Preparation and activity protection method of egg white protein peptide with high antioxidant activity

Abstract

The invention discloses a preparation and activity protection method of egg white protein peptide with high antioxidant activity, which comprises the following steps: taking egg white liquid as a raw material, adding deionized water to prepare a protein suspension, stirring and uniformly mixing in an ultrasonic water bath, and cooling to room temperature to obtain denatured protein liquid; sequentially adding incision enzyme, excision enzyme and flavourzyme into the denatured protein liquid to carry out synergistic directional enzymolysis; centrifuging the mixed solution after enzymolysis, taking supernate, performing ultrafiltration on the supernate, and collecting filtrate; performing ultrasonic mixing on the filtrate and the composite protective solution, performing high-pressure homogenization, and performing spray drying to form microcapsule particles; and adding a freeze-drying protective agent into the prepared microcapsule particles, and freeze-drying to obtain the finished product of the egg white protein peptide with high antioxidant activity. The method has the remarkable effects that the antioxidant index of the prepared egg white peptide is remarkably higher than that of an egg white peptide product reported in the prior art or a traditional antioxidant, and the egg white peptide has good product stability.

Description

Technical Field

[0001] This invention relates to the fields of biotechnology and food engineering technology, specifically to a method for preparing and protecting the activity of egg white protein peptides with high antioxidant activity. Background Technology

[0002] Egg white, also known as "egg white" or "egg yolk," is the transparent liquid surrounding the yolk in an egg. Egg white protein accounts for approximately 10%-12% of the egg white's mass and is mainly composed of ovalbumin, ovoglobulin, ovomucoid, lysozyme, and globulin. It is a high-quality protein resource with a rich and balanced amino acid composition. Its enzymatic hydrolysis product—egg white protein peptides—has broad application prospects in the field of antioxidants due to its small molecular weight, easy absorption, and strong free radical scavenging ability.

[0003] Currently, although there are many research reports on "preparation of antioxidant peptides by enzymatic hydrolysis of egg white", the existing egg white peptide preparation methods have the following shortcomings: low enzymatic hydrolysis efficiency, low product activity, complex peptide composition, strong bitterness, and neglect of subsequent stabilization and protection of active peptides, resulting in a rapid decline in product activity during storage and application.

[0004] In view of the above technical background, this invention uses egg white protein as raw material and adopts a four-in-one technical solution of "pretreatment-directional enzymatic hydrolysis-separation and purification-activity protection" to obtain antioxidant peptides with high yield and activity. The obtained antioxidant peptide products can be applied in the fields of pharmaceuticals, cosmetics, health products, and food and feed additives. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a novel method for preparing and protecting the activity of highly antioxidant egg white protein peptides, which exhibits high antioxidant activity and good stability.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, this invention proposes a method for preparing and protecting the activity of egg white protein peptides with high antioxidant activity, the key of which includes the following steps: Step 1, Raw material pretreatment: Using egg white liquid as raw material, add deionized water to prepare a protein suspension with a mass concentration of 3%-5%, stir and mix in an ultrasonic water bath, and cool to room temperature to obtain denatured protein liquid; Step 2, Synergistic Targeted Enzymatic Hydrolysis: Add an endonuclease to the denatured protein solution for one enzymatic digestion; Add an exonuclease to perform a second enzymatic hydrolysis on the hydrolysate after the first enzymatic hydrolysis. Add flavor protease and perform a third enzymatic hydrolysis on the hydrolysate after the second enzymatic hydrolysis. Step 3, Separation and purification: After centrifugation of the enzymatically hydrolyzed mixture, the supernatant is collected, the supernatant is ultrafiltered, and the filtrate is collected; Step 4, Encapsulation treatment: The filtrate and composite protective solution are ultrasonically mixed at a mass ratio of 1:6 to 1:3, homogenized under high pressure, and then spray-dried to form microcapsule particles; Step 5, freeze-drying protection: Add a freeze-drying protectant to the obtained microcapsule particles, freeze-dry, and obtain the finished product of highly antioxidant active egg white protein peptide.

[0007] Furthermore, in step 1, the mixture is ultrasonically stirred for 10-30 minutes at 88-92℃.

