Sea cucumber flower polypeptide with lipid-lowering effect as well as preparation method and application of sea cucumber flower polypeptide

Abstract

The invention belongs to the technical field of biological processing, and particularly discloses sea cucumber flower polypeptide with a lipid-lowering effect as well as a preparation method and application of the sea cucumber flower polypeptide. The sea cucumber flower polypeptide with the lipid-lowering effect is composed of oligopeptides with the molecular weight smaller than 1000 Da. And the oligopeptide is one or more of GTGATGTF, FTGIVGSL, LAIGETEF, VGITDIESF, VDDEF and YDDVP, and the oligopeptide is one or more of GTGATGTF, FTGIVGSL, LAIGETEF, VGITDIESF, VDDEF and YDDVP The invention discloses a sea cucumber flower polypeptide with a lipid-lowering effect and a preparation method and application thereof.The inhibition rate of the sea cucumber flower polypeptide on cholesterol esterase and pancreatic lipase is remarkably increased, the adsorption capacity of the sea cucumber flower polypeptide on bile acid is higher, and the sea cucumber flower polypeptide does not contain restriction enzyme cutting sites of pepsase and trypsin and is free of toxic and side effects. The lipid-lowering peptide can resist secondary digestion and degradation after human body ingestion, stably maintain structural integrity and biological activity, and solve the problem that the traditional lipid-lowering peptide is easy to digest and damage the activity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biological processing, and particularly relates to a sea cucumber flower polypeptide with lipid-lowering efficacy as well as a preparation method and application thereof. BACKGROUND

[0002] As a precious natural product for both medicine and food, sea cucumber is rich in polysaccharides, saponins, proteins and other bioactive substances, and has shown significant value in the fields of anti-tumor, antioxidant, immune regulation and the like. Sea cucumber flower, as a main by-product generated in the process of sea cucumber processing, contains sea cucumber internal organs and eggs, has a high protein content of up to 80%, and contains all the nutritional ingredients of sea cucumber body wall, and is a high-quality raw material for preparing bioactive peptides. However, the comprehensive development and utilization of sea cucumber flower is still at a low level, and there is a problem of resource waste.

[0003] Lipid-lowering peptides, as a kind of bioactive substances that can regulate lipid metabolism, have important potential in preventing and improving hyperlipidemia, and can be obtained from plant, animal and microbial proteins through enzymatic hydrolysis. However, most natural active peptides exist in the form of protein fragments in the natural state, and need to be released after enzymatic hydrolysis to have activity, and the functional stability thereof is highly dependent on the complete structure sequence. Once the peptide bond is broken or the spatial structure is changed in the process of human digestion by gastric acid or digestive enzymes, the lipid-lowering activity will be significantly lost.

[0004] In the prior art, the preparation of lipid-lowering peptides mostly adopts traditional enzymatic hydrolysis method, which can obtain peptide fragments with certain activity, but it is difficult to ensure that the peptide fragments resist secondary digestion in the gastrointestinal tract after being taken into the human body. In addition, the research on sea cucumber flower mostly focuses on the active substances of the body wall, and there is a lack of systematic preparation and functional stability research on lipid-lowering peptides in sea cucumber flower byproducts. There is a lack of sea cucumber flower lipid-lowering peptide preparation technology that can efficiently obtain and maintain the structure integrity and activity during the digestion process, which limits the high-value utilization of sea cucumber flower resources and the development of functional lipid-lowering products. Therefore, it is of important theoretical and application value to develop a method for preparing sea cucumber flower polypeptides with anti-digestion ability and stable lipid-lowering activity. SUMMARY

[0005] The present application aims to provide a sea cucumber flower polypeptide with lipid-lowering efficacy as well as a preparation method and application thereof. The sea cucumber flower polypeptide has significantly improved inhibition rates of cholesterol esterase and pancreatic lipase, and stronger adsorption capacity of bile acids. The sea cucumber flower polypeptide does not contain the enzyme cutting sites of pepsin and trypsin, can resist secondary digestion and degradation after being taken into the human body, stably maintains the structure integrity and biological activity, and solves the problem that traditional lipid-lowering peptides are easily digested and destroyed in activity.

