Selenium-rich polysaccharide-protein-polyphenol conjugate and its preparation method and application

Abstract

The present invention discloses a selenium-rich polysaccharide-protein-polyphenol conjugate and its preparation method and application, which belong to the field of food processing technology. This method uses jujube as raw material, improves the extraction efficiency through organic solvent degreasing, two-stage dynamic extraction combined with ultrasonic pretreatment, adopts Na2HPO4 buffer and sodium citrate buffer for step-by-step extraction and enzymatic purification to obtain a polysaccharide-protein-polyphenol conjugate; further introduces nanocellulose dispersing stabilizer and specific wavelength light source into the photocatalytic reaction, and efficiently chelates the selenium source and the conjugate, and finally obtains a complex with a particle size of 80~120 nm and a selenium content of 3.5~4.5% through dialysis and freeze-drying. The obtained product has excellent antioxidant properties and hypoglycemic activity, can be used to prepare functional foods or medicines for preventing and treating diabetes, and is also suitable for the fields of anti-inflammatory, intestinal microecological regulation and drug sustained-release carriers, with both high efficiency and safety.

Description

Technical Field

[0001] The present invention relates to the field of food processing, and more specifically, to a selenium-rich polysaccharide-protein-polyphenol conjugate and a preparation method and application thereof. Background Art

[0002] Current diabetes drug treatments still face limitations, such as intolerance and side effects. Therefore, developing novel diabetes prevention and treatment approaches is crucial. Research has shown that nano-selenium has promising hypoglycemic potential, can effectively promote insulin secretion in INS-1 cells, and possesses antioxidant properties, potentially preventing and treating chronic diseases like diabetes.

[0003] However, single-element nanoselenium is unstable and prone to precipitation. Currently, polysaccharides, proteins, and high-molecular-weight polymers are often added as stabilizers. For example, Chinese invention patent CN104825484B discloses a method for large-scale preparation of polysaccharide-modified nanoselenium. Lentinan has a strong stabilizing effect on nanoselenium, maintaining a particle size between 80 and 120 nm and a potential of 34.37 eV.

[0004] Polysaccharide-protein-polyphenol conjugates can effectively inhibit α -glucosidase, α Compared to traditional drug treatments, the ability to inhibit amylase activity and glycosylation reactions to prevent and treat diabetes offers advantages such as being natural, safe, and highly effective. However, limited by current extraction methods, its yield and activity need to be further improved through extraction technology upgrades and modifications. Furthermore, further chelation of nanoselenium with polysaccharide-protein-polyphenol conjugates is an urgent challenge. Summary of the Invention

[0005] The purpose of the present invention is to provide a selenium-rich polysaccharide-protein-polyphenol conjugate and its preparation method and application, so as to conveniently and efficiently solve the problem of limited yield and activity of traditional water-extracted polysaccharide-protein-polyphenol conjugates, and provide technical support for its application in anti-oxidation and hypoglycemic effects.

[0006] In order to achieve these purposes and other advantages according to the present invention, a method for preparing a selenium-rich polysaccharide-protein-polyphenol conjugate is provided, comprising:

[0007] Polysaccharide-protein-polyphenol conjugates were prepared using jujube as raw material;

[0008] Prepare a 2-5 mg / mL polysaccharide-protein-polyphenol conjugate solution, adjust the pH to 7.0-7.4 with phosphate buffer, continue to add 0.5-1 mmol / L Na2SeO3 solution, and then add 0.01-0.05% riboflavin solution dropwise to the mixed solution under light-proof conditions. Place it under a light source of 365-450 nm and an illumination intensity of 50-100 mW / cm 2 , stirring was continued for 20-40 min at a stirring speed of 100-200 rpm. After the reaction was completed, dialyzed with ultrapure water at 4°C in the dark for 48-72 h, and then freeze-dried in vacuum to obtain selenium-rich polysaccharide-protein-polyphenol conjugates.

[0009] Preferably, the process of preparing the polysaccharide-protein-polyphenol conjugate using jujube as raw material comprises:

[0010] The jujube fruit was crushed, and the jujube fruit powder was ultrasonically treated with a n-hexane-ethanol mixed solvent for 15-30 minutes, and then soaked for 24-48 hours. The solvent was repeatedly changed 2-4 times during the soaking period, and then filtered, the supernatant was discarded, and the residue was dried to obtain powder A, wherein the volume ratio of n-hexane to ethanol was (2-3):1, and the frequency of the ultrasonic treatment was 30-50 kHz;

[0011] The components in powder A were extracted using a two-stage dynamic extraction method to obtain a polysaccharide-protein-polyphenol conjugate.

