Pearl peptides with multiple functions, their preparation methods and applications

Abstract

The present invention relates to the technical field of polypeptides, and discloses a pearl peptide with multiple functions, a preparation method thereof and an application. The pearl peptide with multiple functions includes the following polypeptides: NPHCP1: Tyr-Val-Pro-Gly-His-Gly-Trp; NPHCP2: Gly-Tyr-His-Phe-His-Ser-Tyr-Pro; NPHCP3: Tyr-Pro-Asn-Pro-Tyr; NPHCP4: Glu-Gln-Tyr-Val-Pro-Gly-His; NPHCP5: Thr-Val-Tyr-Thr-Pro; The pearl peptide is Hyriopsis cumingii pearl peptide. The Hyriopsis cumingii pearl peptide prepared by the present invention has multiple functions such as whitening, scavenging free radicals and anti-skin photoaging, and improves the application value of freshwater nacre powder in the fields of cosmetics, biomedicine and food.

Description

Technical Field

[0001] The present invention belongs to the technical field of polypeptide preparation, and particularly relates to the preparation and application of pearl peptides with functions of whitening and anti-skin photoaging. Background Art

[0002] Hyriopsis cumingii ( Hyriopsis cumingii ), commonly known as triangular mussel, pearl mussel, river mussel, etc., is an important high-quality freshwater pearl mussel resource in China, and is widely distributed in rivers, lakes, etc. in Hunan, Hubei, Anhui, Jiangsu, Zhejiang, Jiangxi and other places in China. China is the largest producer of freshwater pearls in the world. After pearl harvesting, a large number of discarded mussel shells lack effective processing and utilization, resulting in waste of resources and environmental pollution.

[0003] Mother-of-pearl is a layer of grayish-white shiny nacre secreted by the cells of the mantle tissue and exists inside the pearl shell. Grinding it into fine powder gives mother-of-pearl powder. Mother-of-pearl and pearls are of the same origin. Research shows that the main components of mother-of-pearl powder are very close to those of pearl powder. Its main components are inorganic components, organic components and water. The content of inorganic components is 90%-96%, the organic matter content is about 2.0%-7.0%, and the water content is about 0.2% -2.0%. Mother-of-pearl powder is often used as a substitute for expensive pearl powder in the cosmetics field and has similar effects. Pearls have been a good product for whitening and beautifying since ancient times. "Compendium of Materia Medica" records that pearls have various effects such as "pearls are salty, sweet, cold and non-toxic, calming the nerves, making people moist and having a good complexion, removing facial spots, stopping diarrhea, relieving pox and treating toxins, and making the skin shiny and white". Modern medical research further verifies that pearls and mother-of-pearl powder have effects such as improving eyesight, calming, detoxifying, and whitening. At present, as an important ingredient of whitening and freckle-removing products, it has been included in the cosmetics raw material catalog of the State Food and Drug Administration.

[0004] Pearl protein and its enzymatically hydrolyzed active peptides are the main components of the whitening effect of pearls. The main component of mother-of-pearl protein is keratose, which is firmly combined with organic and inorganic substances and cross-linked with each other to form a strong network structure. Moreover, the structure of keratose is relatively complex, and the interaction of hydrogen bonds, hydrophobic bonds, disulfide bonds, etc. causes its peptide chain to curl tightly, making it insoluble in water and unable to be directly utilized. There are also problems such as being difficult to degrade and low extraction of small peptides. Enzymatic preparation of pearl peptide active peptides is one of the means to realize the high-value utilization of pearl protein. Therefore, how to efficiently degrade mother-of-pearl protein and develop pearl active peptides with high-efficiency whitening activity has broad application prospects in the field of skin-related biomedicine and will further generate huge economic value.

[0005] At present, the development and application process methods of the effective components of nacre mainly include: traditional water extraction, acid hydrolysis extraction, and direct enzymatic hydrolysis, etc. The traditional water extraction method cannot effectively utilize the insoluble proteins in pearls; although the acid hydrolysis extraction method can effectively degrade keratose, most of it is degraded into amino acids, and the functional components are damaged; while the direct enzymatic hydrolysis method has disadvantages such as low efficiency, low yield of small molecular peptides, and high cost. At the same time, there are no relevant reports on the extraction of tyrosinase inhibitory peptides and anti-skin photoaging peptides from the nacre powder of Hyriopsis cumingii.

