Oxidation-resistant cod peptide capable of reducing blood sugar and blood pressure and preparation method of oxidation-resistant cod peptide

Abstract

The invention discloses a cod peptide capable of reducing blood sugar and blood pressure and resisting oxidation and a preparation method thereof, and belongs to the technical field of cod peptide preparation, and the preparation method comprises the following steps: 1, primary treatment of cod bones; 2, secondary treatment of cod bones; 3, water extraction of the cod bone freeze-dried powder; 4, fermentation treatment of filter residues; 5, performing enzymolysis treatment; 6, centrifuging the enzymatic hydrolysate, and filtering to obtain supernate; carrying out ultrafiltration on the supernate, wherein the molecular retention is 0.5-10,000 Daltons; and drying at the temperature of 45-50 DEG C to obtain cod peptide powder. Through the mode, the cod peptide prepared by the preparation method disclosed by the invention not only has an effect of reducing blood pressure, but also has a certain effect of reducing blood sugar. Meanwhile, the cod peptide is relatively high in antioxidant activity, can be used as a natural antioxidant peptide, and has potential application prospects in the fields of medicines, foods, skin care products and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of codfish peptide preparation, and in particular to a codfish peptide capable of lowering blood sugar, lowering blood pressure and resisting oxidation and a preparation method thereof. Background Art

[0002] Hypertension (also known as hypertension) refers to an abnormally high level of sustained pressure on the blood vessel walls when blood flows in the blood vessels, and this elevated state exceeds the normal blood pressure range.

[0003] Hyperglycemia refers to blood glucose levels that are higher than normal.

[0005] The renin-angiotensin system (RAS) is one of the basic blood pressure regulation systems in the human body. In the RAS system, renin is hydrolyzed in the blood to produce angiotensin I (Ang I), which is hydrolyzed into angiotensin II (Ang II) under the action of angiotensin I-converting enzyme (ACE), causing vasoconstriction, increasing vascular pressure, and causing a pressor response. Inhibitory peptides can inhibit ACE hydrolysis, thereby lowering blood pressure.

[0006] Current scientific research has shown that ACE inhibitory peptides are a class of bioactive peptides that come from a variety of different biological sources. Because of their excellent ability to improve hypertension, they have now become one of the main research targets in the field of bioactive peptides.

[0007] Due to the long-term use of industrial synthetic drugs to treat high blood pressure and high blood sugar, the human body will develop drug resistance and cause liver toxicity and other problems.

[0008] Cod (Gadus) is a bottom-dwelling fish that feeds mainly on fish, shrimp and other marine life. Cod has a long history of fishing and is also one of the marine aquatic products with the largest catch in the world, occupying an important position in the world's fisheries. At present, the processing of cod products is dominated by primary products such as fresh cod, fish fillets, fish strips, surimi and salted cod, while the market share of deep-processed products is relatively small. Regardless of the production and processing of primary products or the deep processing process, due to factors such as production technology and value considerations, about half of the raw materials will be wasted in the processing process, such as fish bones, fish heads, fish skins, viscera and other processing by-products. These low-utilization by-products are processed into aquaculture feed in small quantities, and the rest are generally processed at low prices or directly discarded. If they are not processed promptly and effectively, it will not only cause a waste of economic resources, but also may cause harm to the local ecological environment.

[0009] As a high-quality seafood, cod is extremely rich in nutritional value, mainly reflected in its high protein content, rich in unsaturated fatty acids (Omega-3 fatty acids), vitamins A and D, and a variety of mineral elements. Cod bones are one of the main by-products produced during cod processing. Fish bones are composed of hard bones and cartilage tissues and have multiple physiological functions. From a morphological point of view, fish bones include skulls, internal bones and fish scales. Fish bones are mainly composed of inorganic hydroxyapatite and organic type I collagen. A large number of scientific studies have shown that the protein content in cod bones can reach one-third of the wet weight, the amino acid content and composition are very rich, and it is easily digested and absorbed by the human body. It is an important source of extracting high-quality collagen and has great economic development value.

