CN107095312A - A kind of krill polypeptide formulations with reducing blood lipid ability and preparation method thereof - Google Patents

Abstract

The invention belongs to the field of Antarctic krill processing, in particular to an Antarctic krill polypeptide preparation with blood lipid-lowering ability and a preparation method thereof. The method uses frozen Antarctic krill powder as a raw material, and undergoes crushing, electron beam irradiation-ultrasonic treatment, compound enzymolysis, ultrafiltration, and freeze-drying to prepare the Antarctic krill polypeptide. The invention combines electron beam irradiation technology and ultrasonic treatment, can effectively improve the enzymatic hydrolysis speed of Antarctic krill, and improve the blood lipid-lowering ability of the enzymatic hydrolysis product. On the other hand, using controllable enzymatic hydrolysis technology, by controlling the hydrolysis conditions and degree of hydrolysis, as many peptide products as possible can be obtained with the target molecular weight distribution, and at the same time, the enzymatic hydrolysis can be well preserved under relatively mild enzymatic hydrolysis conditions. The nutritional value of the product is extremely high. In addition, the present invention utilizes a filter membrane bag to filter the enzymatic hydrolysis product, and finally the obtained Antarctic krill polypeptide has a molecular weight of less than 7000 Da, has high purity, and has obvious blood lipid-lowering effect.

Description

An Antarctic krill polypeptide preparation with blood lipid-lowering ability and preparation method thereof

technical field

The invention belongs to the field of Antarctic krill processing, in particular to an Antarctic krill polypeptide preparation with blood lipid-lowering ability and a preparation method thereof.

Background technique

In recent years, due to the characteristics of high protein, low fat and rich trace elements, seafood has been highly praised by people. The Antarctic krill has the characteristics of large biomass and wide distribution, so more and more researchers have begun to pay attention to the development and utilization of krill.

Although Antarctic krill is small in size, it has high nutritional value. Its protein content is rich, up to 16.31%, while its fat content is relatively low, only 1.3%. Therefore, it has the potential to develop health food. At the same time, Antarctic krill is rich in trace elements needed by the human body, and its total amount can reach 2.76% of the whole shrimp, which is higher than that of Japanese prawns (1.6%), clams (2.2%) and other daily edible seafood.

The muscles of Antarctic krill are rich in various proteins, and there are as many as 18 kinds of amino acids in its hydrolyzed products, and the glutamic acid content can account for about 11% of the dry weight, which is significantly higher than that in tiger shrimp, tuna, and beef. Glutamic acid content, and it includes all 8 essential amino acids (Essential amino acid, EAA) required by the human body: among them, the content of lysine, which represents the nutritional characteristics, is also considerable. In addition, the essential amino acid (EAA) in the Antarctic krill whole shrimp accounts for 45% of the total amino acid (TAA), and the ratio to the non-essential amino acid (NEAA) is greater than 0.8. The above two ratios just meet the ideal recommended by FAO/WHO. The protein pattern (EAA:TAA≈40%, EAA:NEAA≥60%) is more suitable for the absorption and utilization of the human body.

In recent years, marine bioactive peptides have become a research hotspot in the field of food. Antarctic krill is rich in protein and essential amino acids. It is a high-quality protein raw material for the preparation of protein and bioactive peptides, and has potential huge commercial value. At present, there are few studies on bioactive peptides of Antarctic krill. Therefore, it is necessary to conduct in-depth research on the preparation and biological activity of Antarctic krill polypeptides.

Natural bioactive peptides include active peptides that exist in various systems, organs, tissues, and cells of organisms and some secondary metabolites of organisms, such as peptide hormones, antibiotics, etc. The content of these natural bioactive peptides in the organism is extremely low, and it is very difficult to extract them. Therefore, it is difficult to produce on a large scale and form an industrialization, but it is more economical and convenient to add exogenous enzymes to enzymatically hydrolyze tissue proteins, and then screen out peptides with specific functions. Preparation of polypeptides.

