Preparation method of fish gelatin collagen peptide with high oligopeptide content

Abstract

The invention relates to a preparation method of fish gelatin collagen peptide with high content of oligopeptide proportion, and belongs to the technical field of collagen peptide, and the preparation method comprises the following steps: S1, establishing a protein data taking crushed fish gelatin as a raw material, performing enzymolysis treatment, and performing liquid chromatography separation and mass spectrometry to obtain a protein identification result, establishing a protein database according to the identification data; s2, enzyme screening: according to the protein database obtained in the step S1, querying the optimal conditions of the enzyme; selecting enzyme to perform virtual enzyme digestion on the protein so as to obtain polypeptide contained in the fish gelatin, and screening out proper enzyme by predicting the physicochemical properties of the polypeptide after virtual enzyme digestion and detecting and verifying the molecular weight distribution of a product; and S3, preparing the fish gelatin collagen peptide, namely treating and crushing a fish gelatin raw material, performing enzymolysis by using the screened enzyme, performing centrifugal filtration, sterilizing, cooling, and performing spray drying to obtain fish gelatin collagen peptide powder with high content of oligopeptide. The obtained peptide powder is low in molecular weight, high in collagen tripeptide content and high in product efficacy potential.

Description

Technical Field

[0001] The invention belongs to the technical field of collagen peptides and relates to a method for preparing fish gelatin collagen peptides with a high content of short peptides. Background Art

[0002] Fish maw products often produce scraps during the industrial production process. The scraps are often used for raw material trading in farmers' markets and for the processing of convenience foods. However, the raw material characteristics of different varieties of fish maw scraps are different. For example, cod maw has a relatively low collagen content and an overall soft texture, while fish maw has a high collagen content but a strong fishy smell. Not all fish maw scraps are suitable for further trade and processing. Therefore, a large number of scraps urgently need to be processed in depth and utilized at a high value.

[0003] Compared with other fish waste such as fish scales and fish skin, fish maw has richer collagen content and lighter fishy smell. Therefore, in theory, fish maw scraps are more suitable for the production of collagen peptides than other fish waste. Among collagen peptides, short collagen peptides, that is, collagen peptides with a molecular weight of less than 1000 Daltons, have the most significant effects, including promoting the growth and repair of skin, bones and cartilage, and anti-oxidation.

[0004] Currently, composite proteases are commonly used to hydrolyze raw materials, but due to non-specific enzymatic reactions, their efficiency is low and the molecular weight of the products is high. Although high-purity low-molecular-weight peptide products can be obtained with the aid of nanofiltration membranes and column chromatography, their production efficiency is still low and the cost is high.

[0005] Protein mass spectrometry can perform qualitative and quantitative analysis on the proteins and peptides in the sample, which helps to study the functional and structural characteristics of the sample protein; while molecular dynamics simulation can further determine the stability of the binding between the components and the known targets. Molecular simulation calculations can use virtual technology to assist in screening active peptides and optimal cutting enzymes in the sample, which can save a lot of time and experimental costs.

[0006] To this end, developing a low-molecular peptide product with high production efficiency and cost savings is the direction we are committed to researching. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing collagen low-molecular peptides with fish maw as raw material, which has higher enzymatic hydrolysis efficiency and lower peptide molecular weight and cost. To this end, we first established a fish gelatin protein database using mass spectrometry technology, and then used virtual enzyme cleavage technology to perform preliminary screening of the protease database to obtain a composite enzyme with certain specificity, thereby obtaining a method for preparing high-efficiency and high-content fish gelatin low-molecular peptides.

[0008] The technical solution adopted by the present invention to achieve its purpose is as follows:

[0009] The process is as follows:

[0010] ① Establishment of protein database: pre-treatment → chromatography-mass spectrometry analysis → protein database retrieval, analysis and database establishment;

[0011] ② Virtual enzyme cutting screening: Use virtual enzyme cutting to screen the enzymes "pepsin, trypsin, proline endoproteinase, alkaline protease, neutral protease, papain"; finally, actually detect the molecular weight distribution of the enzymatic hydrolysis products, and measure the enzymatic hydrolysis efficiency by the proportion of small molecular weight.

[0012] ③ Preparation of fish gelatin low molecular weight peptide: raw material crushing → centrifugation → canning and sealing → sterilization and cooling → finished product.