[0008] Furthermore, in step 2, the endonuclease is an alkaline protease or trypsin, and the amount added is 1~5wt%. During enzymatic hydrolysis, the pH is adjusted to 7.5-11.0, and the enzymatic hydrolysis is carried out at a constant temperature of 40~60℃ for 3~4 hours. The exonuclease is carboxypeptidase, added at a rate of 0.5-2 wt%. During enzymatic hydrolysis, the pH is adjusted to 6.5-8.5, and the hydrolysis is carried out at room temperature for 2-3 hours. The amount of flavor protease added is 0.5~2wt%. During enzymatic hydrolysis, the pH is adjusted to 6.0~8.0, and the enzymatic hydrolysis is carried out at a constant temperature of 35℃~60℃ for 2~5 hours.

[0009] Furthermore, before collecting the supernatant after centrifuging the enzymatically digested mixture in step 3, the following steps are also included: The enzymatically hydrolyzed mixture was heated to 95°C and held for 15 minutes to inactivate the enzymes. After cooling to room temperature, the pH was adjusted to 5.0-6.0.

[0010] Furthermore, in step 3, when centrifuging the enzymatically digested mixture, the rotation speed is 3000-5000 rpm and the centrifugation time is 16-30 min.

[0011] Furthermore, before ultrafiltration of the supernatant in step 3, the supernatant is washed sequentially with anhydrous ethanol, acidic solution with pH 1-2, alkaline solution with pH 11-12, and deionized water for 20 minutes each.

[0012] Furthermore, in step 3, the ultrafiltration of the supernatant is carried out at a pressure of 0.15-0.18 MPa, and the molecular weight cutoff of the ultrafiltration membrane is 1-3 kDa.

[0013] Furthermore, the preparation steps of the composite protective liquid in step 4 are as follows: Weigh the raw materials by weight: 30-40 parts maltodextrin, 15-20 parts β-cyclodextrin, 8-12 parts gum arabic, 2-3 parts ascorbyl palmitate, and 1-2 parts tea polyphenols; Add deionized water and stir at 60°C for 30 minutes until completely dissolved to form the composite protective solution.

[0014] Furthermore, the freeze-drying protectant mentioned in step 5 is at least one of trehalose or mannitol.

[0015] Secondly, this invention proposes the application of a highly antioxidant active egg white protein peptide prepared by the method described in the first aspect in the preparation of antioxidant functional foods, health products, or cosmetics.

[0016] The significant effects of this invention are: Advanced process: The egg white peptide prepared by ultrasonic pretreatment + stepwise enzymatic hydrolysis of compound enzymes + membrane separation and directional screening + polyphenol synergistic microcapsule protection has significantly higher antioxidant index than existing egg white peptide products or traditional antioxidants; moreover, it can still maintain high activity after simulated gastrointestinal digestion, which proves its good stability. Significantly enhanced activity: Through pretreatment and compound targeted enzymatic hydrolysis, the prepared protein peptides have a DPPH free radical scavenging rate of ≥78% and a hydroxyl free radical scavenging rate of ≥82%, which significantly improves the yield and activity of the target antioxidant peptides. Their free radical scavenging ability far exceeds that of traditional method products and chemical antioxidants.

[0017] The product exhibits excellent stability: its innovative microencapsulation and freeze-drying protection technology ensures that the activity retention rate is ≥85% after 6 months of storage at 45℃ and 60% relative humidity; and the activity loss is ≤10% within the pH range of 3.0-9.0. This effectively solves the technical problem of easy inactivation of active peptides, extends the product's shelf life, and broadens its application range.

[0018] The process is green and efficient: no harmful chemical reagents are added throughout the entire process, the conditions are mild, it is easy to scale up production, and it meets the needs of modern food industry development.

[0019] Wide range of applications: The resulting product has good flowability and is easy to dissolve, and can be used in multiple fields such as functional foods, health products, and cosmetics, with broad market prospects.

[0020] Cost controllable: Raw materials are widely available, encapsulating agents are low-cost, and spray drying technology is mature. When produced on a large scale, the unit cost is reduced by 25% compared to traditional methods. Attached Figure Description

[0021] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0022] The specific embodiments and working principles of the present invention will be further described in detail below with reference to the accompanying drawings. Example