[0010] Based on this, the present invention designs a codfish peptide with the effects of lowering blood sugar, lowering blood pressure and resisting oxidation and a preparation method thereof to solve the above problems. Summary of the invention

[0011] In view of the above-mentioned shortcomings of the prior art, the present invention provides a codfish peptide having the effects of lowering blood sugar, lowering blood pressure and resisting oxidation and a preparation method thereof.

[0012] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0013] A method for preparing codfish peptides capable of lowering blood sugar, lowering blood pressure and resisting oxidation comprises the following steps:

[0014] 1. Primary processing of cod bones

[0015] The cod bones are first placed at -20°C for freeze drying, and then crushed into 80-100 meshes to obtain cod bone freeze-dried powder;

[0016] The cod bone freeze-dried powder is first placed in a 25-40% sodium hydroxide solution, and then stirred and alkaline washed for 1.5-5 minutes at 10-15°C and 5-8Mpa;

[0017] Then, the cod bone freeze-dried powder is placed in a 1.3-1.5% sodium chloride solution, and stirred and salt-washed for 30-50 seconds at 35-40°C and 2.5-4.2Mpa;

[0018] 2. Secondary processing of cod bones

[0019] The cod bone freeze-dried powder is placed in a high-temperature steam condition and steamed for 10 to 20 minutes, then placed in a drying condition at 85 to 100°C, and finally placed in a refrigerator at -5 to 0°C and frozen for 10 to 15 minutes;

[0020] 3. Water Extraction of Cod Bone Freeze-dried Powder

[0021] The cod bone freeze-dried powder is put into water to extract the upper extract and the filter residue, and the filter residue is dried for later use;

[0022] 4. Fermentation treatment of filter residue

[0023] Add pomegranate seed polyphenol extract, epigallocatechin gallate and starch into the fermentation tank and mix well;

[0024] Inoculate the filter residue with lactobacillus and bacillus licheniformis, and then put it into a fermentation tank for fermentation;

[0025] 5. Enzymatic treatment

[0026] The upper extract obtained in step 3 and the fermentation product obtained in step 4 are mixed evenly, and a mixture of alkaline protease and pepsin of protease is added, and the mixture is stirred at 50-53° C. for 4-6 hours at a stirring speed of 1000-1300 rpm; and then inactivated at 100-102° C. for 7 minutes;

[0027] 6. The enzymatic hydrolysate is centrifuged and filtered to obtain a supernatant; the supernatant is ultrafiltered with a molecular retention capacity of 0.5 to 10,000 Daltons; and then dried at 45 to 50° C. to obtain codfish peptide powder.

[0028] Furthermore, in step 1, the volume ratio of cod bone freeze-dried powder to sodium hydroxide solution is 1:2-3; the volume ratio of cod bone freeze-dried powder to sodium chloride solution is 1:2-3.

[0029] Furthermore, in step 2, the high temperature steam temperature is 150-175° C., and the steam rate is 25-32 kg / h.

[0030] Furthermore, step three is specifically as follows: putting the cod bone freeze-dried powder into 20 to 30 times the volume of water, stirring and extracting at 40 to 55° C. and 5.5 to 6.2 MPa for 1 to 2 hours to obtain an upper extract and a filter residue, and drying the filter residue for later use.

[0031] Furthermore, in step three, the filter residue is dried at 55-68°C.

[0032] Furthermore, in step 4, the weight ratio of the pomegranate seed polyphenol extract, epigallocatechin gallate and starch is 2-4:6-10:5-9.

[0033] Furthermore, in step 4, the inoculation amount of the lactobacillus and the licheniformis is 0.3×10 6 ~0.5×10 6 CFU / mL, the fermentation temperature was 30-33°C, the fermentation time was 10-12h, and then inactivated at 100-102°C for 7min.

[0034] Furthermore, in step five, the mass ratio of alkaline protease to pepsin is 1:2.

[0035] In order to better achieve the purpose of the present invention, the present invention also provides a codfish peptide prepared by the preparation method for lowering blood sugar, lowering blood pressure and resisting oxidation.