The production of biologically active peptides by enzyme preparations has many advantages: (1) It can deal with a large amount of waste generated by fishery, animal husbandry, etc., and the waste generated after enzyme preparation treatment is less than other processing methods, which is conducive to protecting the environment. (2) Because the enzyme preparation has a high degree of specificity, it is easier to identify the composition and various physical and chemical properties of the product. (3) The conditions required by the enzymatic hydrolysis method are generally mild conditions at normal temperature and pressure, which can reduce energy consumption and have better safety. (4) No expensive production equipment is required, the cost is low, and it is convenient for large-scale, low-cost, and industrialized production. (5) The raw materials mainly come from low-value fish and shrimp, animal offal, etc. The raw materials are cheap and cost-effective, which is conducive to improving market competitiveness.

The choice of protease is the key to the preparation of marine bioactive peptides by enzymatic hydrolysis. Each protease has a specific cleavage site, and the hydrolyzate produced by using different proteases to hydrolyze the same protein has different physical, chemical and functional properties. At present, the enzymatic hydrolysis process of Antarctic krill adopts single-enzyme hydrolysis, and the polypeptide structure obtained by this method is often relatively simple and the biological activity is relatively limited. Compound enzymatic hydrolysis uses a variety of proteases to cut proteins, so that more abundant target peptides can be obtained and their biological activity can be improved. At the same time, the molecular weight of the obtained peptides is also shorter, which is more conducive to being absorbed and utilized by the human body.

Contents of the invention

The purpose of the present invention is to provide an Antarctic krill polypeptide preparation with blood lipid-lowering ability and a preparation method thereof, which can efficiently and rapidly prepare target peptides with strong blood lipid-lowering ability.

For realizing above-mentioned technical purpose, the present invention adopts technical scheme as follows:

An Antarctic krill polypeptide preparation with blood lipid-lowering ability, the polypeptide preparation is composed of polypeptides produced by enzymolysis of Antarctic krill powder by elastase and serine carboxypeptidase, and the molecular weight of the polypeptide is below 7000Da.

A preparation method of an Antarctic krill polypeptide preparation with blood lipid-lowering ability, which uses frozen Antarctic krill powder as a raw material, and undergoes crushing, electron beam irradiation-ultrasonic treatment, compound enzymolysis, ultrafiltration, and freeze-drying to obtain a finished product. Specifically include the following steps:

1) Pulverization: the frozen Antarctic krill powder is pulverized into fine powder with a pulverizer;

2) Electron beam irradiation-ultrasonic treatment: place the Antarctic krill powder obtained in step 1) in an electron linear accelerator for irradiation treatment, the radiation intensity is 1.5-3KGy, and then the solid-liquid weight ratio is 1:12-1: Dissolve Antarctic krill powder in deionized water at a ratio of 25, stir magnetically for 15-35 minutes, and finally perform ultrasonic treatment. The ultrasonic conditions are: 300-500W, 40-65°C, 15-30 minutes to obtain Antarctic krill solution ;

3) Composite enzymatic hydrolysis: adjust the pH of the Antarctic krill solution obtained in step 2) to 7.5-11.0, add elastase at a ratio of 2500-3500U/g Antarctic krill, and enzymolyze it in a water bath at 25-40°C for 20 ~45 minutes; after cooling to room temperature, adjust the pH of the solution to 7.5~9.5 again, add serine carboxypeptidase at a ratio of 3000~4000U/g Antarctic krill, and enzymatically hydrolyze in a water bath for 30~40 minutes under the condition of 30~45℃ , and finally inactivate the enzyme in a boiling water bath for 15 to 20 minutes, then centrifuge to take the supernatant, and obtain the enzymatic hydrolyzate of Antarctic krill;

4) Filtration: perform ultrafiltration on the Antarctic krill enzymatic hydrolyzate with ultrafiltration membranes with a molecular weight cut-off of 10,000Da and 7,000Da in sequence to obtain an Antarctic krill polypeptide liquid with a molecular weight of less than 7,000Da;

5) Drying: Use hydrochloric acid to adjust the pH of the Antarctic krill polypeptide solution obtained in step 4) to 2.7-3.2, filter, collect the filtrate, and let it stand at 4°C overnight; use an oil-water separation type high-speed tubular centrifuge to remove grease, collect heavy Liquid phase (aqueous phase), adjust the pH of the aqueous phase to 5.8-7.2 with NaOH, filter, and collect the filtrate. Make the hydroxyapatite into a paste with water, pack it into a column, wash it with an acidic phosphate buffer, then equilibrate it with an acidic phosphate buffer, and absorb the above-mentioned filtrate on a hydroxyapatite chromatography column, Elute with acidic phosphate buffer; collect the target substance, perform ultrafiltration with a filter membrane until the mass fraction is 40%, and then obtain the Antarctic krill polypeptide concentrated solution, freeze the concentrated solution and then vacuum freeze-dry to obtain Antarctic phosphate Shrimp peptide powder.