[0012] Preferably, the process of extracting the components from powder A using a two-stage dynamic extraction method includes:

[0013] A 0.01-0.03 mol / L Na2HPO4 aqueous solution was used for one-stage extraction, wherein the solid-liquid ratio ranged from 1:(10-30), the extraction temperature was 90-96°C, and the extraction time was 1-2 h;

[0014] Two-stage extraction was performed using 0.02-0.05 mol / L sodium citrate buffer, with a solid-liquid ratio of 1:(10-25), an extraction temperature of 90-100°C, an extraction time of 1-2 h, and repeated 2-3 times.

[0015] The extracts were combined and neutralized with acid to pH 7;

[0016] Use rotary evaporation at 40-60℃ to concentrate to 1 / 3-1 / 2 of the original volume;

[0017] Add 2-3% pancreatic enzyme and shake at 37°C for 2-4 hours to remove free protein. After enzymatic hydrolysis, inactivate the enzyme in a boiling water bath for 10 minutes, cool to room temperature, and centrifuge to remove the precipitate.

[0018] Add 3-5 times the volume of anhydrous ethanol to the extract, let it stand at 4°C overnight, centrifuge at 8000-10000 rpm for 5-10 minutes, and collect the precipitate.

[0019] The precipitate was washed with anhydrous ethanol, acetone, and ether, dried, and then redissolved to obtain a polysaccharide-protein-polyphenol conjugate solution;

[0020] The product was dialyzed for 48-72 h using a dialysis bag with a cut-off of 3500 Da, and the polysaccharide-protein-polyphenol conjugate powder was obtained after freeze-drying.

[0021] Preferably, before the photocatalytic reaction, nanocellulose is added as a dispersion stabilizer in an amount of 0.2 to 0.8% of the total mass of the reaction system. The nanocellulose has a particle size of 20 to 100 nm and is derived from bamboo fiber or bacterial cellulose.

[0022] During the photocatalytic reaction, the wavelength of the light source was adjusted to 380-420 nm, and the light intensity was 70-90 mW / cm 2 , the reaction time is shortened to 15~25 min.

[0023] Preferably, before the dialysis operation, 0.1-0.3% of genipin crosslinker is added to the reaction solution, and the solution is allowed to stand at 40-50° C. for 30-60 min to form a three-dimensional network structure to enhance the thermal stability of the complex.

[0024] Preferably, after the extracts are combined, the combined extracts are subjected to pulsed electric field-assisted purification with an electric field strength of 100-200 V / cm, a pulse frequency of 100-300 Hz, and a treatment time of 5-15 min to remove residual small molecule impurities and retain the active ingredients.

[0025] The present invention also provides a selenium-rich polysaccharide-protein-polyphenol conjugate, which is obtained by adopting the above-mentioned preparation method.

[0026] The present invention also provides the use of the selenium-rich polysaccharide-protein-polyphenol conjugate in the preparation of antioxidant foods or medicines.

[0027] The present invention also provides the use of the selenium-rich polysaccharide-protein-polyphenol conjugate in the preparation of blood sugar-lowering foods or medicines.

[0028] The present invention has at least the following beneficial effects:

[0029] (1) The present invention provides PPPs-SeNPs The preparation method has a high yield and strong activity compared to traditional hot water extraction. The prepared nano-selenium particles have a small particle size and a stable solution system. PPPs-SeNPs The selenium content in it can reach 3.5~4.5%.

[0030] (2) The present invention prepares PPPs-SeNPs Uncompounded nano-selenium PPPs Compared with the control group, the ABTS scavenging activity was significantly improved, and IC 50 The value decreased by 22~43%.

[0031] (3) Prepared by the present invention PPPs-SeNPs It can effectively promote the glucose absorption capacity of insulin-resistant HepG2 cells (IR-HepG2). PPPs-SeNPs After treatment, the glucose consumption rate increased to 32.5~36.8%.

[0032] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below with reference to the embodiments so that those skilled in the art can implement the invention with reference to the description.

[0034] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0035] <Example 1>

[0036] A method for preparing a selenium-rich polysaccharide-protein-polyphenol conjugate comprises:

[0037] (1) Preparation of polysaccharide-protein-polyphenol conjugate components:

[0038] The jujube was dried with hot air at 60°C, crushed with a plant crusher, and passed through a 60-mesh sieve.