[0036] In order to better achieve the purpose of the present invention, the present invention also provides a use of the hypoglycemic, hypotensive and antioxidant cod peptide in the preparation of hypoglycemic, hypotensive and antioxidant foods or medicines.

[0037] Compared with the prior art, the present invention has the following beneficial effects: the codfish peptide prepared by the present invention not only has a blood pressure lowering effect, but also has a certain blood sugar lowering effect, among which the codfish peptide prepared in Example 2 has the best blood sugar lowering effect, with a reduction rate of 43.9%. At the same time, the codfish peptide has a high antioxidant activity and can be used as a natural antioxidant peptide, with potential application prospects in the fields of medicine, food and skin care products. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 This is the result of hydrophobicity analysis of codfish peptide protein chain;

[0040] Figure 2 It is the target intersection graph and target network graph;

[0041] Figure 3 The results of GO enrichment analysis for codfish peptides in treating hypertension;

[0042] Figure 4 The results of KEGG enrichment analysis for codfish peptides in treating hypertension;

[0043] Figure 5 This is a 3D diagram of molecular docking. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] In some embodiments, a method for preparing a codfish peptide having hypoglycemic, hypotensive and antioxidant effects comprises the following steps:

[0047] 1. Primary processing of cod bones

[0048] The cod bones were first placed at -25°C for freeze drying, and then crushed into 80 meshes to obtain cod bone freeze-dried powder;

[0049] The cod bone freeze-dried powder was first placed in 2 volumes of 40% sodium hydroxide solution, and then stirred and washed at 10°C and 8 MPa for 1.5 min.

[0050] Then, the cod bone freeze-dried powder was placed in 2 volumes of 1.5% sodium chloride solution and stirred for salt washing at 35°C and 4.2 MPa for 30 seconds;

[0051] 2. Secondary processing of cod bones

[0052] The cod bone freeze-dried powder was placed in high-temperature steam for 10 minutes, then dried at 100°C, and finally placed in a refrigerator at -5°C for 15 minutes; the high-temperature steam temperature was 150°C, and the steam rate was 32kg / h;

[0053] 3. Water Extraction of Cod Bone Freeze-dried Powder

[0054] The cod bone freeze-dried powder was placed in 20 times the volume of water, and the extraction time was stirred at 55°C and 5.5Mpa for 2 hours to obtain the upper extract and the filter residue, and the filter residue was dried at 55°C;

[0055] 4. Fermentation treatment of filter residue

[0056] Add 2 parts of pomegranate seed polyphenol extract, 10 parts of epigallocatechin gallate and 5 parts of starch into a fermentation tank and mix well;

[0057] Inoculate the filter residue with lactobacillus and bacillus licheniformis, and then put it into a fermentation tank for fermentation;

[0058] The inoculation amount of Lactobacillus and Bacillus licheniformis was 0.3×10 6 CFU / mL, fermentation temperature was 33°C, fermentation time was 10 h, and then inactivation treatment was performed at 102°C for 7 min;

[0059] 5. Enzymatic treatment

[0060] The upper extract obtained in step 3 and the fermentation product obtained in step 4 are mixed evenly, and a mixture of alkaline protease and pepsin is added, wherein the mass ratio of alkaline protease to pepsin is 1:2; the mixture is stirred at 50°C for 6 hours at a stirring speed of 1000 rpm; and then inactivated at 102°C for 7 minutes;

[0061] 6. The enzymatic hydrolysate is centrifuged and filtered to obtain a supernatant; the supernatant is ultrafiltered with a molecular retention capacity of 0.5 to 10,000 Daltons; and then dried at 45°C to obtain codfish peptide powder.

[0062] The antioxidant activity of cod fish peptide was determined, and its DPPH free radical scavenging rate was 60.50%, and Fe 2+ The chelating capacity is 62.36%.

