Preparation method of fish gelatin polysaccharide from fish gelatin

Abstract

The invention provides a preparation method of fish gelatin polysaccharide from fish gelatin, which is characterized in that fish maw is subjected to degreasing, proteolysis, alcohol precipitation and column separation to obtain the fish gelatin polysaccharide. According to the application, the crushed cod gelatin is taken as a raw material, the fish gelatin polysaccharide is prepared from the crushed cod gelatin through a specific enzymolysis process in combination with graded purification technologies such as alcohol precipitation, chromatographic column separation and dialysis, glycosaminoglycan in the prepared fish gelatin polysaccharide contains chondroitin sulfate which accounts for 90% of glycosaminoglycan 7, and the repairing effect on the wound of the zebra fish is obvious.

Description

Technical Field

[0001] The present application belongs to the technical field of natural product extraction, and in particular relates to a method for preparing fish gelatin polysaccharide derived from fish gelatin. Background Art

[0002] Fish maw (dried fish maw) contains a certain amount of polysaccharides. Studies have been conducted on the extraction and activity of polysaccharides from the maws of bighead carp, silver carp, silver carp, and large yellow croaker, including antioxidant and liver and kidney protection. Polysaccharides also have anti-inflammatory and immune-enhancing properties.

[0003] Currently, the extraction purity of fish maw polysaccharides can reach 20%, and the purity after purification can reach 52.4%. Therefore, there is still room for improvement in both extraction and purification. Traditional fish maw polysaccharides are mostly extracted by hot water extraction and enzymatic hydrolysis. Among them, the hot water extraction method has a low polysaccharide content, and the single enzymatic hydrolysis method is prone to produce more impurities. The purification methods are mainly Sevege method and chromatography, but the reagent contamination in Sevege method is relatively large, and chromatography is complex and time-consuming.

[0004] At the same time, the polysaccharides produced in current research have varying molecular weights and low degrees of sulfation, which hinder their antioxidant and anti-inflammatory activities. Sulfation, a modification of polysaccharides, is closely related to their biological activity. Generally, the degree of sulfation is directly proportional to their biological activity.

[0005] Fish maw and cod fish maw are traded in large quantities, and scraps often form during industrial production. However, the raw material properties of fish maw scraps vary from species to species. Laboratory tests have shown that cod fish maw scraps contain higher polysaccharide content than fish maw. Therefore, finding ways to use fish maw to obtain isinglass polysaccharides and to enhance their bioactivity is one of the key approaches to achieving economical and high-value applications. Summary of the Invention

[0006] The present invention provides a method for preparing fish glue polysaccharide derived from fish glue to solve the problems existing in the related art. The technical solution is as follows:

[0007] In a first aspect, an embodiment of the present application provides a method for preparing fish maw polysaccharide derived from fish maw, comprising the following steps: removing fat from fish maw, enzymatic hydrolysis, alcohol precipitation, and column separation to obtain fish maw polysaccharide.

[0008] In one embodiment, the degreasing process is to subject the fish maw to Soxhlet extraction; the extraction solvent is petroleum ether.

[0009] In one embodiment, the proteolysis process is as follows: the defatted fish maw is enzymatically hydrolyzed by neutral protease and alkaline protease in sequence.

[0010] In one embodiment, the defatted fish maw is mixed with water, and 1-3% of the weight of the defatted fish maw neutral protease is added for enzymolysis; then 1-3% of the weight of the defatted fish maw alkaline protease is added for enzymolysis.

[0011] In one embodiment, the defatted fish maw is mixed with water at a material-to-liquid ratio of 1:15-25;

[0012] The conditions for enzymatic hydrolysis with neutral protease are: enzymatic hydrolysis at 50-60°C for 3-5h;

[0013] The conditions for alkaline protease hydrolysis are: pH 8.5-9.5, 50-60°C, and hydrolysis for 3-5 hours.

[0014] In one embodiment, after proteolysis, solid-liquid separation is performed, and after the liquid phase is concentrated, 3-5 volumes of anhydrous ethanol are added to perform alcohol precipitation for 8-12 hours.