[0039] 300 g of jujube powder was ultrasonically treated in a 2:1 mixture of n-hexane and ethanol at 40 kHz for 20 minutes. The mixture was then soaked for 24 hours, with the solvent changed 2–4 times to remove small molecules such as fat and pigment. The mixture was filtered, the supernatant discarded, and the residue dried in an oven at 50°C until use (Powder A).

[0040] 10.0 g of powder A was weighed and extracted using a two-stage dynamic extraction method. The extraction procedure was as follows: a first-stage extraction with a 0.02 mol / L Na₂HPO₄ aqueous solution at a solid-liquid ratio of 1:20, an extraction temperature of 90°C, and an extraction time of 1 hour; a second-stage extraction with a 0.05 mol / L sodium citrate buffer at a solid-liquid ratio of 1:20, an extraction temperature of 95°C, and an extraction time of 1 hour. The extractions were repeated two to three times. The extracts were centrifuged and combined, then neutralized with acid to a pH of 7. The extracts were concentrated to half their original volume by rotary evaporation at 50°C. 2-3% pancreatin was added, and the mixture was shaken at 37°C for 2-4 hours to remove free protein. After enzymatic hydrolysis, the extracts were inactivated by boiling in water for 10 minutes, cooled to room temperature, and centrifuged to remove the precipitate. Three volumes of anhydrous ethanol were added to the extract, the extract was allowed to stand overnight at 4°C, and centrifuged at 8000 rpm for 10 minutes to collect the precipitate. The precipitate was washed with anhydrous ethanol, acetone, and ether, dried, and then redissolved to obtain polysaccharide-protein-polyphenol conjugates ( PPPs ) solution, dialyzed using a dialysis bag with a cutoff of 3500 Da for 48 h, and lyophilized to obtain PPPs powder.

[0041] (2) Preparation of selenium-rich polysaccharide-protein-polyphenol conjugate components:

[0042] Add 50 mL of freshly prepared 2 mg / mL PPPs The solution was adjusted to pH 7.2 using phosphate buffer. 50 mL of 0.5 mmol / L Na2SeO3 solution was then added dropwise. 5 mL of 0.02% (w / v) riboflavin solution was then added dropwise to the mixed solution under light-shielding conditions. The solution was then placed under a 365 nm light source with an illumination intensity of 100 mW / cm 2 , stirring was continued for 20 min at a stirring speed of 200 rpm. After the reaction was completed, the mixture was dialyzed with ultrapure water at 4°C in the dark for 72 h, and then freeze-dried in vacuum to obtain selenium-rich polysaccharide-protein-polyphenol conjugate ( PPPs-SeNPs ).

[0043] <Example 2>

[0044] A method for preparing a selenium-rich polysaccharide-protein-polyphenol conjugate, based on Example 1, further comprising:

[0045] Before the photocatalytic reaction, nanocellulose was added as a dispersion stabilizer in an amount of 0.5% of the total mass of the reaction system. The nanocellulose had a particle size of 20 to 100 nm and was derived from bamboo fiber.

[0046] During the photocatalytic reaction, the wavelength of the light source was adjusted to 390 nm and the light intensity was 80 mW / cm 2, the reaction time is shortened to 15min.

[0047] Before dialysis, 0.2% genipin crosslinker was added to the reaction solution and allowed to stand at 40°C for 40 min to form a three-dimensional network structure to enhance the thermal stability of the complex.

[0048] After the extracts were combined, they were subjected to pulsed electric field-assisted purification with an electric field strength of 200 V / cm, a pulse frequency of 200 Hz, and a treatment time of 10 min to remove residual small molecule impurities and retain the active ingredients.

