Fruit anthocyanin as well as extraction method and application thereof

Abstract

The invention provides fruit anthocyanin as well as an extraction method and application thereof. The extraction method comprises the following steps: S1, raw material pretreatment: selecting fresh fruits, removing impurities, cleaning, draining surface moisture, performing crushing treatment, then performing vacuum drying, and finally performing crushing to obtain fruit powder; s2, extracting three-layer microspheres: preparing an extraction substrate solution, adding the three-layer microspheres, and stirring for 8-12 minutes at the temperature of 40-45 DEG C and the rotating speed of 100-150r / min; the rotating speed is kept at 100-150 r / min, the power is set to be 300 W, the temperature is 42-45 DEG C, working is conducted for 4-6 min, pause is conducted for 1-2 min, and intermittent ultrasonic extraction is conducted for 3-4 h; after the extraction is finished, centrifuging an extracting solution, and collecting supernate to obtain a crude extracting solution; and S3, obtaining a final product of the fruit anthocyanin: filtering, adsorbing, eluting and purifying, concentrating and drying the crude extract to obtain the fruit anthocyanin. A targeted attachment-step conversion-enrichment protection and release linkage system is formed among the three-layer structures of the three-layer microspheres, and 1 + 1 + 1gt is realized; and 3, due to the synergistic effect, the activity and the quality stability of the anthocyanin are guaranteed while the extraction rate of the anthocyanin in the fruits is increased.

Description

Technical Field

[0001] This invention belongs to the field of anthocyanin extraction technology, specifically relating to a fruit anthocyanin, its extraction method, and its application. Background Technology

[0002] Anthocyanins, as natural flavonoids, are widely found in the skins, pulps, and seeds of fruits such as grapes and blueberries. They possess strong antioxidant, anti-inflammatory, and immunomodulatory activities, and have broad application prospects in food additives, health products, and pharmaceuticals. Anthocyanins in grapes and blueberries mainly exist in the form of bound glycosides (such as cyanidin-3-glucoside) and acylated anthocyanins, accompanied by flavonol glycosides (quercetin-3-glucoside, kaempferol glycoside), proanthocyanidins (dimer / polymer precursors), and other flavonoids. These substances can be structurally modified to transform into anthocyanin analogs, further enhancing the activity and added value of the product. However, current anthocyanin extraction processes face several bottlenecks, making it difficult to meet the demands of high-value production: First, the dissolution of bound anthocyanins is hindered, resulting in low extraction efficiency. Anthocyanins are mostly encapsulated within the cellulose-pectin network of cell walls, some forming glycosidic and ester complexes. Residual oils from grape seeds and blueberry skins further encapsulate the active ingredients, reducing the overall anthocyanin extraction rate. Secondly, insufficient conversion of precursor substances limits the added value of the product. Proanthocyanidins, as important anthocyanin precursors, need to be depolymerized into monomers to exert their activity, but existing processes involving strong acidity and high-temperature acid hydrolysis easily lead to product oxidation. Furthermore, flavonol glycosides can be converted into anthocyanin analogs, and current processes lack targeted catalytic systems to achieve this directional conversion. Thirdly, anthocyanin activity retention is poor, resulting in unstable quality. Anthocyanins are highly sensitive to temperature, oxygen, and pH. Current anthocyanin extraction processes lack antioxidant protection at each stage, affecting the finished product's activity retention rate. Simultaneously, polyphenol oxidase in the system catalyzes enzymatic oxidation, causing anthocyanin discoloration and activity degradation.

[0003] Based on the above-mentioned technical problems, this invention constructs a fruit anthocyanin extraction process that can simultaneously achieve efficient dissolution, directional conversion, and activity protection. After pretreatment of the fruit raw materials, three layers of microspheres are added. The components of each layer of the microspheres work synergistically to significantly improve the total anthocyanin extraction efficiency, while enhancing the conversion of precursor substances, significantly increasing the added value of the product, and ensuring the activity and quality stability of anthocyanins. Summary of the Invention

[0004] This invention provides a method and application for extracting fruit anthocyanins. Three layers of microspheres are added to pretreated fruit raw materials, and anthocyanins are extracted with intermittent ultrasound assistance. The components of different layers of microspheres form a synergistic linkage system of targeted attachment, stepwise transformation, enrichment and release, which achieves a high extraction rate of fruit anthocyanins while ensuring the activity and quality stability of anthocyanins.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned objective is: a method for extracting anthocyanins from fruits, comprising the following steps: S1: Raw material pretreatment Select fresh fruit, remove impurities, wash it clean, drain the surface water, crush it, then vacuum dry it at 40-50℃ for 3-5 hours, and finally pulverize it to 80-120 mesh to obtain fruit powder. S2: Extraction of three-layer microspheres Prepare an extraction base solution using the fruit powder prepared in S1, and add three layers of microspheres, wherein the amount of the three layers of microspheres added is 4-10% of the mass of the extraction base solution. Stir at 40-45℃ and 100-150 r / min for 8-12 min; maintain the speed of 100-150 r / min, set the power to 300W and the temperature to 42-45℃, and perform intermittent ultrasonic extraction for 4-6 min, with a pause of 1-2 min for 3-4 h; after extraction, centrifuge the extract at 7000-9000 r / min and 2-6℃ for 10-15 min, and collect the supernatant to obtain the crude extract; S3: Obtain the final product, fruit anthocyanins. The crude extract was purified by filtration, adsorption, elution, concentration, and drying to obtain the fruit anthocyanins.

