A method for preparing fish protein peptide

Abstract

The application discloses a preparation method of fish protein peptide and belongs to the technical field of bioactive peptide preparation. The method takes fish meat as raw material, grinds and slushes the fish meat, then adds protein glutamine enzyme to carry out deamidation treatment, and then adds alkaline protease for enzymolysis, and finally, fish protein peptide is prepared through enzyme inactivation, centrifugation, concentration and spray drying. The deamidation treatment converts glutamine residues in fish protein into glutamic acid residues without cutting the peptide bond. On the one hand, the deamidation treatment increases the negative charge on the surface of the protein, expands the protein structure, and improves the subsequent enzymolysis degree and peptide yield without the need for physical pretreatment such as ultrasonic treatment. On the other hand, the deamidation treatment reduces the hydrophobicity of the obtained peptide segment, reduces the bitterness of the product and gives it umami without the need for microbial fermentation or exopeptidase de-bittering. The obtained fish protein peptide has low bitterness, high proportion of small molecule peptides, good antioxidant and angiotensin converting enzyme inhibition activity, the process is green and simple, and is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of bioactive peptide preparation technology, specifically to a method for preparing fish protein peptides. Background Technology

[0002] Fish protein peptides are a mixture of polypeptides obtained by hydrolyzing fish proteins. Their molecular weight lies between that of amino acids and proteins, making them easily digestible and absorbable, and highly water-soluble. They often exhibit physiological activities such as antioxidant activity and inhibition of angiotensin-converting enzyme, and are widely used in functional foods and foods for special medical purposes. my country is rich in fish resources and processing byproducts, making the conversion of these resources into high-value-added fish protein peptides of great significance.

[0003] Fish protein peptides are typically obtained by enzymatic hydrolysis of fish meat using proteases. However, the natural fish protein structure is dense, making it difficult for proteases to fully access the internal peptide bonds, resulting in low hydrolysis efficiency and peptide yield. Furthermore, when proteases cleave peptide bonds, hydrophobic amino acids embedded within the protein are exposed at the peptide ends, forming bitter peptides, leading to a strong bitter taste and poor mouthfeel. To improve hydrolysis efficiency, existing technologies often employ physical pretreatments such as ultrasound and microwaves to assist hydrolysis, but these methods are energy-intensive, require sophisticated equipment, and do not improve the bitterness of the product. To reduce bitterness, existing technologies often employ further enzymatic hydrolysis with exopeptidases or introduce microbial fermentation for debittering. For example, CN102499318A discloses a freshwater fish hydrolyzed protein powder and its preparation method, which involves mixing fish paste with animal protein hydrolysates and flavor proteases for enzymatic hydrolysis, followed by fermentation with active dry yeast to remove the fishy and bitter taste. This debittering method is lengthy, costly, and the fermentation process is easily affected by fluctuations in microbial strains and conditions.

[0004] Deamidation is a method to improve protein properties. Previous studies have shown that deamidation of proteins such as soybean, wheat, and casein using protein glutaminase can convert glutamine residues into glutamate residues, increasing the negative charge on the protein surface, improving solubility, and reducing the bitterness of the hydrolysates to some extent without cleaving peptide bonds. However, current technologies have not yet effectively combined deamidation with enzymatic hydrolysis for the preparation of fish protein peptides, nor have they achieved the simultaneous improvement of enzymatic hydrolysis efficiency, reduction of bitterness, and maintenance of high biological activity without relying on physical pretreatment and microbial fermentation.

[0005] Therefore, it is necessary to provide a method for preparing fish protein peptides that can improve enzymatic hydrolysis efficiency, reduce the bitterness of the product, and maintain high activity. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing fish protein peptides, in order to solve the problems of low enzymatic hydrolysis efficiency, bitter taste of products, high energy consumption and complicated procedures caused by reliance on physical pretreatment or microbial fermentation in existing preparation methods.