[0049] Comparative Example 1

[0050] A method for preparing nano-selenium, comprising:

[0051] In a 250 mL beaker, add 50 mL of distilled water and 50 mL of 0.5 mmol / L Na2SeO3 solution and stir at room temperature for 30 min. Then, add 5 mL of 0.02% (w / v) riboflavin solution dropwise to the mixed solution under light-shielded conditions and place it under a 365 nm light source with an intensity of 100 mW / cm 2 After the reaction was completed, the mixture was dialyzed with ultrapure water at 4°C in the dark for 72 h and freeze-dried to obtain nano-selenium ( SeNPs )

[0052] Comparative Example 2

[0053] A method for preparing a polysaccharide-protein-polyphenol conjugate comprises:

[0054] The jujube fruit was dried with hot air at 60°C, crushed in a plant grinder, and passed through a 60-mesh sieve. 300 g of jujube fruit powder was ultrasonically treated with a mixture of n-hexane and ethanol (2:1) for 20 minutes (40 kHz) and then soaked for 24 hours, with the solvent changed 2-4 times to remove small molecules such as fat and pigment. The supernatant was filtered, discarded, and the residue was oven-dried at 50°C until use (Powder A). 10.0 g of Powder A was weighed and the components in Powder A were extracted using a two-stage dynamic extraction method. The extraction method was as follows: a first-stage extraction with 0.02 mol / L Na₂HPO₄ aqueous solution at a solid-liquid ratio of 1:20, an extraction temperature of 90°C, and an extraction time of 1 hour; a second-stage extraction with 0.05 mol / L sodium citrate buffer at a solid-liquid ratio of 1:20, an extraction temperature of 95°C, and an extraction time of 1 hour. This extraction was repeated 2-3 times. The extracts were combined by centrifugation and neutralized with acid to a pH of 7. The extract was concentrated to half its original volume by rotary evaporation at 50°C. 2–3% pancreatin was added and the mixture was shaken at 37°C for 2–4 hours to remove free protein. After enzymatic hydrolysis, the extract was inactivated in a boiling water bath for 10 minutes, cooled to room temperature, and the precipitate was removed by centrifugation. Three volumes of anhydrous ethanol were added to the extract, the extract was incubated at 4°C overnight, and centrifuged at 8000 rpm for 10 minutes to collect the precipitate. The precipitate was washed with anhydrous ethanol, acetone, and ether, dried, and then redissolved to obtain a polysaccharide-protein-polyphenol conjugate (PPPs) solution. The solution was dialyzed using a 3500 Da cutoff dialysis bag for 48 hours and lyophilized to obtain a PPPs powder.

[0055] <Physical and Chemical Properties>

[0056] 1. Particle size determination: Dilute the sample powder 1000 times and use a Zetasizer-Nano ZS Malvern laser particle size analyzer to measure its particle size.

[0057] 2. Determination of total sugar, total phenol, protein and selenium content:

[0058] Determination of total sugar content: Phenol-sulfuric acid method was used. The sample solution was mixed with concentrated sulfuric acid and phenol reagent. After reaction in a boiling water bath, the absorbance at 490 nm was measured. The total sugar content was calculated using the glucose standard curve.

[0059] Total phenol content was determined using the Folin-Ciocalteu method. After the sample reacted with the Folin-Ciocalteu reagent and sodium carbonate solution, the absorbance at 765 nm was measured, and the total phenol content was calculated using a gallic acid standard curve.

[0060] Protein content was determined using the BCA method (bicinchoninic acid method). After the sample reacted with the BCA reagent, the absorbance at 562 nm was measured, and the protein content was calculated using a bovine serum albumin (BSA) standard curve.

[0061] Selenium content was determined using inductively coupled plasma mass spectrometry (ICP-MS). Samples were digested with nitric acid and hydrogen peroxide in a microwave oven, and selenium content was determined by ICP-MS, calibrated with standard substances.

[0062] The physical and chemical properties of the samples prepared in Examples 1-2 and Comparative Examples 1-2 were measured, and the results are shown in Table 1 below:

[0063] Table 1

[0064]

[0065] The particle size distribution of the samples in Examples 1-2 and Comparative Examples 1-2 is shown in Table 1. SeNPs The average particle size of PPPs Coupling generated PPPs-SeNPs The particle size of the system is 98nm, and the particle size of the system is smaller and more stable. PPPs-SeNPs The total sugar, total phenol, protein, and selenium contents were 42.1%, 23.3%, 26.3%, and 3.67%, respectively. In Example 2, by introducing a nanocellulose dispersion stabilizer, pulsed electric field purification, and genipin crosslinker, the average particle size was reduced to 82 nm, indicating improved dispersion stability. The selenium content was increased to 4.12%, demonstrating enhanced photocatalytic reaction efficiency. The total sugar, total phenol, and protein contents were all slightly increased (43.5%, 24.1%, and 27.8%), indicating a more complete retention of the active ingredients.