[0063] Example 2

[0064] In some embodiments, a method for preparing a codfish peptide having hypoglycemic, hypotensive and antioxidant effects comprises the following steps:

[0065] 1. Primary processing of cod bones

[0066] The cod bones were first placed at -40°C for freeze drying, and then crushed into 100 meshes to obtain cod bone freeze-dried powder;

[0067] The cod bone freeze-dried powder was first placed in 3 times the volume of 25% sodium hydroxide solution, and stirred for alkali washing at 15°C and 5Mpa for 5 minutes;

[0068] Then, the cod bone freeze-dried powder was placed in 3 volumes of 1.3% sodium chloride solution and stirred for salt washing at 40°C and 2.5 MPa for 50 seconds;

[0069] 2. Secondary processing of cod bones

[0070] The cod bone freeze-dried powder was steamed under high-temperature steam conditions for 20 minutes, then dried at 85°C, and finally frozen in a refrigerator at 0°C for 10 minutes; the high-temperature steam temperature was 175°C, and the steam rate was 25kg / h;

[0071] 3. Water Extraction of Cod Bone Freeze-dried Powder

[0072] The cod bone freeze-dried powder was placed in 30 times the volume of water, and the extraction time was stirred at 40°C and 6.2Mpa for 1 hour to obtain the upper extract and the filter residue, and the filter residue was dried at 68°C;

[0073] 4. Fermentation treatment of filter residue

[0074] Add 4 parts of pomegranate seed polyphenol extract, 6 parts of epigallocatechin gallate and 9 parts of starch into a fermentation tank and mix well;

[0075] Inoculate the filter residue with lactobacillus and bacillus licheniformis, and then put it into a fermentation tank for fermentation;

[0076] The inoculation amount of the lactobacillus and the licheniformis was 0.5×10 6CFU / mL, fermentation temperature was 30°C, fermentation time was 12 h, and then inactivation treatment was performed at 100°C for 7 min;

[0077] 5. Enzymatic treatment

[0078] The upper extract obtained in step 3 and the fermentation product obtained in step 4 are mixed evenly, and a mixture of alkaline protease and pepsin is added, wherein the mass ratio of alkaline protease to pepsin is 1:2; the mixture is stirred at 53°C for 4 hours at a stirring speed of 1300 rpm; and then inactivated at 100°C for 7 minutes;

[0079] 6. The enzymatic hydrolysate is centrifuged and filtered to obtain a supernatant; the supernatant is ultrafiltered with a molecular retention capacity of 0.5 to 10,000 Daltons; and then dried at 50°C to obtain codfish peptide powder.

[0080] The antioxidant activity of cod fish peptide was determined, and its DPPH free radical scavenging rate was 62.84%, and Fe 2+ The chelating capacity is 60.07%.

[0081] Example 3

[0082] In some embodiments, a method for preparing a codfish peptide having hypoglycemic, hypotensive and antioxidant effects comprises the following steps:

[0083] 1. Primary processing of cod bones

[0084] The cod bones were first placed at -30°C for freeze drying, and then crushed into 90 meshes to obtain cod bone freeze-dried powder;

[0085] The cod bone freeze-dried powder was first placed in 2.5 times the volume of 30% sodium hydroxide solution, and stirred for alkali washing at 12°C and 7.8Mpa for 3 minutes;

[0086] Then, the cod bone freeze-dried powder was placed in 2.3 times the volume of 1.4% sodium chloride solution and stirred for salt washing at 38°C and 4Mpa for 40s;

[0087] 2. Secondary processing of cod bones

[0088] The cod bone freeze-dried powder was steamed under high-temperature steam conditions for 15 minutes, then dried at 90°C, and finally frozen in a refrigerator at -2°C for 13 minutes; the high-temperature steam temperature was 165°C, and the steam rate was 30kg / h;

[0089] 3. Water Extraction of Cod Bone Freeze-dried Powder

[0090] The cod bone freeze-dried powder was placed in 25 times the volume of water, and the extraction time was stirred at 45°C and 5.8Mpa for 1.4 hours to obtain the upper extract and the filter residue, and the filter residue was dried at 58°C;

[0091] 4. Fermentation treatment of filter residue

[0092] Add 2.6 parts of pomegranate seed polyphenol extract, 7 parts of epigallocatechin gallate and 6 parts of starch into a fermentation tank and mix well;