[0006] Furthermore, the fruits include grapes and blueberries.

[0007] Furthermore, the preparation method of the base solution for extraction in S2 is as follows: mix the fruit powder and deionized water evenly according to the mass ratio of fruit powder to deionized water = 1:8-12, and adjust the pH to 4.5-4.8 to obtain the base solution for extraction.

[0008] Furthermore, the preparation steps of the three-layer microspheres in S2 are as follows: (1) Preparation of core particles Porous chitosan and xylooligosaccharides are added to deionized water and stirred at 180-220 rpm for 25-30 min. The pH is adjusted to 4.8-5.2 to form a uniform suspension. The suspension is sonicated for 12-18 min and then granulated by spray granulation. The inlet air temperature is set to 150-170℃, the outlet air temperature to 65-75℃, and the feed rate to 4-6 mL / min. The collected granules are dried in a vacuum drying oven at 40-50℃ for 1.5-2.5 h to obtain the core granules. (2) Wrap the middle layer Cellulase R-10 and tyrosinase were added to deionized water and stirred at 32-38℃ and 130-170 r / min for 15-25 min to prepare a composite enzyme solution. Citric acid and tartaric acid were added to deionized water and stirred until completely dissolved. The pH was adjusted to 3.0-3.5 to prepare a composite acid solution. The composite enzyme solution was slowly added to the core particles and stirred at 35-40℃ and 100-140 r / min for 45-60 min to adsorb the particles. The composite acid solution was then slowly added dropwise and stirred for 25-30 min. The particles were then dried in a vacuum drying oven at 38-42℃ for 1-2 h to form intermediate layer coated particles. (3) Cover the outermost layer Quaternized modified chitosan and hydroxypropyl methylcellulose were added to an ethanol solution with a concentration of 25-30% and stirred at 30-35℃ and 80-120 r / min for 35-45 min to prepare a coating solution. The intermediate layer coated particles were added to the coating solution, wherein the volume of the coating solution was 6-8 times the mass of the intermediate layer coated particles, and stirred at 60-100 r / min for 45-75 min to make the coating solution uniformly coat the particle surface. The particles were dried at -40℃ to -50℃ and a vacuum degree of 10-20 Pa for 3.5-4.5 h to obtain three-layer microspheres.

[0009] Furthermore, in step (1), the mass ratio of porous chitosan, xylooligosaccharide and deionized water is 7:3:50-80.

[0010] Further, in step (2), the mass ratio of cellulase R-10, tyrosinase and deionized water is 2:1:30-45; the mass ratio of citric acid, tartaric acid and deionized water is 2:1:24-36; the amount of compound enzyme solution added is 4-6 times the mass of the core particles, and the amount of compound acid solution added is 2-3 times the mass of the core particles.

[0011] Furthermore, in step (3), the mass ratio of quaternized modified chitosan, hydroxypropyl methylcellulose and ethanol solution is 3:2:40-60.

[0012] Furthermore, the specific operation of S3 is as follows: The crude extract was vacuum filtered through a 0.45 μm polytetrafluoroethylene (PTFE) membrane. The filtrate was then passed through an HPD-600 macroporous adsorption resin for 1.5-2.5 h. After adsorption, impurities were removed by elution with deionized water, followed by elution with 40% ethanol solution. The eluent was collected and placed in a vacuum rotary evaporator under nitrogen protection. The eluent was concentrated at 50-60 °C and a vacuum of 0.07-0.09 MPa for 30-40 min to obtain a concentrated solution. The concentrated solution was then transferred to a vacuum freeze dryer and dried at -40 °C to -50 °C and a vacuum of 10-20 Pa for 1-2 h to obtain fruit anthocyanins.

[0013] This invention discloses the fruit anthocyanins prepared by the above method.