Preferably, the radiation intensity in step 2) is 1.5KGy, the weight ratio of material to liquid is 1:14, the magnetic stirring time is 17 minutes, and the ultrasonic treatment condition is 350W, 50°C, 20 minutes; in step 3), step 2) The pH of the obtained Antarctic krill solution was adjusted to 8.5, the ratio of elastase was 2900U/g Antarctic krill, and the water bath condition was 28°C for 25 minutes. After cooling, the pH of the solution was adjusted to 8.0 again, and the ratio of serine carboxypeptidase was 3000U/g. g Antarctic krill, the water bath condition is 37°C, 35 minutes, and the enzyme inactivation time is 17 minutes.

Preferably, the radiation intensity in step 2) is 2KGy, the weight ratio of material to liquid is 1:15, the magnetic stirring time is 20 minutes, and the ultrasonic treatment condition is 390W, 45°C, 20 minutes; in step 3), step 2) is first obtained The pH of the Antarctic krill solution is adjusted to 8.5, the ratio of elastase is 3000U/g Antarctic krill, the water bath condition is 30°C, 25 minutes, after cooling, the pH of the solution is adjusted to 7.5 again, and the ratio of serine carboxypeptidase is 3500U/g For Antarctic krill, the water bath condition is 35°C, 36 minutes, and the enzyme inactivation time is 18 minutes.

Preferably, the radiation intensity in step 2) is 2.5KGy, the weight ratio of material to liquid is 1:20, the magnetic stirring time is 30 minutes, and the ultrasonic treatment condition is 400W, 55°C, 30 minutes; in step 3), step 2) The pH of the obtained Antarctic krill solution was adjusted to 11.0, the ratio of elastase was 3500U/g Antarctic krill, and the water bath condition was 37°C for 30 minutes. After cooling, the pH of the solution was adjusted to 8.0 again, and the ratio of serine carboxypeptidase was 4000U/g. g Antarctic krill, the water bath condition is 40°C, 35 minutes, and the enzyme inactivation time is 16 minutes.

Preferably, the radiation intensity in step 2) is 3KGy, the weight ratio of solid to liquid is 1:25, the magnetic stirring time is 27 minutes, and the ultrasonic treatment condition is 440W, 45°C, 25 minutes; in step 3), step 2) is first obtained The pH of the Antarctic krill solution is adjusted to 10.5, the ratio of elastase is 3500U/g Antarctic krill, the water bath condition is 35°C, 35 minutes, after cooling, the pH of the solution is adjusted to 9.0 again, and the ratio of serine carboxypeptidase is 3800U/g For Antarctic krill, the water bath condition is 39°C, 35 minutes, and the enzyme inactivation time is 20 minutes.

Compared with prior art, the beneficial effect of the present invention is:

(1) The present invention uses compound enzymatic hydrolysis technology to prepare Antarctic krill polypeptide, which can obtain more abundant target peptides and improve its biological activity. At the same time, the molecular weight of the obtained polypeptide is also shorter, which will be more conducive to being absorbed and utilized by the human body; The hydrolysis condition is relatively mild, which can well preserve the nutritional value of the enzymatic hydrolysis product, is extremely safe, and does not produce any by-products harmful to the human body; in addition, the enzymatic hydrolysis removes the peptides in the non-functional region of the protein, which can effectively avoid Trouble with immune rejection.

(2) The present invention combines electron beam irradiation-ultrasonic treatment and enzymolysis method for the preparation of Antarctic krill polypeptide, which can not only shorten the enzymolysis time, improve enzymolysis efficiency, but also obtain more abundant target peptides, improve its biological activity. Using electron beam irradiation to treat proteins can change the structural characteristics of proteins, assist in strengthening the peptide bond breaks in proteins, and make the protein structure of Antarctic krill loose, thereby improving the degree of protein hydrolysis; the impact of ultrasonic waves on enzymatic hydrolysis reactions is mainly The cavitation effect, that is, ultrasonic waves can form microbubbles in the liquid medium, and their rupture is accompanied by the release of energy, making the Antarctic krill protein structure soft and rotten, thereby increasing the speed of many chemical reactions.