[0006] In addition, in the existing technology, small molecular peptides are generally chromatographically separated by liquid chromatography. Not only are the separation and purification conditions complex, but also the separation efficiency is low and the cost is high, and it cannot be applied to industrial production. Summary of the Invention

[0007] In view of this, in order to further efficiently utilize the protein resources of freshwater nacre powder and explore new functional activities, the present invention provides a method for preparing Hyriopsis cumingii pearl peptides with whitening activity and anti-skin photoaging function.

[0008] The present aspect provides the following technical solutions:

[0009] A pearl peptide with multiple effects, characterized in that it includes the following polypeptides:

[0010] NPHCP1: Tyr-Val-Pro-Gly-His-Gly-Trp;

[0011] NPHCP2: Gly-Tyr-His-Phe-His-Ser-Tyr-Pro;

[0012] NPHCP3: Tyr-Pro-Asn-Pro-Tyr;

[0013] NPHCP4: Glu-Gln-Tyr-Val-Pro-Gly-His;

[0014] NPHCP5: Thr-Val-Tyr-Thr-Pro;

[0015] The pearl peptide is a Hyriopsis cumingii pearl peptide.

[0016] The present invention also provides a method for preparing the above pearl peptide, characterized in that it includes the following steps:

[0017] S1. After adding distilled water to the nacre powder of Hyriopsis cumingii according to a proportion, adding a composite ionic liquid, and performing high-temperature and high-pressure treatment, adding a composite protease for enzymatic hydrolysis according to a suitable proportion, inactivating the enzyme, and then centrifuging to obtain a supernatant;

[0018] In step S2, the supernatant of step S1, after decolorization, is subjected to ultrafiltration membrane to retain small molecule components, and then vacuum concentrated and freeze-dried to obtain small molecule Hyriopsis cumingii pearl peptides.

[0019] Further, in step S1, the composite ionic liquid comprises the following components in parts by weight: xanthan gum 29 - 47, sodium dodecyl sulfate 6 - 17, aspartic acid 11 - 23, glutamic acid 18 - 33.

[0020] Further, in step S1, the addition amount of the composite ionic liquid is 12 - 28% of the mass of nacre powder.

[0021] In the composite ionic liquid used in the present invention:

[0022] Xanthan gum is a monosaccharide polysaccharide produced by fermentation of the genus Pseudoxanthomonas. Its secondary structure is that the side chain winds around the main chain skeleton in the reverse direction and forms a rod-shaped double helix structure through hydrogen bonding. The tertiary structure is a helical complex formed by the rod-shaped double helix structures binding to each other through weak non-covalent bonds. Due to its special macromolecular structure and colloidal properties, it has excellent thickening, suspending, emulsifying and water-soluble properties, and has good thermal and acid-base stability, so it is widely used in various foods.

[0023] Sodium dodecyl sulfate is a non-toxic anionic surfactant with a biodegradation degree > 90%. It has good compatibility with anionic and non-ionic compounds, and has good emulsifying, foaming, permeating and dispersing properties. It can break non-covalent bonds such as ionic bonds and hydrogen bonds in proteins.

[0024] Aspartic acid and glutamic acid are acidic amino acids.

[0025] The composite ionic liquid of the present invention can, under the condition of physical modification, achieve synergistic compounding of each component. Through the cooperation of aspartic acid and glutamic acid, it reacts with calcium carbonate to form soluble calcium ions. Under the action of sodium dodecyl sulfate, the generation of precipitation is prevented. Under the action of xanthan gum, a stable reaction system is formed to prevent the occurrence of reversible reactions. Under high temperature and high pressure conditions, the composite ionic liquid reacts with the internal structure of Hyriopsis cumingii nacre powder, penetrates into the network structure between the organic matter and the inorganic matter and acts on it, loosens the combination between the organic matter and the inorganic matter, and has a certain destructive effect on the hydrogen bonds, hydrophobic bonds, disulfide bonds, etc. inside the shell keratin, so that the shell keratin of nacre powder can be more fully degraded into bioactive small molecule peptides in subsequent enzymatic hydrolysis, realizing the high-value utilization of nacre powder.

[0026] Further, in step S1, distilled water is added to Hyriopsis cumingii nacre powder in a ratio of 1:3 - 1:5, the treatment pressure is controlled at 0.20 - 0.25 MPa, the reaction temperature is 115 - 121 °C, and physical modification treatment is carried out for 20 - 30 min.