[0007] To achieve the above objectives, the present invention adopts the following technical solution, comprising the following steps: S1, raw material pretreatment: fish meat is washed, deboned, minced, and mixed with water to obtain fish meat slurry, with a material-to-liquid ratio of 1:2 to 1:4, wherein the material-to-liquid ratio is the ratio of fish meat mass to added water volume, expressed in g / mL; S2, deamidation treatment: the pH of the fish meat slurry is adjusted to 6.0 to 7.0, the temperature is raised to 50 to 60°C, and protein glutaminase is added for deamidation treatment to obtain a deamidated slurry, wherein the amount of protein glutaminase added is 10 to 30 U / g based on the substrate protein content, and the treatment time is 1 to 3 hours; S3, enzymatic hydrolysis: the pH of the deamidated slurry is adjusted to 8.0 to 9.0, the temperature is raised to 50 to 60°C, and alkaline protease is added for enzymatic hydrolysis to obtain an enzymatic hydrolysate, wherein the amount of alkaline protease added is 2000 to 4000 U / g based on the substrate protein content, and the enzymatic hydrolysis time is 2 to 4 hours; S4, Enzyme inactivation: Heat the enzyme hydrolysate to 90-95℃ and maintain for 10-15 min; S5, Centrifugation: Centrifuge the enzyme-inactivated solution and collect the supernatant. The centrifugation speed is 8000-10000 r / min and the centrifugation time is 15-20 min; S6, Concentration and drying: Concentrate the supernatant and dry it to obtain fish protein peptides.

[0008] Preferably, the fish meat mentioned in step S1 is one or more of the following: tilapia, silver carp, bighead carp, and cod.

[0009] Preferably, the material-to-liquid ratio in step S1 is 1:2.5 to 1:3.5.

[0010] Preferably, in step S2, the amount of protein glutaminase added is 15-25 U / g based on the substrate protein content, the pH is 6.2-6.8, the temperature is 52-58℃, and the treatment time is 1.5-2.5h.

[0011] Preferably, in step S3, the amount of alkaline protease added is 2500–3500 U / g based on the substrate protein content, the pH is 8.2–8.8, the temperature is 52–58℃, and the enzymatic hydrolysis time is 2.5–3.5 h.

[0012] Preferably, in step S4, the enzyme inactivation temperature is 92-95°C and the enzyme inactivation time is 10-12 min.

[0013] Preferably, in step S5, the centrifugation speed is 9000-10000 r / min and the centrifugation time is 15-18 min.

[0014] Preferably, in step S6, the supernatant is concentrated under reduced pressure to a solid content of 20-40% before being spray-dried.

[0015] Preferably, in step S6, the inlet air temperature of the spray dryer is 160-180°C, and the outlet air temperature is 70-90°C.

[0016] The main reactions in the above deamidation and enzymatic hydrolysis processes are as follows, where P represents the peptide backbone, R... 1 R 2 This represents a group on the peptide chain. In deamidation, protein glutaminase catalyzes the conversion of the amide group on the side chain of glutamine residues to a carboxyl group, as shown in the following reaction formula: P-CH2CH2-CONH2 + H2O → (protein glutaminase) P-CH2CH2-COOH + NH3 In enzymatic hydrolysis, alkaline protease catalyzes the hydrolysis of peptide bonds in proteins and peptides. The reaction formula is as follows: R 1 -CO-NH-R 2 + H2O → (Alkaline protease) R 1 -COOH + H2N-R 2 This invention deamidizes fish protein before enzymatic hydrolysis. Protein glutaminase specifically converts the amide group of the glutamine residue side chain into a carboxyl group without cleaving the peptide backbone. The pKa of the carboxyl group of the glutamate residue side chain is approximately 4.25. Under the pH conditions of step S2, most of this carboxyl group dissociates into a negatively charged carboxylate group, and the released ammonia exists mainly in the form of ammonium ions. Therefore, deamidation significantly increases the negative charge of fish protein and peptides. On the one hand, it increases the electrostatic repulsion between protein molecules, lowers the isoelectric point, unfolds the tightly folded protein structure, and improves solubility, thereby increasing the contact area between alkaline protease and substrate and exposing more peptide bonds that can be cleaved. This increases the degree of hydrolysis and peptide yield in subsequent enzymatic hydrolysis, and enriches the product into small peptide molecules, eliminating the need for physical pretreatment such as ultrasound or microwave. On the other hand, the hydrophobicity of peptides is the main reason for their bitterness. Deamidation further reduces the hydrophobicity of peptides, thereby reducing the bitterness of fish protein peptides. At the same time, the formation of glutamate residues imparts umami flavor to the product, eliminating the need for debittering with exopeptidases or microbial fermentation. Deamidation performed before enzymatic hydrolysis is superior to enzymatic hydrolysis in terms of improving hydrolysis efficiency and inhibiting bitterness. Furthermore, the acidic groups introduced by deamidation and the peptides released by enzymatic hydrolysis have the ability to chelate metal ions, scavenge free radicals, and inhibit angiotensin-converting enzyme, thus maintaining high product activity.