(3) The molecular weight of the Antarctic krill polypeptide prepared by the present invention is small, all below 7000 Da, which will be more conducive to being absorbed and utilized by the human body.

(4) The present invention applies the freeze-drying technology, which can minimize the loss of biological activity of the Antarctic krill polypeptide during the drying process, and at the same time obtain the Antarctic krill polypeptide powder with good storage performance.

(5) The Antarctic krill polypeptide powder prepared by the present invention has a good blood lipid-lowering effect.

detailed description

In order to make the content of the present invention easier to understand, the technical solutions of the present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

Example 1

A preparation method of an Antarctic krill polypeptide preparation with blood lipid-lowering ability, which uses frozen Antarctic krill powder as a raw material, and undergoes crushing, electron beam irradiation-ultrasonic treatment, compound enzymolysis, ultrafiltration, and freeze-drying to obtain a finished product. Specifically include the following steps:

1) Pulverization: the frozen Antarctic krill powder is pulverized into fine powder with a pulverizer;

2) Electron beam irradiation-ultrasonic treatment: the Antarctic krill powder obtained in step 1) is placed in an electron linear accelerator for irradiation treatment, and the radiation intensity is 1.5KGy, and then the solid-liquid weight ratio is 1-14. Dissolve the Antarctic krill powder in deionized water, stir it magnetically for 17 minutes, and finally perform ultrasonic treatment. The ultrasonic conditions are: 350W, 50°C, 20 minutes to obtain the Antarctic krill solution;

3) Composite enzymatic hydrolysis: adjust the pH of the Antarctic krill solution obtained in step 2) to 8.5, add elastase at a ratio of 2900U/g Antarctic krill, and perform enzymatic hydrolysis in a water bath at 28°C for 25 minutes; after cooling to room temperature Adjust the pH of the solution to 8.0 again, add serine carboxypeptidase at a ratio of 3000U/g Antarctic krill, enzymatically hydrolyze in a water bath for 35 minutes at 37°C, and finally inactivate the enzyme in a boiling water bath for 17 minutes, then centrifuge to take the supernatant , to obtain Antarctic krill enzymatic hydrolyzate;

4) Filtration: perform ultrafiltration on the Antarctic krill enzymatic hydrolyzate with ultrafiltration membranes with a molecular weight cut-off of 10,000Da and 7,000Da in sequence to obtain an Antarctic krill polypeptide liquid with a molecular weight of less than 7,000Da;

5) Drying: Use hydrochloric acid to adjust the pH of the Antarctic krill polypeptide solution obtained in step 4) to 2.7-3.2, filter, collect the filtrate, and let it stand at 4°C overnight; use an oil-water separation type high-speed tubular centrifuge to remove grease, collect heavy Liquid phase (water phase). Use NaOH to adjust the pH of the aqueous phase to 5.8-7.2, filter, and collect the filtrate. Make the hydroxyapatite into a paste with water, pack it into a column, wash it with an acidic phosphate buffer, then equilibrate it with an acidic phosphate buffer, and absorb the above-mentioned filtrate on a hydroxyapatite chromatography column, Elute with acidic phosphate buffer; collect the target substance, perform ultrafiltration with a filter membrane until the mass fraction is 40%, and then obtain the Antarctic krill polypeptide concentrate, freeze the concentrate and then vacuum freeze-dry to obtain Antarctic phosphate Shrimp peptide powder.

