Preparation method of euphausia superba peptide with antioxidant activity

Abstract

The invention belongs to the technical field of antarctic krill peptide preparation, and discloses a preparation method of antarctic krill peptide with antioxidant activity, which comprises the following steps: unfreezing antarctic krill, adding water, homogenizing to obtain slurry, adding a modified nano silicon dioxide agent into the slurry, and stirring to obtain nano silicon dioxide modified slurry liquid; carrying out enzymolysis treatment on the nano silicon dioxide modified pulp liquid, after the treatment is finished, taking supernate, and filtering to obtain a product I; and 2, fermenting residues obtained after taking the supernate in the step 2, after the treatment is finished, taking the supernate, concentrating and drying to obtain a product 2, merging the product 1 and the product 2, and performing spray drying to obtain the euphausia superba peptide with antioxidant activity. When the euphausia superba peptide is prepared, the yield is high, the removal rate of hydroxyl radicals and superoxide anions of the product is high, and the antioxidant activity of the product is excellent.

Description

Technical Field

[0001] The present invention belongs to the technical field of Antarctic krill peptide preparation. Specifically, it relates to a method for preparing Antarctic krill peptide with antioxidant activity. Background Art

[0002] Antarctic krill is one of the organisms with the largest biomass and the most successful reproduction on Earth. It is an important new marine resource, and the development of Antarctic krill in China is still in its initial stage. Active peptides are the most important active substances in the human body and play a key role in the processes of human growth and development, metabolism, diseases, aging, and death.

[0003] The Chinese invention patent with the patent application number CN201911354876.5 discloses a method for preparing Antarctic krill peptide with antioxidant activity, including the following steps: (1) Homogenization: After thawing Antarctic krill, add water for homogenization to obtain slurry A; (2) Enzymolysis: Add compound protease to slurry A in batches and adjust the pH value, and carry out heat preservation enzymolysis to obtain enzymolysis solution A; (3) Inactivating enzymes and centrifuging: Inactivate the enzymolysis solution A in step (2) and then centrifuge; (4) Concentrating and drying: Take the supernatant after centrifugation, filter, and obtain Antarctic krill peptide.

[0004] The above-mentioned existing methods for preparing Antarctic krill peptide use enzymolysis reaction to extract krill peptide from Antarctic krill. Moreover, the antioxidant activity of this kind of Antarctic krill peptide is low, the scavenging rates of hydroxyl radicals and superoxide anions are poor, and the yield of krill peptide is poor, which limits the preparation efficiency of krill peptide. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing Antarctic krill peptide with antioxidant activity, which is used to solve the technical problems proposed in the background art, so that the prepared Antarctic krill peptide has high antioxidant activity, high scavenging rates of hydroxyl radicals and superoxide anions, and can improve the preparation efficiency of Antarctic krill peptide.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: A method for preparing Antarctic krill peptide with antioxidant activity, including the following steps: Step 1: After thawing Antarctic krill, add water for homogenization to obtain slurry. Subsequently, add a modified nano-silica agent to the slurry and stir to obtain a nano-silica modified slurry liquid; Step 2: Carry out enzymolysis treatment on the nano-silica modified slurry liquid. After the treatment is completed, take the supernatant and filter to obtain Product 1; Step 3: Ferment the residue obtained after taking the supernatant in Step 2. After the treatment is completed, take the supernatant for concentration and drying to obtain Product 2. Combine Product 1 and Product 2 and then spray dry to obtain Antarctic krill peptide with antioxidant activity.

[0007] The following is a further optimization of the above technical solution by the present invention: The mass ratio of the slurry to the modified nano-silica agent is (28 - 31):5; the stirring speed for the stirring treatment is 350 - 400 r / min, and the stirring time is 1 h.