[0006] To solve the above technical problems, the technical solution adopted by the present application is as follows: A sea cucumber flower polypeptide with lipid-lowering effect, the sea cucumber flower polypeptide with lipid-lowering effect is composed of short peptides with molecular weight less than 1000 Da; The short peptide is one or more of GTGATGTF, FTGIVGSL, LAIGETEF, VGITDIESF, VDDEF, YDDVP.

[0007] Preferably, the amino acid sequence of the short peptide GTGATGTF is shown as SEQ ID NO:1; The amino acid sequence of the short peptide FTGIVGSL is shown as SEQ ID NO:2; The amino acid sequence of the short peptide LAIGETEF is shown as SEQ ID NO:3; The amino acid sequence of the short peptide VGITDIESF is shown as SEQ ID NO:4; The amino acid sequence of the short peptide VDDEF is shown as SEQ ID NO:5; The amino acid sequence of the short peptide YDDVP is shown as SEQ ID NO:6.

[0008] The application also provides a preparation method of the sea cucumber flower polypeptide, comprising the following steps: S1, freeze-dried powder of sea cucumber flower is dissolved in ice water, and stirring is uniformly carried out to obtain sea cucumber flower homogenate; S2, a n-hexane-absolute ethanol mixed solution is added to the sea cucumber flower homogenate obtained in step S1, extraction is carried out, the upper oil is removed, and defatted sea cucumber flower homogenate is obtained; S3, simulated gastric juice and intestinal juice are added to the defatted sea cucumber flower homogenate obtained in S2, enzyme hydrolysis is carried out, and enzyme hydrolysis is repeated twice, after enzyme hydrolysis is completed, temperature is increased to inactivate the enzyme, centrifugation is carried out, the precipitate is discarded, ultrafiltration is carried out, and sea cucumber flower lipid-lowering polypeptide concentrated solution is obtained; S4, the sea cucumber flower lipid-lowering polypeptide concentrated solution obtained in S3 is freeze-dried to obtain sea cucumber flower lipid-lowering polypeptide.

[0009] Preferably, in S1, the ratio of the freeze-dried powder of sea cucumber flower to the ice water solution is 1:35-45.

[0010] Preferably, in S2, the volume ratio of n-hexane to absolute ethanol in the n-hexane-absolute ethanol mixed solution is 2-4:1.

[0011] Preferably, in S2, the extraction conditions are specifically as follows: extraction is carried out at 50 DEG C for 4-6 h, and extraction is repeated 1-2 times.

[0012] Preferably, in S3, the simulated gastric juice is composed of a gastric electrolyte solution (SGF) and pepsin (2000 U / mL) and is mixed in a volume ratio of 1:0.5-1.5; The simulated intestinal fluid is mixed by the intestinal electrolyte solution (SIF) and pancreatin (100 U / mL) at a volume ratio of 1:0.5-1.5, and 10 mmol / L bile is added to form the simulated intestinal fluid, and 1M HCl is used to keep the pH value stable during the digestion process.

[0013] Preferably, the SGF comprises the following components: 6.9 mmol / L KCl, 0.9 mmol / L KH2PO4, 25 mmol / L NaHCO3, 47.2 mmol / L NaCl, 0.1 mmol / L MgCl2(H2O)6, 0.5 mmol / L (NH4)2CO3, 15.6 mmol / L HCl. The SIF comprises the following components: 6.8 mmol / L KCl, 0.8 mmol / L KH2PO4, 85 mmol / L NaHCO3, 38.4 mmol / L NaCl, 0.33 mmol / L MgCl2(H2O)6, 8.4 mmol / L HCl.

[0014] Preferably, in S3, the volume ratio of the simulated gastric fluid, the simulated intestinal fluid and the defatted sea cucumber flower homogenate is 1-2:10.

[0015] Preferably, in S3, after the simulated gastric fluid is added, the pH value is adjusted to 2.0-5.0, and the reaction is carried out at a temperature of 30-40℃ for 60-150 min; after the simulated intestinal fluid is added, the pH value is adjusted to 7.0-9.0, and the reaction is carried out at a temperature of 35-38℃ for 60-120 min.