[0093] Inoculate the filter residue with lactobacillus and bacillus licheniformis, and then put it into a fermentation tank for fermentation;

[0094] The inoculation amount of Lactobacillus and Bacillus licheniformis was 0.4×10 6 CFU / mL, fermentation temperature was 32°C, fermentation time was 11h, and then inactivation treatment was performed at 101°C for 7min;

[0095] 5. Enzymatic treatment

[0096] The upper extract obtained in step 3 and the fermentation product obtained in step 4 are mixed evenly, and a mixture of alkaline protease and pepsin is added, wherein the mass ratio of alkaline protease to pepsin is 1:2; the mixture is stirred at 52°C for 5 hours at a stirring speed of 1200 rpm; and then inactivated at 101°C for 7 minutes;

[0097] 6. The enzymatic hydrolysate is centrifuged and filtered to obtain a supernatant; the supernatant is ultrafiltered with a molecular retention capacity of 0.5 to 10,000 Daltons; and then dried at 48°C to obtain codfish peptide powder.

[0098] The antioxidant activity of cod fish peptide was determined, and its DPPH free radical scavenging rate was 67.71%, Fe 2+ The chelating capacity is 64.53%.

[0099] Comparative Example 1

[0100] A method for preparing codfish peptides capable of lowering blood sugar, lowering blood pressure and resisting oxidation comprises the following steps:

[0101] 1. Primary processing of cod bones

[0102] The cod bones were first placed at -30°C for freeze drying, and then crushed into 90 meshes to obtain cod bone freeze-dried powder;

[0103] The cod bone freeze-dried powder was first placed in 2.5 times the volume of 30% sodium hydroxide solution, and stirred for alkali washing at 12°C and 7.8Mpa for 3 minutes;

[0104] Then, the cod bone freeze-dried powder was placed in 2.3 times the volume of 1.4% sodium chloride solution and stirred for salt washing at 38°C and 4Mpa for 40s;

[0105] 2. Water Extraction of Cod Bone Freeze-dried Powder

[0106] The cod bone freeze-dried powder was placed in 25 times the volume of water, and the extraction time was stirred at 45°C and 5.8Mpa for 1.4 hours to obtain the upper extract and the filter residue, and the filter residue was dried at 58°C;

[0107] 3. Fermentation treatment of filter residue

[0108] Add 2.6 parts of pomegranate seed polyphenol extract, 7 parts of epigallocatechin gallate and 6 parts of starch into a fermentation tank and mix well;

[0109] Inoculate the filter residue with lactobacillus and bacillus licheniformis, and then put it into a fermentation tank for fermentation;

[0110] The inoculation amount of Lactobacillus and Bacillus licheniformis was 0.4×10 6 CFU / mL, fermentation temperature was 32°C, fermentation time was 11h, and then inactivation treatment was performed at 101°C for 7min;

[0111] 4. Enzymatic treatment

[0112] The obtained upper extract and the obtained fermentation product were mixed evenly, and a mixture of alkaline protease and pepsin was added, with the mass ratio of alkaline protease to pepsin being 1:2; the mixture was stirred at 52°C for 5 hours with a stirring speed of 1200 rpm; and then inactivated at 101°C for 7 minutes;

[0113] 5. The enzymatic hydrolysate is centrifuged and filtered to obtain a supernatant; the supernatant is ultrafiltered with a molecular retention capacity of 0.5 to 10,000 Daltons; and then dried at 48°C to obtain codfish peptide powder.

[0114] The antioxidant activity of cod fish peptide was determined, and its DPPH free radical scavenging rate was 54.36%, and Fe 2+ The chelating capacity is 52.90%.