[0013] Operation points ①:

[0014] Pretreatment: Crush the fish glue tail material, take 150-200ug total protein and enzymatically hydrolyze it overnight (18-24h) in a 37℃ water bath, add trypsin at a mass ratio of 1:40 for enzyme to protein and hydrolyze it overnight. After desalting, take the supernatant for nanoliter liquid chromatography separation and then detect it with a Q-Exactive high-resolution mass spectrometer.

[0015] Chromatographic separation: Liquid A used in the liquid phase was 0.1% formic acid aqueous solution, and liquid B was 0.1% formic acid acetonitrile aqueous solution (acetonitrile was 80%); the liquid chromatography column (50 μm*150 mm, Acclaim PepMapTM RSLC, thermo scientific Technology Inc.) was equilibrated with 92% liquid A, and the injection volume was 1 μL for separation by the chromatographic column. The relevant liquid phase gradient was set as follows:

[0016] 0min---98min, linear gradient of solution B from 8% to 28%;

[0017] 98min---113min, linear gradient of solution B from 28% to 37%;

[0018] 113min---117min, linear gradient of solution B from 37% to 100%;

[0019] 117min----120min, liquid B is maintained at 100%.

[0020] Mass spectrometry identification: The enzymatic hydrolysis products were separated by nanoliter liquid chromatography and then analyzed by mass spectrometry using a Q-Exactive high-resolution mass spectrometer. The analysis time was 120 min. Detection method: positive ion. The mass-to-charge ratio of the polypeptide and polypeptide fragments was collected according to the following method: 20 fragment spectra (MS2 scan) were collected after each full scan (full scan). The scanning range was 400-1800, the primary resolution was 60000, the secondary resolution was 15000, and the collision energy was CE28eV. The raw file of the mass spectrometry test (Raw File) was searched in the corresponding database using the software Proteome Discoverer 2.5, and finally the protein identification results were obtained, and a protein library was established based on the identification data.

[0021] Operation points ②:

[0022] Enzyme screening: Based on the fish glue protein library obtained in operation ①, the optimal conditions of the enzyme were queried using the bioinformatics resource platform of the Swiss Institute of Bioinformatics (SIB) (https: / / web.expasy.org / peptide_mass / ); after determining the optimal enzymatic conditions, one or more of pepsin, trypsin, proline endoproteinase, alkaline protease, neutral protease, and papain were selected (https: / / web.expasy.org / peptide_cutter / ), and the protein was virtually enzymatically cleaved to obtain the polypeptides contained in the fish glue. The physicochemical properties of the polypeptides after virtual enzymatic cleavage were predicted using the online website ToxinPred (http: / / crdd.osdd.net / raghava / toxinpred / ), and the molecular weight distribution of the products was tested and verified, and the enzymatic efficiency was measured by the proportion of small molecular weight.

[0023] Product verification: The molecular weight distribution of fish gelatin collagen peptides was determined by HPLC; 5 mg / mL protein peptide solutions treated with relevant enzymes were prepared, passed through a 0.22 μm membrane, and liquid phase determination was performed using TSKgel G2000 SWXL, with acetonitrile (60%) containing 0.1% TFA as the mobile phase, a flow rate of 0.8 mL / min, and isocratic elution for analysis. The molecular weight distribution of the peptides of each sample was calculated using the regression equation based on the logarithm of the molecular weight of the standard and the elution time.

[0024] Operation points ③:

[0025] Cooking wine immersion ultrasonic cleaning: prepare 3-6% cooking wine, the mass ratio of fish glue to cooking wine is 1:10-15, and clean it at 10-30W / L ultrasonic power for 15-30min at room temperature to remove the sources of fishy smell such as oil and blood in the fish glue by cavitation effect; after the end, use clean water, supplemented with the same ultrasonic power and cleaning time, clean the fish glue 2-3 times to remove the solution residual in the fish glue during the above steps.

[0026] Composite enzyme ultrasonic enzymolysis: use 0.5-3.0% enzyme (one or more of pepsin, trypsin, proline endoproteinase, alkaline protease, neutral protease, papain) to decompose at 35-50°C for 1-18h, and finally heat the obtained collagen solution at 80-90°C for 15-20min to inactivate the enzyme, and centrifuge to remove the residue that cannot be enzymolyzed;

[0027] Activated carbon decolorization and fishy smell removal: add 0.1-0.5% powdered activated carbon (using the large specific surface area to efficiently adsorb colored substances and bitter amino acids) to the filtered fish gelatin collagen solution, decolorize it at room temperature for 0.5-1.5 hours and then filter it to obtain a decolorized, debittered and fishy fish gelatin collagen stock solution. Subsequently, use a rotary evaporator to reduce pressure and concentrate the fish gelatin content of the stock solution to 100-150g / L. The reduced pressure heating in the process can remove volatile substances such as the fishy smell. Then, sterilize it at 75°C for 30 minutes, cool it, and spray dry it to obtain the finished product.