[0016] Preferably, in S3, after the enzymolysis is completed, the temperature is increased to 85-95℃ to inactivate the enzyme, and centrifugation is carried out at 8000-10000 r / min for 5-15 min, and ultrafiltration is carried out to obtain a sea cucumber flower lipid-lowering polypeptide concentrate.

[0017] Preferably, in S4, the freeze-drying temperature is-75--55℃, and the freeze-drying time is 48-72 h.

[0018] The application also provides the use of the sea cucumber flower polypeptide in the preparation of a functional health product.

[0019] The application also provides the use of the sea cucumber flower polypeptide in the preparation of a health product with a lipid-lowering effect.

[0020] Compared with the prior art, the application has the following advantages and technical effects: The application discloses sea cucumber flower polypeptide with lipid-lowering efficacy as well as a preparation method and application thereof.

[0021] The application fully utilizes sea cucumber by-products, converts resources with a protein content of 80% into high-value lipid-lowering polypeptides, realizes comprehensive utilization of biological resources, and provides high-quality raw materials for the field of functional food and health products.

[0022] The technical solutions of the application are further described in detail below with the aid of drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A statistical graph of the inhibition rate of the sea cucumber flower lipid-lowering polypeptide provided for example 1 on cholesterol esterase; Figure 2 A statistical graph of the adsorption rate of the sea cucumber flower lipid-lowering polypeptide provided for example 1 on bile acid; Figure 3 A statistical graph of the inhibition rate of the sea cucumber flower lipid-lowering polypeptide provided for example 1 on pancreatic lipase; Figure 4 A structural formula of sea cucumber flower lipid-lowering short peptide GTGATGTF provided for example 1; Figure 5 A structural formula of sea cucumber flower lipid-lowering short peptide VDDEF provided for example 1; Figure 6 A structural formula of sea cucumber flower lipid-lowering short peptide FTGIVGSL provided for example 1; Figure 7 A structural formula of sea cucumber flower lipid-lowering short peptide VGITDIESF provided for example 1; Figure 8 A structural formula of sea cucumber flower lipid-lowering short peptide YDDVP provided for example 1; Figure 9 A structural formula of sea cucumber flower lipid-lowering short peptide LAIGETEF provided for example 1. DETAILED DESCRIPTION

[0024] The technical solutions of the application are further described in detail below with the aid of drawings and examples.

[0025] Unless otherwise defined, technical terms or scientific terms used in the present application shall have the ordinary meanings as understood by a person with ordinary skills in the art to which the present application pertains.

[0026] In the present application, unless otherwise specified, other test materials and instruments and equipment are conventional test materials in the art, which can be purchased through commercial channels.

[0027] In the present application, the gastric electrolyte solution (SGF) is configured as follows: 6.9 mL of 6.9 mmol / L KCl, 0.9 mL of 0.9 mmol / L KH2PO4, 12.5 mL of 25 mmol / L NaHCO3, 11.8 mL of 47.2 mmol / L NaCl, 0.4 mL of 0.1 mmol / L MgCl2(H2O)6, 0.5 mL of 0.5 mmol / L (NH4)2CO3, and 1.3 mL of 15.6 mmol / L HCl are dissolved in 400 mL of distilled water to prepare the SGF.

[0028] The intestinal electrolyte solution (SIF) is configured as follows: 6.8 mL of 6.8 mmol / L KCl, 0.8 mL of 0.8 mmol / L KH2PO4, 42.5 mL of 85 mmol / L NaHCO3, 9.6 mL of 38.4 mmol / L NaCl, 1.1 mL of 0.33 mmol / L MgCl2(H2O)6, and 0.7 mL of 8.4 mmol / L HCl are dissolved in 400 mL of distilled water to prepare the SIF.

[0029] The simulated gastric juice is prepared by mixing the SGF and pepsin (2000 U / mL) at a volume ratio of 1:1; The simulated intestinal juice is prepared by mixing the SIF and pancreatin (100 U / mL) at a volume ratio of 1:1 and adding 10 mmol / L bile, and 1M HCl is used to maintain the pH value stable during the digestion process.