[0017] The technical effects achieved by this invention are: 1. This invention introduces deamidation before enzymatic hydrolysis, which expands and improves the solubility of fish protein. It improves the degree of hydrolysis and the yield of fish protein peptides without the need for physical pretreatment such as ultrasound or microwave. It has low energy consumption and simple equipment. 2. This invention reduces the hydrophobicity of peptides by deamidation, thereby reducing the bitterness of fish protein peptides and imparting umami flavor without the need for exopeptidase or microbial fermentation, simplifying the process and avoiding quality fluctuations caused by fermentation. 3. The fish protein peptides obtained by this invention have a high proportion of small molecule peptides, good antioxidant and angiotensin-converting enzyme inhibitory activities, are easily absorbed by the body, and the process is green and simple, making it suitable for industrial production. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise stated, the methods used in the following embodiments are conventional methods.

[0019] The main raw materials and reagents used in the following examples and comparative examples are as follows: Fresh tilapia meat, purchased from a local seafood market, with a crude protein content of approximately 18.5%; Protein glutaminase, trade name Protein Glutaminase "Amano" 500, with an enzyme activity of approximately 5.0 × 10⁻⁶. 2 U / g, purchased from Amano Enzyme Co., Ltd.; food-grade alkaline protease, enzyme activity 2.0 × 10⁻⁶. 5 U / g, purchased from Ningxia Xiasheng Industrial Group Co., Ltd.; o-phthalaldehyde, dithiothreitol, L-serine, 1,1-diphenyl-2-trinitrophenylhydrazine, caffeine, and chromatographically pure acetonitrile, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; hydrochloric acid, sodium hydroxide, trichloroacetic acid, ethyl acetate, copper sulfate and potassium sodium tartrate used in the biuret method, and sulfuric acid, potassium sulfate, and boric acid used in the Kjeldahl nitrogen determination, all were analytical grade and purchased from Sinopharm Chemical Reagent Co., Ltd.; angiotensin-converting enzyme, hippuryl-histyl-leucine, and gel permeation chromatography molecular weight standards were purchased from Sigma-Aldrich. In all cases, the amounts of protein glutaminase and alkaline protease added were calculated based on the substrate protein content in the fish meat.

[0020] Example 1

[0021] A method for preparing fish protein peptides includes the following steps: S1, taking fresh tilapia meat, washing, deboning, and mincing it, adding deionized water at a material-to-liquid ratio of 1:3 to obtain a fish meat slurry; S2, adjusting the pH of the fish meat slurry to 6.5 with hydrochloric acid solution, heating to 55℃, adding 20 U / g protein glutaminase based on substrate protein, and stirring at this temperature for 2 hours to obtain a deamidated slurry; S3, adjusting the pH of the deamidated slurry to 8.5 with sodium hydroxide solution, heating to 55℃, adding 3000 U / g alkaline protease based on substrate protein, and stirring at this temperature for 3 hours to obtain an enzymatic hydrolysate; S4, heating the enzymatic hydrolysate to 93℃ and maintaining it for 12 minutes to inactivate the enzyme; S5, centrifuging the enzyme-inactivated solution at 9000 r / min for 18 minutes and collecting the supernatant. S6. The supernatant is concentrated under reduced pressure to a solid content of 30%, and then spray-dried. The inlet air temperature of the spray dryer is 170℃ and the outlet air temperature is 80℃ to obtain fish protein peptides.