[0015] In one embodiment, the column separation uses a DEAE52 chromatographic column and elution is performed using a 0.1-1.6 mol / L NaCl eluent.

[0016] In one embodiment, after column separation, the eluted component is dialyzed; wherein the molecular weight cutoff of the dialysis membrane is 5 kDa, and the dialysis conditions are dialysis at 4-10° C. for 24-96 hours, during which the dialysis water is replaced 5 times.

[0017] In a second aspect, an embodiment of the present application provides a fish gelatin polysaccharide, which is prepared by any of the above-mentioned methods for preparing fish gelatin polysaccharides derived from fish gelatin.

[0018] In a third aspect, an embodiment of the present application provides an application of fish gelatin polysaccharide, and the application of the fish gelatin polysaccharide in the preparation of a product that promotes wound repair.

[0019] The advantages or beneficial effects of the above technical solution include at least:

[0020] This application uses codfish gelatin scraps as raw materials, and prepares fish gelatin polysaccharide from the codfish gelatin scraps through a specific enzymatic hydrolysis process combined with alcohol precipitation, chromatographic column separation and dialysis and other graded purification techniques. The glycosaminoglycans in the prepared fish gelatin polysaccharide contain chondroitin sulfate, which accounts for 90% of the glycosaminoglycans, and has a significant effect on repairing zebrafish wounds.

[0021] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0023] Figure 1 Graph showing the absorbance of the eluted components separated by the chromatographic column of the embodiment;

[0024] Figure 2 1 is a liquid chromatography analysis chart of fish gelatin polysaccharide in Example;

[0025] Figure 3 This is a blank control group image of zebrafish embryo tail fin excision and repair;

[0026] Figure 4 This is a control group picture of the zebrafish embryo tail fin excision and repair model;

[0027] Figure 5 Figure 1 shows the fish gelatin treatment for zebrafish embryo tail fin resection and repair. DETAILED DESCRIPTION

[0028] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and description are to be regarded as illustrative in nature and not restrictive.

[0029] The present application provides a method for preparing fish maw polysaccharide derived from fish maw, comprising the following steps: removing fat from fish maw, performing proteinase hydrolysis, alcohol precipitation, and column separation to obtain fish maw polysaccharide.

[0030] In one embodiment, the fish maw is cod fish maw. Cod fish maw is a large traded commodity, and scraps often form during industrial production. Laboratory measurements have shown that the polysaccharide content of cod fish maw scraps is approximately 0.6%, so it can be used to extract fish maw polysaccharides. However, the scraps must be cleaned of protein and fat.

[0031] As one embodiment, the fat removal process is to perform Soxhlet extraction on the fish maw. The extraction solvent is petroleum ether.

[0032] After obtaining the fish maw, the fish maw is defatted using petroleum ether through Soxhlet extraction. The defatted fish maw is then dried in an oven at 40-55°C to remove the petroleum ether and moisture, resulting in defatted fish maw. The Soxhlet extraction takes 3-5 hours to fully remove the fat.

[0033] In one embodiment, the proteolysis process involves sequentially hydrolyzing the defatted fish maw with a neutral protease and then an alkaline protease. Single enzymatic hydrolysis does not fully hydrolyze the protein, easily resulting in a high level of impurities. A combined enzymatic hydrolysis using a neutral protease and an alkaline protease, particularly one followed by alkaline protease, provides more complete protein hydrolysis, resulting in a lower protein content in the subsequent alcohol precipitation step.

[0034] As one embodiment, the defatted fish maw is mixed with water at a material-liquid ratio of 1:15-25.

[0035] As one embodiment, the defatted fish maw is mixed with water, and 1-3% of the weight of the defatted fish maw neutral protease is added for enzymolysis; the neutral protease is enzymolyzed at 50-60° C. for 3-5 hours.

[0036] As one embodiment, after enzymatic hydrolysis with neutral protease, 1-3% of the weight of the defatted fish maw is added for enzymatic hydrolysis. The alkaline protease is enzymatically hydrolyzed at 50-60°C for 3-5 hours. Because alkaline protease works directly under alkaline conditions, the pH of the solution is adjusted to 8.5-9.5 before the alkaline protease is added. In this embodiment, sodium hydroxide is used to adjust the pH, and further, an aqueous solution of sodium hydroxide is used to adjust the pH, and the concentration can be selected according to specific conditions.