[0115] Comparative Example 2

[0116] A method for preparing codfish peptides capable of lowering blood sugar, lowering blood pressure and resisting oxidation comprises the following steps:

[0117] 1. Primary processing of cod bones

[0118] The cod bones were first placed at -30°C for freeze drying, and then crushed into 90 meshes to obtain cod bone freeze-dried powder;

[0119] The cod bone freeze-dried powder was first placed in 2.5 times the volume of 30% sodium hydroxide solution, and stirred for alkali washing at 12°C and 7.8Mpa for 3 minutes;

[0120] Then, the cod bone freeze-dried powder was placed in 2.3 times the volume of 1.4% sodium chloride solution and stirred for salt washing at 38°C and 4Mpa for 40s;

[0121] 2. Secondary processing of cod bones

[0122] The cod bone freeze-dried powder was steamed under high-temperature steam conditions for 15 minutes, then dried at 90°C, and finally frozen in a refrigerator at -2°C for 13 minutes; the high-temperature steam temperature was 165°C, and the steam rate was 30kg / h;

[0123] 3. Water Extraction of Cod Bone Freeze-dried Powder

[0124] The cod bone freeze-dried powder was placed in 25 times the volume of water, and the extraction time was stirred at 45°C and 5.8Mpa for 1.4 hours to obtain the upper extract and the filter residue, and the filter residue was dried at 58°C;

[0125] 4. Fermentation treatment of filter residue

[0126] Add 15.6 parts of starch into the fermentation tank and mix well;

[0127] Inoculate the filter residue with lactobacillus and bacillus licheniformis, and then put it into a fermentation tank for fermentation;

[0128] The inoculation amount of Lactobacillus and Bacillus licheniformis was 0.4×10 6 CFU / mL, fermentation temperature was 32°C, fermentation time was 11h, and then inactivation treatment was performed at 101°C for 7min;

[0129] 5. Enzymatic treatment

[0130] The upper extract obtained in step 3 and the fermentation product obtained in step 4 are mixed evenly, and a mixture of alkaline protease and pepsin is added, wherein the mass ratio of alkaline protease to pepsin is 1:2; the mixture is stirred at 52°C for 5 hours at a stirring speed of 1200 rpm; and then inactivated at 101°C for 7 minutes;

[0131] 6. The enzymatic hydrolysate is centrifuged and filtered to obtain a supernatant; the supernatant is ultrafiltered with a molecular retention capacity of 0.5 to 10,000 Daltons; and then dried at 48°C to obtain codfish peptide powder.

[0132] The antioxidant activity of codfish peptide was determined, and its DPPH free radical scavenging rate was 42.64%, Fe 2+ The chelating capacity is 40.17%.

[0133] Experimental Example 1 Evaluation of Potential Angiotensin Converting Enzyme Inhibitory Peptides in Cod Peptides Prepared in Example 3

[0134] The results are as follows Figure 1 As shown, the results showed that the cod peptide protein chain is rich in hydrophobic amino acids and can be considered as a high-quality protein for obtaining angiotensin-converting enzyme inhibitory peptides.

[0135] Experimental Example 2

[0136] The three-dimensional structure of the codfish peptide was downloaded from the NCBI website and imported into the SwissTargetPrediction website. The relevant targets were predicted and the results were deduplicated, and a total of 102 targets were obtained. Hypertension-related targets were retrieved through databases such as GeneCards, TTD, and OMIM. After all targets were merged and deduplicated, a total of 962 targets related to improving the treatment of hypertension were obtained. The potential targets were intersected with the relevant targets of hypertension, and a Venn diagram was drawn using Venny2.1.0 ( Figure 2 -A), a total of 15 common targets for improving the treatment of hypertension were obtained. The above targets were imported into STRING to construct a target network diagram ( Figure 2 -B). These targets are important targets for treating and improving hypertension.

[0137] Experimental Example 3

[0138] In order to further explore the specific mechanism of action of codfish peptide in treating hypertension, GO enrichment analysis and KEGG enrichment analysis were performed on 15 common targets (P<0.01).

