Preparation method and application of hippocampal peptide

Abstract

The invention relates to the technical field of food processing, in particular to a preparation method and application of hippocampal peptide. The preparation method of the hippocampal peptide comprises the following steps: performing ultrasonic treatment on a degreased hippocampal powder aqueous solution, and performing vacuum cooking to obtain a first solution; adding hydrolase into the first solution for enzymolysis to obtain a second solution; carrying out alcohol precipitation reaction on the second solution to obtain a third solution and a precipitate; purifying the precipitate to obtain a second hippocampal peptide initial solution; and mixing the hippocampal peptide first initial solution and the hippocampal peptide second initial solution to obtain the hippocampal peptide. And ultrasonic treatment is matched with low-temperature vacuum cooking, so that the hydrolysis degree of the degreased hippocampus powder is improved, the enzymolysis efficiency is improved, and the extraction effect of hippocampus peptide is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of product processing, and specifically relates to a preparation method and application of hippocampal peptide. Background Art

[0002] Seahorse is a precious marine Chinese medicinal material, known as the "ginseng in the sea" in my country, and has high medicinal and health value. China is the main consumer of seahorse, and the Chinese medicinal material market accounts for about 70% of the total global seahorse trading volume. Modern scientific research shows that there are many kinds of chemical components in seahorse, mainly including peptides, amino acids, steroids, fatty acids, trace elements, phospholipids, nucleosides, etc. Animal experimental studies have also shown that seahorse extracts have significant therapeutic effects in anti-inflammatory, antioxidant, anti-fatigue, anti-tumor, sex hormone-like effects and improving the body's immunity.

[0003] Hippocampal peptide can increase the body's ability to tolerate (lack of) oxygen, and has a strong health-care effect in clinical practice. The glycoprotein in hippocampal peptide has anticoagulant, antithrombotic, anti-tumor and lipid-lowering effects, which can prevent central neurodegenerative diseases such as Alzheimer's disease. At the same time, it can also inhibit the polymerization of fibrin monomers and change the structure of fibrin clots, thereby facilitating drug fibrinolysis.

[0004] However, in the related art, when hippocampal peptides are extracted from hippocampus, the peptide recovery rate is low, which is difficult to meet actual needs. Summary of the invention

[0005] In view of the technical problems existing in the prior art, the present invention provides a preparation method and application of hippocampal peptide.

[0006] In the first aspect, the present invention provides a method for preparing hippocampal peptide, which adopts the following technical scheme:

[0007] A method for preparing hippocampal peptide, comprising:

[0008] The defatted seahorse powder aqueous solution is subjected to ultrasonic treatment and then vacuum-cooked to obtain a first solution.

[0009] A hydrolase is added to the first solution for enzymolysis to obtain a second solution.

[0010] The second solution is subjected to alcohol precipitation reaction to obtain a third solution and a precipitate;

[0011] The third solution is used to obtain a first initial hippocampal peptide solution;

[0012] Purifying the precipitate to obtain the second initial solution of hippocampal peptide;

[0013] The first initial solution of hippocampal peptide and the second initial solution of hippocampal peptide are mixed to obtain hippocampal peptide.

[0014] Among them, the hydrolases include: flavor protease and papain.

