Shrimp head polypeptide gel composition as well as preparation method and application thereof

Abstract

The invention relates to the technical field of solid waste treatment, in particular to a shrimp head polypeptide gel composition as well as a preparation method and application thereof. The invention provides application of a shrimp head polypeptide gel composition in promoting feeding of blue crabs and / or promoting unshelling growth of the blue crabs. The preparation method of the shrimp head polypeptide gel composition comprises the following steps: (1) mincing shrimp heads, adding water to carry out autolysis enzymolysis, filtering to obtain shrimp peptide liquid, and concentrating the shrimp peptide liquid into paste to obtain shrimp peptide paste; (2) chopping and mixing fish meat into minced fillet, adding table salt, glutamine transaminase and monosodium glutamate into the minced fillet, and chopping, mixing and blending to obtain a gel minced fillet matrix; and (3) adding the shrimp peptide paste and auxiliary materials into the gel minced fillet matrix, chopping, mixing and blending to obtain a mixture, and cooking, cooling and molding the mixture. The prepared shrimp head polypeptide gel composition can effectively embed shrimp head peptides and auxiliary materials with high water solubility, and the protein content is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid waste treatment, in particular to a shrimp head polypeptide gel composition and a preparation method and application thereof. BACKGROUND

[0002] Shrimp head is a solid by-product in the process of shrimp processing, accounting for 25-33% of the total weight of a whole shrimp, and is rich in nutrients, containing 10-15% (fresh weight) of crude protein, 2.5-5.5% (fresh weight) of crude fat, astaxanthin and various mineral elements, and has great development and utilization value.

[0003] Shrimp head contains many endogenous enzymes, which can autolyze at a suitable temperature, thereby hydrolyzing the crude protein contained in the shrimp head into polypeptide substances and dissolving the contents in water. Shrimp head polypeptide has rich biological activities (antioxidation, anti-inflammatory, immune enhancement, growth promotion, etc.) and strong digestibility and absorption, but at the same time, it has strong water solubility and is easily dissolved in water in aquaculture, causing water pollution and eutrophication and leading to the death of cultured organisms. At present, polypeptides are more commonly used in land-based farming (not easily dissolved), such as the technology disclosed in CN105961842A; the application of polypeptides in aquaculture is less common, and most of them exist in the form of small-dose additives to avoid the dissolution of polypeptides, such as the technologies disclosed in CN119423215A and CN119366587A. There are still technical difficulties in large-scale application of polypeptides in aquaculture.

[0004] Therefore, it is particularly urgent to develop a gel composition made of shrimp head polypeptide and applied in aquaculture. SUMMARY

[0005] The present application uses shrimp head autolysis to extract shrimp head polypeptide, cross-links gel by mixing polypeptide and auxiliary materials with surimi, and better embeds polypeptide with strong water solubility, thereby preparing a gel composition with high protein content, good texture, no water turbidity, high content of shrimp head polypeptide, and promoting the feeding and growth and molting of blue crab.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions: In one aspect, the present application provides the application of shrimp head polypeptide gel composition in promoting the feeding and / or molting and growth of blue crab, and the preparation method of the shrimp head polypeptide gel composition comprises the following steps: (1) Preparation of shrimp peptide paste: grind the shrimp head, perform autolysis enzymolysis by adding water, filter to obtain shrimp peptide liquid, and concentrate the shrimp peptide liquid into paste to obtain shrimp peptide paste; (2) Preparation of gelatinous surimi matrix: chop the fish meat into surimi, add salt, glutamine transaminase and monosodium glutamate to the surimi for chopping and pounding to obtain a gelatinous surimi matrix; (3) Mixing and gel forming: The shrimp peptide paste and excipients obtained in step (1) are added to the gelled fish paste matrix obtained in step (2), and then chopped and crushed to obtain a mixture. The mixture is then steamed and cooled to form a gel.

[0007] In this invention, the concentration is achieved by boiling and concentrating the shrimp peptide liquid until it reaches a creamy, stringy paste-like state.

[0008] It should be noted that aquaculture needs to consider the pollution of water quality and feed stability issues caused by shrimp head peptides. If shrimp head peptides are made into a gel composition and added to the aquaculture water, they will dissolve directly, polluting the aquatic environment, causing aquatic death, and leading to eutrophication. This invention uses a method of autolysis and concentration to form a silky, stringy shrimp peptide paste. Simultaneously, this invention mixes shrimp head paste, fish paste, and other auxiliary materials into a gel composition, which alleviates the problem of shrimp head peptides dissolving in water, thus solving both the water solubility issue and the water pollution problem.