[0037] As one embodiment, after the alkaline protease hydrolysis is completed, the solution is heated to 75-90° C. for 10-15 minutes to inactivate the enzyme.

[0038] In one embodiment, the enzymatic activity of the neutral protease is at least 160,000 DU / g; the enzymatic activity of the alkaline protease is at least 580,000 DU / g.

[0039] As one embodiment, after proteinase hydrolysis, solid-liquid separation is performed, and after the liquid phase is concentrated, 3-5 times the volume of anhydrous ethanol is added to carry out alcohol precipitation for 8-12 hours.

[0040] Solid-liquid separation is carried out by centrifugation, and the centrifugal conditions are: 3500-4500 rpm for 25-40 min.

[0041] The liquid phase was concentrated by rotary evaporation, specifically by concentrating the liquid to 1 / 5 of its original volume at 45-55°C.

[0042] In one embodiment, column separation utilizes a DEAE52 column, using a 0.1-1.6 mol / L NaCl eluent. The DEAE52 column is a weakly alkaline anion exchange cellulose hydrophilic polymer filler with macromolecular sugar chains grafted onto its surface, resulting in a higher specific surface area and improved biocompatibility, maintaining a higher loading capacity while also achieving better resolution. It is highly effective in separating polysaccharides.

[0043] As one embodiment, the alcohol precipitate is dissolved in water to prepare a 1.0 mg / mL solution, and the chromatographic column separation is performed at a flow rate of 0.8 mL / min.

[0044] As one embodiment, elution is performed using 0.1 mol / L, 0.6 mol / L, 1.1 mol / L, and 1.6 mol / L NaCl solutions in sequence to collect four components.

[0045] As one embodiment, after column separation, the eluted component is dialyzed; wherein the molecular weight cutoff of the dialysis membrane is 5kDa, and the dialysis conditions are dialysis at 4-10°C for 24-96h, during which the dialysis water is replaced 5 times.

[0046] As one embodiment thereof, the method further includes a freeze-drying process, in which the dialyzed product is freeze-dried to obtain fish gelatin polysaccharide powder.

[0047] The present application provides a fish gelatin polysaccharide, which is prepared by any of the above-mentioned methods for preparing fish gelatin polysaccharides derived from fish gelatin.

[0048] The present application also provides an application of fish gelatin polysaccharide, and the application of the fish gelatin polysaccharide in the preparation of a product that promotes wound repair.

[0049] The following is a further description with reference to specific embodiments.

[0050] Example 1

[0051] Fat removal: After obtaining 50 g of codfish gelatin crumbs, first place them in a 50°C oven to dry, then use 200 mL of petroleum ether to degrease them by Soxhlet extraction. Then, place the completely defatted codfish gelatin crumbs in a 50°C oven to dry, and finally remove the petroleum ether and water to obtain the crude codfish gelatin polysaccharide SP-1;

[0052] Protein impurity removal: SP-1 was mixed with 20 times its weight of water, then crushed, 3.0% neutral protease of SP-1 dry weight was added and enzymatically hydrolyzed at 60°C for 4 hours, then the pH was adjusted to 9 with NaOH, 2.0% alkaline protease of SP-1 dry weight was added and enzymatically hydrolyzed at 60°C for 5 hours, and the solution was heated to 80°C for 10 minutes to inactivate the enzyme; centrifuged at 4000 rpm for 30 minutes to obtain the supernatant; the supernatant was concentrated to 1 / 5 of the original volume under 50°C rotary evaporation, and 5 times the volume of anhydrous ethanol was added for alcohol precipitation for 10 hours. The alcohol precipitate was dissolved in water to prepare a 1.0 mg / mL solution, and the flow rate was 0.8 mL / min. It was eluted with 0.1 mol / L, 0.6 mol / L, 1.1 mol / L, and 1.6 mol / L NaCl solutions, respectively, to collect 4 fractions. Different fractions were dialyzed using a dialysis membrane with a molecular weight cutoff of 5 kDad at 4°C for 72 hours, during which the dialysis water was changed 5 times;

[0053] Drying: After freeze drying, fish gelatin polysaccharide powder SP-3 is obtained.