[0030] Example 1 A preparation method of a sea cucumber flower polypeptide having lipid-lowering efficacy, comprising the following steps: S1, sea cucumber flower freeze-dried powder is dissolved in ice water at a solid-liquid ratio of 1:40, stirred uniformly, and sea cucumber flower homogenate is obtained; S2, a mixture of n-hexane and anhydrous ethanol at a volume ratio of 2:1 is added to the sea cucumber flower homogenate obtained in step S1, and extraction is carried out at 50℃ for 6h, the upper oil is removed, and defatted sea cucumber flower homogenate is obtained; S3, adding simulated gastric juice to the defatted sea cucumber flower homogenate obtained in S2, adjusting pH to 2.0, and carrying out enzymolysis for 120 min at a temperature of 37℃, then adding simulated intestinal juice to adjust pH to 7.0, and carrying out enzymolysis for 120 min at a temperature of 37℃, while maintaining pH stable with 1M HCl during the digestion process. After the enzymolysis is completed, the temperature is raised to 90℃ to inactivate the enzyme, centrifugation is carried out at 8000 r / min for 15 min, the precipitate is discarded, and ultrafiltration is carried out with 3000 Da and 1000 Da ultrafiltration membranes to obtain sea cucumber flower lipid-reducing polypeptide concentrated liquids of three different components (component 1 is a polypeptide with a molecular weight of less than 1000 Da, component 2 is a polypeptide with a molecular weight of 1000-3000 Da, and component 3 is a polypeptide with a molecular weight of more than 3000 Da); S4, freeze-drying the sea cucumber flower lipid-reducing polypeptide concentrated liquid obtained in S3 at -55℃ for 72 h to obtain sea cucumber flower lipid-reducing polypeptides.

[0031] Example 2 A preparation method of sea cucumber flower polypeptides with lipid-reducing efficacy, comprising the following steps: S1, dissolving sea cucumber flower freeze-dried powder in ice water at a solid-liquid ratio of 1:35, and stirring uniformly to obtain sea cucumber flower homogenate; S2, adding a mixture of n-hexane and anhydrous ethanol with a volume ratio of 3:1 to the sea cucumber flower homogenate obtained in step S1, and extracting at 50℃ for 4 h to remove the upper layer of oil and fat, thereby obtaining defatted sea cucumber flower homogenate; S3, adding simulated gastric juice to the defatted sea cucumber flower homogenate obtained in S2, adjusting pH to 3.0, and carrying out enzymolysis for 60 min at a temperature of 30℃, then adding simulated intestinal juice to adjust pH to 8.0, and carrying out enzymolysis for 60 min at a temperature of 35℃, while maintaining pH stable with 1M HCl during the digestion process. After the enzymolysis is completed, the temperature is raised to 85℃ to inactivate the enzyme, centrifugation is carried out at 9000 r / min for 10 min, the precipitate is discarded, and ultrafiltration is carried out with 3000 Da and 1000 Da ultrafiltration membranes to obtain sea cucumber flower lipid-reducing polypeptide concentrated liquids of three different components (component 1 is a polypeptide with a molecular weight of less than 1000 Da, component 2 is a polypeptide with a molecular weight of 1000-3000 Da, and component 3 is a polypeptide with a molecular weight of more than 3000 Da); S4, freeze-drying the sea cucumber flower lipid-reducing polypeptide concentrated liquid obtained in S3 at -65℃ for 60 h to obtain sea cucumber flower lipid-reducing polypeptides.