[0008] Further optimization: The preparation method of the modified nano-silica agent is as follows: S01: Heat-treat nano-silica in an environment of 210 - 230 °C for 1 h, then cool it to 55 °C at a rate of 3 - 5 °C / min and keep it warm for 1 h; S02: Add 2 - 4 parts of sodium hyaluronate and 1 - 3 parts of silane coupling agent KH550 by weight to 5 - 8 parts of sodium citrate solution, then add 3 - 5 parts of β-cyclodextrin, and stir evenly to obtain a base liquid; S03: Compound nano-aluminum oxide and montmorillonite according to a weight ratio of 2:5, then heat-treat them in an environment of 280 - 310 °C for 1 h, and after the treatment is completed, cool them to room temperature to obtain a composite material; S04: Stir the composite material and the base liquid evenly according to a weight ratio of 3:5 to obtain a modified liquid. Immerse the heat-preserved nano-silica into a sufficient amount of the modified liquid for stirring and modification treatment. After the stirring is completed, filter and dry to obtain the modified nano-silica agent.

[0009] Further optimization: The mass fraction of the sodium citrate solution is 2 - 5%; the stirring speed for the stirring modification treatment is 350 - 400 r / min, and the stirring time is 1 h.

[0010] Further optimization: The specific method of the enzymatic hydrolysis treatment is as follows: Add an enzymatic hydrolysis material to the nano-silica modified slurry liquid for enzymatic hydrolysis. The mass ratio of the enzymatic hydrolysis material to the nano-silica modified slurry liquid is (4 - 7):15; The temperature of the enzymatic hydrolysis is 38 - 42 °C, the enzymatic hydrolysis is carried out for 1 h, the pH value during the enzymatic hydrolysis is 5.5 - 6.0, and after the enzymatic hydrolysis is completed, inactivate the enzyme.

[0011] Further optimization: The enzymatic hydrolysis material is trypsin, alkaline protease, and papain.

[0012] Further optimization: The mass ratio of trypsin, alkaline protease, and papain is (3 - 5):(2 - 3):1.

[0013] Further optimization: The specific operation method of the fermentation treatment of the residue material is as follows: S11: After taking the supernatant in step two, the residue material obtained is mixed with glucose and water according to a weight ratio of (12 - 15):4:(5 - 7), and then inoculated with fermentation bacteria, and the inoculation is completed; S12: Finally, perform fermentation treatment. After 12 days of fermentation, the fermentation treatment of the residue is completed.

[0014] Further optimization: The fermentation bacteria are inoculated with Bacillus coagulans, and the inoculation amount of the fermentation bacteria is 15-20% of the total amount of the residue in step two.

[0015] Further optimization: The fermentation temperature of the fermentation treatment is 36-40 °C.

[0016] The present invention adopts the above technical solutions and has at least the following beneficial effects: In the present invention, Antarctic krill peptide is prepared by thawing Antarctic krill, then stirring and blending with a modified nano-silica agent, combined with enzymatic hydrolysis and fermentation treatment. Through the improvement of the combined process, the yield and recovery rate of the prepared Antarctic krill peptide are high, and the hydroxyl radical and superoxide anion scavenging rates of the product are high, and the antioxidant activity performance of the product is excellent; the modified nano-silica agent is prepared by thermally improving nano-silica and then stirring and blending with a modified liquid to optimize its activity efficiency. The nano-aluminum oxide and montmorillonite in the modified liquid are calcined and then combined with the base liquid, and the base liquid is prepared by blending raw materials such as sodium hyaluronate, silane coupling agent KH550 and β-cyclodextrin. Through the co-blending improvement of the raw materials, the enzymatic hydrolysis treatment effect is further enhanced in the system, the yield and recovery rate of the product are optimized, and at the same time, combined with the fermentation treatment of the residue, Antarctic krill peptide is obtained through specific enzymatic hydrolysis temperature, enzymatic hydrolysis conditions and fermentation conditions, so that the hydroxyl radical and superoxide anion scavenging rates in Antarctic krill peptide are high, and the yield and recovery rate of the product are high. Specific embodiments

[0017] The following combines specific embodiments to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0018] Example 1: A preparation method of Antarctic krill peptide with antioxidant activity, comprising the following steps: Step 1, thaw Antarctic krill and add water to make a slurry, and then add a modified nano-silica agent to the slurry for stirring treatment to obtain a nano-silica modified slurry liquid.

[0019] In the above step 1, the mass ratio of the slurry to the modified nano-silica agent is 28:5; the stirring speed of the stirring treatment is 350 r / min, and the stirring time is 1 h.