[0028] The beneficial effects of the present invention are:

[0029] 1. Before enzymatic hydrolysis, the fish glue is first degreased and deodorized, and after enzymatic hydrolysis, activated carbon adsorption and reduced pressure evaporation are combined to remove most of the bitter and fishy smell of the fish glue collagen peptide solution, thereby improving the palatability of the product.

[0030] 2. Virtual enzymatic cleavage technology screens out a combination of proteases for high-efficiency enzymatic hydrolysis, with high enzymatic hydrolysis yield. The resulting peptide powder has a low molecular weight and a high content of collagen tripeptide, and the product has strong efficacy potential.

[0031] 3. The equipment and raw materials used in the preparation process are simple and easy to operate, and the maintenance cost of the preparation equipment is low. In particular, the use of isinglass crushed raw materials reduces the preparation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the GPC spectrum of molecular weight distribution detection of Example 1.

[0033] Figure 2 This is the molecular weight distribution detection GPC spectrum of Example 2.

[0034] Figure 3 It is a sample picture of the products prepared in Example 1 and Example 2. DETAILED DESCRIPTION

[0035] According to previous studies, considering the rich collagen content of cha fish glue (up to 88%) and the estimated cost of scraps (cheap by-products), cha fish glue scraps were selected as the raw materials for the preparation of fish glue low molecular peptides, and the cleaning and degreasing process before the enzymatic hydrolysis of fish glue was combined to greatly reduce the fishy smell of fish glue collagen peptides; at the same time, a cha fish glue collagen database was established using mass spectrometry analysis technology, and proteases such as pepsin, trypsin, and proline endonuclease were used for virtual enzymatic hydrolysis to screen out a combination of proteases with high efficiency, and finally adjust the temperature, enzymatic hydrolysis time and other process parameters. This technical solution can prepare a fish glue collagen peptide with low fishy smell and molecular weight at a relatively low cost.

[0036] In addition, according to the differences in collagen types in different fish maws, the type and content ratio of the complex enzyme can be appropriately adjusted.

[0037] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should belong to the scope of protection of the present invention.

[0038] Example 1

[0039] Take the isinglass scraps as the sample. The specific operation steps are as follows:

[0040] ① Recommended protein database:

[0041] Pretreatment: Crush the fish maw tail (fish maw scraps), take 150-200ug of total protein and place it in a 37°C water bath for enzymatic hydrolysis overnight (18-24h), add trypsin at a mass ratio of enzyme to protein of 1:40 for enzymatic hydrolysis overnight, after desalting, take the supernatant for nanoliter liquid chromatography separation and then detect with Q-Exactive high-resolution mass spectrometer.

[0042] Chromatographic separation: Liquid A used in the liquid phase was 0.1% formic acid aqueous solution, and liquid B was 0.1% formic acid acetonitrile aqueous solution (acetonitrile was 80%); the liquid chromatography column (50 μm*150 mm, Acclaim PepMapTM RSLC, thermo scientific Technology Inc.) was equilibrated with 92% liquid A, and the injection volume was 1 μL for separation by the chromatographic column. The relevant liquid phase gradient was set as follows:

[0043] 0min---98min, linear gradient of solution B from 8% to 28%;

[0044] 98min---113min, linear gradient of solution B from 28% to 37%;

[0045] 113min---117min, linear gradient of solution B from 37% to 100%;

[0046] 117min----120min, liquid B is maintained at 100%.

[0047] Mass spectrometry identification: The enzymatic hydrolysis products were separated by nanoliter liquid chromatography and then analyzed by mass spectrometry using a Q-Exactive high-resolution mass spectrometer. The analysis time was 120 min. The detection method was positive ion. The mass-to-charge ratio of the polypeptide and polypeptide fragments was collected according to the following method: 20 fragment spectra (MS2 scan) were collected after each full scan. The scanning range was 400-1800, the primary resolution was 60000, the secondary resolution was 15000, and the collision energy was CE28eV. The raw file of the mass spectrometry test (Raw File) was searched in the corresponding database using the software Proteome Discoverer 2.5, and finally the protein identification results were obtained, and a protein library was established based on the identification data.