[0066] <Antioxidant Evaluation-ABTS Scavenging Activity>

[0067] Prepare a sample solution (0-10 mg / mL) using deionized water. Use a pipette to draw 0.1 mL of the sample solution and add 3.6 mL of ABTS solution. Mix thoroughly, let the solution stand at room temperature for 1 minute, and then measure the absorbance of the reaction solution at a wavelength of 734 nm. The ABTS free radical scavenging rate is calculated as follows:

[0068] (1)

[0069] Where: A2 is the absorbance of the sample group; A1 is the absorbance of the control group, including 80% methanol solution and sample; A0 is the absorbance of the blank group including ABTS and deionized water.

[0070] <Evaluation of hypoglycemic effect - Effect on glucose uptake in HepG2 cells>

[0071] 200 μL of HepG2 cells were plated at 2×10 4Cells were seeded at a density of 100 cells / well on a 96-well plate. After overnight culture, the culture medium was removed. After washing with PBS, the cells were induced in DMEM culture medium with a final concentration of 3 μmol / L dexamethasone (Dex) for 48 h to construct an insulin resistance cell model. The culture medium was aspirated, the cells were washed with PBS, and the culture medium from each well was aspirated. Culture medium containing 0.10 mg / mL sample was added and cultured for 24 h. The glucose content of the culture supernatant after culture was determined using a glucose kit. The glucose consumption rate was calculated according to formula (2):

[0072] (2)

[0073] Where: C 空白 is the glucose content of the group without added cells, C 模型 is the glucose content of the added cells and sample groups.

[0074] The samples prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were subjected to antioxidant evaluation and blood sugar lowering evaluation. The results are shown in Table 2 below:

[0075] Table 2

[0076]

[0077] In Example 1, Comparative Example 1 and Comparative Example 2 PPPs-SeNPs、SeNPs and PPPs The comparative analysis of ABTS free radical scavenging effects of the two groups is shown in Table 2. As shown in Table 2, the free radical scavenging effects of the two groups are significantly different. SeNPs Clear ABTS IC 50 The value is 1.35 mg / ml, PPPs Clear ABTS IC 50 The value is 0.49 mg / ml, while in Example 1, the two are combined to form a selenium-rich polysaccharide-protein-polyphenol conjugate ( PPPs-SeNPs ) Clear ABTS IC 50 The value was 0.38 mg / ml, which was significantly better than SeNPs and PPPs The effect of acting alone. PPPs compared to ， IC 50 The value decreased by 22.4%; SeNPs compared to ， IC 50 The ABTS clearance IC of Example 2 was reduced by 71.8%. 50 The value further decreased to 0.28 mg / ml, indicating that nanocellulose and cross-linking modification synergistically enhanced the antioxidant capacity.

[0078] In Example 1, Comparative Example 1 and Comparative Example 2 PPPs-SeNPs、SeNPs and PPPs The comparative analysis of the glucose consumption effect of 0.1 mg / ml is shown in Table 2. SeNPs Due to its significant toxicity to HepG2 cells, it is not suitable for use alone. 0.1 mg / ml PPPs The sample caused the glucose consumption of insulin-resistant HepG2 cells to be 27.02%, and the two were combined to form a selenium-rich polysaccharide-protein-polyphenol conjugate in Example 1 ( PPPs-SeNPs ), the cellular glucose consumption at a concentration of 0.1 mg / ml was 32.5%, which was PPPs compared to ， Glucose consumption increased by 5.48%. The glucose consumption rate of Example 2 reached 36.8%, proving that it is more effective in improving insulin resistance.

[0079] By optimizing the extraction, photocatalysis, and purification processes, the present invention significantly improves the stability, selenium loading rate, and biological activity of the selenium-rich complex. The improved solution of Example 2 demonstrates significant advantages in particle size control, selenium content, and blood sugar-lowering effects, providing an efficient and safe technical solution for diabetes prevention and treatment and the development of functional foods.

[0080] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A method for preparing a selenium-rich polysaccharide-protein-polyphenol conjugate, characterized in that: include: Polysaccharide-protein-polyphenol conjugates were prepared using jujube as raw material; Prepare a 2-5 mg / mL polysaccharide-protein-polyphenol conjugate solution, adjust the pH to 7.0-7.4 with phosphate buffer, continue to add 0.5-1 mmol / L Na2SeO3 solution, and then add 0.01-0.05% riboflavin solution dropwise to the mixed solution under light-proof conditions. Place the solution under a 365-450 nm light source for photocatalytic reaction with a light intensity of 50-100 mW / cm 2 , stirring was continued for 20-40 min at a stirring speed of 100-200 rpm. After the reaction was completed, the mixture was dialyzed with ultrapure water at 4°C in the dark for 48-72 h, and then freeze-dried in vacuum to obtain a selenium-rich polysaccharide-protein-polyphenol conjugate. Before the photocatalytic reaction, nanocellulose is added as a dispersion stabilizer in an amount of 0.2-0.8% of the total mass of the reaction system. The nanocellulose has a particle size of 20-100 nm and is derived from bamboo fiber or bacterial cellulose.