[0020] In the above step 1, the preparation method of the modified nano-silica agent is: S01: Heat-treat nano-silica in an environment of 210 °C for 1 h, then cool it to 55 °C at a rate of 3 °C / min and keep it warm for 1 h; S02: Add 2 parts of sodium hyaluronate and 1 part of silane coupling agent KH550 by weight to 5 parts of sodium citrate solution, and then add 3 parts of β-cyclodextrin, and stir evenly to obtain the base liquid; S03: Compound nano-aluminum oxide and montmorillonite according to a weight ratio of 2:5, then heat-treat in an environment of 280 °C for 1 h, and after the treatment is over, cool it to room temperature to obtain the composite material; S04: Stir the composite material and the base liquid evenly according to a weight ratio of 3:5 to obtain the modified liquid. Immerse the heat-preserved nano-silica into a sufficient amount of the modified liquid and stir for modification treatment. After stirring is over, filter and dry to obtain the modified nano-silica agent.

[0021] In the step S02, the mass fraction of the sodium citrate solution is 2%.

[0022] In the step S04, the stirring speed of the stirring modification treatment is 350 r / min, and the stirring time is 1 h.

[0023] Step 2: Perform enzymatic hydrolysis treatment on the nano-silica modified slurry liquid. After the treatment is over, take the supernatant and filter to obtain Product 1.

[0024] In the above step 2, the specific method of the enzymatic hydrolysis treatment is: First, add an enzymatic hydrolysis material to the nano-silica modified slurry liquid for enzymatic hydrolysis. The mass ratio of the enzymatic hydrolysis material to the nano-silica modified slurry liquid is 4:15; The temperature of the enzymatic hydrolysis is 38 °C, the enzymatic hydrolysis is carried out for 1 h, the pH value during the enzymatic hydrolysis is 5.5, and after the enzymatic hydrolysis is over, inactivate the enzyme.

[0025] The enzymatic hydrolysis material is trypsin, alkaline protease and papain; the mass ratio of trypsin, alkaline protease and papain is 3:2:1.

[0026] During the enzyme inactivation treatment, the nano-silica modified slurry liquid after the enzymatic hydrolysis can be inactivated at 100 °C for 10 min.

[0027] Step 3: Ferment the residue obtained after taking the supernatant in step 2. After the treatment is over, take the supernatant, concentrate and dry it to obtain Product 2. Combine Product 1 and Product 2 and then spray dry to obtain Antarctic krill peptide with antioxidant activity.

[0028] In the above step 3, the specific operation method of the residue fermentation treatment is: S11: After taking the supernatant in Step 2, the residue obtained is mixed with glucose and water in a weight ratio of 12:4:5, and then fermenting bacteria are inoculated to end the inoculation. S12: Finally, fermentation treatment is carried out. The fermentation temperature for the fermentation treatment is 36 °C. After 12 days of fermentation, the fermentation treatment of the residue is completed.

[0029] In the S11 step, the fermenting bacteria are inoculated with Bacillus coagulans, and the inoculation amount of the fermenting bacteria is 15% of the total amount of the residue in Step 2.

[0030] In this embodiment, the Bacillus coagulans is an existing strain and can be directly purchased on the market.

[0031] Example 2: A preparation method of Antarctic krill peptide with antioxidant activity includes the following steps: Step 1, thaw Antarctic krill and add water for homogenization to obtain a slurry. Subsequently, a modified nano-silica agent is added to the slurry for stirring treatment to obtain a nano-silica modified slurry liquid.

[0032] In the Step 1, the mass ratio of the slurry to the modified nano-silica agent is 31:5; the stirring speed for the stirring treatment is 400 r / min, and the stirring time is 1 h.

[0033] The preparation method of the modified nano-silica agent is as follows: S01: Heat-treat nano-silica in an environment of 230 °C for 1 h, then cool it to 55 °C at a rate of 5 °C / min and keep it warm for 1 h; S02: Add 4 parts of sodium hyaluronate and 3 parts of silane coupling agent KH550 by weight to 8 parts of sodium citrate solution, and then add 5 parts of β-cyclodextrin, and stir evenly to obtain a base liquid; S03: Compound nano-aluminum oxide and montmorillonite in a weight ratio of 2:5, and then heat-treat them in an environment of 310 °C for 1 h. After the treatment is completed, cool them to room temperature to obtain a composite material; S04: Stir the composite material and the base liquid evenly in a weight ratio of 3:5 to obtain a modified liquid. Immerse the heat-preserved nano-silica into a sufficient amount of the modified liquid for stirring modification treatment. After the stirring is completed, carry out suction filtration and drying to obtain the modified nano-silica agent.