[0014] The present invention also discloses the application of the above-mentioned fruit anthocyanins in the preparation of food or cosmetics with antioxidant activity.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The core particles of the three-layer microspheres in this invention include porous chitosan and xylooligosaccharides. The porous structure of the porous chitosan can enhance the binding force between the microspheres and the raw materials. The xylooligosaccharides absorb water and swell to generate micromechanical force, which efficiently destroys the cell wall cellulose-pectin network. This provides a channel for the direct dissolution of free anthocyanins and breaks the binding of bound and acylated anthocyanins to the cell wall, reducing the inherent anthocyanin residue. In this invention, the middle layer of the three-layer microspheres includes cellulase R-10 (a cellulase containing esterase activity), tyrosinase, and a citric acid-tartaric acid complex. On one hand, cellulase R-10 simultaneously breaks glycosidic and ester bonds, releasing bound and acylated anthocyanins. Tyrosinase directionally catalyzes the conversion of flavonol glycosides into anthocyanin analogs. The complex enzyme system formed by the two enzymes simultaneously improves the total anthocyanin content and antioxidant performance. On the other hand, the complex acid solution can break the C / C bonds and glycosidic bonds between proanthocyanidin molecules, depolymerizing dimer / multimer proanthocyanidins into active monomeric anthocyanins. Citric acid can precisely regulate the acidity of the system and enhance the depolymerization efficiency, while tartaric acid has antioxidant properties and can inhibit the oxidation of monomeric anthocyanins after depolymerization, while maintaining the stability of the system. The two work synergistically to improve the purity of anthocyanin conversion. The outermost layer of the three-layer microspheres of this invention is a stable coating layer formed by a combination of quaternized modified chitosan and hydroxypropyl methylcellulose (HPMC). The swelling properties of HPMC enable controlled release of enzymes and acids in the middle layer. The quaternized modified chitosan rapidly adsorbs and enriches active products, reducing their contact with impurities and polyphenol oxidases. Combined with the antioxidant effect of tartaric acid, it constructs a full-process protection barrier to improve the activity retention rate of fruit anthocyanins. The three-layer structure of the three-layer microspheres of this invention forms a targeted attachment-step conversion-enrichment and release linkage system, achieving a synergistic effect of 1+1+1>3: the core layer precisely breaks the cell wall to provide contact channels for the functional substances in the middle layer, avoiding ineffective diffusion of functional components; the outermost HPMC controls the release rhythm, and the quaternized modified chitosan simultaneously enriches the converted products, reducing activity loss; while achieving a high extraction rate of fruit anthocyanins, it ensures the activity and quality stability of anthocyanins. Detailed Implementation

[0016] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0017] It should be understood that the following descriptions of the proportions, concentrations, and process parameters of the substances involved in the fruit anthocyanin extraction method and the three-layer microsphere preparation method of this invention are preferred embodiments and should not be construed as limiting the scope of protection of the independent claims. The embodiments described are only for explaining the invention and are not intended to limit the scope of the invention. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available food-grade reagents and materials. Specifically, the cellulase R-10 activity is 1000 U / g, and the tyrosinase activity is 2000 U / g. Example 1

[0018] The preparation steps of the three-layer microspheres are as follows: (1) Preparation of core particles Chitosan was slowly added to a 1% (v / v) acetic acid solution and magnetically stirred at room temperature for 30 min to obtain a 1% (w / w) chitosan-acetic acid solution. Glycerin was added to the chitosan-acetic acid solution and stirring was continued until completely mixed. The volume ratio of chitosan-acetic acid solution to glycerin was 20:1. The mixed solution was poured into a mold, and the solution thickness was controlled to be 5 mm. After standing at room temperature for 10 min, the mold was frozen at -18℃ for 2 h. The frozen solution was placed in a freeze dryer and vacuum dried for 6-8 h to obtain porous chitosan.

[0019] Porous chitosan: xylooligosaccharide: deionized water were added to deionized water at a mass ratio of 7:3:50. The mixture was stirred at 180 rpm for 25 min and the pH was adjusted to 4.8 to form a uniform suspension. The suspension was sonicated for 12 min and then granulated using a spray granulation method. The inlet air temperature was set to 150℃, the outlet air temperature to 65℃, and the feed rate to 4 mL / min. The collected granules were dried in a vacuum drying oven at 40℃ for 1.5 h to obtain the core granules. (2) Wrap the middle layer Cellulase R-10 and tyrosinase were added to deionized water at a mass ratio of 2:1:30 and stirred at 32°C and 130 rpm for 15 min to prepare a composite enzyme solution. Citric acid and tartaric acid were added to deionized water at a mass ratio of 2:1:24 and stirred until completely dissolved. The pH was adjusted to 3.0 to prepare a composite acid solution. The composite enzyme solution was slowly added to the core particles and stirred at 35°C and 100 rpm for 45 min to adsorb the particles. The composite acid solution was then slowly added dropwise and stirred for 25 min. The particles were then dried in a vacuum drying oven at 38°C for 1 h to form intermediate layer coated particles. The amount of composite enzyme solution added was 4 times the mass of the core particles, and the amount of composite acid solution added was 2 times the mass of the core particles. (3) Cover the outermost layer Chitosan was slowly added to a 1% (v / v) acetic acid solution and magnetically stirred at room temperature for 30 min to obtain a 1% (w / w) chitosan-acetic acid solution. A 10% (w / w) NaOH solution was slowly added dropwise to the chitosan-acetic acid solution to adjust the pH to 8. 3-chloro-2-hydroxypropyltrimethylammonium chloride was then added to the system, with a mass ratio of chitosan-acetic acid solution to 3-chloro-2-hydroxypropyltrimethylammonium chloride of 1:2. Magnetic stirring was continued at room temperature for 3 h. After the reaction was complete, the pH was adjusted to 6.5 with a 1% (v / v) acetic acid solution. The neutralized solution was filtered through a Buchner funnel, and the filter cake was washed three times with deionized water. The washed precipitate was spread evenly and dried in an oven at 60℃ for 1 h. After drying, it was ground into powder to obtain quaternized modified chitosan.