Example 2

A preparation method of an Antarctic krill polypeptide preparation with blood lipid-lowering ability, which uses frozen Antarctic krill powder as a raw material, and undergoes crushing, electron beam irradiation-ultrasonic treatment, compound enzymolysis, ultrafiltration, and freeze-drying to obtain a finished product. Specifically include the following steps:

1) Pulverization: the frozen Antarctic krill powder is pulverized into fine powder with a pulverizer;

2) Electron beam irradiation-ultrasonic treatment: place the Antarctic krill powder obtained in step 1) in an electron linear accelerator for irradiation treatment with a radiation intensity of 2KGy, and then antarctic The krill powder was dissolved in deionized water, stirred magnetically for 20 minutes, and finally ultrasonicated. The ultrasonic conditions were: 390W, 45°C, 20 minutes to obtain an Antarctic krill solution;

3) Composite enzymatic hydrolysis: adjust the pH of the Antarctic krill solution obtained in step 2) to 8.5, add elastase at a ratio of 3000U/g Antarctic krill, and perform enzymatic hydrolysis in a water bath at 30°C for 25 minutes; after cooling to room temperature Adjust the pH of the solution to 7.5 again, add serine carboxypeptidase at a ratio of 3500U/g Antarctic krill, enzymatically hydrolyze in a water bath for 36 minutes at 35°C, and finally inactivate the enzyme in a boiling water bath for 18 minutes, then centrifuge to take the supernatant , to obtain Antarctic krill enzymatic hydrolyzate;

4) Filtration: perform ultrafiltration on the Antarctic krill enzymatic hydrolyzate with ultrafiltration membranes with a molecular weight cut-off of 10,000Da and 7,000Da in sequence to obtain an Antarctic krill polypeptide liquid with a molecular weight of less than 7,000Da;

5) Drying: Use hydrochloric acid to adjust the pH of the Antarctic krill polypeptide solution obtained in step 4) to 2.7-3.2, filter, collect the filtrate, and let it stand at 4°C overnight; use an oil-water separation type high-speed tubular centrifuge to remove grease, collect the heavy Liquid phase (water phase). Use NaOH to adjust the pH of the aqueous phase to 5.8-7.2, filter, and collect the filtrate. Make the hydroxyapatite into a paste with water, pack it into a column, wash it with an acidic phosphate buffer, then equilibrate it with an acidic phosphate buffer, and absorb the above-mentioned filtrate on a hydroxyapatite chromatography column, Elute with acidic phosphate buffer; collect the target substance, perform ultrafiltration with a filter membrane until the mass fraction is 40%, and then obtain the Antarctic krill polypeptide concentrate, freeze the concentrate and then vacuum freeze-dry to obtain Antarctic phosphate Shrimp peptide powder.

Example 3

A preparation method of an Antarctic krill polypeptide preparation with blood lipid-lowering ability, which uses frozen Antarctic krill powder as a raw material, and undergoes crushing, electron beam irradiation-ultrasonic treatment, compound enzymolysis, ultrafiltration, and freeze-drying to obtain a finished product. Specifically include the following steps:

1) Pulverization: the frozen Antarctic krill powder is pulverized into fine powder with a pulverizer;

2) Electron beam irradiation-ultrasonic treatment: the Antarctic krill powder obtained in step 1) is placed in an electron linear accelerator for irradiation treatment, the radiation intensity is 2.5KGy, and then the solid-liquid weight ratio is 1-20, and the Antarctic krill powder was dissolved in deionized water, stirred magnetically for 20 minutes, and finally ultrasonically treated, the ultrasonic conditions were 400W, 55°C, 30 minutes, and Antarctic krill solution was obtained;

3) Composite enzymatic hydrolysis: adjust the pH of the Antarctic krill solution obtained in step 2) to 11, add elastase at a ratio of 3500U/g Antarctic krill, and perform enzymatic hydrolysis in a water bath at 37°C for 30 minutes; after cooling to room temperature Adjust the pH of the solution to 8.0 again, add serine carboxypeptidase at a ratio of 4000U/g Antarctic krill, enzymatically hydrolyze in a water bath for 35 minutes at 40°C, and finally inactivate the enzyme in a boiling water bath for 16 minutes, then centrifuge to get the supernatant , to obtain Antarctic krill enzymatic hydrolyzate;

4) Filtration: perform ultrafiltration on the Antarctic krill enzymatic hydrolyzate with ultrafiltration membranes with a molecular weight cut-off of 10,000Da and 7,000Da in sequence to obtain an Antarctic krill polypeptide liquid with a molecular weight of less than 7,000Da;