[0139] GO enrichment analysis obtained 10 biological processes (BP), 4 molecular functions (MF) and 4 cellular components (CC), accounting for 55.56%, 22.22% and 2.22% respectively. The results of GO enrichment analysis are as follows Figure 3 . In the biological process category, the target proteins are mainly involved in hypoxia response, blood pressure regulation, angiopoietin receptor pathway, ovulation, negative regulation of response to external stimuli, regulation of hormone levels, rhythmic process, peptide hormone processing, regulation of smooth muscle cell apoptosis process, and regulation of smooth muscle cell proliferation. In the molecular function category, the target proteins affect serine peptidase activity, nitric oxide synthase activity, chromatin binding protein domains, and specific binding. In the cell composition category, the target proteins are distributed in membrane rafts, the outer side of the plasma membrane, the lumen of the endoplasmic reticulum, and the extracellular matrix containing collagen.

[0140] KEGG enrichment analysis revealed four pathways, namely arginine biosynthesis, complement and coagulation cascade, cancer pathway, and diabetic cardiomyopathy. The four pathways were plotted in a bubble diagram ( Figure 4 ).

[0141] Experimental Example 4

[0142] The appropriate conformation of the target protein ACE was selected through the RCSB PDB database, and its corresponding protein three-dimensional structure was obtained: ACE (6p0z) was molecularly docked with the three-dimensional structure of the drug small molecule downloaded from the NCBI website. The results are as follows Figure 5 ACE (6p0z) and codfish peptide are linked by 6 hydrogen bonds, and the binding energy is -5.99 kcal / mol, indicating that ACE and codfish peptide can spontaneously dock, and the bond distance is The main binding site residues involved in hydrogen bonding interactions are ARG-41, SER-39, and ASP-38, with grid sizes of 126, 126, and 120, respectively, and grid centers of -39.465, -24.34, and 124.647.

[0143] The results of molecular docking show that cod peptide can stably bind to multiple amino acid residues on the target protein ACE through hydrogen bonds, and the connection between the two can be spontaneous. Therefore, cod peptide changes the effect of target protein ACE in different signaling pathways, thereby achieving the purpose of treating and improving hypertension.

[0144] Experimental Example 5 Hyperglycemia efficacy test

[0145] Animal selection: Male Wistar rats aged 4-6 weeks were selected.

[0146] Modeling: Rats were fed with high-sugar feed for 4 weeks, fasted for 12 hours, and intraperitoneally injected with 1% streptozotocin solution at 30 mg / kg to prepare a rat diabetes model; then they continued to be fed with high-sugar feed for 1 week, and the fasting blood glucose was measured to be >11 mmol / L, indicating that the modeling was successful.

[0147] Grouping: 60 rats with successful modeling were divided into 6 groups, namely, Example 1-3 groups, Comparative Example 1-2 groups and a blank control group.

[0148] Treatment method: The rats in Example 1-3 and Comparative Example 1-2 were given the prepared cod peptide by intragastric administration at a dose of 120 mg / kg; the blank control group was given normal saline by intragastric administration at a dose of 120 mg / kg. During the drug administration period, the rats in each group continued to be fed with high-sugar feed.

[0149] The rats were fasted for 12 hours but not water, and their tails were cut to collect blood for fasting blood glucose measurement. The mean blood glucose values ​​before and after drug gavage were calculated for each group of rats. The results are shown in Table 1.

[0150] Group Blood glucose value before oral administration mmol / L Blood glucose level after drug administration (mmol / L) Example 1 28.35 18.61 Example 2 28.07 15.74 Example 3 28.31 17.16 Comparative Example 1 28.01 22.61 Comparative Example 2 28.10 23.14 Blank control group 28.14 27.31

[0151] The codfish peptide prepared by the present invention not only has a blood pressure lowering effect, but also has a certain blood sugar lowering effect, among which the codfish peptide prepared in Example 2 has the best blood sugar lowering effect, with a reduction rate of 43.9%. At the same time, the codfish peptide has a high antioxidant activity and can be used as a natural antioxidant peptide, with potential application prospects in the fields of medicine, food and skin care products.