[0054] Example 2

[0055] Fat removal: After obtaining 50 g of codfish gelatin crumbs, first place them in a 50°C oven to dry, then use 200 mL of petroleum ether to degrease them by Soxhlet extraction. Then, place the completely defatted codfish gelatin crumbs in a 50°C oven to dry, and finally remove the petroleum ether and water to obtain the crude codfish gelatin polysaccharide SP-1;

[0056] Protein impurity removal: SP-1 was mixed with 15 times its weight of water, then crushed, 1.0% neutral protease of the dry weight of SP-1 was added and enzymatically hydrolyzed at 50°C for 5 hours, then the pH was adjusted to 9 with NaOH, and 3.0% alkaline protease of the dry weight of SP-1 was added and enzymatically hydrolyzed at 55°C for 4 hours. After the end, the solution was heated to 80°C for 10 minutes to inactivate the enzyme; centrifuged at 4000 rpm for 30 minutes to obtain the supernatant; the supernatant was concentrated to 1 / 5 of the original volume under rotary evaporation at 50°C, and 3 times the volume of anhydrous ethanol was added for alcohol precipitation for 8 hours. The alcohol precipitate was dissolved in water to prepare a 1.0 mg / mL solution, and the flow rate was 0.8 mL / min. It was eluted with 0.1 mol / L, 0.6 mol / L, 1.1 mol / L, and 1.6 mol / L NaCl solutions, respectively, to collect 4 fractions. Different fractions were dialyzed using a dialysis membrane with a molecular weight cutoff of 5 kDad at 4°C for 72 hours, during which the dialysis water was changed 5 times;

[0057] Drying: After freeze drying, fish gelatin polysaccharide powder SP-3 is obtained.

[0058] Example 3

[0059] Fat removal: After obtaining 50 g of codfish gelatin crumbs, first place them in a 50°C oven for drying, then degrease them using 200 ml of petroleum ether via Soxhlet extraction. The defatted codfish gelatin crumbs are then placed in a 50°C oven for drying, and finally the petroleum ether and water are removed to obtain the crude codfish gelatin polysaccharide SP-1.

[0060] Protein impurity removal: SP-1 was mixed with 25 times its weight of water, then crushed, 2.0% neutral protease of SP-1 dry weight was added and enzymatically hydrolyzed at 55°C for 3 hours, then the pH was adjusted to 9 with NaOH, 1.0% alkaline protease of SP-1 dry weight was added and enzymatically hydrolyzed at 50°C for 3 hours, and the solution was heated to 80°C for 10 minutes to inactivate the enzyme; centrifuged at 4000 rpm for 30 minutes to obtain the supernatant; the supernatant was concentrated to 1 / 5 of the original volume under rotary evaporation at 50°C, and 3 times the volume of anhydrous ethanol was added for alcohol precipitation for 12 hours. The precipitate was dissolved in water to prepare a 1.0 mg / mL solution, and the flow rate was 0.8 mL / min. It was eluted with 0.1 mol / L, 0.6 mol / L, 1.1 mol / L, and 1.6 mol / L NaCl solutions, respectively, to collect 4 fractions. Different fractions were dialyzed using a dialysis membrane with a molecular weight cutoff of 5 kDad at 4°C for 72 hours, during which the dialysis water was changed 5 times;

[0061] Drying: After freeze drying, fish gelatin polysaccharide powder SP-3 is obtained.

[0062] Comparative Example 1

[0063] Protein impurity removal in Comparative Example 1: SP-1 was mixed with 20 times its weight of water and then pulverized. Neutral protease (3.0% by weight of SP-1) was added and enzymatically hydrolyzed at 60°C for 4 hours. After completion, the solution was heated to 80°C for 10 minutes to inactivate the enzyme. The supernatant was then centrifuged at 4000 rpm for 30 minutes. Other steps and methods were the same as in Example 1.