[0009] On the other hand, the present invention provides the application of a shrimp head polypeptide gel composition in the preparation of products for reducing pollution in aquaculture water and / or improving water quality, wherein the preparation method of the shrimp head polypeptide gel composition includes the following steps: (1) Preparation of shrimp peptide paste: mince the shrimp head, add water for autolytic enzymatic hydrolysis, filter to obtain shrimp peptide liquid, concentrate the shrimp peptide liquid into paste to obtain shrimp peptide paste. (2) Preparation of gel-type fish paste matrix: Fish meat is chopped into fish paste, salt, transglutaminase and monosodium glutamate are added to the fish paste and chopped and crushed to obtain gel-type fish paste matrix; (3) Mixing and gel forming: The shrimp peptide paste and excipients obtained in step (1) are added to the gelled fish paste matrix obtained in step (2), and then chopped and crushed to obtain a mixture. The mixture is then steamed and cooled to form a gel.

[0010] On the other hand, the present invention provides a method for preparing a shrimp head polypeptide gel composition, the preparation method comprising the following steps: (1) Preparation of shrimp peptide paste: mince the shrimp head, add water for autolytic enzymatic hydrolysis, filter to obtain shrimp peptide liquid, concentrate the shrimp peptide liquid into paste to obtain shrimp peptide paste. (2) Preparation of gel-type fish paste matrix: Fish meat is chopped into fish paste, salt, transglutaminase and monosodium glutamate are added to the fish paste and chopped and crushed to obtain gel-type fish paste matrix; (3) Mixing and gel forming: The shrimp peptide paste and excipients obtained in step (1) are added to the gelled fish paste matrix obtained in step (2), and then chopped and crushed to obtain a mixture. The mixture is then steamed and cooled to form a gel.

[0011] Preferably, in step (1), the conditions for autolytic enzymatic hydrolysis are: the ratio of shrimp head to water is 1:1 (g:mL), the enzymatic hydrolysis temperature is 40-55℃, and the enzymatic hydrolysis time is 1-5h.

[0012] Preferably, the amount of salt added is 1-3% of the weight of the fish paste, the amount of transglutaminase added is 0.1-0.5% of the weight of the fish paste, and the amount of monosodium glutamate added is 0.05-0.5% of the weight of the fish paste.

[0013] Preferably, the excipients include soybean meal, starch, fish oil microcapsule powder, multivitamins and minerals, antioxidants, sodium diacetate and betaine; The amount of soybean meal added is 10-20% of the weight of the shrimp head polypeptide gel composition; the amount of starch added is 5-10% of the weight of the shrimp head polypeptide gel composition; the amount of fish oil microcapsule powder added is 1-2% of the weight of the shrimp head polypeptide gel composition; the amount of multivitamins and minerals added is 1-2% of the weight of the shrimp head polypeptide gel composition; the amount of antioxidant added is 0.01-0.05% of the weight of the shrimp head polypeptide gel composition; the amount of sodium diacetate added is 0.01-0.1% of the weight of the shrimp head polypeptide gel composition; and the amount of betaine added is 0.01-0.5% of the weight of the shrimp head polypeptide gel composition.

[0014] Preferably, the chopping time in steps (2) and (3) is 3-7 minutes.

[0015] Preferably, the cooking temperature of the mixture is 70-100℃ and the cooking time is 5-20 minutes.

[0016] The invention also provides the application of the preparation method described herein in increasing the protein content in shrimp head polypeptide gel compositions.

[0017] The invention also provides the application of the preparation method described in this invention in the embedding of shrimp head peptides.

[0018] On the other hand, the present invention provides a shrimp head polypeptide gel composition, wherein the shrimp head polypeptide gel composition comprises a gelled fish paste matrix, shrimp peptide paste, soybean meal (CP Feed), starch (Guangdong Jianda Biotechnology Co., Ltd.), fish oil microcapsule powder (Zhejiang Tianhecheng Biotechnology Co., Ltd.), multivitamins and minerals (Vino Zhongyang Co., Ltd.), antioxidants, sodium diacetate, and betaine; wherein; The amount of the gelled fish paste matrix added is 30-50% of the weight of the shrimp head polypeptide gel composition; the amount of the shrimp peptide paste added is 20-40% of the weight of the shrimp head polypeptide gel composition; the amount of the soybean meal added is 10-20% of the weight of the shrimp head polypeptide gel composition; the amount of the starch added is 5-10% of the weight of the shrimp head polypeptide gel composition; the amount of the fish oil microcapsule powder added is 1-2% of the weight of the shrimp head polypeptide gel composition; the amount of the multivitamin and multimineral added is 1-2% of the weight of the shrimp head polypeptide gel composition; the amount of the antioxidant added is 0.01-0.05% of the weight of the shrimp head polypeptide gel composition; the amount of sodium diacetate added is 0.01-0.1% of the weight of the shrimp head polypeptide gel composition; and the amount of betaine added is 0.01-0.5% of the weight of the shrimp head polypeptide gel composition.