[0032] Example 3 A preparation method of sea cucumber flower polypeptides with lipid-reducing efficacy, comprising the following steps: S1, dissolving sea cucumber flower freeze-dried powder in ice water at a solid-liquid ratio of 1:45, and stirring uniformly to obtain sea cucumber flower homogenate; S2, adding the homogenate of sea cucumber flower obtained in step S1 with a mixture of n-hexane and anhydrous ethanol in a volume ratio of 4:1, extracting at 50℃ for 5h, removing the upper oil, and obtaining defatted sea cucumber flower homogenate; S3, adding simulated gastric juice to the defatted sea cucumber flower homogenate obtained in S2, adjusting pH to 4.0, and enzymatically digesting at 40℃ for 90min, then adding simulated intestinal juice to adjust pH to 9.0, and enzymatically digesting at 38℃ for 90min, while maintaining pH with 1M HCl during the digestion process. After the enzymatic digestion, the temperature was raised to 95℃ to inactivate the enzyme, centrifuged at 10000r / min for 10min, the precipitate was discarded, and ultrafiltration was performed with 3000Da and 1000Da ultrafiltration membranes to obtain three different components of sea cucumber flower lipid-lowering polypeptide concentrate (component 1 is polypeptide with molecular weight below 1000Da, component 2 is polypeptide with molecular weight between 1000-3000Da, and component 3 is polypeptide with molecular weight above 3000Da); S4, freeze-drying the sea cucumber flower lipid-lowering polypeptide concentrate obtained in S3 at -75℃ for 48h to obtain sea cucumber flower lipid-lowering polypeptide.

[0033] The sea cucumber flower lipid-lowering polypeptide prepared in Example 1 was verified for its effect through the following tests.

[0034] 1. According to the effect of in vitro lipid-lowering experiment, the component less than 1000Da obtained is determined as the polypeptide component with the best lipid-lowering effect.

[0035] The in vitro lipid-lowering activity was determined according to the following test scheme: The PNPB (4mmol / L) was dissolved in acetonitrile and stored at -20℃. The polypeptide solution and cholesterol esterase were dissolved in ultrapure water. The reaction was carried out in a phosphate buffer (0.1mol / L, pH=7) containing sodium taurocholate (5.16mmol / L) and NaCl (0.1mol / L). PNPB was added to start the reaction, which was carried out at 25.0℃ for 30min, and then allowed to stand for 3min. The absorbance value was measured at 405nm.

[0036] ; In the formula: A1 is the blank group; A2 is the blank control group; A3 is the sample group; and A4 is the sample control group.

[0037] The three components obtained in Example 1 were subjected to control experiments respectively, and the cholesterol esterase activity inhibition system is shown in Table 1.

[0038] Table 1 Cholesterol esterase activity inhibition system ;

[0039] The results are shown in Table 1. Figure 1 ​

[0040] From Figure 1 It can be seen that the polypeptide with a molecular weight below 1000 Da has the highest inhibition rate on cholesterol lipase, indicating that it has good inhibitory effect on cholesterol esterase. This part of the component is the sea cucumber flower lipid-lowering polypeptide. Cholesterol esterase is a very important enzyme in the process of cholesterol ester. Cholesterol ester can be absorbed by the human body only after being hydrolyzed into free cholesterol and combined with other substances to form cholesterol micelles. The sea cucumber flower lipid-lowering polypeptide can reduce the absorption of cholesterol in the human body by inhibiting the activity of cholesterol esterase, thereby playing a role in lowering blood lipid and preventing the occurrence of high blood lipid.

[0041] The adsorption effect of the sea cucumber flower lipid-lowering polypeptide provided in the above embodiment 1 on bile acid was determined, and the specific test scheme was as follows: Different masses (1, 5, 10, 15, 20, 25 mg) of polypeptide samples were weighed, 1 mL of 0.01M HCl was used to simulate normal human body temperature gastric juice digestion for 1 h, then 0.1 mM cholate 4 mL and porcine pancreatic enzyme (10 mg / mL) 5 mL were added to each sample, and 37℃ continuous oscillation incubation was carried out for 1 h. After centrifugation at 4000 r / min for 40 min, the supernatant was collected for determination of unabsorbed bile acid. The determination method was as follows: 2.5 mL of supernatant was taken in a test tube, 7.5 mL of 60% H2SO4 was added, and it was reacted at 70℃ water bath for 25 min. After cooling to room temperature, the absorbance was measured at 387 nm, and the buffer solution was used as blank control. The adsorption rate of each bile acid was calculated according to the formula: ; In the formula: A0 is the control group (phosphate buffer instead of cholate solution); A1 is the sample group; A 盐 is the blank group (phosphate buffer solution instead of sample solution).

[0042] The three components obtained in embodiment 1 were subjected to control experiments respectively, and the results are shown in Figure 2 .