[0020] Quaternized ammonium modified chitosan and hydroxypropyl methylcellulose were added to a 25% ethanol solution at a mass ratio of 3:2:40. The mixture was stirred at 30°C and 80 rpm for 35 min to prepare a coating solution. The intermediate layer coated particles were added to the coating solution, with the volume of the coating solution being 6 times the mass of the intermediate layer coated particles. The mixture was stirred at 60 rpm for 45 min to ensure that the coating solution uniformly coated the particle surface. The particles were then dried at -40°C and 10 Pa vacuum for 3.5 h to obtain three-layer microspheres. Example 2

[0021] The preparation steps of the three-layer microspheres are as follows: (1) Preparation of core particles Chitosan was slowly added to a 1% (v / v) acetic acid solution and magnetically stirred at room temperature for 30 min to obtain a 1% (w / w) chitosan-acetic acid solution. Glycerin was added to the chitosan-acetic acid solution and stirring was continued until completely mixed. The volume ratio of chitosan-acetic acid solution to glycerin was 20:1. The mixed solution was poured into a mold, and the solution thickness was controlled to be 5 mm. After standing at room temperature for 10 min, the mold was frozen at -18℃ for 2 h. The frozen solution was placed in a freeze dryer and vacuum dried for 6-8 h to obtain porous chitosan.

[0022] Porous chitosan: xylooligosaccharide: deionized water were added to deionized water at a mass ratio of 7:3:60. The mixture was stirred at 200 rpm for 27 min, and the pH was adjusted to 5.0 to form a uniform suspension. The suspension was sonicated for 15 min and then granulated using a spray granulation method. The inlet air temperature was set to 160℃, the outlet air temperature to 70℃, and the feed rate to 5 mL / min. The collected granules were dried in a vacuum drying oven at 45℃ for 2 h to obtain the core granules. (2) Wrap the middle layer Cellulase R-10 and tyrosinase were added to deionized water at a mass ratio of 2:1:35 and stirred at 35°C and 150 rpm for 20 min to prepare a composite enzyme solution. Citric acid and tartaric acid were added to deionized water at a mass ratio of 2:1:30 and stirred until completely dissolved. The pH was adjusted to 3.3 to prepare a composite acid solution. The composite enzyme solution was slowly added to the core particles and stirred at 38°C and 120 rpm for 50 min to adsorb the particles. The composite acid solution was then slowly added dropwise and stirred for 27 min. The particles were then dried in a vacuum drying oven at 40°C for 1 h to form intermediate layer coated particles. The amount of composite enzyme solution added was 5 times the mass of the core particles, and the amount of composite acid solution added was 2.5 times the mass of the core particles. (3) Cover the outermost layer Chitosan was slowly added to a 1% (v / v) acetic acid solution and magnetically stirred at room temperature for 30 min to obtain a 1% (w / w) chitosan-acetic acid solution. A 10% (w / w) NaOH solution was slowly added dropwise to the chitosan-acetic acid solution to adjust the pH to 8. 3-chloro-2-hydroxypropyltrimethylammonium chloride was then added to the system, with a mass ratio of chitosan-acetic acid solution to 3-chloro-2-hydroxypropyltrimethylammonium chloride of 1:2. Magnetic stirring was continued at room temperature for 3 h. After the reaction was complete, the pH was adjusted to 6.5 with a 1% (v / v) acetic acid solution. The neutralized solution was filtered through a Buchner funnel, and the filter cake was washed three times with deionized water. The washed precipitate was spread evenly and dried in an oven at 60℃ for 1 h. After drying, it was ground into powder to obtain quaternized modified chitosan.

[0023] Quaternized ammonium modified chitosan and hydroxypropyl methylcellulose were added to a 27% ethanol solution at a mass ratio of 3:2:50. The mixture was stirred at 32°C and 100 rpm for 40 min to prepare a coating solution. The intermediate layer coating particles were added to the coating solution, with the volume of the coating solution being 7 times the mass of the intermediate layer coating particles. The mixture was stirred at 70 rpm for 50 min to ensure that the coating solution uniformly coated the particle surface. The particles were then dried at -45°C and 15 Pa vacuum for 4 h to obtain three-layer microspheres. Example 3

[0024] The preparation steps of the three-layer microspheres are as follows: (1) Preparation of core particles Chitosan was slowly added to a 1% (v / v) acetic acid solution and magnetically stirred at room temperature for 30 min to obtain a 1% (w / w) chitosan-acetic acid solution. Glycerin was added to the chitosan-acetic acid solution and stirring was continued until completely mixed. The volume ratio of chitosan-acetic acid solution to glycerin was 20:1. The mixed solution was poured into a mold, and the solution thickness was controlled to be 5 mm. After standing at room temperature for 10 min, the mold was frozen at -18℃ for 2 h. The frozen solution was placed in a freeze dryer and vacuum dried for 6-8 h to obtain porous chitosan.