[0019] On the other hand, the present invention provides the application of the shrimp head polypeptide gel composition in mud crab farming.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention makes full use of shrimp heads, extracts shrimp head polypeptides and astaxanthin from shrimp heads through autolysis, and then boils and concentrates them for use in mud crab farming. While replacing fish meal, it is beneficial to the high-value utilization of shrimp heads and the production of mud crab farming products.

[0021] (2) The present invention uses fish meat, combined with salt and Tg enzyme for chopping, and then mixes auxiliary materials and shrimp peptide paste for chopping, heating and cooling to successfully gel. The texture is good and does not become cloudy. It can effectively lock the shrimp peptide with strong water solubility and good activity in the shrimp head polypeptide gel composition, so that shrimp protein peptide (shrimp peptide) can be successfully applied to the mud crab farming as one of the main ingredients.

[0022] (3) The shrimp head polypeptide gel composition prepared by the present invention has a high protein content, with crude protein content accounting for 21.64±1.69% of the wet weight, and is rich in nutrients, and contains fish protein, shrimp polypeptide, astaxanthin and other nutrients; the shrimp peptide paste prepared has a high protein content, with crude protein content accounting for 30.08±0.62% of the wet weight.

[0023] (4) The shrimp head polypeptide gel composition can simulate the shellfish meat in nature and sink naturally in the water, which is conducive to the feeding of benthic mud crabs. At the same time, it can maintain its shape for a long time in the water. Even if the mud crab bites it, it will not cause the shrimp head polypeptide gel composition to fall apart or make the water murky. It has good shape retention. At the same time, the mud crab can easily hug and gnaw on the shrimp head polypeptide gel composition or hold it and pinch it into small portions to eat, which has a good feeding effect.

[0024] (5) The shrimp head polypeptide gel composition made with shrimp head polypeptide can promote the molting and growth of blue crabs. Attached Figure Description

[0025] Figure 1 The images show the formed state of the shrimp head polypeptide gel composition in Examples 1-7.

[0026] Figure 2 Example 5 shows the finished shrimp head polypeptide gel composition.

[0027] Figure 3 The images show the turbidity of the shrimp head polypeptide gel composition in water. A represents the state of the shrimp head polypeptide gel composition in Example 1 after being kneaded and squeezed in water. B represents the state of the shrimp head polypeptide gel composition in Example 5 after being kneaded and squeezed in water. C represents the state of the shrimp head polypeptide gel composition in Example 5 after being left to stand in water for 10 minutes.

[0028] Figure 4 This image shows a blue crab feeding on a polypeptide gel composition containing shrimp heads that have sunk to the bottom.

[0029] Figure 5 The effects of feeding blue crabs with shrimp head polypeptide gel composition, commercial feed, and shellfish in a recirculating aquaculture system for two weeks on water quality. Detailed Implementation

[0030] The technical solution of the present invention will be described below with reference to embodiments. However, the present invention is not limited to the following embodiments. Unless otherwise specified, the experimental methods and detection methods described in each embodiment are conventional methods; unless otherwise specified, the reagents and materials can be purchased commercially.

[0031] Example 1 This embodiment provides a method for preparing a shrimp head polypeptide gel composition (hereinafter referred to as Control) containing sodium alginate, dried shrimp peptide powder, and 30% fish paste, including the following steps: S1. Mince the shrimp heads, add water, with a material-to-liquid ratio of 1:1 (g:mL), autodissolve in a water bath at 55℃ for 3 hours, and filter to obtain shrimp peptide solution; S2. Shrimp peptide liquid is freeze-dried into powder to obtain dried shrimp peptide powder; S3. Remove the bones and skin from the fish, then chop and mince the meat into a paste. Chopping time: 5 minutes. S4. Add 2% salt by weight of the fish to the fish paste, chop and mix for 5 minutes to crush it; S5. Based on the total weight percentage of the shrimp head polypeptide gel composition, the following amounts of each substance were added: 30% fish paste, 25% dried shrimp peptide powder, 14% soybean meal, 10% starch, 1.5% lecithin, 1.5% fish oil microcapsule powder, 2% sodium alginate, 2% multivitamins and minerals, 0.5% choline chloride, 0.1% molting agent, and 1.8% ice. Continue chopping for 5 minutes to mix evenly and then pound. S6. The mixture is placed in a water bath at 90°C for 5 minutes and then cooled and molded.