[0027] In the present invention, high-temperature conditions are conducive to the decomposition of reactants and the formation of free radicals, thereby increasing the chemical reaction rate. Under high-pressure conditions, when bubbles burst to generate high pressure, a strong shock wave is also accompanied, which has a good impact on the heterogeneous system with solids participating, resulting in strong intermolecular collisions and aggregations. Through the actions of high temperature and high pressure, special reaction conditions are provided for chemical reactions that are difficult or impossible to achieve under general conditions.

[0028] Further, in step S1, the composite enzyme used for enzymatic hydrolysis is the combination of bromelain and neutral protease bromelain. Synchronous enzymatic hydrolysis is adopted. The addition amount of bromelain is 0.10 - 0.30 g / 100g, and the addition amount of neutral protease bromelain is 0.2 - 0.6 g / 100g. The pH is adjusted to 6.0 - 7.0, the temperature is 45 - 60 °C. After enzymatic hydrolysis for 4 - 7 h, heat inactivation is carried out at 100 °C for 20 min, and then the supernatant is obtained by centrifugation.

[0029] Through the composite enzymatic hydrolysis reaction, not only can the efficiency of enzymatic hydrolysis and the yield of small-molecule active substances be improved, but also the small-molecule active peptides extracted have high activity and specificity, endowing them with specific biological activities.

[0030] Further, in step S2, combined decolorization with activated carbon and diatomaceous earth is adopted. After filtration, the filtrate is further subjected to ultrafiltration to retain the components with a molecular weight less than 3000 Da.

[0031] The innovation of the present invention lies in that: through the addition of composite ionic liquid, under high-temperature and high-pressure conditions, on the one hand, the release rate of small-molecule active substances can be increased, and on the other hand, the component proportion of small-molecule active peptide segments can be controlled by the addition amount, making it more prominent in some biological activity functions and meeting the requirements of different application scenarios.

[0032] The present invention also provides an application of the above-mentioned pearl peptides in the preparation of products for scavenging free radicals, inhibiting tyrosinase, and anti-skin photoaging.

[0033] In the present invention, through the combination of composite ionic liquid intervention and high-temperature and high-pressure pretreatment, the content of soluble small-molecule peptides prepared by enzymatic hydrolysis can be effectively increased. Compared with the ordinary enzymatic hydrolysis preparation of the prior art, the degree of hydrolysis is significantly improved; moreover, composite enzymatic hydrolysis can significantly improve the efficiency of hydrolyzing insoluble proteins.

[0034] The applicant has found through a large number of creative experiments that a reasonable pretreatment method and the combination of proteases play a key role in degrading insoluble pearl proteins, and can solve the technical problems such as poor water solubility and difficult utilization of freshwater nacre proteins in the prior art.

[0035] In addition, through the intervention of the composite ionic liquid of the present invention, under the same preparation conditions, a stable composition of specific sequence pearl peptides can be obtained, and the proportion of each sequence can be controlled within the expected range. The target product can be obtained by the way of ultrafiltration membrane retention, which can ensure that the product has the target biological activity. This can effectively solve the problems in the prior art that the separation and purification conditions of small molecule peptides are complex, the cost is high, the separation efficiency is low, and industrial production cannot be realized.

[0036] The Hyriopsis cumingii pearl peptides prepared by the present invention have high tyrosinase inhibitory activity, and at the same time have the functions of scavenging free radicals and anti-skin photoaging, and have high safety and no toxic and side effects, which can solve the technical problems that traditional tyrosinase inhibitors such as kojic acid and arbutin may have toxic and side effects in the prior art.

[0037] By adopting the preparation method of the present invention, the added value of Hyriopsis cumingii shell waste is effectively increased, and the application value of freshwater nacre powder in the fields of cosmetics, biomedicine and food is improved. Brief Description of the Drawings

[0038] Figure 1 Total ion chromatogram of LC-MS for separation and identification of Hyriopsis cumingii pearl peptides. Detailed Description of the Invention

[0039] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention.

[0040] Example 1

[0041] A pearl peptide with multiple effects, characterized by including the following polypeptides:

[0042] NPHCP1: Tyr-Val-Pro-Gly-His-Gly-Trp;

[0043] NPHCP2: Gly-Tyr-His-Phe-His-Ser-Tyr-Pro;

[0044] NPHCP3: Tyr-Pro-Asn-Pro-Tyr;

[0045] NPHCP4: Glu-Gln-Tyr-Val-Pro-Gly-His;

[0046] NPHCP5: Thr-Val-Tyr-Thr-Pro;

[0047] The pearl peptide is Hyriopsis cumingii pearl peptide.