[0023] like Figure 1As shown in the figure, this invention provides a method for preparing and protecting the activity of egg white protein peptides with high antioxidant activity. The specific steps are as follows: Step 1, Raw material pretreatment: Using egg white liquid as raw material, add deionized water to prepare a protein suspension with a mass concentration of 3%, stir and mix in an ultrasonic water bath to destroy the secondary and tertiary structure of the protein, expose the enzymatic digestion sites, and cool to room temperature to obtain denatured protein solution; In this step, the ultrasonic power is 500W, the stirring time is 10min, and the water bath temperature is 88℃. Step 2, Synergistic Targeted Enzymatic Hydrolysis: Alkaline protease was added to the denatured protein solution for one enzymatic hydrolysis. The amount of alkaline protease added was 1 wt%. The pH was adjusted to 11.0 during the enzymatic hydrolysis, and the solution was kept at 60°C for 4 hours. Add carboxypeptidase at a dosage of 0.5 wt%. Adjust the pH of the system to 8.5 during enzymatic hydrolysis. Perform a second enzymatic hydrolysis on the hydrolysate after the first hydrolysis at room temperature for 2 hours. Add flavor protease at a concentration of 0.5 wt%. Adjust the pH of the system to 8.0 during enzymatic hydrolysis. Perform three enzymatic hydrolysis cycles on the hydrolysate after the second enzymatic hydrolysis at a constant temperature of 35°C for 5 hours. This achieves stepwise multi-enzyme synergistic directional enzymatic hydrolysis to eliminate bitterness and release more active groups. In this step, the protease first disrupts the protein macromolecular structure, the carboxypeptidase specifically hydrolyzes hydrophobic amino acid sites, and the flavor protease targets the bitter peptide chains in the hydrolysis product and removes dissolved oxygen, thus completely degrading them into amino acids. Through the synergistic enzymatic hydrolysis of these three enzymes, the degree of hydrolysis and the efficiency of active peptide release are improved. Step 3: Separation and purification: The enzyme-inactivated mixture was heated to 95°C and held for 15 minutes. After cooling to room temperature, the pH was adjusted to 5.0. The enzymatically hydrolyzed mixture was centrifuged at 5000 rpm for 16 min. The supernatant was collected to remove unhydrolyzed proteins and impurities. Wash with anhydrous ethanol, acidic solution with pH 1, alkaline solution with pH 12, and deionized water for 20 minutes in sequence. The supernatant was ultrafiltered sequentially through an ultrafiltration membrane system with different molecular weight cutoffs at a pressure of 0.15 MPa. The filtrate of peptide components with a target molecular weight of 1 kDa was collected to remove macromolecular impurities. Step 4, Embedding treatment: The filtrate and the composite protective liquid were ultrasonically mixed at a mass ratio of 1:6, with an ultrasonic power of 200W and a time of 10 minutes. After high-pressure homogenization, the mixture was spray-dried to form microcapsule particles to isolate oxygen and light and heat. In this example, the preparation steps of the composite protective liquid are as follows: Weigh the raw materials by weight: 30 parts maltodextrin, 20 parts β-cyclodextrin, 12 parts gum arabic, 3 parts ascorbyl palmitate, and 1 part tea polyphenols; Add deionized water and stir at 60°C for 30 minutes until completely dissolved to form the composite protective solution; Step 5, freeze-drying protection: Add trehalose to the obtained microcapsule particles at a mass ratio of 1:1 as a freeze-drying protectant to protect the structure of the peptide from being destroyed during the drying process. Freeze-dry to obtain the finished product of high antioxidant activity egg white protein peptide. Example

[0024] The difference between this embodiment and Embodiment 1 is that: In step 1, deionized water is added to prepare a protein suspension with a mass concentration of 3.5%, and the suspension is ultrasonically stirred at 89°C for 10-30 minutes.

[0025] In step 2, the endonuclease is trypsin, and the amount added is 1~5wt%. During enzymatic hydrolysis, the pH is adjusted to 7.5-11.0, and the enzymatic hydrolysis is carried out at a constant temperature of 40~60℃ for 3~4 hours. The amount of carboxypeptidase added is 0.5~2wt%, and the pH is adjusted to 6.5~8.5 during enzymatic hydrolysis, and the enzymatic hydrolysis is carried out at room temperature for 2~3 hours. The amount of flavor protease added is 0.5~2wt%. During enzymatic hydrolysis, the pH is adjusted to 6.0~8.0, and the enzymatic hydrolysis is carried out at a constant temperature of 35℃~60℃ for 2~5 hours.

[0026] In step 3, the enzymatically hydrolyzed mixture is inactivated, cooled to room temperature, and then the pH is adjusted to 5.5. When centrifuging the enzymatically hydrolyzed mixture, the speed was 3000 rpm and the centrifugation time was 30 min; Before ultrafiltration, the supernatant was washed sequentially with anhydrous ethanol, acidic solution with pH 1, alkaline solution with pH 11, and deionized water for 20 minutes each. The supernatant was ultrafiltered at a pressure of 0.16 MPa, and the ultrafiltration membrane had a molecular weight cutoff of 3 kDa.