[0015] By adopting the above technical scheme, ultrasound helps to destroy the cell wall of the hippocampus, promotes the release of solutes, and enters the aqueous solution. In addition, ultrasonic treatment also helps to destroy the structure of the protein, breaking the peptide molecular chain into smaller fragments, making it easier to be hydrolyzed by enzymes, which is conducive to extraction and purification, thereby improving the efficiency of peptide extraction. Vacuum conditions help to reduce the boiling point of water, thereby achieving a cooking effect at a lower temperature and reducing the destruction of heat-sensitive components. Hydrolases can effectively hydrolyze the protein in defatted hippocampus powder into small molecular polypeptides, making it easier to release solutes in hippocampal cells. Alcohol precipitation reaction helps to separate glycoprotein small molecules from the solution to form a precipitate and a third solution containing hippocampal crude peptides. The third solution ultrafiltration membrane intercepts macromolecular impurities and allows small molecular polypeptides to pass through, thereby obtaining a first initial solution of hippocampal peptides with higher purity; and the precipitate rich in glycoproteins is purified (for example, using the Sevage method) to remove free proteins to obtain a second initial solution of hippocampal peptides rich in glycoproteins; the first initial solution of hippocampal peptides and the second initial solution of hippocampal peptides are mixed to obtain a hippocampal peptide solution with higher peptide purity. Papain in the hydrolase can destroy the cell wall and the protein structure inside the cell, and hydrolyze the peptide bonds in the protein molecules into smaller peptides or amino acids. In this process, the solutes in the hippocampal cells can be released more easily. Flavor proteases can further degrade proteins and release the polypeptide fragments therein, so that more hippocampal peptides can be effectively extracted.

[0016] Furthermore, the ultrasonic conditions are as follows: the defatted hippocampus powder aqueous solution is ultrasonically treated for 15 min to 25 min at an ultrasonic power of 500 W to 700 W and an ultrasonic temperature of 40° C. to 60° C.

[0017] By adopting the above technical solution, the release of solutes in cells can be promoted, so that the release of hippocampal peptide is more sufficient, and the destruction of the structure of hippocampal peptide can be avoided, so that the molecular structure of hippocampal peptide can be better preserved, and the extraction effect of hippocampal peptide can be further improved.

[0018] Furthermore, the vacuum cooking conditions are: cooking for 10 min to 30 min at a vacuum degree of 0.03 MPa to 0.07 MPa and a cooking temperature of 45° C. to 65° C.

[0019] By adopting the above technical scheme, vacuum cooking can accelerate the rupture of cell walls at a lower temperature, making it easier for solutes in cells to dissolve, so that the release of hippocampal peptides is more complete; it can also avoid the damage to the structure of hippocampal peptides at high temperatures; and, under vacuum, it can reduce the degradation and denaturation of hippocampal peptides under high temperatures and oxygen, further improving the extraction effect of hippocampal peptides.

[0020] Furthermore, the mass ratio of the hydrolase to the defatted seahorse powder is 0.08 to 0.012.

[0021] By adopting the above technical solution, setting the mass ratio of the hydrolase to the defatted seahorse powder to 0.08-0.012 can fully hydrolyze the protein and promote the complete release of the solute.

[0022] Therefore, the efficiency and quality of extracting hippocampal peptides from hippocampus can be significantly improved by the rational use of hydrolases combined with ultrasonic treatment, vacuum cooking, etc.

[0023] Furthermore, the papain is a modified papain, which is prepared by the following preparation steps: mixing 50 μg / ml to 150 μg / ml succinic anhydride solution, 5 mg / ml to 30 mg / ml papain solution and 15 mmol / L to 35 mmol / L potassium dihydrogen phosphate solution, and reacting for 3 h to 5 h at a temperature of 25° C. to 50° C. and a pH of 5 to 7.

[0024] By adopting the above technical scheme, succinic anhydride is an acid anhydride containing two carboxyl groups, which can react with the amino group of papain to introduce two carboxyl groups, and the ring structure of succinic anhydride opens to form an amide bond with the amino group of papain, thereby changing the surface charge and microenvironment of the enzyme molecule, so that the enzyme activity of the modified papain under alkaline conditions is improved, and the optimal pH value is also shifted toward the alkaline direction.

[0025] Furthermore, the enzymatic hydrolysis conditions are: under the conditions of pH 8-11, temperature 30°C-60°C, and enzymatic hydrolysis time 5h-7h.

[0026] By adopting the above technical scheme, the modified papain and flavor protease can be used to maximize their activity, and the hydrolase can act more effectively on the protein substrate, promoting the rupture of the cell wall and the release of hippocampal peptides. In addition, the modified papain can play a good catalytic role, with enough time to fully react with the substrate, promoting the release of hippocampal peptides.