[0048] ②Virtual enzyme cutting screening:

[0049] The 45 proteins obtained by protein identification were subjected to virtual enzyme digestion (using the ExPASy Peptide Cutter (http: / / web.expas.org / peptidecutter / ) program), and single enzyme screening (enzymatic digestion at 37°C / 5h, where the single enzymes were pepsin, trypsin, proline endoproteinase, alkaline protease, neutral protease, and papain) and composite enzyme screening (enzymatic digestion at 37°C / 5h, where the enzyme combinations were pepsin + trypsin, pepsin + proline endoproteinase, trypsin + proline endoproteinase, pepsin + trypsin + proline endoproteinase, alkaline protease + neutral protease, and alkaline protease) were performed. + papain, neutral protease + papain), and the most efficient enzyme combination was screened by the oligopeptide rate after virtual enzymatic hydrolysis (the peptides after virtual enzymatic hydrolysis were input into ToxinPred for amino acid sequence analysis: http: / / crdd.osdd.net / raghava / toxinpred / ), and finally treated with pepsin and trypsin (1.0% of the raw material mass, pepsin and trypsin ratio of 1:1) at 37℃ / 5h; then 1.2% proline endoprotease by mass of the raw material was added and treated at 47℃ / 8h, and the oligopeptide rate obtained by enzyme digestion was the highest and the efficiency was the highest.

[0050] ③ Preparation of fish gelatin low molecular peptide:

[0051] Cooking wine immersion ultrasonic cleaning: prepare 5% cooking wine, the mass ratio of fish glue to cooking wine is 1:15, and clean it at 20W / L ultrasonic power for 25 minutes at room temperature; after the end, use clean water, supplemented with the same ultrasonic power, cleaning time and liquid-to-mass ratio, clean the fish glue twice to remove the residual solution of the fish glue during the above steps, and then crush the fish glue raw material.

[0052] Compound enzyme hydrolysis: 1.0% of the weight of the fish glue crumbs was used for decomposition at 37°C for 5 hours with a combination of pepsin and trypsin (the ratio of the two enzymes was 1:1), followed by the addition of 1.2% of proline endoproteinase for decomposition at 45°C for 8 hours, and the resulting collagen solution was heated at 80°C for 20 minutes to inactivate the enzymes, and then centrifuged to remove the residue that could not be hydrolyzed;

[0053] Activated carbon decolorization and fishy removal: add 0.2% powdered activated carbon to the filtered fish gelatin collagen solution, decolorize it at room temperature for 1.0h and then filter it to obtain a decolorized, debittered and fishy fish gelatin collagen stock solution. Subsequently, use a rotary evaporator to reduce pressure and concentrate the fish gelatin content of the stock solution to 120g / L. Finally, sterilize it at 75℃ for 30min, cool it, and spray dry it to obtain the finished product.

[0054] The obtained finished products were tested, and the test results are shown in Tables 1, 2 and Figure 1 .

[0055] Table 1

[0056]

[0057] The obtained fish gelatin peptide has molecules within 1000 Daltons accounting for 91.63% (conforming to the "oligopeptide" standard of GB / T22729-2008 marine fish oligopeptide powder), molecules within 500 Daltons accounting for 61.25%, and the collagen tripeptide content is 16.96%, which has great efficacy potential.

[0058] Table 2

[0059] Serial number Test items Test Data Remark 1 Aspartic acid (Asp), g / 100g 4.86 -- 2 Threonine (Thr), g / 100g 2.32 -- 3 Serine (Ser), g / 100g 2.29 -- 4 Glutamic acid (Glu), g / 100g 7.92 -- 5 Glycine (Gly), g / 100g 17.5 -- 6 Alanine (Ala), g / 100g 8.21 -- 7 Cystine (Cys), g / 100g 0.22 -- 8 Valine (Val), g / 100g 2.27 -- 9 Methionine (Met), g / 100g 1.25 -- 10 Isoleucine (IIe), g / 100g 1.70 -- 11 Leucine (Leu), g / 100g 2.49 -- 12 Tyrosine (Tyr), g / 100g 0.32 -- 13 Phenylalanine (Phe), g / 100g 2.45 -- 14 Lysine (Lys), g / 100g 3.18 -- 15 Histidine (His), g / 100g 0.41 -- 16 Arginine (Arg), g / 100g 6.21 -- 17 Proline (Pro), g / 100g 8.99 -- 18 Tryptophan, mg / kg 486.29 -- 19 Molecular weight distribution See Figure 1 --