[0025] Porous chitosan: xylooligosaccharide: deionized water in a mass ratio of 7:3:70 was added to deionized water. The mixture was stirred at 200 rpm for 28 min, and the pH was adjusted to 5.1 to form a uniform suspension. The suspension was sonicated for 16 min, and then granules were prepared by spray granulation. The inlet air temperature was set to 165℃, the outlet air temperature to 73℃, and the feed rate to 5 mL / min. The collected granules were dried in a vacuum drying oven at 47℃ for 2 h to obtain the core granules. (2) Wrap the middle layer Cellulase R-10 and tyrosinase were added to deionized water at a mass ratio of 2:1:40 and stirred at 37°C and 160 rpm for 22 min to prepare a composite enzyme solution. Citric acid and tartaric acid were added to deionized water at a mass ratio of 2:1:32 and stirred until completely dissolved. The pH was adjusted to 3.0-3.4 to prepare a composite acid solution. The composite enzyme solution was slowly added to the core particles and stirred at 38°C and 135 rpm for 55 min to adsorb the particles. The composite acid solution was then slowly added dropwise and stirred for 28 min. The particles were then dried in a vacuum drying oven at 40°C for 1.5 h to form intermediate layer coated particles. The amount of composite enzyme solution added was 5.5 times the mass of the core particles, and the amount of composite acid solution added was 2.5 times the mass of the core particles. (3) Cover the outermost layer Chitosan was slowly added to a 1% (v / v) acetic acid solution and magnetically stirred at room temperature for 30 min to obtain a 1% (w / w) chitosan-acetic acid solution. A 10% (w / w) NaOH solution was slowly added dropwise to the chitosan-acetic acid solution to adjust the pH to 8. 3-chloro-2-hydroxypropyltrimethylammonium chloride was then added to the system, with a mass ratio of chitosan-acetic acid solution to 3-chloro-2-hydroxypropyltrimethylammonium chloride of 1:2. Magnetic stirring was continued at room temperature for 3 h. After the reaction was complete, the pH was adjusted to 6.5 with a 1% (v / v) acetic acid solution. The neutralized solution was filtered through a Buchner funnel, and the filter cake was washed three times with deionized water. The washed precipitate was spread evenly and dried in an oven at 60℃ for 1 h. After drying, it was ground into powder to obtain quaternized modified chitosan.

[0026] Quaternized modified chitosan and hydroxypropyl methylcellulose were added to a 28% ethanol solution at a mass ratio of 3:2:55. The mixture was stirred at 33°C and 115 rpm for 40 min to prepare a coating solution. The intermediate layer coated particles were added to the coating solution, wherein the volume of the coating solution was 7.5 times the mass of the intermediate layer coated particles. The mixture was stirred at 85 rpm for 65 min to ensure that the coating solution uniformly coated the particle surface. The particles were then dried at -48°C and 16 Pa vacuum for 4 h to obtain three-layer microspheres. Example 4

[0027] The preparation steps of the three-layer microspheres are as follows: (1) Preparation of core particles Chitosan was slowly added to a 1% (v / v) acetic acid solution and magnetically stirred at room temperature for 30 min to obtain a 1% (w / w) chitosan-acetic acid solution. Glycerin was added to the chitosan-acetic acid solution and stirring was continued until completely mixed. The volume ratio of chitosan-acetic acid solution to glycerin was 20:1. The mixed solution was poured into a mold, and the solution thickness was controlled to be 5 mm. After standing at room temperature for 10 min, the mold was frozen at -18℃ for 2 h. The frozen solution was placed in a freeze dryer and vacuum dried for 6-8 h to obtain porous chitosan.

[0028] Porous chitosan: xylooligosaccharide: deionized water were added to deionized water at a mass ratio of 7:3:80. The mixture was stirred at 220 rpm for 30 min and the pH was adjusted to 5.2 to form a uniform suspension. The suspension was sonicated for 18 min and then granulated using a spray granulation method. The inlet air temperature was set to 170℃, the outlet air temperature to 75℃, and the feed rate to 6 mL / min. The collected granules were dried in a vacuum drying oven at 50℃ for 2.5 h to obtain the core granules. (2) Wrap the middle layer Cellulase R-10 and tyrosinase were added to deionized water at a mass ratio of 2:1:45 and stirred at 38°C and 170 rpm for 25 min to prepare a composite enzyme solution. Citric acid and tartaric acid were added to deionized water at a mass ratio of 2:1:36 and stirred until completely dissolved. The pH was adjusted to 3.5 to prepare a composite acid solution. The composite enzyme solution was slowly added to the core particles and stirred at 40°C and 140 rpm for 60 min to adsorb the particles. The composite acid solution was then slowly added dropwise and stirred for 30 min. The particles were then dried in a vacuum drying oven at 42°C for 2 h to form intermediate layer coated particles. The amount of composite enzyme solution added was 6 times the mass of the core particles, and the amount of composite acid solution added was 3 times the mass of the core particles. (3) Cover the outermost layer Chitosan was slowly added to a 1% (v / v) acetic acid solution and magnetically stirred at room temperature for 30 min to obtain a 1% (w / w) chitosan-acetic acid solution. A 10% (w / w) NaOH solution was slowly added dropwise to the chitosan-acetic acid solution to adjust the pH to 8. 3-chloro-2-hydroxypropyltrimethylammonium chloride was then added to the system, with a mass ratio of chitosan-acetic acid solution to 3-chloro-2-hydroxypropyltrimethylammonium chloride of 1:2. Magnetic stirring was continued at room temperature for 3 h. After the reaction was complete, the pH was adjusted to 6.5 with a 1% (v / v) acetic acid solution. The neutralized solution was filtered through a Buchner funnel, and the filter cake was washed three times with deionized water. The washed precipitate was spread evenly and dried in an oven at 60℃ for 1 h. After drying, it was ground into powder to obtain quaternized modified chitosan.