[0027] Furthermore, before subjecting the second solution to alcohol precipitation reaction, the method further comprises: centrifuging the enzymatic hydrolysate to obtain a supernatant, and then concentrating the supernatant to obtain the second solution.

[0028] By adopting the above-mentioned technical scheme, enzymolysis solution can separate insoluble solid impurities (such as cell debris, incompletely dissolved protein, etc.) from supernatant during centrifugation, thereby obtaining a relatively pure enzymolysis product, which helps to improve the effect of subsequent alcohol precipitation reaction and reduce the interference of impurities. Moreover, the second solution obtained by centrifugation and concentration, its composition and concentration are all more stable, which is conducive to the carrying out of subsequent alcohol precipitation reaction. And, the adding of centrifugation and concentration step can remove impurities and concentrated solution, can make in the same time, improve production efficiency, also reduce production cost.

[0029] Furthermore, the ratio of the volume of the second solution to the volume of ethanol with a volume concentration of 20% to 40% is 1:(1-2).

[0030] By adopting the above technical solution and controlling the amount of ethanol added, the hippocampal glycoprotein can be fully precipitated. Too much ethanol may cause the glycoprotein molecules to aggregate excessively, forming larger particles or clumps.

[0031] Furthermore, the ultrafiltration membrane has a molecular weight cutoff of 2 kDa to 20 kDa.

[0032] By adopting the above technical scheme, hippocampal peptides in different molecular weight ranges can be obtained, for example, PH-I (>20kDa), PH-II (10-20kDa), PH-III (5-10kDa), PH-IV (2.5-5kDa), PH-V (<2.2kDa), and PH-V (<2.5kDa) hippocampal peptide solutions can be obtained to obtain hippocampal peptides rich in hippocampal glycoprotein.

[0033] In a second aspect, the present invention provides an application of hippocampal peptide prepared by any of the above preparation methods in improving the sexual function of rats.

[0034] It can be understood that the beneficial effects of the hippocampal peptide provided by the present invention are the same as the beneficial effects of the hippocampal peptide prepared by any of the above preparation methods, and will not be described in detail here.

[0035] In summary, the present invention includes at least one of the following beneficial technical effects:

[0036] (1) The present invention uses ultrasonic treatment to enhance the speed and frequency of molecular movement of defatted seahorse powder, destroy the tissue cell wall of the seahorse, release the substances in the cells, and soften the structure of the protein. Combined with low-temperature vacuum cooking, the hydrolysis degree of the defatted seahorse powder is improved, which is beneficial to improving the enzymatic hydrolysis efficiency, thereby improving the extraction effect of hippocampal peptides.

[0037] (2) The present invention adjusts the ultrasonic conditions as follows: the defatted hippocampus powder aqueous solution is ultrasonically treated for 15 min to 25 min at an ultrasonic power of 500 W to 700 W and an ultrasonic temperature of 40° C. to 60° C., which can promote the release of solutes in cells, making the release of hippocampus peptide more sufficient, and can also avoid the damage to the structure of hippocampus peptide, so that the molecular structure of hippocampus peptide can be better preserved, further improving the extraction effect of hippocampus peptide.

[0038] (3) The present invention adjusts the vacuum cooking conditions to: a vacuum degree of 0.03MPa to 0.07MPa, a cooking temperature of 45°C to 65°C, and cooking for 10min to 30min, so that the solutes in the cells are more easily dissolved and the release is more complete; it can also avoid the damage to the structure of hippocampal peptides at high temperatures; it can reduce degradation and denaturation under high temperatures and oxygen, and further improve the extraction effect of hippocampal peptides.

[0039] (4) The present invention improves the activity of the enzyme by using modified papain, thereby improving the effect of enzymatic hydrolysis, allowing the modified papain to play a good catalytic role and further improving the extraction effect of hippocampal peptides.

[0040] (5) The present invention realizes the preparation of hippocampal glycoprotein while preparing hippocampal peptides, thereby improving the preparation efficiency and achieving full utilization of precious hippocampal medicinal materials. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with specific embodiments.