[0043] From Figure 2 It can be seen that the polypeptide with a molecular weight below 1000 Da has the highest inhibition rate on cholesterol lipase, indicating that it has good inhibitory effect on cholesterol esterase. This part of the component is the sea cucumber flower lipid-lowering polypeptide. Cholesterol esterase is a very important enzyme in the process of cholesterol ester. Cholesterol ester can be absorbed by the human body only after being hydrolyzed into free cholesterol and combined with other substances to form cholesterol micelles. The sea cucumber flower lipid-lowering polypeptide can reduce the absorption of cholesterol in the human body by inhibiting the activity of cholesterol esterase, thereby playing a role in lowering blood lipid and preventing the occurrence of high blood lipid.

[0044] The adsorption effect of the sea cucumber flower lipid-lowering polypeptide provided in the above embodiment 1 on bile acid was determined, and the specific test scheme was as follows: First, 4-nitrobenzene laurate was dissolved in 5 mmol / L sodium acetate solution (containing 1% Trition X-100) to prepare a 0.8 mg / mL 4-nitrobenzene laurate solution. Pancreatic lipase, PBS solution, polypeptide solutions of various concentrations, and 4-nitrobenzene laurate were added to 96-well plates, respectively. After reacting at 37°C for 30 min, the absorbance was measured at 405 nm, and the inhibition rate was calculated using the formula.

[0045] ; In the formula, A1 is the positive control, A0 is the negative control, B1 is the experimental group, and B0 is the control group.

[0046] The three groups obtained in Example 1 were subjected to control experiments, and the pancreatic lipase activity inhibition system is shown in Table 2.

[0047] Table 2 Pancreatic lipase activity inhibition system ;

[0048] The results are as follows Figure 3 As shown.

[0049] Depend on Figure 3 It is known that peptides with a molecular weight below 1000 Da exhibit the highest inhibition rate against pancreatic lipase, indicating that they have the best lipid-lowering effect. Pancreatic lipase (PL), produced by pancreatic acinar cells, is responsible for hydrolyzing dietary triglycerides into diacylglycerols, monoacylglycerols, glycerols, and fatty acid anions. Inhibiting the activity of pancreatic lipase can effectively reduce the absorption efficiency of fat in the small intestine, thereby achieving the purpose of lowering lipids.

[0050] The component with the best lipid-lowering effect was selected, and its polypeptide sequence was identified using UPLC-MS. The specific experimental protocol is as follows: 1. Liquid Chromatography Conditions: The instrument was an ultra-high performance liquid chromatograph (UHPLC), with a C18 column. Mobile phase A consisted of double-distilled water containing 0.1% formic acid, and mobile phase B consisted of acetonitrile solution containing 0.1% formic acid. The flow rate was 0.5 mL / min, and the temperature was 40℃. The gradient conditions were as follows: 0-2.5 min: maintain 99% A solution and 1% B solution; 2.5-5 min: increase B solution from 1% to 5% and decrease A solution from 99% to 95%; 5-10 min: increase B solution from 5% to 10% and decrease A solution from 95% to 90%; 10-30 min: increase B solution from 10% to 25% and decrease A solution from 90% to 75%; 31-35 min: increase B solution from 25% to 40% and decrease A solution from 75% to 60%; 36-40 min:

[0051] 2. Mass spectrometry conditions: The mass spectrometer was a Thermo QE Orbitrap. The ion mode was ESI. +, mass range 50-2000 m / z; Capillary 3.0 kV; Sampling Cone 35.0 V; Ion Source Temperature 105 °C; Desolvation Temperature 350 °C; Cone Gas Flow 50.0 L / h; Desolvation Gas Flow: 600.0 L / Hr; Collision Energy: 6.0 eV; Collision Gas Flow: 0.6 mL / min; Scan Time: 0.26 sec; Internal Scan Time: 0.02 sec.

[0052] The identified polypeptide sequences are: GTGATGTF, FTGIVGSL, LAIGETEF, VGITDIESF, VDDEF, YDDVP, and the structural formula is as shown in Figures 4-9 The amino acid sequence of the short peptide GTGATGTF is as shown in SEQ ID NO: 1.

[0053] SEQ ID NO: 1: Gly-Thr-Gly-Ala-Thr-Gly-Thr-Phe. The amino acid sequence of the short peptide FTGIVGSL is as shown in SEQ ID NO: 2.