[0048] Example 2

[0049] A preparation method of the pearl peptide of Example 1, characterized by comprising the following steps:

[0050] S1. After washing and drying the nacre powder of Hyriopsis cumingii (200 - 400 mesh), add distilled water in proportion, then add a composite ionic liquid. After high-temperature and high-pressure treatment, add a composite protease for enzymatic hydrolysis in an appropriate proportion. After inactivating the enzyme, centrifuge to obtain the supernatant;

[0051] S2. The supernatant of step S1, after decolorization, uses an ultrafiltration membrane to retain the small molecule components, and then obtains small molecule Hyriopsis cumingii pearl peptide through vacuum concentration and freeze-drying.

[0052] Further, in step S1, the composite ionic liquid comprises the following components in parts by weight: xanthan gum 36, sodium dodecyl sulfate 11, aspartic acid 17, glutamic acid 26.

[0053] Further, in step S1, the addition amount of the composite ionic liquid is 18% of the mass of the nacre powder.

[0054] Further, in step S1, distilled water is added to the nacre powder of Hyriopsis cumingii in a ratio of 1:4, the treatment pressure is controlled at 0.22 MPa, the reaction temperature is 120 °C, and the physical modification treatment is carried out for 25 min.

[0055] Further, in step S1, the composite enzyme selected for enzymatic hydrolysis is a combination of bromelain and neutral protease bromelain. Synchronous enzymatic hydrolysis is adopted. The addition amount of bromelain is 0.20 g / 100 g, and the addition amount of neutral protease bromelain is 0.4 g / 100 g. Adjust the pH to 6.5 and the temperature to 50 °C. After enzymatic hydrolysis for 5 h, inactivate the enzyme at 100 °C for 20 min, and then centrifuge to take the supernatant.

[0056] Further, in step S2, combined decolorization with activated carbon and diatomaceous earth is adopted. After filtration, the filtrate further uses an ultrafiltration membrane to retain the components with a molecular weight less than 3000 Da.

[0057] Example 3

[0058] This example provides a preparation method of the same pearl peptide as in Example 2. The difference is that in step S1, the addition amount of the composite ionic liquid is 12% of the mass of the nacre powder.

[0059] Example 4

[0060] This embodiment provides a method for preparing pearl peptides identical to that of Embodiment 2, except that in step S1, the addition amount of the composite ionic liquid is 23% of the mass of nacre powder.

[0061] Embodiment 5

[0062] This embodiment provides a method for preparing pearl peptides identical to that of Embodiment 2, except that in step S1, the addition amount of the composite ionic liquid is 28% of the mass of nacre powder.

[0063] Embodiment 6

[0064] This embodiment provides a method for preparing pearl peptides identical to that of Embodiment 2, except that in step S1, the composite ionic liquid comprises the following components in parts by weight: xanthan gum 33, sodium dodecyl sulfate 8, aspartic acid 14, glutamic acid 22.

[0065] Embodiment 7

[0066] This embodiment provides a method for preparing pearl peptides identical to that of Embodiment 2, except that in step S1, the composite ionic liquid comprises the following components in parts by weight: xanthan gum 45, sodium dodecyl sulfate 15, aspartic acid 20, glutamic acid 29.

[0067] Embodiment 8

[0068] This embodiment provides a method for preparing pearl peptides identical to that of Embodiment 2, except that in step S1, the composite ionic liquid comprises the following components in parts by weight: xanthan gum 29, sodium dodecyl sulfate 6, aspartic acid 11, glutamic acid 18.

[0069] Further, in step S1, the hyriopsis cumingii nacre powder is added to distilled water in a ratio of 1:3, the treatment pressure is controlled at 0.20 MPa, the reaction temperature is 121 °C, and physical modification treatment is carried out for 20 min.

[0070] Further, in step S1, the composite enzyme selected for enzymatic hydrolysis is a combination of bromelain and neutral protease bromelain. Synchronous enzymatic hydrolysis is adopted. The addition amount of bromelain is 0.10 g / 100 g, and the addition amount of neutral protease bromelain is 0.2 g / 100 g. The pH is adjusted to 7.0, the temperature is 45 °C. After enzymatic hydrolysis for 6 h, heat inactivation treatment is carried out at 100 °C for 20 min, and then the supernatant is taken by centrifugation.