[0042] The following raw materials in the present invention are all commercially available products, and are intended to make the raw materials of the present invention fully disclosed, and should not be understood as limiting the source of the raw materials. The preparation of defatted seahorse powder is as follows: the artificially cultivated frozen American lineated seahorses purchased on the market are freeze-dried at -40°C for 48 hours, crushed in a pulverizer, and the seahorse fatty acids are removed by carbon dioxide supercritical fluid extraction technology to obtain defatted seahorse powder. The crude protein content in the defatted seahorse powder is determined to be 68.2±11.3%.

[0043] Preparation Example 1

[0044] Preparation Example 1 provides a modified papain, which is obtained by the following preparation steps:

[0045] 100 μg / ml succinic anhydride solution, 20 mg / ml papain solution and 25 mmol / L potassium dihydrogen phosphate solution were mixed and stirred evenly, and the reaction time was 4 hours at a temperature of 30° C. and a pH of 6.

[0046] Example 1

[0047] Example 1 provides a method for preparing hippocampal peptide, and the operating steps are as follows:

[0048] S1: Dissolve 100 g of defatted seahorse powder in distilled water at a weight ratio of 1:15 between the material and the liquid, stir magnetically for 30 min, then ultrasonically treat for 20 min at an ultrasonic power of 400 W and an ultrasonic temperature of 50°C, seal, and vacuum cook at a vacuum degree of 0.02 MPa and a cooking temperature of 55°C for 20 min to obtain a first solution.

[0049] S2: Add flavor protease and papain to the first solution, perform enzymolysis for 6 hours at a pH of 9.0 and a temperature of 50°C, then inactivate the enzyme at 100°C for 15 minutes, and cool to room temperature to obtain a second solution, in which the mass of flavor protease and papain each accounts for 0.03 of the mass of defatted seahorse powder.

[0050] S3: The second solution was added to 30% ethanol at a ratio of 1:1.5 for alcohol precipitation reaction, and the mixture was allowed to stand at room temperature for 10 hours to obtain a precipitate rich in glycoprotein; and the supernatant was collected to obtain a third solution, which was a crude hippocampal peptide solution.

[0051] S4: The third solution is ultrafiltered using a 2.2 kDa third solution membrane to obtain two peptide fragments of molecular weight PH-I (>2.2 kDa) and PH-II (<2.2 kDa), thereby obtaining the first initial solution of hippocampal peptides.

[0052] S5: The glycoprotein-rich precipitate was subjected to the Sevage method to remove free proteins, and the second initial solution of glycoprotein-rich hippocampal peptides was obtained after extraction three times.

[0053] S6: Mixing the first initial hippocampal peptide solution and the second initial hippocampal peptide solution rich in glycoprotein.

[0054] Example 2

[0055] Example 2 provides a method for preparing hippocampal peptide, which is the same as Example 1, except that, in step S2, before subjecting the second solution to alcohol precipitation reaction, it also includes: centrifuging the enzymatic hydrolyzate at 9000 rpm for 20 min to obtain a supernatant, and then concentrating the supernatant to 1 / 5 of the original volume to obtain a second solution.

[0056] Example 3

[0057] Example 3 provides a method for preparing hippocampal peptide, which is the same as Example 2, except that in step S1, the ultrasonic power is 500 W and the ultrasonic temperature is 50° C. for 20 min.

[0058] Example 4

[0059] Example 4 provides a method for preparing hippocampal peptide, which is the same as Example 2, except that in step S1, the ultrasonic power is 600 W and the ultrasonic temperature is 50° C. for 20 min.

[0060] Example 5

[0061] Example 5 provides a method for preparing hippocampal peptide, which is the same as Example 2, except that in step S1, the ultrasonic power is 700 W and the ultrasonic temperature is 50° C. for 20 min.

[0062] Example 6

[0063] Example 6 provides a method for preparing hippocampal peptide, which is the same as Example 4, except that in step S1, the vacuum degree is 0.03 MPa, the cooking temperature is 55° C., and the cooking time is 20 min.