[0022] Example 2

[0023] A method for preparing fish protein peptides includes the following steps: S1, taking fresh tilapia meat, washing, deboning, and mincing it, adding deionized water at a material-to-liquid ratio of 1:2 to obtain a fish meat slurry; S2, adjusting the pH of the fish meat slurry to 6.0 with hydrochloric acid solution, heating to 50℃, adding 10 U / g protein glutaminase based on substrate protein, and stirring at this temperature for 1 h to obtain a deamidated slurry; S3, adjusting the pH of the deamidated slurry to 8.0 with sodium hydroxide solution, heating to 50℃, adding 2000 U / g alkaline protease based on substrate protein, and stirring at this temperature for 2 h to obtain an enzymatic hydrolysate; S4, heating the enzymatic hydrolysate to 90℃ and maintaining it for 10 min to inactivate the enzyme; S5, centrifuging the enzyme-inactivated solution at 8000 r / min for 15 min and collecting the supernatant. S6. The supernatant is concentrated under reduced pressure to a solid content of 20%, and then spray-dried. The inlet air temperature of the spray dryer is 160℃ and the outlet air temperature is 70℃, thus obtaining fish protein peptides.

[0024] Example 3

[0025] A method for preparing fish protein peptides includes the following steps: S1, taking fresh tilapia meat, washing, deboning, and mincing it, adding deionized water at a material-to-liquid ratio of 1:4 to obtain a fish meat slurry; S2, adjusting the pH of the fish meat slurry to 7.0 with hydrochloric acid solution, heating to 60℃, adding 30 U / g protein glutaminase based on substrate protein, and stirring at this temperature for 3 hours to obtain a deamidated slurry; S3, adjusting the pH of the deamidated slurry to 9.0 with sodium hydroxide solution, heating to 60℃, adding 4000 U / g alkaline protease based on substrate protein, and stirring at this temperature for 4 hours to obtain an enzymatic hydrolysate; S4, heating the enzymatic hydrolysate to 95℃ and maintaining it for 15 minutes to inactivate the enzyme; S5, centrifuging the enzyme-inactivated solution at 10000 r / min for 20 minutes and collecting the supernatant. S6. The supernatant is concentrated under reduced pressure to a solid content of 40%, and then spray-dried. The inlet air temperature of the spray dryer is 180℃ and the outlet air temperature is 90℃ to obtain fish protein peptides.

[0026] Comparative Example 1 The only difference between this comparative example and Example 1 is that the deamidation treatment in step S2 is omitted. That is, after the fish meat slurry is mashed, protein glutaminase is not added. Instead, the pH is directly adjusted and alkaline protease is added for enzymatic hydrolysis. The remaining steps, parameters and raw materials are the same as in Example 1.

[0027] Comparative Example 2 The only difference between this comparative example and Example 1 is that the deamidation treatment in step S2 is replaced by ultrasonic pretreatment. That is, after the fish meat slurry is mashed, protein glutaminase is not added, but ultrasonic treatment is carried out at an ultrasonic power of 400W, an ultrasonic frequency of 30kHz, and a temperature of 45℃ for 22 minutes. Then the pH is adjusted and alkaline protease is added for enzymatic hydrolysis. The remaining steps, parameters and raw materials are the same as in Example 1.

[0028] Comparative Example 3 The only difference between this comparative example and Example 1 is that the order of deamidation and enzymatic hydrolysis is reversed. After the fish meat slurry is mashed, the pH is first adjusted to 8.5, the temperature is raised to 55°C, and 3000 U / g alkaline protease is added according to the substrate protein to hydrolyze for 3 hours. After the enzymatic hydrolysis is completed, the temperature is raised to 93°C and held for 12 minutes to inactivate the alkaline protease. Then the liquid is cooled and the pH is adjusted to 6.5. At 55°C, 20 U / g protein glutaminase is added according to the substrate protein to treat for 2 hours. Subsequently, enzyme inactivation, centrifugation, concentration and drying are carried out according to the conditions of Example 1. The remaining steps, parameters and raw materials are the same as those in Example 1.

[0029] The fish protein peptides prepared in Examples 1-3 and Comparative Examples 1-3 were tested for degree of hydrolysis, peptide yield, bitterness value, peak area ratio of peptides with molecular weight less than 1000 Da, DPPH free radical scavenging rate and angiotensin-converting enzyme inhibition rate, respectively. The results are shown in Tables 1 and 2.