5) Drying: Use hydrochloric acid to adjust the pH of the Antarctic krill polypeptide solution obtained in step 4) to 2.7-3.2, filter, collect the filtrate, and let it stand at 4°C overnight; use an oil-water separation type high-speed tubular centrifuge to remove grease, collect heavy Liquid phase (water phase). Use NaOH to adjust the pH of the aqueous phase to 5.8-7.2, filter, and collect the filtrate. Make the hydroxyapatite into a paste with water, pack it into a column, wash it with an acidic phosphate buffer, then equilibrate it with an acidic phosphate buffer, and absorb the above-mentioned filtrate on a hydroxyapatite chromatography column, Elute with acidic phosphate buffer; collect the target substance, perform ultrafiltration with a filter membrane until the mass fraction is 40%, and then obtain the Antarctic krill polypeptide concentrated solution, freeze the concentrated solution and then vacuum freeze-dry to obtain Antarctic phosphate Shrimp peptide powder.

Example 4

A preparation method of an Antarctic krill polypeptide preparation with blood lipid-lowering ability, which uses frozen Antarctic krill powder as a raw material, and undergoes crushing, electron beam irradiation-ultrasonic treatment, compound enzymolysis, ultrafiltration, and freeze-drying to obtain a finished product. Specifically include the following steps:

1) Pulverization: the frozen Antarctic krill powder is pulverized into fine powder with a pulverizer;

2) Electron beam irradiation-ultrasonic treatment: place the Antarctic krill powder obtained in step 1) in an electron linear accelerator for irradiation treatment with a radiation intensity of 3KGy, and then antarctic Dissolve the krill powder in deionized water, stir it magnetically for 27 minutes, and finally perform ultrasonic treatment, the ultrasonic condition is 440W, 55°C, 25 minutes, to obtain the Antarctic krill solution;

3) Composite enzymatic hydrolysis: adjust the pH of the Antarctic krill solution obtained in step 2) to 10.5, add elastase at a ratio of 3500U/g Antarctic krill, and perform enzymatic hydrolysis in a water bath for 35 minutes at 35°C; after cooling to room temperature Adjust the pH of the solution to 9.0 again, add serine carboxypeptidase at a ratio of 3800U/g Antarctic krill, enzymatically hydrolyze in a water bath for 35 minutes at 39°C, and finally inactivate the enzyme in a boiling water bath for 20 minutes, then centrifuge to get the supernatant , to obtain Antarctic krill enzymatic hydrolyzate;

4) Filtration: perform ultrafiltration on the Antarctic krill enzymatic hydrolyzate with ultrafiltration membranes with a molecular weight cut-off of 10,000Da and 7,000Da in sequence to obtain an Antarctic krill polypeptide liquid with a molecular weight of less than 7,000Da;

5) Drying: Use hydrochloric acid to adjust the pH of the Antarctic krill polypeptide solution obtained in step 4) to 2.7-3.2, filter, collect the filtrate, and let it stand at 4°C overnight; use an oil-water separation type high-speed tubular centrifuge to remove grease, collect the heavy Liquid phase (water phase). Use NaOH to adjust the pH of the aqueous phase to 5.8-7.2, filter, and collect the filtrate. Make the hydroxyapatite into a paste with water, pack it into a column, wash it with an acidic phosphate buffer, then equilibrate it with an acidic phosphate buffer, and absorb the above-mentioned filtrate on a hydroxyapatite chromatography column, Elute with acidic phosphate buffer; collect the target substance, perform ultrafiltration with a filter membrane until the mass fraction is 40%, and then obtain the Antarctic krill polypeptide concentrate, freeze the concentrate and then vacuum freeze-dry to obtain Antarctic phosphate Shrimp peptide powder.

Example 5

Using the therapeutic hyperlipidemia rat model, the Antarctic krill polypeptide obtained in Example 4 was used for a 60-day blood lipid regulation experiment. After feeding the SD rats with the basic diet for one week, fasting for 18 hours, taking tail blood, and using OLYMPUSAU400 automatic biochemical analyzer to measure serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein Protein cholesterol (HDL-C), according to the level of TC and TG, the animals were randomly divided into 4 groups: high-fat model group and three test groups of low, high and middle doses. Since the beginning of the formal test, the animals in each group were replaced with high-fat feed. At the same time, the test groups were given different concentrations of Antarctic krill peptides in the feed, 0.25, 1.0, and 2.0 g/kg BW. Krill polypeptide powder was added with distilled water to make up to 100ml, and the high-fat model group was given distilled water for gavage, and the volume of gavage was 1.0ml/100gBW. Weighed once a week for 60 consecutive days. After fasting for 18 hours at the end of the test, blood was collected to measure serum TC, TG, and HDL-C after the test. The test results are shown below.