[0064] Example 7

[0065] Example 7 provides a method for preparing hippocampal peptide, which is the same as Example 4, except that in step S1, the vacuum degree is 0.05 MPa, the cooking temperature is 55° C., and the cooking is performed for 20 min.

[0066] Example 8

[0067] Example 8 provides a method for preparing hippocampal peptide, which is the same as Example 4, except that in step S1, the vacuum degree is 0.07 MPa, the cooking temperature is 55° C., and the cooking time is 20 min.

[0068] Example 9

[0069] Example 9 provides a method for preparing hippocampal peptide, which is the same as Example 7, except that in step S1, the mass of flavor protease and papain each accounts for 0.04 of the mass of defatted hippocampal powder.

[0070] Example 10

[0071] Example 10 provides a method for preparing hippocampal peptide, which is the same as Example 7, except that in step S1, the mass of flavor protease and papain each accounts for 0.05 of the mass of defatted hippocampal powder.

[0072] Embodiment 11

[0073] Example 11 provides a method for preparing hippocampal peptide, which is the same as Example 7, except that in step S1, the mass of flavor protease and papain each accounts for 0.06 of the mass of defatted hippocampal powder.

[0074] Example 12

[0075] Example 12 provides a method for preparing hippocampal peptide, which is the same as Example 10, except that in step S1, an equal amount of papain is replaced with the modified papain prepared in Preparation Example 1.

[0076] Comparative Example 1

[0077] Comparative Example 1 provides a method for preparing hippocampal peptide, which is the same as Example 1, except that in step S1, there is no vacuum cooking step.

[0078] Comparative Example 2

[0079] Comparative Example 2 provides a method for preparing hippocampal peptide, which is the same as Example 1, except that in step S1, there is no ultrasonic treatment step.

[0080] Performance Testing

[0081] The hippocampal peptides obtained in the above examples and comparative examples were assayed for effective components.

[0082] (1) Purity determination of glycoprotein in hippocampal peptide: The glycoprotein obtained in S5 was subjected to DEAE-52 column chromatography and Sephad G-100 column chromatography to determine the purity of the target glycoprotein.

[0083] The purity of the glycoproteins in Example 1 and Example 12 was measured to be 70.9% and 84.7% respectively, indicating that the preparation method of the hippocampal peptide of the present invention can obtain a relatively high content of glycoprotein in the hippocampal peptide.

[0084] (2) Determination of hippocampal peptide yield: The hippocampal peptide yield is the ratio of the total amount of PH-I (>2.2 kDa) and PH-II (<2.2 kDa) collected to the defatted hippocampal whole powder. The results are shown in Table 1.

[0085] Table 1 Test results obtained from the embodiments and comparative examples

[0086]

[0087]

[0088] It can be seen from Table 1 that the peptide yield of the hippocampal peptide obtained by the method for preparing the hippocampal peptide of the present invention is 47.1% to 62.5%, indicating that the method for preparing the hippocampal peptide of the present invention has a good effect of improving the yield of the hippocampal peptide.

[0089] In Example 1 and Example 2, the yield of hippocampal peptide in Example 2 is 49.4%, which is greater than the yield of hippocampal peptide in Example 1, and the extraction effect of hippocampal peptide is improved, indicating that the preparation method of hippocampal peptide in Example 2 has a better effect. This is because before the second solution is subjected to alcohol precipitation reaction, it also includes: centrifuging the enzymatic hydrolyzate to obtain a supernatant, and then concentrating the supernatant to obtain a second solution, which can help improve the effect of the subsequent alcohol precipitation reaction and reduce the interference of impurities.

[0090] In Examples 2 to 5, the yield of hippocampal peptide in Examples 3 to 5 is 51.7% to 54.3%, which is greater than the yield of hippocampal peptide in Example 2, thereby improving the extraction effect of hippocampal peptide, indicating that the preparation method of hippocampal peptide in Examples 3 to 5 has a better effect, which is related to setting the ultrasonic power to 500W to 700W and the ultrasonic temperature to 40°C to 60°C for ultrasonic treatment for 15min to 25min, which can improve the extraction effect of hippocampal peptide.