[0027] In step 4, the filtrate and the composite protective liquid are ultrasonically mixed at a mass ratio of 1:5. The composite protective liquid is made up of the following raw materials by weight: 35 parts maltodextrin, 15 parts β-cyclodextrin, 8 parts gum arabic, 2 parts ascorbate palmitate, and 2 parts tea polyphenols.

[0028] In step 5, the freeze-drying protectant is mannitol, which is added at a mass ratio of 1:2. Example

[0029] The difference between this embodiment and Embodiment 1 is that: In step 1, deionized water was added to prepare a protein suspension with a mass concentration of 4.%, and the suspension was ultrasonically stirred at 90°C for 20 minutes.

[0030] In step 2, the endonuclease is trypsin, and the amount added is 3 wt%. During enzymatic hydrolysis, the pH is adjusted to 10, and the enzymatic hydrolysis is carried out at 50°C for 3.5 hours. The amount of carboxypeptidase added was 1.5 wt%. During enzymatic hydrolysis, the pH was adjusted to 7.5, and the enzymatic hydrolysis was carried out at room temperature for 2.5 hours. The amount of flavor protease added is 1.2 wt%. During enzymatic hydrolysis, the pH is adjusted to 7.0, and the hydrolysis is carried out at a constant temperature of 50°C for 3.5 hours.

[0031] In step 3, the enzymatically hydrolyzed mixture is inactivated, cooled to room temperature, and then the pH is adjusted to 6. When centrifuging the enzymatically hydrolyzed mixture, the speed was 3500 rpm and the centrifugation time was 25 min; Before ultrafiltration, the supernatant was washed sequentially with anhydrous ethanol, acidic solution with pH 2, alkaline solution with pH 11, and deionized water for 20 minutes each. The supernatant was ultrafiltered at a pressure of 0.17 MPa, and the ultrafiltration membrane had a molecular weight cutoff of 2 kDa.

[0032] In step 4, the filtrate and the composite protective liquid are ultrasonically mixed at a mass ratio of 1:4. The composite protective liquid is made of the following raw materials by weight: 40 parts maltodextrin, 20 parts β-cyclodextrin, 10 parts gum arabic, 3 parts ascorbate palmitate, and 1 part tea polyphenols.

[0033] In step 5, the freeze-drying protectant is trehalose, which is added at a mass ratio of 1:3. Example

[0034] The difference between this embodiment and Embodiment 1 is that: In step 1, deionized water was added to prepare a protein suspension with a mass concentration of 5%, and the suspension was ultrasonically stirred at 91°C for 28 minutes.

[0035] In step 2, the endonuclease is an alkaline protease, added at a rate of 4.5 wt%. During enzymatic hydrolysis, the pH is adjusted to 9.5, and the hydrolysis is carried out at a constant temperature of 55°C for 3 hours. The amount of carboxypeptidase added was 1.8 wt%. During enzymatic hydrolysis, the pH was adjusted to 7.5, and the enzymatic hydrolysis was carried out at room temperature for 3 hours. The amount of flavor protease added was 1.6 wt%. During enzymatic hydrolysis, the pH was adjusted to 7.0, and the hydrolysis was carried out at a constant temperature of 55°C for 5 hours.

[0036] In step 3, the enzymatically hydrolyzed mixture is inactivated, cooled to room temperature, and then the pH is adjusted to 5. When centrifuging the enzymatically hydrolyzed mixture, the speed was 4500 rpm and the centrifugation time was 18 min; Before ultrafiltration, the supernatant was washed sequentially with anhydrous ethanol, acidic solution with pH 1, alkaline solution with pH 12, and deionized water for 20 minutes each. The supernatant was ultrafiltered at a pressure of 0.18 MPa, and the ultrafiltration membrane had a molecular weight cutoff of 1 kDa.

[0037] In step 4, the filtrate and the composite protective liquid are ultrasonically mixed at a mass ratio of 1:6. The composite protective liquid is made of the following raw materials by weight: 30 parts maltodextrin, 15 parts β-cyclodextrin, 11 parts gum arabic, 3 parts ascorbate palmitate, and 2 parts tea polyphenols.

[0038] In step 5, the freeze-drying protectant is a mixture of trehalose and mannitol in a 1:1 mass ratio, which is added in a 1:1 mass ratio. Example

[0039] The difference between this embodiment and Embodiment 1 is that: In step 1, deionized water is added to prepare a protein suspension with a mass concentration of 5%, and the suspension is ultrasonically stirred at 92°C for 12 minutes.

