dry mixture of shrimp and crab processing byproducts at a weight ratio (wet weight) of 9:1, adding 12% (w / w) distilled water based on the total mass of the mixed system, and stirring to mix thoroughly;

[0067] (3) The above mixed system was kept stirred at a speed of 80 r / min for 5 min; then the mixed system was heated to 45° C. and kept stirred at a speed of 60 r / min for 60 min to perform complementary synergistic enzymolysis of endogenous enzymes in shrimps and crabs;

[0068] (4) After the enzymatic hydrolysis is completed, the mixed system is filtered at 0.40 mm to obtain a filtrate and a filter residue, which are then dried at 60° C. to obtain a dried filtrate and a dried filter residue. The dried filtrate contains 34.5 g / 100 g crude protein (of which 8.2 g / 100 g is carotene-protein complex) and 23 μg / g astaxanthin, and more than 83% of the protein peptides have a molecular weight of <40 KDa.

[0069] Compared with Example 1, it can be seen that when the mixed system is not subjected to ultrasonic treatment, the molecular weight of the protein peptide in the dried filtrate is relatively large, and the content of easily absorbed nutrients contained in the dried filtrate is relatively low. Based on theoretical research and experiments, the present invention team found that ultrasonic treatment can improve the efficiency of enzymatic hydrolysis by assisting the dissolution of endogenous enzymes in crushed particles (intracellular) into the solution.

[0070] The raw materials and equipment used in the present invention, unless otherwise specified, are all commonly used raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are all conventional methods in the art.

[0071] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing protein powder from shrimp and crab processing byproducts, characterized in that: The following steps are involved: The shrimp and crab processing byproducts are cleaned, drained and crushed to form a semi-dry mixture of processing byproducts with different sizes of particles; the semi-dry mixture of shrimp and crab processing byproducts is mixed in a mass ratio of 9:1 to 7:3, and distilled water is added, and the mixture is stirred to obtain a mixed system; the mixed system is ultrasonically treated under stirring conditions and then heated to allow endogenous enzymes in the shrimp and crab to perform complementary and synergistic enzymolysis, and then extracted to obtain shrimp and crab processing byproduct protein powder, wherein the endogenous enzymes in the shrimp include trypsin and cathepsin B, and the endogenous enzymes in the crab include serine protease and lipase, the shrimp is a Chinese whip shrimp, and the crab is a fine-pointed round-toed crab.

2. The preparation method according to claim 1, characterized in that: The particle size of the semi-dry mixture of shrimp processing by-products is 0.048-0.075 mm.

3. The preparation method according to claim 1, characterized in that: The particle size of the semi-dry mixture of crab processing by-products is 0.058-0.080 mm.

4. The preparation method according to claim 1, characterized in that: The mass of the added distilled water is 12-18% (w / w) of the total mass of the mixed system.

5. The preparation method according to claim 1, characterized in that: The temperature of the heated mixing system is 42-48°C.

6. The preparation method according to claim 1, characterized in that: The time for heating the mixing system is 60 to 75 minutes.

7. The preparation method according to claim 1, characterized in that: The stirring speed of the mixing system is 50-80 r / min.

8. The preparation method according to claim 1, characterized in that: The ultrasonic treatment method is ultrasonic treatment with low power and frequency.

9. An application of shrimp and crab processing byproduct protein powder obtained according to the preparation method of claim 1, characterized in that: The shrimp and crab processing byproduct protein powder prepared by the preparation method of claim 1 is used in the preparation of aquatic feed or a nutritional additive or nutritional enhancer in pet feed.