[0091] In Examples 4 and 6 to 8, the yield of hippocampal peptide in Examples 6 to 8 is 53.7% to 56.3%, which is greater than the peptide yield in Example 4, thereby improving the extraction effect of hippocampal peptide, indicating that the preparation method of hippocampal peptide in Examples 6 to 8 has a better effect, which is related to setting the vacuum degree to 0.03 MPa to 0.07 MPa, the cooking temperature to 45°C to 65°C, and cooking for 10min to 30min, which can improve the extraction effect of hippocampal peptide.

[0092] In Examples 7 and 9 to 11, the peptide yields of Examples 9 to 11 were 59.4% to 62.3%, which was greater than the peptide yield of Example 7, thereby improving the extraction effect of hippocampal peptides. This indicates that the preparation methods of hippocampal peptides of Examples 9 to 11 have better effects, which is related to setting the mass ratio of the hydrolase to the mass of the defatted hippocampal powder to 0.08 to 0.012, which can improve the extraction effect of hippocampal peptides.

[0093] In Example 10 and Example 12, the peptide yield of Example 12 is 62.5%, which is greater than the peptide yield of Example 10, and the extraction effect of hippocampal peptide is improved, indicating that the preparation method of hippocampal peptide in Example 12 has a better effect, which is related to the fact that regulating papain to modified papain can improve enzyme activity.

[0094] Combined with the data indicators of Comparative Example 1 and Comparative Examples 1 to 2, it is shown that the present invention can improve the extraction effect of glycoprotein-rich hippocampal peptides through ultrasonic treatment and low-temperature vacuum cooking.

[0095] The following is the application of glycoprotein-rich hippocampal peptides in improving the sexual function of rats, with a view to applying them in the field of warming kidney and strengthening yang health products.

[0096] The hippocampal peptide extract rich in hippocampal glycoprotein obtained in Example 12 was diluted with polysorbate-80 to a crude drug concentration of 0.10 g / ml.

[0097] Experimental animals: 80 sexually mature 3-month-old SD rats, half male and half female.

[0098] Female rat preparation:

[0099] (1) Ovariectomy: After female rats were anesthetized with ether, they were fixed in a supine position under the last rib of the rat. The psoas muscles were cut open along the scapular line under the left and right ribs to reveal milky white shiny fat masses. After separating the fat, the pink ovaries and uterine horns located outside and below the kidneys on both sides were revealed. A thread was used to ligate the fallopian tubes and fat under the ovaries. The ovaries were cut off. After ensuring that there was no bleeding, the uterine horns were returned to the abdominal cavity, the abdominal muscles and skin were sutured, and the wound was coated with iodine. Penicillin was injected intramuscularly every day for 3 consecutive days after the operation to prevent postoperative infection.

[0100] (2) Postoperative feeding: Forty ovariectomized rats were randomly divided into 8 cages, with 5 rats in each cage, and fed normal food and water every day.

[0101] Male rat preparation:

[0102] 40 male rats were randomly divided into 4 groups, namely blank control group A, low dose group B (0.5 g / kg), medium dose group C (1.0 g / kg), and high dose group D (1.5 g / kg), with 10 rats in each group. The blank control group was given normal saline by gavage at 5 ml / kg, and the other groups were given corresponding drug solutions by gavage at the doses in the table twice a day for 15 consecutive days.

[0103] Mating experiment: 48 hours before the experiment, female rats with ovarian removal were subcutaneously injected with estradiol benzoate 20 ng / rat, and 4 hours before the experiment, progesterone injection 500 ng / rat was subcutaneously injected again. Male rats were placed in a 50×30×20 cm cage for 10 minutes to adapt to the environment, and a female rat was added to each cage for mating experiments.

[0104] After the female mouse was placed in the chamber, the following indicators were observed and recorded: (1) the time from the time the female mouse was placed in the chamber to the time the male mouse first captured the female mouse (capture latency); (2) the time from the time the female mouse was placed in the chamber to the time the male mouse first ejaculated (ejaculation latency); (3) the number of times the male mouse captured the female mouse and the number of times the male mouse ejaculated within 20 min.