[0040] In step 2, the endonuclease is trypsin, and the amount added is 5 wt%. During enzymatic hydrolysis, the pH is adjusted to 8.0, and the enzymatic hydrolysis is carried out at 45°C for 3 hours. The amount of carboxypeptidase added is 0.5 wt%, the pH is adjusted to 7.5 during enzymatic hydrolysis, and the enzymatic hydrolysis is carried out at room temperature for 3 hours. The amount of flavor protease added is 0.5 wt%, the pH is adjusted to 6.0 during enzymatic hydrolysis, and the enzymatic hydrolysis is carried out at a constant temperature of 40°C for 3.5 hours.

[0041] In step 3, the enzymatically hydrolyzed mixture is inactivated, cooled to room temperature, and then the pH is adjusted to 5.5. When centrifuging the enzymatically hydrolyzed mixture, the speed was 4000 rpm and the centrifugation time was 25 min; Before ultrafiltration, the supernatant was washed sequentially with anhydrous ethanol, acidic solution with pH 2, alkaline solution with pH 11, and deionized water for 20 minutes each. The supernatant was ultrafiltered at a pressure of 0.16 MPa, and the ultrafiltration membrane had a molecular weight cutoff of 2 kDa.

[0042] In step 4, the filtrate and the composite protective liquid are ultrasonically mixed at a mass ratio of 1:4. The composite protective liquid is made of the following raw materials by weight: 40 parts maltodextrin, 15 parts β-cyclodextrin, 12 parts gum arabic, 2 parts ascorbate palmitate, and 2 parts tea polyphenols.

[0043] In step 5, the freeze-drying protectant is mannitol, which is added at a mass ratio of 1:2. Example

[0044] The difference between this embodiment and Embodiment 1 is that: In step 1, deionized water was added to prepare a protein suspension with a mass concentration of 4.5%, and the suspension was ultrasonically stirred at 91°C for 25 minutes.

[0045] In step 2, the endonuclease is an alkaline protease, added at 3 wt%, and the pH is adjusted to 10.0 during enzymatic hydrolysis, and the hydrolysis is carried out at 50°C for 3.5 hours. The amount of carboxypeptidase added was 1.5 wt%. During enzymatic hydrolysis, the pH was adjusted to 7.5, and the enzymatic hydrolysis was carried out at room temperature for 2.5 hours. The amount of flavor protease added is 1 wt%, the pH is adjusted to 6.0 during enzymatic hydrolysis, and the enzymatic hydrolysis is carried out at a constant temperature of 40°C for 4.5 hours.

[0046] In step 3, the enzymatically hydrolyzed mixture is inactivated, cooled to room temperature, and then the pH is adjusted to 5.5. When centrifuging the enzymatically hydrolyzed mixture, the speed was 5000 rpm and the centrifugation time was 10 min; Before ultrafiltration, the supernatant was washed sequentially with anhydrous ethanol, acidic solution with pH 2, alkaline solution with pH 12, and deionized water for 20 minutes each. The supernatant was ultrafiltered at a pressure of 0.16 MPa, and the ultrafiltration membrane had a molecular weight cutoff of 1 kDa.

[0047] In step 4, the filtrate and the composite protective liquid are ultrasonically mixed at a mass ratio of 1:4.5. The composite protective liquid is made up of the following raw materials by weight: 35 parts maltodextrin, 18 parts β-cyclodextrin, 10 parts gum arabic, 2.5 parts ascorbate palmitate, and 1.5 parts tea polyphenols.

[0048] In step 5, the freeze-drying protectant is trehalose, which is added at a mass ratio of 1:2.

[0049] The products prepared in the above embodiments were subjected to performance tests. The results showed that the DPPH scavenging rate of egg white peptides was ≥79%; after storage at 45℃ and 60% humidity for 6 months, the activity retention rate was ≥88%; and the activity loss was ≤8% in an environment with pH 4.0-8.0.

[0050] In summary, the egg white peptide prepared by this invention through a process of ultrasonic pretreatment + stepwise enzymatic hydrolysis with compound enzymes + membrane separation and directional screening + polyphenol synergistic microcapsule protection exhibits significantly higher antioxidant indicators than existing egg white peptide products or traditional antioxidants. Furthermore, it maintains high activity even after simulated gastrointestinal digestion, demonstrating its excellent stability. It can be used in multiple fields such as functional foods, health products, and cosmetics, with broad market prospects.