[0064] Comparative Example 2

[0065] Protein impurity removal in Comparative Example 1: SP-1 was mixed with 20 times its weight of water, then pulverized. The pH was adjusted to 9 using NaOH. Alkaline protease (2.0% by weight of SP-1) was added and enzymatically digested at 60°C for 5 hours. The solution was then heated to 80°C for 10 minutes to inactivate the enzyme. The supernatant was then centrifuged at 4000 rpm for 30 minutes. Other steps and methods were the same as in Example 1.

[0066] Comparative Example 3

[0067] In Comparative Example 3, the supernatant was concentrated to 1 / 5 of its original volume by rotary evaporation at 50°C, and then precipitated with 3 volumes of anhydrous ethanol for 12 hours. The precipitate was dissolved in water to prepare a 1.0 mg / mL solution, which was dialyzed using a 5 kDad dialysis membrane at 4°C for 72 hours, during which the dialysis water was changed five times. Other steps and methods were the same as in Example 1.

[0068] Test example:

[0069] The four components collected in Example 1 were subjected to absorbance detection, and the absorbance curve was as follows: Figure 1 As shown. Figure 1 It can be seen that the separation boundaries of the four components are obvious, and component 4, which is the component collected by elution with 1.6 mol / L NaCl solution, has the largest maximum absorbance.

[0070] The polysaccharide content of fish gelatin polysaccharide powder SP-3 (the collected component eluted with 1.6 mol / L NaCl solution) in Example 1 was detected using the phenol-sulfuric acid method:

[0071] A 1 mg / mL glucose standard solution was accurately prepared and diluted to 0 mg / mL, 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, 0.5 mg / mL, and 0.6 mg / mL glucose working solutions. 2 mL of each working solution was added to 1 mL of 5% phenol solution. After mixing, 5 mL of concentrated sulfuric acid was added. The samples were placed in a boiling water bath for 15 minutes, followed by an ice-water bath. The absorbance was measured at 490 nm. The polysaccharide content of the samples was calculated using the simulation curve formula. The calculated polysaccharide content was 56.21%.

[0072] The molecular weight of SP-3 was determined by high performance liquid chromatography-gel permeation chromatography using dextran of different molecular weights as standards; the results are shown in Table 1.

[0073] The fish gelatin polysaccharide powder SP-3 prepared in Example 1 (fractions collected by elution with 1.6 mol / L NaCl solution) was subjected to polysaccharide composition analysis. SP-3 was hydrolyzed using heparinase and chondroitinase, and the product was then subjected to reductive amination. The disaccharide components of the sample SP-3 were analyzed by reverse phase liquid chromatography. The chromatographic results are shown in FIG. Figure 2 The results are shown in Table 1.

[0074] The sulfate content of fish gelatin polysaccharide powder SP-3 prepared in Example 1 (fractions collected by elution with a 1.6 mol / L NaCl solution) was determined using the barium chloride-gelatin turbidimetric method, using potassium sulfate as the standard. Both the standard and the sample were dissolved in 1M hydrochloric acid, followed by addition of 3% trichloroacetic acid and the barium chloride-gelatin solution. After standing for 20 minutes, the absorbance was measured at 360 nm. The results are shown in Table 1.

[0075] Table 1 Chemical analysis of fish gelatin polysaccharide SP-3

[0076] Molecular weight Sulfate content Disaccharide main component Example 1 34520Da 39.75％ 89.8% Chondroitin Sulfate + 4.3% Hyaluronic Acid Comparative Example 1 52860Da 38.23％ / Comparative Example 2 57080Da 37.19％ / Comparative Example 3 42050Da 32.46％ /

[0077] Note: The sulfate content of Comparative Examples 1-3 was not converted into the content of the main disaccharide component.