[0071] Embodiment 9

[0072] This embodiment provides a method for preparing pearl peptides identical to that of Embodiment 2, except that in step S1, the composite ionic liquid comprises the following components in parts by weight: xanthan gum 47, sodium dodecyl sulfate 17, aspartic acid 23, glutamic acid 33.

[0073] Further, in step S1, nacre powder of Hyriopsis cumingii is added to distilled water at a ratio of 1:5, the treatment pressure is controlled at 0.25 MPa, the reaction temperature is 118 °C, and physical modification treatment is carried out for 30 min.

[0074] Further, in step S1, the composite enzyme selected for enzymatic hydrolysis is a combination of bromelain and neutral protease bromelain. Synchronous enzymatic hydrolysis is adopted. The addition amount of bromelain is 0.30 g / 100 g, and the addition amount of neutral protease bromelain is 0.6 g / 100 g. The pH is adjusted to 6.0, the temperature is 60 °C. After enzymatic hydrolysis for 4 h, enzyme inactivation treatment is carried out at 100 °C for 20 min, and then the supernatant is taken by centrifugation.

[0075] Comparative Example 1

[0076] This example provides a method for preparing pearl peptides the same as that in Example 2, except that no composite ionic liquid is added.

[0077] Comparative Example 2

[0078] This example provides a method for preparing pearl peptides the same as that in Example 2, except that xanthan gum is not contained in the composite ionic liquid.

[0079] Comparative Example 3

[0080] This example provides a method for preparing pearl peptides the same as that in Example 2, except that sodium dodecyl sulfate is not contained in the composite ionic liquid.

[0081] Comparative Example 4

[0082] This example provides a method for preparing pearl peptides the same as that in Example 2, except that aspartic acid and glutamic acid are not contained in the composite ionic liquid.

[0083] Experimental effect test

[0084] The pearl peptides prepared in Example 2 are respectively subjected to reductive alkylation treatment as samples. Through liquid chromatography-mass spectrometry (LC-MS / MS) analysis, the raw file of the original mass spectrometry results is obtained, and the total ion chromatogram ( Figure 1). The mass spectrometry data was analyzed by the software PEAKS Studio 8.5 to identify the peptide sequences with higher scores. Further, using tyrosinase (PDB: 2Y9X) as the receptor and small molecule peptides as the ligands, molecular docking was performed using the Autodock Vina software to obtain the whitening active peptide sequence with the lowest binding energy, as shown in the following table. The relative content of each active peptide was calculated using the area normalization method (measuring the area of each peak of the peptide and the total chromatographic peak area on the chromatogram excluding the solvent peak, and calculating the percentage of the area of each peak in the total peak area); the results are shown in the following table.

[0085]

[0086] Using the same method, the relative content of each active peptide in the pearl peptides prepared in Examples 3 - 5 was calculated; the results are shown in the following table.

[0087]

[0088] Antioxidant activity;

[0089] Operate according to the instructions of the existing technology kit product (). The ABTS and DPPH radical scavenging rates were calculated as follows:

[0090]

[0091] In the formula:

[0092] A0——Absorbance value of the blank control;

[0093] A1——Absorbance value after the sample reacts with ABTS (DPPH);

[0094] A2——Absorbance value of the sample.

[0095] The pearl peptides with a molecular weight less than 3000 Da prepared in Examples 2 - 5 and Comparative Examples 1 - 4 were formulated into a solution of 10.0 mg / mL, and the ABTS and DPPH radical scavenging abilities were tested respectively. The results are shown in the following table.

[0096]

[0097] Whitening activity (tyrosinase inhibitory activity);

[0098] Tyrosinase inhibitory activity is one of the in vitro activities for evaluating whitening activity and can be used to reflect its inhibitory ability on melanogenesis. It is carried out according to the provisions of T / GDCA 006-2021. Add L-tyrosine solution, the solution of pearl peptides with a molecular weight less than 3000 Da prepared in Examples 2-5 and Comparative Examples 1-4 at a concentration of 10.0 mg / mL, and PBS buffer into a 96-well plate, incubate in a water bath at 37 °C for 10 min, add 20 μL of tyrosinase solution, mix well and react at 37 °C for 5 min ± 5 s, and then immediately put it into a microplate reader for measurement. Replace L-tyrosine with L-dopa and repeat the above operation. The inhibition rates of mono- and diphenolase activities are calculated according to the following formula:

[0099]

[0100] In the formula:

[0101] Y——Inhibition rate of tyrosinase activity, %;

[0102] Ad——Absorbance of the sample reaction well;

[0103] Ac——Absorbance of the sample background well;

[0104] Ab——Average absorbance of the solvent reaction wells;

[0105] Aa——Average absorbance of the solvent background wells.