[0032] Example 2 This embodiment provides a method for preparing a shrimp head polypeptide gel composition (QZ1) containing agar powder, shrimp peptide paste, and 30% fish paste, including the following steps: S1. Mince the shrimp heads, add water, with a material-to-liquid ratio of 1:1 (g:mL), autodissolve in a water bath at 55℃ for 3 hours, and filter to obtain shrimp peptide solution; S2. Shrimp peptide liquid is boiled and concentrated until it becomes a silky, thread-like paste to obtain shrimp peptide paste. S3. Remove the bones and skin from the fish, then mince the meat into a paste. Mince for 5 minutes. S4. Add 2% salt and 0.1% MSG by weight of the fish paste to the fish paste, and continue chopping and mixing for 5 minutes; S5. Based on the total weight percentage of the shrimp head polypeptide gel composition, the added amounts of each substance are as follows: fish paste 30%, shrimp peptide paste 36.35%, soybean meal 20%, starch 10%, agar powder 2%, multivitamins and minerals 1.5%, fish oil microcapsule powder 1.5%, antioxidant (containing ethoxyquinoline and butylated hydroxytoluene, Weifang Jiayijia Biotechnology Co., Ltd.) 0.02%, sodium diacetate 0.05%, betaine 0.05%; continue chopping for 5 minutes, mix evenly and pound thoroughly; S6. The mixture is placed in a water bath at 90°C for 5 minutes and then cooled and molded.

[0033] Example 3 This embodiment provides a method for preparing a shrimp head polypeptide gel composition (QZ2) containing agar powder, shrimp peptide paste, and 40% fish paste, including the following steps: S1. Mince the shrimp heads, add water, with a material-to-liquid ratio of 1:1 (g:mL), autodissolve in a water bath at 55℃ for 3 hours, and filter to obtain shrimp peptide solution; S2. Shrimp peptide liquid is boiled and concentrated until it becomes a silky, thread-like paste to obtain shrimp peptide paste. S3. Remove the bones and skin from the fish, then mince the meat into a paste. Mince for 5 minutes. S4. Add 2% salt and 0.1% MSG by weight of the fish to the fish paste, and continue chopping and mixing for 5 minutes; S5. Based on the total weight percentage of the shrimp head polypeptide gel composition, the added amounts of each substance are as follows: fish paste 40%, shrimp peptide paste 26.38%, soybean meal 20%, starch 10%, agar powder 2%, multivitamins and minerals 1.5%, fish oil microcapsule powder 1.5%, antioxidant (containing ethoxyquinoline and butylated hydroxytoluene, Weifang Jiayijia Biotechnology Co., Ltd.) 0.02%, sodium diacetate 0.05%, and betaine 0.05%. Continue chopping and mixing for 5 minutes until evenly combined and mashed. S6. The mixture is placed in a water bath at 90°C for 5 minutes and then cooled and molded.

[0034] Example 4 This embodiment provides a method for preparing a shrimp head polypeptide gel composition (Tg1) with added Tg enzyme (transglutaminase) and 30% fish paste, including the following steps: S1. Mince the shrimp heads, add water, with a material-to-liquid ratio of 1:1 (g:mL), autodissolve in a water bath at 55℃ for 3 hours, and filter to obtain shrimp peptide solution; S2. Shrimp peptide liquid is boiled and concentrated until it becomes a silky, thread-like paste to obtain shrimp peptide paste. S3. Remove the bones and skin from the fish, then mince the meat into a paste. Mince for 5 minutes. S4. Add 2% salt, 0.1% MSG, and 0.2% Tg enzyme by weight of the fish paste to the fish paste, and continue chopping and mixing for 5 minutes. S5. Based on the total weight percentage of the shrimp head polypeptide gel composition, the added amounts of each substance are as follows: fish paste 30%, shrimp peptide paste 38.38%, soybean meal 20%, starch 10%, multivitamins and minerals 1.5%, fish oil microcapsule powder 1.5%, antioxidant (containing ethoxyquinoline and butylated hydroxytoluene, Weifang Jiayijia Biotechnology Co., Ltd.) 0.02%, sodium diacetate 0.05%, betaine 0.05%; continue chopping for 5 minutes, mix evenly and pound thoroughly; S6. The mixture is placed in a water bath at 90°C for 5 minutes and then cooled and molded.