[0054] SEQ ID NO: 2: Phe-Thr-Gly-Ile-Val-Gly-Ser-Leu. The amino acid sequence of the short peptide LAIGETEF is as shown in SEQ ID NO: 3.

[0055] SEQ ID NO: 3: Leu-Ala-Ile-Gly-Glu-Thr-Glu-Phe. The amino acid sequence of the short peptide VGITDIESF is as shown in SEQ ID NO: 4.

[0056] SEQ ID NO: 4: Val-Gly-Ile-Thr-Asp-Ile-Glu-Ser-Phe. The amino acid sequence of the short peptide VDDEF is as shown in SEQ ID NO: 5.

[0057] SEQ ID NO: 5: Val-Asp-Asp-Glu-Phe. The amino acid sequence of the short peptide YDDVP is as shown in SEQ ID NO: 6.

[0058] SEQ ID NO: 6: Tyr-Asp-Asp-Val-Pro.

[0059] ​It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A sea cucumber flower polypeptide having lipid-lowering efficacy, characterized in that, The sea cucumber flower polypeptide with lipid-lowering efficacy is composed of short peptides with a molecular weight less than 1000 Da. The short peptides are one or more of GTGATGTF, FTGIVGSL, LAIGETEF, VGITDIESF, VDDEF and YDDVP.

2. The polypeptide of claim 1, wherein, The amino acid sequence of the short peptide GTGATGTF is shown as SEQ ID NO:

1. The amino acid sequence of the short peptide FTGIVGSL is shown as SEQ ID NO:

2. The amino acid sequence of the short peptide LAIGETEF is shown as SEQ ID NO:

3. The amino acid sequence of the short peptide VGITDIESF is shown as SEQ ID NO:

4. The amino acid sequence of the short peptide VDDEF is shown as SEQ ID NO:

5. The amino acid sequence of the short peptide YDDVP is shown as SEQ ID NO:

6.

3. The method for preparing sea cucumber flower polypeptide according to any one of claims 1-2, characterized in that, The method comprises the following steps: S1, sea cucumber flower freeze-dried powder is dissolved in ice water, and stirred uniformly to obtain sea cucumber flower homogenate; S2, a n-hexane-absolute ethanol mixed solution is added to the sea cucumber flower homogenate obtained in step S1, and extracted to remove the upper oil and fat, thereby obtaining defatted sea cucumber flower homogenate; S3, simulated gastric juice and intestinal juice are added to the defatted sea cucumber flower homogenate obtained in step S2, and enzymatically hydrolyzed, and the enzymatic hydrolysis is repeated twice; after the enzymatic hydrolysis is completed, the enzyme is inactivated by heating, centrifuged, the precipitate is discarded, and ultrafiltration is performed to obtain sea cucumber flower lipid-lowering polypeptide concentrate; S4, the sea cucumber flower lipid-lowering polypeptide concentrate obtained in step S3 is freeze-dried to obtain sea cucumber flower lipid-lowering polypeptide.

4. The preparation method according to claim 3, characterized in that, In S1, the ratio of sea cucumber flower freeze-dried powder to ice water is 1:35-45.

5. The preparation method according to claim 3, characterized in that, In S2, the volume ratio of n-hexane to absolute ethanol in the n-hexane-absolute ethanol mixed solution is 2-4:

1.

6. The preparation method according to claim 3, characterized in that, In S2, the extraction conditions are specifically as follows: extraction at 50℃ for 4-6h, and repeated extraction for 1-2 times.

7. The preparation method according to claim 3, characterized in that, In S3, after the enzymatic hydrolysis is completed, the enzyme is inactivated by heating to 85-95℃, and centrifuged at 8000-10000r / min for 10-15min.

8. The preparation method according to claim 3, characterized in that, In S4, the freeze-drying temperature is-75--55℃, and the freeze-drying time is 48-72h.

9. The sea cucumber flower polypeptide of claim 1 is used in the preparation of functional health products.

10. The sea cucumber flower polypeptide of claim 1 is used in the preparation of health products with lipid-lowering efficacy.

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