[0030] The above indicators were determined as follows. The degree of hydrolysis was determined using the phthalaldehyde method. The sample solution was mixed with fresh phthalaldehyde reagent, reacted at room temperature for 2 minutes, and the absorbance was measured at 340 nm. The amount of free amino groups was calculated using L-serine as a standard curve. The total number of peptide bonds in fish protein was calculated as 8.0 mmol / g, expressed as a percentage of the number of broken peptide bonds relative to the total number of peptide bonds. Peptide yield was expressed as a percentage of the mass of soluble peptides in the supernatant relative to the crude protein mass of the raw fish meat. The soluble peptide content in the supernatant was determined using the biuret method. The biuret reaction only reacts with peptide bonds and not with the free ammonia released during deamidation, thus avoiding overestimation of peptide yield due to inorganic nitrogen released during deamidation. The crude protein content of the raw fish meat was determined using the Kjeldahl method, with a nitrogen conversion factor of 6.25. Bitterness was determined using a sensory evaluation method. The sample was prepared as a 10 mg / mL aqueous solution, and ten trained evaluators scored it from 0 to 9 points using different concentrations of caffeine solution as a reference. 0 points represented no bitterness, and 9 points represented extremely bitterness; the average value was taken. The peak area percentage of peptides with a molecular weight less than 1000 Da was determined using high-performance gel permeation chromatography (HPLC). A gel column for peptide analysis was used, with acetonitrile-water-trifluoroacetic acid as the mobile phase and a detection wavelength of 220 nm. A standard curve of molecular weight logarithm versus retention time was plotted using known molecular weight standards. The peak area percentage, rather than the absolute mass fraction, was calculated using the peak area normalization method. DPPH free radical scavenging rate determination: The sample was prepared into a 5 mg / mL solution and mixed with an equal volume of 0.1 mmol / L DPPH anhydrous ethanol solution. The mixture was reacted at room temperature in the dark for 30 min, and the absorbance was measured at 517 nm. The scavenging rate was calculated as [1 - (A1 - A2) ÷ A0] × 100%, where A1 is the absorbance of the sample after reacting with DPPH, A2 is the background of the sample with anhydrous ethanol instead of DPPH, and A0 is the blank with distilled water instead of the sample. Angiotensin-converting enzyme inhibition rate determination: The sample was prepared into a 1 mg / mL solution, mixed with hippuryl-histyl-leucine substrate, and then angiotensin-converting enzyme was added. The reaction was carried out at 37℃ for 30 min, and hydrochloric acid was added to terminate the reaction. The hippuric acid generated was extracted with ethyl acetate and the absorbance was measured at 228 nm. The inhibition rate was calculated as [(A control - A sample) ÷ (A control - A blank)] × 100%, where A control is the absorbance of hippuric acid without sample, A sample is the absorbance of hippuric acid with sample, and A blank is the absorbance without enzyme.

[0031] Table 1. Degree of hydrolysis, peptide yield, bitterness value, and percentage of small molecule peptide peak area of ​​fish protein peptides obtained in the examples and comparative examples.

[0032] Table 2. Antioxidant and angiotensin-converting enzyme inhibitory activities of the fish protein peptides obtained in the Examples and Comparative Examples

[0033] As shown in Tables 1 and 2, the fish protein peptides obtained in Examples 1-3 were superior to the comparative examples in terms of degree of hydrolysis, peptide yield, bitterness value, proportion of small molecule peptide peak area, DPPH free radical scavenging rate, and angiotensin-converting enzyme inhibition rate. Comparative Example 1, without deamidation treatment, had a compact protein structure and low solubility, making it difficult for the enzyme to function fully. Therefore, the degree of hydrolysis, peptide yield, and proportion of small molecule peptide peak area all decreased significantly. Simultaneously, the peptide fragments were highly hydrophobic, resulting in a bitterness value as high as 6.5 and low activity, indicating that deamidation treatment plays a crucial role in improving enzymatic hydrolysis efficiency, reducing bitterness, and enhancing activity. Comparative Example 2 used ultrasonic pretreatment instead of deamidation. Although ultrasound could disrupt the protein structure to some extent and increase the degree of hydrolysis and peptide yield compared to Comparative Example 1, it could not change the hydrophobicity of the peptide fragments. The bitterness value remained as high as 6.0, and the activity was lower than in the examples, indicating that simple physical pretreatment cannot achieve the debittering and quality improvement effects of deamidation. Comparative Example 3 reversed the order of deamidation and enzymatic hydrolysis, performing enzymatic hydrolysis and enzyme inactivation first, followed by deamidation. In this case, deamidation acts on the already generated peptides rather than the complete protein, and cannot improve the enzymatic hydrolysis efficiency by unfolding the protein structure. Therefore, the degree of hydrolysis, peptide yield, and proportion of small molecule peptide peak area are similar to those of Comparative Example 1. At the same time, deamidation can only partially reduce the hydrophobicity of the generated peptides. Although the bitterness value is lower than that of Comparative Example 1, the debittering effect is not as good as the example where deamidation is performed first and then enzymatic hydrolysis. This shows that the order of deamidation first and then enzymatic hydrolysis is indispensable for balancing enzymatic hydrolysis efficiency and low bitterness. In addition, although the degree of hydrolysis and proportion of small molecule peptide peak area are slightly higher in Example 3, due to the excessive degree of deamidation and enzymatic hydrolysis, some active peptides are further degraded, and its activity is slightly lower than that of Example 1. This indicates that moderate treatment conditions are more conducive to balancing product yield and activity.