[0035] Example 5 This embodiment provides a method for preparing a shrimp head polypeptide gel composition (hereinafter referred to as Tg2) with added Tg enzyme and 40% fish paste, including the following steps: S1. Mince the shrimp heads, add water, with a material-to-liquid ratio of 1:1 (g:mL), autodissolve in a water bath at 55℃ for 3 hours, and filter to obtain shrimp peptide solution; S2. Shrimp peptide liquid is boiled and concentrated until it becomes a silky, thread-like paste to obtain shrimp peptide paste. S3. Remove the bones and skin from the fish, then mince the meat into a paste. Mince for 5 minutes. S4. Add 2% salt, 0.2% Tg enzyme, and 0.1% MSG by weight of the fish paste to the fish paste, and continue chopping and mixing for 5 minutes; S5. Based on the total weight percentage of the shrimp head polypeptide gel composition, the added amounts of each substance are as follows: fish paste 40%, shrimp peptide paste 28.38%, soybean meal 20%, starch 10%, multivitamins and minerals 1.5%, fish oil microcapsule powder 1.5%, antioxidant (containing ethoxyquinoline and butylated hydroxytoluene, Weifang Jiayijia Biotechnology Co., Ltd.) 0.02%, sodium diacetate 0.05%, betaine 0.05%; continue chopping for 5 minutes, mix evenly and pound.

[0036] S6. The mixture is placed in a water bath at 90°C for 5 minutes and then cooled and molded.

[0037] Example 6 This embodiment provides a method for preparing a shrimp head polypeptide gel composition (TQ1) with added Tg enzyme, agar powder, and 30% fish paste, including the following steps: S1. Mince the shrimp heads, add water, with a material-to-liquid ratio of 1:1 (g:mL), autodissolve in a water bath at 55℃ for 3 hours, and filter to obtain shrimp peptide solution; S2. Shrimp peptide liquid is boiled and concentrated until it becomes a silky, thread-like paste to obtain shrimp peptide paste. S3. Remove the bones and skin from the fish, then mince the meat into a paste. Mince for 5 minutes. S4. Add 2% salt, 0.2% Tg enzyme, and 0.1% MSG by weight of the fish paste to the fish paste, and continue chopping and mixing for 5 minutes; S5. Based on the total weight percentage of the shrimp head polypeptide gel composition, the added amounts of each substance are as follows: 30% fish paste, 36.38% shrimp peptide paste, 20% soybean meal, 10% starch, 2% agar powder, 1.5% multivitamins and minerals, 1.5% fish oil microcapsule powder, 0.02% antioxidant (containing ethoxyquinoline and butylated hydroxytoluene, Weifang Jiayijia Biotechnology Co., Ltd.), 0.05% sodium diacetate, and 0.05% betaine; continue chopping for 5 minutes to mix evenly and then pound.

[0038] S6. The mixture is placed in a water bath at 90°C for 5 minutes and then cooled and molded.

[0039] Example 7 This embodiment provides a method for preparing a shrimp head polypeptide gel composition (TQ2) with added Tg enzyme, agar powder, and 40% fish paste, including the following steps: S1. Mince the shrimp heads, add water, with a material-to-liquid ratio of 1:1 (g:mL), autodissolve in a water bath at 55℃ for 3 hours, and filter to obtain shrimp peptide solution; S2. Shrimp peptide liquid is boiled and concentrated until it becomes a silky, thread-like paste to obtain shrimp peptide paste. S3. Remove the bones and skin from the fish, then mince the meat into a paste. Mince for 5 minutes. S4. Add 2% salt, 0.2% Tg enzyme, and 0.1% MSG by weight of the fish paste to the fish paste, and continue chopping and mixing for 5 minutes; S5. Based on the total weight percentage of the shrimp head polypeptide gel composition, the added amounts of each substance are as follows: fish paste 40%, shrimp peptide paste 26.38%, soybean meal 20%, starch 10%, agar powder 2%, multivitamins and minerals 1.5%, fish oil microcapsule powder 1.5%, antioxidant (containing ethoxyquinoline and butylated hydroxytoluene, Weifang Jiayijia Biotechnology Co., Ltd.) 0.02%, sodium diacetate 0.05%, betaine 0.05%; continue chopping for 5 minutes, mix evenly and pound thoroughly; S6. The mixture is placed in a water bath at 90°C for 5 minutes and then cooled and molded.