[0034] In the S02 step, the mass fraction of the sodium citrate solution is 5%.

[0035] In the S04 step, the stirring speed for the stirring modification treatment is 400 r / min, and the stirring time is 1 h.

[0036] Step 2, carry out enzymatic hydrolysis treatment on the nano-silica modified slurry liquid. After the treatment is completed, take the supernatant and filter it to obtain Product 1.

[0037] In the second step, the specific method of enzymatic hydrolysis treatment is as follows: Add the enzymatic hydrolysis material to the nano-silica modified pulp liquid for enzymatic hydrolysis. The mass ratio of the enzymatic hydrolysis material to the nano-silica modified pulp liquid is 7:15. The temperature of enzymatic hydrolysis is 42 °C, enzymatic hydrolysis is carried out for 1 h, the pH value during enzymatic hydrolysis is 6.0, and after enzymatic hydrolysis, inactivate the enzyme.

[0038] The enzymatic hydrolysis material is trypsin, alkaline protease and papain; the mass ratio of trypsin, alkaline protease and papain is 5:3:1.

[0039] During the enzyme inactivation treatment, the nano-silica modified pulp liquid after enzymatic hydrolysis can be inactivated at 110 °C for 15 min.

[0040] Step 3: Ferment the residue obtained after taking the supernatant in Step 2. After the treatment is completed, take the supernatant, concentrate and dry it to obtain Product 2. Combine Product 1 and Product 2 and then spray dry to obtain antioxidant-active Antarctic krill peptide.

[0041] The specific operation method of the residue fermentation treatment in Step 3 is as follows: S11: Mix the residue obtained after taking the supernatant in Step 2, glucose and water according to a weight ratio of 15:4:7, and then inoculate the fermentation bacteria to complete the inoculation; S12: Finally, carry out fermentation treatment. The fermentation temperature of the fermentation treatment is 40 °C. After fermenting for 12 d, the fermentation treatment of the residue is completed.

[0042] In the S11 step, the fermentation bacteria are inoculated with Bacillus coagulans, and the inoculation amount of the fermentation bacteria is 20% of the total amount of the residue in Step 2.

[0043] Example 3: A preparation method of antioxidant-active Antarctic krill peptide, comprising the following steps: Step 1: Thaw Antarctic krill and add water for homogenization to obtain a slurry. Subsequently, add a modified nano-silica agent to the slurry and stir to obtain a nano-silica modified pulp liquid.

[0044] In the first step, the mass ratio of the slurry to the modified nano-silica agent is 30:5; the stirring speed of the stirring treatment is 375 r / min, and the stirring time is 1 h.

[0045] In the first step, the preparation method of the modified nano-silica agent is as follows: S01: Heat-treat nano-silica in an environment of 220 °C for 1 h, then cool it to 55 °C at a rate of 4 °C / min and keep it warm for 1 h; S02: Add 3 parts of sodium hyaluronate and 2 parts of silane coupling agent KH550 by weight to 6.5 parts of sodium citrate solution, and then add 4 parts of β-cyclodextrin, stir evenly to obtain the base liquid; S03: Compound nano-aluminum oxide and montmorillonite according to a weight ratio of 2:5, and then heat-treat in an environment of 300 °C for 1 h. After the treatment is completed, cool to room temperature to obtain the composite material; S04: Stir the composite material and the base liquid evenly according to a weight ratio of 3:5 to obtain the modified liquid. Immerse the heat-preserved nano-silica in a sufficient amount of the modified liquid and stir for modification treatment. After stirring, filter and dry to obtain the modified nano-silica agent.

[0046] In the step S02, the mass fraction of the sodium citrate solution is 3.5%.

[0047] In the step S04, the stirring speed of the stirring modification treatment is 375 r / min, and the stirring time is 1 h.