(1) Effect of Antarctic krill polypeptide on rat TC

As can be seen from Table 1, the serum TC levels of rats in the 1.0 and 2.0g/kgBW dose groups were significantly lower than those in the high-fat model group after the test (P<0.05); the serum TC levels in the high-fat model group were significantly higher than before the experiment (P<0.05). <0.05).

(2) Effect of Antarctic krill polypeptide on rat TG

As can be seen from Table 2, the serum TG levels of rats in the 1.0 and 2.0g/kgBW dose groups were significantly lower than the high fat model group after the experiment (P<0.05); the serum TG levels of the high fat model group were significantly higher than before the experiment (P<0.05). <0.05).

(3) Effect of Antarctic krill polypeptide on rat HDL-C

It can be seen from Table 3 that the serum HDL-C levels of the rats in each dosage group were compared with the hyperlipidemia model group, and the difference was not statistically significant (P>0.05).

In conclusion, the rats were fed with high-fat diet for 60 days, and the serum TC and TG levels of the rats in each group were significantly increased, and the serum TC and TG levels of rats in the high-fat model group after the experiment were significantly different from those before the experiment ( P<0.05), suggesting that the rat hyperlipidemia model was established successfully. Three experimental groups were fed with high-fat diet and given different doses of Antarctic krill polypeptide. The levels of serum TC and TG of SD rats in the 1.0g/kgBW and 2.0g/kgBW groups were significantly lower than those in the high-fat model group (P<0.05) , confirming that Antarctic krill polypeptide has an auxiliary blood lipid-lowering effect on SD rats.

Table 1 Serum TC levels of each group before and after the experiment

Note: # means compared with the high-fat model group, P<0.05; * means there is a significant difference between the experiment and the pre-experiment, P<0.05.

Table 2 Serum TG levels in each group before and after the experiment

Note: # means compared with the high-fat model group, P<0.05; * means there is a significant difference between the experiment and the pre-experiment, P<0.05.

Table 3 Serum HDL-C levels of each group before and after the experiment

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deduction or replacement can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (6)