[0040] Effect Verification (Examples 1-7: Physicochemical Properties of Shrimp Head Polypeptide Gel Composition and Feeding Effect on Blue Crabs) 1. The shape and texture of the shrimp head polypeptide gel composition: such as Figure 1 As shown, the Control composition made with dried shrimp peptide powder, without the addition of Tg enzyme and agar powder, and 40% fish paste, exhibited poor gelation and microgel properties. This was because the use of shrimp peptide powder without the addition of Tg enzyme resulted in poor gelation and insufficient cross-linking of the shrimp head polypeptide gel composition. The excessive powder content in the shrimp head polypeptide gel composition also affected gel formation. The Tg composition with Tg enzyme alone, without agar, showed the best gelation effect, followed by the QZ group with agar but no Tg enzyme. The TQ group with both Tg enzyme and agar showed the worst effect. Furthermore, the shrimp head polypeptide gel composition with 40% fish paste showed better gelation and gelation effect than the 30% fish paste composition. Therefore, the shrimp head polypeptide gel composition Tg2 prepared in Example 5 exhibited the best gelation degree, with a firmer and more elastic texture. Figure 2 As shown, adding Tg enzyme to fish paste can improve the texture and elasticity of the shrimp head polypeptide gel composition by catalyzing reactions such as intermolecular / internal cross-linking of proteins and the linkage between proteins and amino acids. Therefore, using 40% fish paste, combined with 0.2% Tg enzyme, 2% salt, and 28.38% shrimp peptide paste, after chopping and mixing, and then heating in a water bath at 90℃ for 5 minutes, a gel can be formed well. This effectively encapsulates the 28.38% shrimp peptide paste and other excipients, resulting in a good texture that is not easily disintegrated.

[0041] 2. Turbidity of the shrimp head polypeptide gel composition: such as Figure 3 As shown in Figure C, when the shrimp head polypeptide gel composition Tg2 prepared in Example 5 was placed in water, the shrimp head polypeptide gel composition sank directly to the bottom without any undulation, which is beneficial for the consumption of benthic mud crabs. After 10 minutes, the water quality remained clear, and the embedded shrimp head polypeptides did not dissolve in the water, indicating that the shrimp head polypeptides can be effectively applied to aquaculture. Figure 3 As shown in Figure A, after squeezing and kneading the shrimp head polypeptide gel composition from the Control group in water, the water became cloudy. After the shrimp head polypeptide gel composition was broken down, some of its contents dissolved in the water. Figure 3 As shown in Figure B, after squeezing and kneading the shrimp head polypeptide gel composition of group Tg2 in water, the water quality was much clearer than that of group Control, indicating better cross-linking of the contents. Therefore, by using 40% fish paste, combined with 0.2% Tg enzyme and 2% salt, and after chopping and mixing, and then heating in a water bath at 90℃ for 5 minutes, 28.38% shrimp peptide paste and other excipients can be effectively encapsulated to form a gel. This makes the highly water-soluble polypeptides less likely to dissolve in water, allowing them to withstand animal biting without polluting the water quality and ensuring the intake of polypeptides.

[0042] 3. Protein content of shrimp head polypeptide paste and shrimp head polypeptide gel composition: The protein content of the shrimp head polypeptide paste formed by autolysis and concentration and the shrimp head polypeptide gel composition with Tg2 in Example 5 were detected by Kjeldahl method. The results showed that the protein content of shrimp head polypeptide paste was 30.08±0.62%, and the protein content of shrimp head polypeptide gel composition (containing water) was 21.64±1.69%, which showed high protein content.

[0043] 4. Feeding methods for the crab and shrimp head polypeptide gel composition: such as... Figure 4 As shown, the prepared shrimp head polypeptide gel composition Tg2 can simulate meat such as shellfish in nature. The blue crab can naturally pick up the shrimp head polypeptide gel composition and eat it directly, or pick up the shrimp head polypeptide gel composition and tear it into small pieces with its claws and put it into its mouth. During this process, the shrimp head polypeptide and other contents will not dissolve in the water. The remaining uneaten parts can sink to the bottom in a good small piece shape without scattering or dissolving, making it easy to remove.

[0044] 5. Feeding Effect of Shrimp Head Polypeptide Gel Composition: 30-100g mud crabs were fed in a recirculating aquaculture system for 60 days. Twelve mud crabs were fed with the shrimp head polypeptide gel composition Tg2, four with clam meat, and four with commercial crab feed (Xiamen Hailin Biotechnology Co., Ltd.). The daily feed intake was 3g in the morning and 5g in the evening, for a total of 8g. The results showed that 8 out of the 12 mud crabs fed with the shrimp head polypeptide gel composition Tg2 molted, with two molting twice, for a total of 10 molts. This was higher than the 1 molt out of 4 mud crabs in the clam meat group and the 2 molts out of 4 mud crabs fed with commercial crab feed. The shrimp head polypeptide gel composition contains abundant shrimp head protein peptides, astaxanthin, calcium ions, and other substances that promote the growth and molting of mud crabs. Therefore, the shrimp head polypeptide gel composition can promote the molting and growth of mud crabs.