[0048] Step two, perform enzymatic hydrolysis treatment on the nano-silica modified slurry liquid. After the treatment is completed, take the supernatant and filter to obtain product one.

[0049] In the said step two, the specific method of the enzymatic hydrolysis treatment is: Add the enzymatic hydrolysis material to the nano-silica modified slurry liquid for enzymatic hydrolysis. The mass ratio of the enzymatic hydrolysis material to the nano-silica modified slurry liquid is 5.5:15; The temperature of the enzymatic hydrolysis is 40 °C, the enzymatic hydrolysis is carried out for 1 h, the pH value during the enzymatic hydrolysis is 5.7, and after the enzymatic hydrolysis is completed, inactivate the enzyme.

[0050] The enzymatic hydrolysis material is trypsin, alkaline protease and papain; the mass ratio of trypsin, alkaline protease and papain is 4:2.5:1.

[0051] During the enzyme inactivation treatment, the nano-silica modified slurry liquid after the enzymatic hydrolysis can be inactivated at 105 °C for 12 min.

[0052] Step three, perform fermentation treatment on the residue obtained after taking the supernatant in step two. After the treatment is completed, take the supernatant, concentrate and dry to obtain product two. Combine product one and product two and then spray dry to obtain the antioxidant active Antarctic krill peptide.

[0053] In the said step three, the specific operation method of the residue fermentation treatment is: S11: Mix the residue obtained after taking the supernatant in step two with glucose and water according to a weight ratio of 13.5:4:6, and then inoculate the fermentation bacteria. After the inoculation is completed; S12: Finally, perform fermentation treatment. The fermentation temperature for the fermentation treatment is 38°C. After 12 days of fermentation, the fermentation treatment of the residue material is completed.

[0054] In the step S11, the fermentation bacteria are inoculated with Bacillus coagulans, and the inoculation amount of the fermentation bacteria is 17.5% of the total amount of the residue material in step two.

[0055] Example 4: A preparation method of antarctic krill peptide with antioxidant activity includes the following steps: Step one, thaw antarctic krill and add water to make a homogenate to obtain a slurry. Subsequently, add a modified nano-silica agent to the slurry and stir to obtain a nano-silica modified slurry liquid.

[0056] In the step one, the mass ratio of the slurry to the modified nano-silica agent is 29:5; the stirring speed for the stirring treatment is 360 r / min, and the stirring time is 1 h.

[0057] In the step one, the preparation method of the modified nano-silica agent is as follows: S01: Heat-treat nano-silica in an environment of 215°C for 1 h, then cool it to 55°C at a rate of 4°C / min and keep it warm for 1 h; S02: Add 3 parts of sodium hyaluronate and 2 parts of silane coupling agent KH550 by weight to 6 parts of sodium citrate solution, and then add 4 parts of β-cyclodextrin and stir evenly to obtain a base liquid; S03: Compound nano-aluminum oxide and montmorillonite according to a weight ratio of 2:5, then heat-treat them in an environment of 290°C for 1 h. After the treatment is completed, cool them to room temperature to obtain a composite material; S04: Stir the composite material and the base liquid evenly according to a weight ratio of 3:5 to obtain a modified liquid. Immerse the heat-preserved nano-silica into a sufficient amount of the modified liquid and stir for modification treatment. After the stirring is completed, filter and dry to obtain a modified nano-silica agent.

[0058] In the step S02, the mass fraction of the sodium citrate solution is 3%.

[0059] In the step S04, the stirring speed for the stirring modification treatment is 360 r / min, and the stirring time is 1 h.

[0060] Step two, perform enzymatic hydrolysis treatment on the nano-silica modified slurry liquid. After the treatment is completed, take the supernatant and filter to obtain product one.

[0061] In the step two, the specific method of the enzymatic hydrolysis treatment is as follows: Add an enzymatic hydrolysis material to the nano-silica modified slurry liquid for enzymatic hydrolysis. The mass ratio of the enzymatic hydrolysis material to the nano-silica modified slurry liquid is 5:15; The temperature of enzymatic hydrolysis is 39 °C, enzymatic hydrolysis is carried out for 1 h, the pH value during enzymatic hydrolysis is 5.6, and after enzymatic hydrolysis, the enzyme is inactivated.