1. An Antarctic krill polypeptide preparation with blood lipid-lowering ability, characterized in that the polypeptide preparation is composed of polypeptides produced by enzymolysis of Antarctic krill powder by elastase and serine carboxypeptidase, and the molecular weight of the polypeptide is below 7000Da . 2. A preparation method of an Antarctic krill polypeptide preparation with blood lipid-lowering ability, characterized in that the preparation process is based on frozen Antarctic krill powder as raw material, through pulverization, electron beam irradiation-ultrasonic treatment, compound enzymolysis, ultra- Filtration, freeze-drying make finished product, specifically comprise the following steps: 1) Pulverization: the frozen Antarctic krill powder is pulverized into fine powder with a pulverizer; 2) Electron beam irradiation-ultrasonic treatment: place the Antarctic krill powder obtained in step 1) in an electron linear accelerator for irradiation treatment, the radiation intensity is 1.5-3KGy, and then the solid-liquid weight ratio is 1:12-1: Dissolve Antarctic krill powder in deionized water at a ratio of 25, stir magnetically for 15-35 minutes, and finally perform ultrasonic treatment. The ultrasonic conditions are: 300-500W, 40-65°C, 15-30 minutes to obtain Antarctic krill solution ; 3) Composite enzymatic hydrolysis: adjust the pH of the Antarctic krill solution obtained in step 2) to 7.5-11.0, add elastase at a ratio of 2500-3500U/g Antarctic krill, and enzymolyze it in a water bath at 25-40°C for 20 ~45 minutes; after cooling to room temperature, adjust the pH of the solution to 7.5~9.5 again, add serine carboxypeptidase at a ratio of 3000~4000U/g Antarctic krill, and enzymatically hydrolyze in a water bath for 30~40 minutes under the condition of 30~45℃ , and finally inactivate the enzyme in a boiling water bath for 15 to 20 minutes, then centrifuge to take the supernatant, and obtain the enzymatic hydrolyzate of Antarctic krill; 4) Filtration: perform ultrafiltration on the Antarctic krill enzymatic hydrolyzate with ultrafiltration membranes with a molecular weight cut-off of 10,000Da and 7,000Da in sequence to obtain an Antarctic krill polypeptide liquid with a molecular weight of less than 7,000Da; 5) Drying: Use hydrochloric acid to adjust the pH of the Antarctic krill polypeptide solution obtained in step 4) to 2.7-3.2, filter, collect the filtrate, and let it stand at 4°C overnight; use an oil-water separation type high-speed tubular centrifuge to remove grease, collect heavy Liquid phase (water phase), use NaOH to adjust the pH of the water phase to 5.8-7.2, filter, collect the filtrate, make hydroxyapatite into a paste with water, pack the column, and wash it with acidic phosphate buffer after packing , and then equilibrated with acidic phosphate buffer, the above filtrate was adsorbed on the hydroxyapatite chromatography column, and eluted with acidic phosphate buffer; %, to obtain the Antarctic krill polypeptide concentrated solution, freeze the concentrated solution and then carry out vacuum freeze-drying to obtain Antarctic krill polypeptide powder. 3. a kind of preparation method of the Antarctic krill polypeptide preparation with hypolipidemic ability according to claim 2, it is characterized in that, step 2) in radiation intensity is 1.5KGy, and solid-liquid weight ratio is 1:14, magnetic stirring The time is 17 minutes, and the ultrasonic treatment condition is 350W, 50°C, 20 minutes; in step 3), first adjust the pH of the Antarctic krill solution obtained in step 2) to 8.5, and the ratio of elastase is 2900U/g Antarctic krill, water bath The condition is 28°C for 25 minutes, after cooling, adjust the pH of the solution to 8.0 again, the ratio of serine carboxypeptidase is 3000U/g Antarctic krill, the water bath condition is 37°C, 35 minutes, and the enzyme inactivation time is 17 minutes. 4. a kind of preparation method of the Antarctic krill polypeptide preparation with hypolipidemic ability according to claim 2, is characterized in that, in step 2), radiation intensity is 2KGy, and solid-liquid weight ratio is 1:15, and magnetic stirring time For 20 minutes, the ultrasonic treatment condition is 390W, 45°C, 20 minutes; in step 3), first adjust the pH of the Antarctic krill solution obtained in step 2) to 8.5, and the ratio of elastase is 3000U/g Antarctic krill, and the water bath condition 30°C for 25 minutes, after cooling, adjust the pH of the solution to 7.5 again, the ratio of serine carboxypeptidase is 3500U/g Antarctic krill, the water bath conditions are 35°C, 36 minutes, and the enzyme inactivation time is 18 minutes. 5. A kind of preparation method of the Antarctic krill polypeptide preparation with hypolipidemic ability according to claim 2, it is characterized in that, step 2) in radiation intensity is 2.5KGy, and solid-liquid weight ratio is 1:20, magnetic stirring The time is 30 minutes, the ultrasonic treatment condition is 400W, 55°C, 30 minutes; in step 3), the pH of the Antarctic krill solution obtained in step 2) is first adjusted to 11.0, and the ratio of elastase is 3500U/g Antarctic krill, water bath The condition is 37°C for 30 minutes, after cooling, adjust the pH of the solution to 8.0 again, the ratio of serine carboxypeptidase is 4000U/g Antarctic krill, the water bath condition is 40°C, 35 minutes, and the enzyme inactivation time is 16 minutes. 6. the preparation method of a kind of Antarctic krill polypeptide preparation with hypolipidemic ability according to claim 2, it is characterized in that, step 2) in radiation intensity is 3KGy, and solid-liquid weight ratio is 1:25, and magnetic stirring time For 27 minutes, the ultrasonic treatment conditions are 440W, 45°C, 25 minutes; in step 3), first adjust the pH of the Antarctic krill solution obtained in step 2) to 10.5, and the ratio of elastase is 3500U/g Antarctic krill, and the water bath conditions 35°C for 35 minutes, after cooling, adjust the pH of the solution to 9.0 again, the ratio of serine carboxypeptidase is 3800U/g Antarctic krill, the water bath conditions are 39°C, 35 minutes, and the enzyme inactivation time is 20 minutes.