[0045] 6. The effect of shrimp head polypeptide gel composition on water quality: (The text abruptly ends here, likely due to an incomplete sentence or missing information.) Figure 5 As shown in Table 1, after two weeks of rearing in the recirculating aquaculture system, water quality was tested using aquatic water quality test strips (Wuhu Jinghui Biotechnology Co., Ltd.). The results showed that the shellfish group had the best water quality, followed by the shrimp head polypeptide gel composition group (Tg2), and lastly the commercial crab feed group. All water quality indicators in the shellfish group did not exceed the standards, while the shrimp head polypeptide gel composition and commercial feed exceeded the nitrite standard. The nitrite and carbonate contents of the shrimp head polypeptide gel composition group were lower than those of the commercial feed group. Therefore, the shrimp head polypeptide gel composition group produced less turbidity and had a smaller impact on water quality.

[0046] Table 1. Water quality indicators after two weeks of mud crab rearing

[0047] Furthermore, it should be noted that traditional aquatic feed is in granular form, with main and auxiliary ingredients compressed, as disclosed in patent CN105495038A. Compressed granular feed has poor binding properties and is prone to disintegration and dissolution in water over a prolonged period, causing water pollution. Gel feed, on the other hand, uses a gel method to shape and cross-link auxiliary ingredients such as protein and starch, resulting in less pollution of aquaculture water and better palatability by mimicking animal meat. Existing technologies and patents mostly use colloidal substances such as sodium alginate, gelatin, and alginic acid for cross-linking, as disclosed in patents CN102972661A, CN118985793A, and CN119744992A. However, these colloidal substances themselves have low nutritional value and constitute a large proportion of the feed. During the addition process, a large amount of water needs to be added for dissolution and cross-linking, significantly reducing the overall protein and other nutrient content of the feed. Meanwhile, substances such as sodium alginate and gelatin are difficult to solidify polypeptides in shrimp heads, which easily disperse and dissolve in water, making the water turbid.

[0048] Existing feeds are mostly in granular form, which is significantly different from the gel composition of this invention. The gel composition of this invention not only greatly alleviates the water solubility problem of shrimp head peptides, but also sinks naturally to the bottom with good stability. Crabs have a strong feeding instinct and can easily gnaw and consume the feed, with less likelihood of disintegration. Furthermore, the gel composition of this invention can solidify auxiliary materials such as protein and starch through a gel process, resulting in less pollution of the aquaculture water. It also simulates shellfish meat, offering good palatability. In contrast, existing granular feeds are made by pressing the main and auxiliary materials, resulting in poor binding properties, easy disintegration in water, and water pollution.

[0049] This invention relates to gel compositions (morphology) and the application of shrimp head polypeptides (which have strong water solubility, can cloud water, and are rarely used in aquaculture) in the aquaculture field. The core of this invention is to encapsulate shrimp head polypeptides (highly water-soluble) with a gel-like fish paste matrix and specific excipients, making the gel composition gel-like, which is beneficial for the feeding and growth of mud crabs, and does not pollute the water quality.

[0050] It should be understood that the disclosed invention is not limited to the specific methods, schemes, and substances described, as these are all subject to variation. It should also be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of the invention, which is limited only by the appended claims.

Claims

1. The application of a shrimp head polypeptide gel composition in promoting feeding and / or molting growth in mud crabs, characterized in that, The preparation method of the shrimp head polypeptide gel composition includes the following steps: (1) Preparation of shrimp peptide paste: mince the shrimp head, add water for autolytic enzymatic hydrolysis, filter to obtain shrimp peptide liquid, concentrate the shrimp peptide liquid into paste to obtain shrimp peptide paste. (2) Preparation of gel-type fish paste matrix: Fish meat is chopped into fish paste, salt, transglutaminase and monosodium glutamate are added to the fish paste and chopped and crushed to obtain gel-type fish paste matrix; (3) Mixing and gel forming: The shrimp peptide paste and excipients obtained in step (1) are added to the gelled fish paste matrix obtained in step (2), and then chopped and crushed to obtain a mixture. The mixture is then steamed and cooled to form a gel.