[0060] Figure 1 It is the GPC spectrum for molecular weight distribution detection of the product, where the first table is a description of the molecular weight of the detected sample, Mp polymer peak molecular weight; Mn polymer number average molecular weight; Mw polymer weight average molecular weight; Mz polymer viscosity average molecular weight; Mn is generally used to represent the average of all molecular weights; the first column on the left of the second table is each peak, the second column from the left is the highest value of the corresponding peak molecular weight range, the third from the left is the lowest value of the corresponding peak molecular weight range, and the fourth from the left is the proportion of the peak (molecular weight range) in the sample mass (for example, the second row is 5000-5356 molecular weight, accounting for 0.01% of the total). Figure 3The first and second from the left are the products obtained in Example 1, and the powder is fine and white with very weak fishy smell.

[0061] Example 2

[0062] Red fish glue tail material was used, and steps ① and ② were the same as those in Example 1, and only the "compound enzyme hydrolysis" was modified in step ③: 1.0% of the weight of the fish glue scraps was used as a combination of pepsin and trypsin (the ratio of the two enzymes was 1:1) for decomposition at 37°C for 5 hours, and then 1.0% of proline endoproteinase was added for decomposition at 37°C for 5 hours.

[0063] The finished product was tested, and the test results are shown in Table 3 and Figure 2 Molecular weight distribution detection: The oligopeptide content (within 1000 Daltons) of the peptide powder obtained in Example 2 was 78.09%.

[0064] Table 3

[0065]

[0066]

[0067] Figure 2 It is the GPC spectrum of the molecular weight distribution detection of the product, among which the first table is the molecular weight description of the detected sample, Mp polymer peak molecular weight; Mn polymer number average molecular weight; Mw polymer weight average molecular weight; Mz polymer viscosity average molecular weight; Mn is generally used to represent the average value of all molecular weights; the first column on the left of the second table is each peak, the second column from the left is the highest value of the corresponding peak molecular weight range, the third from the left is the lowest value of the corresponding peak molecular weight range, and the fourth from the left is the proportion of the peak (molecular weight range) in the sample mass. Figure 3 The first and second from the right in the middle are the products obtained in Example 2, the powder is yellowish and the fishy smell is stronger than that in Example 1.

[0068] In addition, the prior art does not use trachoma to prepare low molecular peptides; and in terms of low molecular peptide preparation, the enzymatic method is the most important production method, followed by membrane filtration or chromatographic purification to obtain high-purity collagen low molecular peptide powder; the enzymes used are mainly alkaline protease, papain and proline endoprotease; but because the efficiency of the enzyme combination is not high, the sample produced after enzymatic hydrolysis has only a low proportion of oligopeptide content, such as an oligopeptide content of only 5-15%, while the oligopeptide content after purification can be as high as 90%, but the required operating steps and instruments are more complicated. The present invention only needs to perform enzymatic hydrolysis to achieve an oligopeptide content of more than 90%.

Claims

1. A method for preparing fish gelatin collagen peptide with a high content of short peptides, characterized in that: The following steps are involved: S1. Establishing a protein database: Using fish maw scraps as raw materials, enzymatic hydrolysis, liquid chromatography separation and mass spectrometry analysis were performed to obtain protein identification results, and a protein database was established based on the identification data; S2. Enzyme screening: Based on the protein database obtained in step S1, the optimal conditions of the enzyme are queried using the bioinformatics resource platform of the Swiss Institute of Bioinformatics (SIB); after determining the optimal enzymatic hydrolysis conditions, one or more enzymes are selected from pepsin, trypsin, proline endoproteinase, alkaline protease, neutral protease, and papain, and the protein is virtually enzymatically cleaved to obtain the polypeptides contained in the fish glue, and the physicochemical properties of the polypeptides after virtual enzymatic cleavage are predicted using the online website ToxinPred, and the molecular weight distribution of the product is tested and verified, and the enzymatic hydrolysis efficiency is measured by the proportion of small molecular weight, so as to screen out the appropriate enzyme; S3. Preparation of fish gelatin collagen peptides: After the fish gelatin raw material is processed and crushed, it is enzymatically hydrolyzed with the enzyme screened out in step S2, and then centrifugally filtered, sterilized and cooled, and spray-dried to obtain fish gelatin collagen peptide powder with a high content of short peptides.