[0029] Quaternized ammonium modified chitosan and hydroxypropyl methylcellulose were added to a 30% ethanol solution at a mass ratio of 3:2:60. The mixture was stirred at 35°C and 120 rpm for 45 min to prepare a coating solution. The intermediate layer coated particles were added to the coating solution, with the volume of the coating solution being 8 times the mass of the intermediate layer coated particles. The mixture was stirred at 100 rpm for 75 min to ensure that the coating solution uniformly coated the particle surface. The particles were then dried at -50°C and 20 Pa vacuum for 4.5 h to obtain three-layer microspheres.

[0030] The physicochemical properties of the three-layer microspheres prepared in Examples 1-4 were determined (including average particle size, enzyme activity retention rate, and aqueous phase dispersion stability), and the results are shown in Table 1.

[0031] Table 1. Physicochemical properties of the trilayer microspheres prepared in Examples 1-4

[0032] As can be seen from the data in Table 1, the three-layer microspheres prepared in Examples 1-4 all exhibited good physicochemical properties, among which the microspheres prepared in Example 3 had the best comprehensive physicochemical properties. Example 5

[0033] A method for extracting grape anthocyanins, comprising the following steps: S1: Raw material pretreatment Select fresh grapes, remove the stems and impurities, wash them clean, drain the surface water, crush them, then vacuum dry them at 40℃ for 3 hours, and finally pulverize them to 80 mesh to obtain grape powder. S2: Extraction of three-layer microspheres Grape powder and deionized water were mixed evenly according to a mass ratio of grape powder to deionized water of 1:8. The pH was adjusted to 4.5 to obtain the extraction base solution. Three layers of microspheres were added, with the amount of the three layers of microspheres being 4% of the mass of the extraction base solution. The mixture was stirred at 40°C and 100 r / min for 8 min. The mixture was then subjected to intermittent ultrasonic extraction for 3 h, with the speed maintained at 100 r / min, power set at 300 W, and temperature at 42°C, followed by a 1 min pause. After extraction, the extract was centrifuged at 7000 r / min and temperature at 2°C for 10 min, and the supernatant was collected to obtain the crude extract. S3: Obtain the final product, grape anthocyanins. The crude extract was filtered under vacuum through a 0.45 μm polytetrafluoroethylene (PTFE) membrane. The filtrate was then passed through an HPD-600 macroporous adsorption resin. After adsorption for 1.5 h, impurities were removed by elution with deionized water, followed by elution with 40% ethanol solution. The eluent was collected and placed in a vacuum rotary evaporator under nitrogen protection. The eluent was concentrated at 50 °C and 0.07 MPa for 30 min to obtain a concentrated solution. The concentrated solution was then transferred to a vacuum freeze dryer and dried at -40 °C and 10 Pa for 1 h to obtain grape anthocyanins. Example 6

[0034] A method for extracting grape anthocyanins, comprising the following steps: S1: Raw material pretreatment Fresh grapes were selected, destemmed, and impurities were removed. After being washed clean and drained of surface moisture, the grapes were crushed and then vacuum dried at 43°C for 3.5 hours. Finally, the grapes were pulverized to 100 mesh to obtain grape powder. S2: Extraction of three-layer microspheres Grape powder and deionized water were mixed evenly according to a mass ratio of grape powder to deionized water of 1:9. The pH was adjusted to 4.6 to obtain the extraction base solution. Three layers of microspheres were added, with the amount of the three layers of microspheres being 6% of the mass of the extraction base solution. The mixture was stirred at 42℃ and 120 r / min for 9 min. The mixture was then subjected to intermittent ultrasonic extraction for 3.5 h, with the speed maintained at 120 r / min, power set at 300 W, and temperature at 43℃, for 5 min followed by a 1 min pause. After extraction, the extract was centrifuged at 7500 r / min and 4℃ for 12 min, and the supernatant was collected to obtain the crude extract. S3: Obtain the final product, grape anthocyanins. The crude extract was vacuum filtered through a 0.45 μm polytetrafluoroethylene (PTFE) membrane. The filtrate was then passed through an HPD-600 macroporous adsorption resin. After adsorption for 1.8 h, impurities were removed by elution with deionized water, followed by elution with 40% ethanol solution. The eluent was collected and placed in a vacuum rotary evaporator under nitrogen protection. The eluent was concentrated at 52 °C and 0.07 MPa for 32 min to obtain a concentrated solution. The concentrated solution was then transferred to a vacuum freeze dryer and dried at -42 °C and 12 Pa for 1.2 h to obtain grape anthocyanins. Example 7