2. The application of the shrimp head polypeptide gel composition in the preparation of products for reducing pollution in aquaculture water and / or improving water quality, characterized in that, The preparation method of the shrimp head polypeptide gel composition includes the following steps: (1) Preparation of shrimp peptide paste: mince the shrimp head, add water for autolytic enzymatic hydrolysis, filter to obtain shrimp peptide liquid, concentrate the shrimp peptide liquid into paste to obtain shrimp peptide paste. (2) Preparation of gel-type fish paste matrix: Fish meat is chopped into fish paste, salt, transglutaminase and monosodium glutamate are added to the fish paste and chopped and crushed to obtain gel-type fish paste matrix; (3) Mixing and gel forming: The shrimp peptide paste and excipients obtained in step (1) are added to the gelled fish paste matrix obtained in step (2), and then chopped and crushed to obtain a mixture. The mixture is then steamed and cooled to form a gel.

3. A method for preparing a shrimp head polypeptide gel composition, characterized in that, The preparation method includes the following steps: (1) Preparation of shrimp peptide paste: mince the shrimp head, add water for autolytic enzymatic hydrolysis, filter to obtain shrimp peptide liquid, concentrate the shrimp peptide liquid into paste to obtain shrimp peptide paste. (2) Preparation of gel-type fish paste matrix: Fish meat is chopped into fish paste, salt, transglutaminase and monosodium glutamate are added to the fish paste and chopped and crushed to obtain gel-type fish paste matrix; (3) Mixing and gel forming: The shrimp peptide paste and excipients obtained in step (1) are added to the gelled fish paste matrix obtained in step (2), and then chopped and crushed to obtain a mixture. The mixture is then steamed and cooled to form a gel.

4. The application according to claim 1 or 2, or the preparation method according to claim 3, characterized in that, In step (1), the conditions for autolytic enzymatic hydrolysis are: the ratio of shrimp head to water is 1:1, the enzymatic hydrolysis temperature is 40-55℃, and the enzymatic hydrolysis time is 1-5h.

5. The application according to claim 1 or 2, or the preparation method according to claim 3, characterized in that, The amount of salt added is 1-3% of the weight of the fish paste, the amount of transglutaminase added is 0.1-0.5% of the weight of the fish paste, and the amount of monosodium glutamate added is 0.05-0.5% of the weight of the fish paste.

6. The application according to claim 1 or 2, or the preparation method according to claim 3, characterized in that, The excipients include soybean meal, starch, fish oil microcapsule powder, multivitamins and minerals, antioxidants, sodium diacetate, and betaine; The amount of soybean meal added is 10-20% of the weight of the shrimp head polypeptide gel composition; the amount of starch added is 5-10% of the weight of the shrimp head polypeptide gel composition; the amount of fish oil microcapsule powder added is 1-2% of the weight of the shrimp head polypeptide gel composition; the amount of multivitamins and minerals added is 1-2% of the weight of the shrimp head polypeptide gel composition; the amount of antioxidant added is 0.01-0.05% of the weight of the shrimp head polypeptide gel composition; the amount of sodium diacetate added is 0.01-0.1% of the weight of the shrimp head polypeptide gel composition; and the amount of betaine added is 0.01-0.5% of the weight of the shrimp head polypeptide gel composition.

7. The application according to claim 1 or 2, or the preparation method according to claim 3, characterized in that, The chopping time in steps (2) and (3) is 3-7 minutes.

8. The application according to claim 1 or 2, or the preparation method according to claim 3, characterized in that, The cooking temperature of the mixture is 70-100℃, and the cooking time is 5-20 minutes.

9. A shrimp head polypeptide gel composition, characterized in that, The shrimp head polypeptide gel composition comprises a gelled fish paste matrix, shrimp peptide paste, soybean meal, starch, fish oil microcapsule powder, multivitamins and minerals, antioxidants, sodium diacetate, and betaine; wherein... The amount of the gelled fish paste matrix added is 30-50% of the weight of the shrimp head polypeptide gel composition; the amount of the shrimp peptide paste added is 20-40% of the weight of the shrimp head polypeptide gel composition; the amount of the soybean meal added is 10-20% of the weight of the shrimp head polypeptide gel composition; the amount of the starch added is 5-10% of the weight of the shrimp head polypeptide gel composition; the amount of the fish oil microcapsule powder added is 1-2% of the weight of the shrimp head polypeptide gel composition; the amount of the multivitamin and multimineral added is 1-2% of the weight of the shrimp head polypeptide gel composition; the amount of the antioxidant added is 0.01-0.05% of the weight of the shrimp head polypeptide gel composition; the amount of sodium diacetate added is 0.01-0.1% of the weight of the shrimp head polypeptide gel composition; and the amount of betaine added is 0.01-0.5% of the weight of the shrimp head polypeptide gel composition.

10. The application of the shrimp head polypeptide gel composition according to claim 9 in mud crab farming.

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