[0106] Fit the inhibition rate curve to obtain the regression equation and calculate the IC50 value of the active peptide, and convert it into the kojic acid equivalent value according to the following formula.

[0107]

[0108] In the formula:

[0109] D——Kojic acid equivalent value, mg / mg;

[0110] C——IC50 value of the test sample, mg / mL;

[0111] C0——IC50 value of kojic acid, mg / mL.

[0112] Test the inhibition rates on L-tyrosine and L-dopa respectively, and the results are shown in the following table.

[0113]

[0114] Anti-skin photoaging (effect on the viability of HaCaT cells after UV-B damage);

[0115] The cells were cultured in DMEM medium containing 10% fetal bovine serum and placed in a constant temperature and humidity cell incubator with 5% CO2 at 37 °C for standby. When the HaCaT cells reached about 75% confluence in a T25 cell culture flask, they were digested with 0.25% trypsin and transferred to a 96-well cell culture plate. After the cells adhered to the wall, the culture medium was aspirated, and the cells were washed with PBS. Then, they were irradiated with a UV-B ultraviolet lamp (9 W, spectrum between 285 - 350 nm) at a distance of 16 cm from the 96-well plate for 1 min. Then, 100 μL of a 100.0 μg / mL solution prepared from pearl peptides with a molecular weight less than 3000 Da prepared in Examples 2 - 5 and Comparative Examples 1 - 4 was added. After 24 h of culture, the cell viability was measured using a CCK-8 kit, and the results are shown in the following table.

[0116]

[0117] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention 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-restrictive. 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 embraced within the present invention.

[0118] 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. It should be noted that the technical features not detailed in the present invention can all be realized by any existing technology.

Claims

1. A method for preparing pearl peptide, characterized in that, It includes the following steps: S1. After adding nacre powder of Hyriopsis cumingii into distilled water in proportion, a composite ionic liquid is added. After high-temperature and high-pressure treatment, enzymatic hydrolysis is carried out by adding a composite protease in a suitable proportion. After inactivating the enzyme, centrifugation is performed to obtain the supernatant; S2. The supernatant of step S1, after decolorization, uses an ultrafiltration membrane to retain small molecule components, and after vacuum concentration and freeze-drying, small molecule nacre peptides of Hyriopsis cumingii can be obtained; The composite ionic liquid includes the following components in parts by weight: xanthan gum 29-47, sodium dodecyl sulfate 6-17, aspartic acid 11-23, glutamic acid 18-33; In step S1, the addition amount of the composite ionic liquid is 12-28% of the mass of the nacre powder; The nacre powder of Hyriopsis cumingii is added into distilled water in a ratio of 1:3 - 1:5, the treatment pressure is controlled at 0.20 - 0.25 MPa, the reaction temperature is 115 - 121 °C, and physical modification treatment is carried out for 20 - 30 min; The composite protease selected for enzymatic hydrolysis is a combination of bromelain and neutral protease. Synchronous enzymatic hydrolysis is adopted. The addition amount of bromelain is 0.10 - 0.30 g / 100 g, and the addition amount of neutral protease is 0.2 - 0.6 g / 100 g. The pH is adjusted to 6.0 - 7.0, the temperature is 45 - 60 °C. After enzymatic hydrolysis for 4 - 7 h, the enzyme is inactivated at 100 °C for 20 min, and then the supernatant is taken by centrifugation; In step S2, combined decolorization with activated carbon and diatomite is adopted. After filtration, the filtrate further uses an ultrafiltration membrane to retain components with a molecular weight less than 3000 Da; The components include the following polypeptides: NPHCP1: Tyr-Val-Pro-Gly-His-Gly-Trp; NPHCP2: Gly-Tyr-His-Phe-His-Ser-Tyr-Pro; NPHCP3: Tyr-Pro-Asn-Pro-Tyr; NPHCP4: Glu-Gln-Tyr-Val-Pro-Gly-His; and NPHCP5: Thr-Val-Tyr-Thr-Pro; The pearl peptide is the nacre peptide of Hyriopsis cumingii.

2. Application of the pearl peptide prepared by the preparation method of claim 1 in antioxidant, whitening, and anti-skin photoaging products.

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