[0035] A method for extracting grape anthocyanins, comprising the following steps: S1: Raw material pretreatment Select fresh grapes, remove the stems and impurities, wash them clean, drain the surface water, crush them, then vacuum dry them at 44℃ for 4 hours, and finally pulverize them to 100 mesh to obtain grape powder. S2: Extraction of three-layer microspheres Grape powder and deionized water were mixed evenly according to a mass ratio of grape powder to deionized water of 1:10. The pH was adjusted to 4.6 to obtain the extraction base solution. Three layers of microspheres were added, with the amount of the three layers of microspheres being 7% of the mass of the extraction base solution. The mixture was stirred at 43°C and 130 r / min for 10 min. The mixture was then subjected to intermittent ultrasonic extraction for 3.5 h, with the speed maintained at 130 r / min, power set at 300 W, and temperature at 43°C, for 5 min followed by a 1.5 min pause. After extraction, the extract was centrifuged at 8000 r / min and 4°C for 13 min, and the supernatant was collected to obtain the crude extract. S3: Obtain the final product, grape anthocyanins. The crude extract was vacuum filtered through a 0.45 μm polytetrafluoroethylene (PTFE) membrane. The filtrate was then passed through an HPD-600 macroporous adsorption resin. After adsorption for 2 hours, impurities were removed by elution with deionized water, followed by elution with 40% ethanol solution. The eluent was collected and placed in a vacuum rotary evaporator under nitrogen protection. The eluent was concentrated at 54°C and 0.07 MPa for 35 minutes to obtain a concentrated solution. The concentrated solution was then transferred to a vacuum freeze dryer and dried at -45°C and 15 Pa for 1.5 hours to obtain grape anthocyanins. Example 8

[0036] A method for extracting grape anthocyanins, comprising the following steps: S1: Raw material pretreatment Fresh grapes were selected, destemmed, and impurities were removed. After being washed clean and drained of surface moisture, the grapes were crushed and then vacuum dried at 46°C for 4.5 hours. Finally, the grapes were pulverized to 120 mesh to obtain grape powder. S2: Extraction of three-layer microspheres Grape powder and deionized water were mixed evenly according to a mass ratio of grape powder to deionized water of 1:11. The pH was adjusted to 4.7 to obtain the extraction base solution. Three layers of microspheres were added, with the amount of the three layers of microspheres being 8% of the mass of the extraction base solution. The mixture was stirred at 45°C and 140 r / min for 10 min. The mixture was then subjected to intermittent ultrasonic extraction for 3.5 h, with the speed maintained at 140 r / min, power set at 300 W, and temperature at 45°C, for 6 min followed by a 1 min pause. After extraction, the extract was centrifuged at 8500 r / min and 5°C for 14 min, and the supernatant was collected to obtain the crude extract. S3: Obtain the final product, grape anthocyanins. The crude extract was filtered under vacuum through a 0.45 μm polytetrafluoroethylene (PTFE) membrane. The filtrate was then passed through an HPD-600 macroporous adsorption resin. After adsorption for 2.2 h, impurities were removed by elution with deionized water, followed by elution with 40% ethanol solution. The eluent was collected and placed in a vacuum rotary evaporator under nitrogen protection. The eluent was concentrated at 58 °C and 0.08 MPa for 38 min to obtain a concentrated solution. The concentrated solution was then transferred to a vacuum freeze dryer and dried at -47 °C and 18 Pa for 1.5 h to obtain grape anthocyanins. Example 9

[0037] A method for extracting grape anthocyanins, comprising the following steps: S1: Raw material pretreatment Select fresh grapes, remove the stems and impurities, wash them clean, drain the surface water, crush them, then vacuum dry them at 50℃ for 5 hours, and finally pulverize them to 120 mesh to obtain grape powder. S2: Extraction of three-layer microspheres Grape powder and deionized water were mixed evenly according to a mass ratio of grape powder to deionized water of 1:12. The pH was adjusted to 4.8 to obtain the extraction base solution. Three layers of microspheres were added, with the amount of the three layers of microspheres being 10% of the mass of the extraction base solution. The mixture was stirred at 45°C and 150 r / min for 12 min. The mixture was then subjected to intermittent ultrasonic extraction for 4 h, with the speed maintained at 150 r / min, power set at 300 W, and temperature at 45°C, followed by a 2-min pause. After extraction, the extract was centrifuged at 9000 r / min and 6°C for 15 min, and the supernatant was collected to obtain the crude extract. S3: Obtain the final product, grape anthocyanins. The crude extract was filtered under vacuum through a 0.45 μm polytetrafluoroethylene (PTFE) membrane. The filtrate was then passed through an HPD-600 macroporous adsorption resin. After adsorption for 2.5 h, impurities were removed by elution with deionized water, followed by elution with 40% ethanol solution. The eluent was collected and placed in a vacuum rotary evaporator under nitrogen protection. The eluent was concentrated at 60 °C and a vacuum of 0.09 MPa for 40 min to obtain a concentrated solution. The concentrated solution was then transferred to a vacuum freeze dryer and dried at -50 °C and a vacuum of 20 Pa for 2 h to obtain grape anthocyanins. Example 10