[0105] The experimental results are shown in Table 2. It can be seen that after 15 days of administration of different doses of hippocampal water extract, the sexual function of rats was significantly improved. Compared with group A, the capture latency, ejaculation latency, and the number of times male rats captured female rats and ejaculation within 20 minutes in groups C and D were significantly improved (P<0.01). In other words, after 15 days of gavage of hippocampal water extract, each dose group can significantly improve the sexual function of male rats.

[0106] Table 2 Results of application of glycoprotein-rich hippocampal peptides in improving sexual function in rats

[0107] Group Capture latency (s1) Number of captures (n1) Ejaculation latency period (s2) Number of ejaculations (n2) A 305.2±110.4 7.1±2.4 1232.2±462.3 1.3±1.8 B 183.4±57.2 15.6±4.4 933.4±396.4 3.5±1.7 C 138.3±51.9 22.3±5.1 682.7±355.7 6.7±3.2 D 122.5±50.6 31.6±4.8 559.8±319.7 7.5±2.9

[0108] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A method for preparing hippocampal peptide, characterized in that: include: The defatted seahorse powder aqueous solution is subjected to vacuum cooking after ultrasonic treatment to obtain a first solution; Adding a hydrolase to the first solution for enzymolysis to obtain a second solution; The second solution is subjected to alcohol precipitation reaction to obtain a third solution and a precipitate; Ultrafiltration of the third solution to obtain a first initial hippocampal peptide solution; Purifying the precipitate to obtain the second initial solution of hippocampal peptide; Mixing the first initial solution of hippocampal peptide and the second initial solution of hippocampal peptide to obtain hippocampal peptide; Wherein, the hydrolase comprises: flavor protease and papain.

2. The method for preparing hippocampal peptide according to claim 1, characterized in that: The ultrasonic conditions are as follows: the defatted hippocampus powder aqueous solution is ultrasonically treated for 15 min to 25 min at an ultrasonic power of 500 W to 700 W and an ultrasonic temperature of 40° C. to 60° C.

3. The method for preparing hippocampal peptide according to claim 1, characterized in that: The vacuum cooking conditions are: cooking for 10 min to 30 min at a vacuum degree of 0.03 MPa to 0.07 MPa and a cooking temperature of 45° C. to 65° C.

4. The method for preparing hippocampal peptide according to claim 1, characterized in that: The mass ratio of the hydrolase to the defatted seahorse powder is 0.08 to 0.

012.

5. The method for preparing hippocampal peptide according to any one of claims 1 to 4, characterized in that: The papain is a modified papain; The modified papain is obtained by the following preparation steps: 50 μg / ml to 150 μg / ml succinic anhydride solution, 5 mg / ml to 30 mg / ml papain solution and 15 mmol / L to 35 mmol / L potassium dihydrogen phosphate solution are mixed, and the reaction time is 3 hours to 5 hours under the conditions of temperature of 25°C to 50°C and pH of 5 to 7.

6. The method for preparing hippocampal peptide according to claim 1, characterized in that: The enzymatic hydrolysis conditions are: under the conditions of pH 8-11, temperature 30° C.-60° C., and enzymatic hydrolysis time 5 h-7 h.

7. The method for preparing hippocampal peptide according to claim 1, characterized in that: Before subjecting the second solution to alcohol precipitation reaction, the method further comprises: centrifuging the enzymatic hydrolysate to obtain a supernatant, and then concentrating the supernatant to obtain the second solution.

8. The method for preparing hippocampal peptide according to claim 1, characterized in that: The ratio of the volume of the second solution to the volume of ethanol with a volume concentration of 20% to 40% is 1:(1-2).

9. The method for preparing hippocampal peptide according to claim 1, characterized in that: The molecular weight cut-off of the ultrafiltration membrane is 2 kDa to 20 kDa.

10. Use of the hippocampal peptide prepared by the method for preparing the hippocampal peptide according to any one of claims 1 to 9 in improving the sexual function of rats.

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