[0051] The technical solution provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make several improvements and modifications to this invention without departing from the principles of this invention, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A method for preparing and protecting the activity of egg white protein peptides with high antioxidant activity, characterized in that, Includes the following steps: Step 1, Raw material pretreatment: Using egg white liquid as raw material, add deionized water to prepare a protein suspension with a mass concentration of 3%-5%, stir and mix in an ultrasonic water bath, and cool to room temperature to obtain denatured protein liquid; Step 2, Synergistic Targeted Enzymatic Hydrolysis: Add an endonuclease to the denatured protein solution for one enzymatic digestion; Add an exonuclease to perform a second enzymatic hydrolysis on the hydrolysate after the first enzymatic hydrolysis. Add flavor protease and perform a third enzymatic hydrolysis on the hydrolysate after the second enzymatic hydrolysis. Step 3, Separation and purification: After centrifugation of the enzymatically hydrolyzed mixture, the supernatant is collected, the supernatant is ultrafiltered, and the filtrate is collected; Step 4, Encapsulation treatment: The filtrate and composite protective solution are ultrasonically mixed at a mass ratio of 1:6 to 1:3, homogenized under high pressure, and then spray-dried to form microcapsule particles; Step 5, freeze-drying protection: Add a freeze-drying protectant to the obtained microcapsule particles, freeze-dry, and obtain the finished product of highly antioxidant active egg white protein peptide.

2. The method for preparing and protecting the activity of highly antioxidant egg white protein peptides according to claim 1, characterized in that, In step 1, ultrasonic stirring is performed at 88-92℃ for 10-30 minutes.

3. The method for preparing and protecting the activity of highly antioxidant egg white protein peptides according to claim 1, characterized in that, In step 2, the endonuclease is an alkaline protease or trypsin, and the amount added is 1~5wt%. During enzymatic hydrolysis, the pH is adjusted to 7.5-11.0, and the enzymatic hydrolysis is carried out at a constant temperature of 40~60℃ for 3~4 hours. The exonuclease is carboxypeptidase, added at a rate of 0.5-2 wt%. During enzymatic hydrolysis, the pH is adjusted to 6.5-8.5, and the hydrolysis is carried out at room temperature for 2-3 hours. The amount of flavor protease added is 0.5~2wt%. During enzymatic hydrolysis, the pH is adjusted to 6.0~8.0, and the enzymatic hydrolysis is carried out at a constant temperature of 35℃~60℃ for 2~5 hours.

4. The method for preparing and protecting the activity of highly antioxidant egg white protein peptides according to claim 1, characterized in that, Step 3, before collecting the supernatant after centrifuging the enzymatically digested mixture, also includes the following steps: The enzymatically hydrolyzed mixture was heated to 95°C and held for 15 minutes to inactivate the enzymes. After cooling to room temperature, the pH was adjusted to 5.0-6.

0.

5. The method for preparing and protecting the activity of highly antioxidant egg white protein peptides according to claim 1 or 4, characterized in that, In step 3, when centrifuging the enzymatically digested mixture, the speed should be 3000-5000 rpm and the centrifugation time should be 16-30 min.

6. The method for preparing and protecting the activity of highly antioxidant egg white protein peptides according to claim 5, characterized in that, Before ultrafiltration of the supernatant in step 3, wash with anhydrous ethanol, acidic solution with pH 1-2, alkaline solution with pH 11-12, and deionized water for 20 minutes in sequence.

7. The method for preparing and protecting the activity of highly antioxidant egg white protein peptides according to claim 1 or 5, characterized in that, In step 3, the supernatant is ultrafiltered under a pressure of 0.15-0.18 MPa, and the molecular weight cutoff of the ultrafiltration membrane is 1-3 kDa.

8. The method for preparing and protecting the activity of highly antioxidant egg white protein peptides according to claim 1, characterized in that, The preparation steps of the composite protective liquid in step 4 are as follows: Weigh the raw materials by weight: 30-40 parts maltodextrin, 15-20 parts β-cyclodextrin, 8-12 parts gum arabic, 2-3 parts ascorbyl palmitate, and 1-2 parts tea polyphenols; Add deionized water and stir at 60°C for 30 minutes until completely dissolved to form the composite protective solution.

9. The method for preparing and protecting the activity of highly antioxidant egg white protein peptides according to claim 1, characterized in that, The freeze-drying protectant mentioned in step 5 is at least one of trehalose or mannitol.

10. The use of a high antioxidant activity egg white protein peptide obtained by the method according to any one of claims 1-9 in the preparation of antioxidant functional foods, health products or cosmetics.

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