2. The method for preparing fish gelatin collagen peptide with a high content of short peptides according to claim 1, characterized in that: The fish maw was crushed, 150-200ug of total protein was taken and placed in a 37°C water bath, trypsin was added at a mass ratio of 1:40 for enzyme to protein and enzymatic hydrolysis was carried out overnight. After desalting, the supernatant was taken for nanoliter liquid chromatography separation and then detected and analyzed using a Q-Exactive high-resolution mass spectrometer.

3. The method for preparing fish gelatin collagen peptide with a high content of short peptides according to claim 1, characterized in that: Liquid chromatography separation is specifically: Liquid A used in the liquid phase is a 0.1% formic acid aqueous solution, and liquid B is a 0.1% formic acid acetonitrile aqueous solution, wherein the acetonitrile content is 80%; Liquid chromatography column: 50μm*150mm, Acclaim PepMapTM RSLC, thermo scientific Technology Inc; balanced with 92% A solution, injection volume 1μL was separated by the chromatographic column, and the relevant liquid phase gradient was set as follows: 0min-98min, linear gradient of solution B from 8% to 28%; 98min-113min, linear gradient of solution B from 28% to 37%; 113min-117min, linear gradient of solution B from 37% to 100%; 117min-120min, liquid B is maintained at 100%.

4. The method for preparing fish gelatin collagen peptide with a high content of short peptides according to claim 1, characterized in that: Mass spectrometry analysis is as follows: The enzymatic hydrolysis products were separated by liquid chromatography and analyzed by mass spectrometry using a Q-Exactive high-resolution mass spectrometer. Analysis time: 120 min; Detection method: positive ion; The mass-to-charge ratios of peptides and peptide fragments were collected as follows: After each full scan, 20 fragmentation spectra MS2 scans were collected; the scanning range was 400-1800, the primary resolution was 60000, the secondary resolution was 15000, and the collision energy was CE28 eV; the original mass spectrometry test files were retrieved from the corresponding database using the software Proteome Discoverer 2.5, and finally the protein identification results were obtained, and a protein database was established based on the identification data.

5. The method for preparing fish gelatin collagen peptide with a high content of short peptides according to claim 1, characterized in that: In step S2, the molecular weight distribution of the product is detected and verified as follows: the molecular weight distribution of fish gelatin collagen peptide is determined by HPLC; 5 mg / mL of protein peptide solution treated with relevant enzymes is prepared respectively, treated with a 0.22 μm membrane, and liquid phase determination is performed using TSKgel G2000 SWXL, using acetonitrile containing 0.1% TFA as the mobile phase, the flow rate is 0.8 mL / min, and isocratic elution is performed for analysis, and the molecular weight distribution of the peptide of each sample is calculated by using the logarithm of the molecular weight of the standard and the elution time as a regression equation.

6. The method for preparing fish gelatin collagen peptide with a high content of short peptides according to claim 1, characterized in that: In step S3, 3-6% cooking wine is first prepared, and the mass ratio of the fish glue raw material to the cooking wine is 1: (10-15). The fish glue is cleaned at room temperature with an ultrasonic power of 10-30 W / L for 15-30 minutes. After the cleaning, clean water is used to clean the fish glue 2-3 times with the same ultrasonic power and cleaning time, and then the fish glue raw material is processed and crushed.

7. The method for preparing fish gelatin collagen peptide with a high content of short peptides according to claim 1, characterized in that: The enzymatic hydrolysis in step S3 is specifically as follows: using 0.5-3.0% enzyme to decompose at 35-50°C for 1-18h, heating the collagen solution obtained at 80-90°C for 15-20min to inactivate the enzyme, and centrifugally filtering to remove the residue that cannot be hydrolyzed by the enzyme.

8. The method for preparing fish gelatin collagen peptide with a high content of short peptides according to claim 1, characterized in that: In step S3, after centrifugal filtration, it is subjected to activated carbon deodorization treatment, specifically: 0.1-0.5% powdered activated carbon is added to the filtered fish gelatin collagen solution, and the solution is decolorized for 0.5-1.5 hours at room temperature and then filtered to obtain a decolorized, debittered and deodorized fish gelatin collagen stock solution, and then a rotary evaporator is used to reduce pressure and concentrate the fish gelatin content of the stock solution to 100-150 g / L, sterilized at 75°C for 30 minutes, cooled, and spray-dried to obtain the finished product.

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