[0062] During the enzyme inactivation treatment, the nano-silica modified slurry liquid after the end of enzymatic hydrolysis can be inactivated at 100 °C for 15 min.

[0063] The enzymatic hydrolysis material is trypsin, alkaline protease and papain; the mass ratio of trypsin, alkaline protease and papain is 4:2:1.

[0064] Step 3: Ferment the residue obtained after taking the supernatant in Step 2. After the treatment is completed, take the supernatant for concentration and drying to obtain Product 2. Combine Product 1 and Product 2 and then spray dry to obtain Antarctic krill peptide with antioxidant activity.

[0065] In the said Step 3, the specific operation method of fermenting the residue is as follows: S11: The residue obtained after taking the supernatant in Step 2 is mixed with glucose and water in a weight ratio of 13:4:5, and then inoculated with fermentation bacteria, and the inoculation is completed; S12: Finally, carry out fermentation treatment. The fermentation temperature for fermentation treatment is 38 °C. After fermentation for 12 d, the fermentation treatment of the residue is completed.

[0066] In the said S11 step, the fermentation bacteria are inoculated with Bacillus coagulans, and the inoculation amount of the fermentation bacteria is 16% of the total amount of the residue in Step 2.

[0067] Comparative Example 1: Based on the above-mentioned Example 3, the difference from Example 3 is that the modified nano-silica agent is not added.

[0068] Comparative Example 2: Based on the above-mentioned Example 3, the difference from Example 3 is that the modified liquid is not added during the preparation of the modified nano-silica agent.

[0069] Comparative Example 3: Based on the above-mentioned Example 3, the difference from Example 3 is that the composite material is not added during the preparation of the modified nano-silica agent.

[0070] Comparative Example 4: Based on the above-mentioned Example 3, the difference from Example 3 is that during the preparation of the modified nano-silica agent, sodium hyaluronate and β-cyclodextrin are not added to its base liquid.

[0071] Comparative Example 5: Based on the above-mentioned Example 3, the difference from Example 3 is that the nano-silica modified slurry liquid is not subjected to enzymatic hydrolysis treatment.

[0072] Comparative Example 6: Based on the above-mentioned Embodiment 3, the difference from Embodiment 3 is that the slag fermentation treatment is not adopted in Step 3.

[0073] The product performance tests of Embodiments 1-4 and Comparative Examples 1-6 are as follows: Hydroxyl radical scavenging rate (%) Superoxide anion scavenging rate (%) Active peptide yield (%) Example 1 83.5 71.2 24.7 Example 2 83.8 72.3 25.4 Example 3 84.4 73.0 25.1 Example 4 83.7 72.1 25.0 Comparative Example 1 61.2 56.3 15.3 Comparative Example 2 65.9 61.2 18.5 Comparative Example 3 72.8 68.9 20.1 Comparative Example 4 78.3 72.4 22.3 Comparative Example 5 70.9 65.3 19.2 Comparative Example 6 75.8 70.2 21.2 It can be obtained from Embodiments 1-4 and Comparative Examples 1-6 that the product prepared in Embodiment 3 of the present invention has excellent hydroxyl radical scavenging rate, superoxide anion scavenging rate and active peptide yield, and at the same time, the performance of the product can be improved in a coordinated manner.

[0074] In the product preparation method, when the modified nano-silica agent is not added, the performance of the product changes significantly; at the same time, when the modified liquid is not added during the preparation of the modified nano-silica agent, the composite material is not added to the modified liquid, and sodium hyaluronate and β-cyclodextrin are not added to the base liquid, the performance of the product all shows a deteriorating trend; and when the enzymatic hydrolysis treatment and the slag fermentation treatment are not adopted in the product preparation method, the performance of the product all shows a deteriorating trend to varying degrees; the performance effect of the Antarctic krill peptide prepared under the specific method and specific process conditions of the present invention is the most significant.

[0075] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention; therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention.