2. The method for preparing the selenium-rich polysaccharide-protein-polyphenol conjugate according to claim 1, wherein The process of preparing polysaccharide-protein-polyphenol conjugates using jujube as raw material includes: The jujube fruit was crushed, and the jujube fruit powder was ultrasonically treated with a n-hexane-ethanol mixed solvent for 15-30 minutes, and then soaked for 24-48 hours. The solvent was repeatedly changed 2-4 times during the soaking period, and then filtered, the supernatant was discarded, and the residue was dried to obtain powder A, wherein the volume ratio of n-hexane to ethanol was (2-3):1, and the frequency of the ultrasonic treatment was 30-50 kHz; The components in powder A were extracted using a two-stage dynamic extraction method to obtain a polysaccharide-protein-polyphenol conjugate.

3. The method for preparing the selenium-rich polysaccharide-protein-polyphenol conjugate according to claim 2, wherein: The process of extracting the components from powder A using the two-stage dynamic extraction method includes: A 0.01-0.03 mol / L Na2HPO4 aqueous solution was used for one-stage extraction, wherein the solid-liquid ratio ranged from 1:(10-30), the extraction temperature was 90-96°C, and the extraction time was 1-2 h; Two-stage extraction was performed using 0.02-0.05 mol / L sodium citrate buffer, with a solid-liquid ratio of 1:(10-25), an extraction temperature of 90-100°C, an extraction time of 1-2 h, and repeated 2-3 times. The extracts were combined and neutralized with acid to pH 7; Use rotary evaporation at 40-60℃ to concentrate to 1 / 3-1 / 2 of the original volume; Add 2-3% pancreatic enzyme and shake at 37°C for 2-4 hours to remove free protein. After enzymatic hydrolysis, inactivate the enzyme in a boiling water bath for 10 minutes, cool to room temperature, and centrifuge to remove the precipitate. Add 3-5 times the volume of anhydrous ethanol to the extract, let it stand at 4°C overnight, centrifuge at 8000-10000 rpm for 5-10 minutes, and collect the precipitate. The precipitate was washed with anhydrous ethanol, acetone, and ether, dried, and then redissolved to obtain a polysaccharide-protein-polyphenol conjugate solution; The product was dialyzed for 48-72 h using a dialysis bag with a cut-off of 3500 Da, and the polysaccharide-protein-polyphenol conjugate powder was obtained after freeze-drying.

4. The method for preparing the selenium-rich polysaccharide-protein-polyphenol conjugate according to claim 1, wherein During the photocatalytic reaction, the light source wavelength was adjusted to 380-420 nm, the light intensity was 70-90 mW / cm², and the reaction time was shortened to 15-25 min.

5. The method for preparing the selenium-rich polysaccharide-protein-polyphenol conjugate according to claim 1, wherein Before dialysis, 0.1-0.3% genipin crosslinker was added to the reaction solution and allowed to stand at 40-50°C for 30-60 min to form a three-dimensional network structure to enhance the thermal stability of the complex.

6. The method for preparing the selenium-rich polysaccharide-protein-polyphenol conjugate according to claim 3, wherein: After the extracts are combined, they are subjected to pulsed electric field-assisted purification with an electric field strength of 100-200 V / cm, a pulse frequency of 100-300 Hz, and a treatment time of 5-15 min to remove residual small molecule impurities and retain the active ingredients.

7. A selenium-rich polysaccharide-protein-polyphenol conjugate, characterized in that: The selenium-rich polysaccharide-protein-polyphenol conjugate is obtained by the preparation method according to any one of claims 1 to 6.

8. Use of the selenium-rich polysaccharide-protein-polyphenol conjugate according to claim 7 in the preparation of antioxidant functional products.

9. Use of the selenium-rich polysaccharide-protein-polyphenol conjugate according to claim 7 in the preparation of a product with hypoglycemic function.

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