[0078] As can be seen from Table 1, after preparation and fractional purification in this application, the sulfate content of the collected components eluted with a 1.6 mol / L NaCl solution by column separation was 39.75%, with the polysaccharide component primarily consisting of chondroitin sulfate, accounting for approximately 89.8%, and a certain amount of hyaluronic acid. After removing most of the protein impurities, the fish gelatin polysaccharide content was high, primarily consisting of chondroitin sulfate, which accounted for nearly 90%. The sulfate content in Comparative Examples 1-3 was reduced by more than 1 percentage point compared to Example 1.

[0079] Effect Examples

[0080] The fish gelatin polysaccharide powder SP-3 (fractions collected by elution with 1.6 mol / L NaCl solution) prepared in Example 1 was subjected to a wound repair experiment: the zebrafish embryo tail fin amputation model was used for testing. 24 fish embryos with tail fin amputation were exposed to 0.5 mg / mL fish gelatin polysaccharide SP-3 solution. A blank control group and a model control group were also set up. After 48 hours of exposure, the fish embryos were photographed under a microscope, and the tail fin regeneration length was measured and statistically analyzed. The results are shown in Figure 2. Figure 3-5 As shown, Figure 3 is the blank control; Figure 4 is the model control; Figure 5 For example.

[0081] from Figure 3-5 In the figure, the zebrafish embryos treated with fish gelatin polysaccharide of Example 1 had a tail fin repair rate of 18%, while the repair rate of the model control group was 0. This shows that the fish gelatin polysaccharide of the present application can effectively repair wounds with significant effects.

[0082] In the description of this specification, the reference terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials, or characteristics described may be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification, as well as features of different embodiments or examples, unless they are mutually inconsistent.

[0083] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0084] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various modifications or substitutions within the technical scope disclosed in this application, and such modifications or substitutions should be included within the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for preparing fish glue polysaccharide derived from fish glue, characterized in that: The following steps are involved: Fish maw is subjected to fat removal, protein hydrolysis, alcohol precipitation and column separation to obtain fish maw polysaccharide.

2. The method for preparing fish glue polysaccharide derived from fish glue according to claim 1, wherein The degreasing process is to subject the fish maw to Soxhlet extraction; the extraction solvent is petroleum ether.

3. The method for preparing fish glue polysaccharide from fish glue source according to claim 1, wherein The proteolysis process is as follows: the fish maw after fat removal is enzymatically hydrolyzed by neutral protease and alkaline protease in sequence.

4. The method for preparing fish glue polysaccharide derived from fish glue according to claim 3, wherein The defatted fish maw is mixed with water, and 1-3% of the weight of the defatted fish maw neutral protease is added for enzymolysis; then 1-3% of the weight of the defatted fish maw alkaline protease is added for enzymolysis.

5. The method for preparing fish glue polysaccharide from fish glue source according to claim 4, wherein Mix the defatted fish maw with water at a material-liquid ratio of 1:15-25; The conditions for enzymatic hydrolysis with neutral protease are: enzymatic hydrolysis at 50-60°C for 3-5h; The conditions for alkaline protease hydrolysis are: pH 8.5-9.5, 50-60°C, and hydrolysis for 3-5 hours.

6. The method for preparing fish glue polysaccharide derived from fish glue according to claim 1, wherein After proteinase hydrolysis, solid-liquid separation is performed, and after the liquid phase is concentrated, 3-5 times the volume of anhydrous ethanol is added for alcohol precipitation for 8-12 hours.

7. The method for preparing fish glue polysaccharide derived from fish glue according to claim 1, wherein A DEAE52 column was used for column separation, and 0.1-1.6 mol / L NaCl eluent was used for elution.

8. The method for preparing fish glue polysaccharide derived from fish glue according to claim 1, wherein After column separation, the eluted components are dialyzed; the molecular weight cutoff of the dialysis membrane is 5kDa, and the dialysis conditions are dialysis at 4-10°C for 24-96 hours, during which the dialysis water is replaced 5 times.

9. A fish gelatin polysaccharide, characterized in that The fish gelatin polysaccharide is prepared by the method for preparing fish gelatin polysaccharide derived from fish gelatin according to any one of claims 1 to 8.

10. An application of fish gelatin polysaccharide, characterized in that: The application of the fish gelatin polysaccharide in the preparation of a product promoting wound repair.

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