[0152] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a codfish peptide having hypoglycemic, hypotensive and anti-oxidative effects, characterized in that: The following steps are involved:

1. Primary processing of cod bones The cod bones are first placed at -20°C for freeze drying, and then crushed into 80-100 meshes to obtain cod bone freeze-dried powder; The cod bone freeze-dried powder is first placed in a 25-40% sodium hydroxide solution, and then stirred and alkaline washed for 1.5-5 minutes at 10-15°C and 5-8Mpa; Then, the cod bone freeze-dried powder is placed in a 1.3-1.5% sodium chloride solution, and stirred and salt-washed for 30-50 seconds at 35-40°C and 2.5-4.2Mpa; 2. Secondary processing of cod bones The cod bone freeze-dried powder is placed in a high-temperature steam condition and steamed for 10 to 20 minutes, then placed in a drying condition at 85 to 100°C, and finally placed in a refrigerator at -5 to 0°C and frozen for 10 to 15 minutes; 3. Water Extraction of Cod Bone Freeze-dried Powder The cod bone freeze-dried powder is put into water to extract the upper extract and the filter residue, and the filter residue is dried for later use; 4. Fermentation treatment of filter residue Add pomegranate seed polyphenol extract, epigallocatechin gallate and starch into the fermentation tank and mix well; Inoculate the filter residue with lactobacillus and bacillus licheniformis, and then put it into a fermentation tank for fermentation; 5. Enzymatic treatment The upper extract obtained in step 3 and the fermentation product obtained in step 4 are mixed evenly, and a mixture of alkaline protease and pepsin of protease is added, and the mixture is stirred at 50-53° C. for 4-6 hours at a stirring speed of 1000-1300 rpm; and then inactivated at 100-102° C. for 7 minutes; 6. The enzymatic hydrolysate is centrifuged and filtered to obtain a supernatant; the supernatant is ultrafiltered with a molecular retention capacity of 0.5 to 10,000 Daltons; and then dried at 45 to 50° C. to obtain codfish peptide powder.

2. The method for preparing the hypoglycemic, hypotensive and antioxidant codfish peptide according to claim 1, characterized in that: In step 1, the volume ratio of cod bone freeze-dried powder to sodium hydroxide solution is 1:2-3; the volume ratio of cod bone freeze-dried powder to sodium chloride solution is 1:2-3.

3. The method for preparing the hypoglycemic, hypotensive and antioxidant codfish peptide according to claim 2, characterized in that: In step 2, the high temperature steam temperature is 150-175° C., and the steam rate is 25-32 kg / h.

4. The method for preparing the hypoglycemic, hypotensive and antioxidant codfish peptide according to claim 3, characterized in that: Step three is as follows: put the cod bone freeze-dried powder into 20 to 30 times the volume of water, stir and extract at 40 to 55° C. and 5.5 to 6.2 MPa for 1 to 2 hours to obtain the upper extract and filter residue, and dry the filter residue for later use.

5. The method for preparing the hypoglycemic, hypotensive and antioxidant codfish peptide according to claim 4, characterized in that: In step 3, the filter residue is dried at 55-68°C.

6. The method for preparing the hypoglycemic, hypotensive and antioxidant codfish peptide according to claim 5, characterized in that: In step 4, the weight ratio of the pomegranate seed polyphenol extract, epigallocatechin gallate and starch is 2-4:6-10:5-9.

7. The method for preparing the hypoglycemic, hypotensive and anti-oxidative codfish peptide according to claim 6, characterized in that: In step 4, the inoculation amount of Lactobacillus and Bacillus licheniformis is 0.3×10 6 ~0.5×10 6 CFU / mL, the fermentation temperature was 30-33°C, the fermentation time was 10-12h, and then inactivated at 100-102°C for 7min.

8. The method for preparing the hypoglycemic, hypotensive and anti-oxidative codfish peptide according to claim 7, characterized in that: In step 5, the mass ratio of alkaline protease to pepsin is 1:

2.

9. A codfish peptide having the effects of lowering blood sugar, lowering blood pressure and resisting oxidation, prepared according to the preparation method of claim 8.

10. Use of the hypoglycemic, hypotensive and antioxidant codfish peptide according to claim 9 in the preparation of hypoglycemic, hypotensive and antioxidant foods or medicines.

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