[0034] Unless otherwise specified, all raw materials used in the above embodiments and comparative examples of this invention are commercially available. The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for preparing fish protein peptides, characterized in that, Includes the following steps: S1, Raw material pretreatment: The fish meat is washed, deboned, minced, and then mixed with water to obtain fish meat slurry. The material-to-liquid ratio is 1:2 to 1:4, where the material-to-liquid ratio is the ratio of the mass of the fish meat to the volume of the added water, expressed in g / mL. S2, Deamidation treatment: Adjust the pH of the fish meat slurry to 6.0-7.0, raise the temperature to 50-60℃, add protein glutaminase to perform deamidation treatment to obtain deamidated slurry. The amount of protein glutaminase added is 10-30 U / g based on the substrate protein content, and the treatment time is 1-3 h. S3, Enzymatic hydrolysis: Adjust the pH of the deamidated slurry to 8.0-9.0, heat to 50-60℃, add alkaline protease to hydrolyze and obtain the hydrolysate. The amount of alkaline protease added is 2000-4000 U / g based on the substrate protein content, and the hydrolysis time is 2-4 h. S4, Enzyme inactivation: Heat the enzyme hydrolysate to 90-95℃ and maintain it for 10-15 minutes; S5, Centrifugation: After centrifuging the enzyme-inactivated liquid, take the supernatant. The centrifugation speed is 8000-10000 r / min and the centrifugation time is 15-20 min. S6, Concentration and Drying: The supernatant is concentrated and then dried to obtain fish protein peptides.

2. The method for preparing fish protein peptides according to claim 1, characterized in that, The fish meat mentioned in step S1 is one or more of the following: tilapia, silver carp, bighead carp, and cod.

3. The method for preparing fish protein peptides according to claim 1, characterized in that, The material-to-liquid ratio in step S1 is 1:2.5 to 1:3.

5.

4. The method for preparing fish protein peptides according to claim 1, characterized in that, In step S2, the amount of protein glutaminase added is 15–25 U / g based on the substrate protein content, the pH is 6.2–6.8, the temperature is 52–58℃, and the treatment time is 1.5–2.5 h.

5. The method for preparing fish protein peptides according to claim 1, characterized in that, In step S3, the amount of alkaline protease added is 2500–3500 U / g based on the substrate protein content, the pH is 8.2–8.8, the temperature is 52–58℃, and the enzymatic hydrolysis time is 2.5–3.5 h.

6. The method for preparing fish protein peptides according to claim 1, characterized in that, In step S4, the enzyme inactivation temperature is 92–95℃, and the enzyme inactivation time is 10–12 min.

7. The method for preparing fish protein peptides according to claim 1, characterized in that, In step S5, the centrifugation speed is 9000-10000 r / min and the centrifugation time is 15-18 min.

8. The method for preparing fish protein peptides according to claim 1, characterized in that, In step S6, the supernatant is concentrated under reduced pressure to a solids content of 20-40% before being spray-dried.

9. The method for preparing fish protein peptides according to claim 1, characterized in that, In step S6, the inlet air temperature of the spray dryer is 160-180°C, and the outlet air temperature is 70-90°C.

10. A fish protein peptide, characterized in that, The fish protein peptide is prepared by the method for preparing a fish protein peptide according to any one of claims 1 to 9.

Images