[0076] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A preparation method of Antarctic krill peptides with antioxidant activity, characterized in that: It includes the following steps: Step 1: Thaw Antarctic krill and add water to make a slurry. Then, add a modified nano-silica agent to the slurry and stir it to obtain a nano-silica modified slurry liquid; Step 2: Subject the nano-silica modified slurry liquid to enzymatic hydrolysis. After the treatment is completed, take the supernatant and filter it to obtain Product 1; Step 3: Ferment the residue obtained after taking the supernatant in Step 2. After the treatment is completed, take the supernatant, concentrate and dry it to obtain Product 2. Combine Product 1 and Product 2 and then spray dry them to obtain Antarctic krill peptides with antioxidant activity.

2. The preparation method of an Antarctic krill peptide with antioxidant activity according to claim 1, characterized in that: The mass ratio of the slurry to the modified nano-silica agent is (28 - 31):5; the stirring speed for the stirring treatment is 350 - 400 r / min, and the stirring time is 1 h.

3. The preparation method of an Antarctic krill peptide with antioxidant activity according to claim 1, characterized in that: The preparation method of the modified nano-silica agent is as follows: S01: Heat treat nano-silica in an environment of 210 - 230 °C for 1 h, then cool it to 55 °C at a rate of 3 - 5 °C / min and keep it warm for 1 h; S02: Add 2 - 4 parts of sodium hyaluronate and 1 - 3 parts of silane coupling agent KH550 by weight to 5 - 8 parts of sodium citrate solution, and then add 3 - 5 parts of β-cyclodextrin, and stir evenly to obtain a base liquid; S03: Compound nano-aluminum oxide and montmorillonite according to a weight ratio of 2:5, then heat treat them in an environment of 280 - 310 °C for 1 h. After the treatment is completed, cool them to room temperature to obtain a composite material; S04: Stir the composite material and the base liquid evenly according to a weight ratio of 3:5 to obtain a modified liquid. Immerse the heat-preserved nano-silica into a sufficient amount of the modified liquid and stir for modification. After the stirring is completed, filter and dry it to obtain the modified nano-silica agent.

4. A preparation method of an Antarctic krill peptide with antioxidant activity according to claim 3, characterized in that: The mass fraction of the sodium citrate solution is 2 - 5%; the stirring speed for the stirring modification treatment is 350 - 400 r / min, and the stirring time is 1 h.

5. The preparation method of an Antarctic krill peptide with antioxidant activity according to claim 3, characterized in that: The specific method of the enzymatic hydrolysis treatment is as follows: Add an enzymatic hydrolysis material to the nano-silica modified slurry liquid for enzymatic hydrolysis. The mass ratio of the enzymatic hydrolysis material to the nano-silica modified slurry liquid is (4 - 7):15; The temperature of the enzymatic hydrolysis is 38 - 42 °C, and the enzymatic hydrolysis is carried out for 1 h. The pH value during the enzymatic hydrolysis is 5.5 - 6.

0. After the enzymatic hydrolysis is completed, inactivate the enzyme.

6. The preparation method of an Antarctic krill peptide with antioxidant activity according to claim 5, characterized in that: The enzymatic hydrolysis material is trypsin, alkaline protease and papain.

7. A preparation method of an Antarctic krill peptide with antioxidant activity according to claim 6, characterized in that: The mass ratio of trypsin, alkaline protease and papain is (3 - 5):(2 - 3):

1.

8. The preparation method of an Antarctic krill peptide with antioxidant activity according to claim 1, characterized in that: The specific operation method of the residue fermentation treatment is as follows: S11: Mix the residue obtained after taking the supernatant in Step 2 with glucose and water according to a weight ratio of (12 - 15):4:(5 - 7), and then inoculate with a fermentation bacterium to complete the inoculation; S12: Finally, carry out fermentation treatment. After 12 d of fermentation, the fermentation treatment of the residue is completed.

9. The preparation method of an Antarctic krill peptide with antioxidant activity according to claim 8, characterized in that: The fermentation bacterium is inoculated with Bacillus coagulans, and the inoculation amount of the fermentation bacterium is 15 - 20% of the total amount of the residue in Step 2.

10. A preparation method of an Antarctic krill peptide with antioxidant activity according to claim 8, characterized in that: The fermentation temperature of the fermentation treatment is 36 - 40 °C.