[0038] A method for extracting anthocyanins from blueberries includes the following steps: S1: Raw material pretreatment Select fresh blueberries, remove the stems and impurities, wash them clean, drain the surface water, crush them, then vacuum dry them at 40℃ for 3 hours, and finally pulverize them to 80 mesh to obtain blueberry powder. S2: Extraction of three-layer microspheres Blueberry powder and deionized water were mixed evenly according to a mass ratio of blueberry powder to deionized water of 1:8. The pH was adjusted to 4.5 to obtain the extraction base solution. Three layers of microspheres were added, with the amount of the three layers of microspheres being 4% of the mass of the extraction base solution. The mixture was stirred at 40°C and 100 r / min for 8 min. The mixture was then subjected to intermittent ultrasonic extraction for 3 h, with the speed maintained at 100 r / min, power set at 300 W, and temperature at 42°C, followed by a 1 min pause. After extraction, the extract was centrifuged at 7000 r / min and temperature at 2°C for 10 min, and the supernatant was collected to obtain the crude extract. S3: Obtain the final product, blueberry anthocyanins. The crude extract was vacuum filtered through a 0.45 μm polytetrafluoroethylene (PTFE) membrane. The filtrate was then passed through an HPD-600 macroporous adsorption resin. After adsorption for 1.5 h, impurities were removed by elution with deionized water, followed by elution with 40% ethanol solution. The eluent was collected and placed in a vacuum rotary evaporator under nitrogen protection. The eluent was concentrated at 50 °C and 0.07 MPa for 30 min to obtain a concentrated solution. The concentrated solution was then transferred to a vacuum freeze dryer and dried at -40 °C and 10 Pa for 1 h to obtain blueberry anthocyanins. Example 11

[0039] A method for extracting anthocyanins from blueberries includes the following steps: S1: Raw material pretreatment Select fresh blueberries, remove the stems and impurities, wash them clean, drain the surface water, crush them, then vacuum dry them at 45℃ for 4 hours, and finally pulverize them to 100 mesh to obtain blueberry powder. S2: Extraction of three-layer microspheres Blueberry powder and deionized water were mixed evenly at a mass ratio of 1:10 (blueberry powder:deionized water) and the pH was adjusted to 4.7 to obtain the extraction base solution. Three layers of microspheres were added, with the amount of microspheres added being 8% of the mass of the extraction base solution. The mixture was stirred at 43°C and 130 r / min for 10 min. The mixture was then subjected to intermittent ultrasonic extraction for 3.5 h, with the speed maintained at 130 r / min, power set at 300 W, and temperature at 44°C, for 5 min followed by a 1.5 min pause. After extraction, the extract was centrifuged at 8000 r / min and 4°C for 13 min, and the supernatant was collected to obtain the crude extract. S3: Obtain the final product, blueberry anthocyanins. The crude extract was filtered under vacuum through a 0.45 μm polytetrafluoroethylene (PTFE) membrane. The filtrate was then passed through an HPD-600 macroporous adsorption resin. After adsorption for 2 hours, impurities were removed by elution with deionized water, followed by elution with 40% ethanol solution. The eluent was collected and placed in a vacuum rotary evaporator under nitrogen protection. The eluent was concentrated at 55°C and 0.08 MPa for 35 minutes to obtain a concentrated solution. The concentrated solution was then transferred to a vacuum freeze dryer and dried at -45°C and 15 Pa for 1.5 hours to obtain blueberry anthocyanins. Example 12

[0040] A method for extracting anthocyanins from blueberries includes the following steps: S1: Raw material pretreatment Select fresh blueberries, remove the stems and impurities, wash them clean, drain the surface water, crush them, then vacuum dry them at 50℃ for 5 hours, and finally pulverize them to 120 mesh to obtain blueberry powder. S2: Extraction of three-layer microspheres Blueberry powder and deionized water were mixed evenly at a mass ratio of 1:12 (blueberry powder:deionized water) and the pH was adjusted to 4.8 to obtain the extraction base solution. Three layers of microspheres were added, with the amount of microspheres added being 10% of the mass of the extraction base solution. The mixture was stirred at 45°C and 150 r / min for 12 min. The mixture was then subjected to intermittent ultrasonic extraction for 4 h, with the speed maintained at 150 r / min, power set at 300 W, and temperature at 45°C, followed by a 2-min pause. After extraction, the extract was centrifuged at 9000 r / min and 6°C for 15 min, and the supernatant was collected to obtain the crude extract. S3: Obtain the final product, blueberry anthocyanins. The crude extract was filtered under vacuum through a 0.45 μm polytetrafluoroethylene (PTFE) membrane. The filtrate was then passed through an HPD-600 macroporous adsorption resin. After adsorption for 2.5 h, impurities were removed by elution with deionized water, followed by elution with 40% ethanol solution. The eluent was collected and placed in a vacuum rotary evaporator under nitrogen protection. The eluent was concentrated at 60 °C and 0.09 MPa for 40 min to obtain a concentrated solution. The concentrated solution was then transferred to a vacuum freeze dryer and dried at -50 °C and 20 Pa for 2 h to obtain blueberry anthocyanins. Comparative Example 1

[0041] The difference between this comparative example and Example 9 is that the core particles of the three-layer microspheres are ordinary chitosan, while the other conditions are the same as in Example 9. Comparative Example 2

[0042] The difference between this comparative example and Example 9 is that the intermediate layer of the three-layer microspheres does not contain cellulase R-10 and tyrosinase; all other conditions are the same as in Example 9. Comparative Example 3

[0043] The difference between this comparative example and Example 9 is that the intermediate layer of the three-layer microspheres does not contain the citric acid-tartaric acid complex acid, while the other conditions are the same as in Example 9. Comparative Example 4

[0044] The difference between this comparative example and Example 9 is that the three-layer microspheres do not contain an intermediate layer, while the other conditions are the same as in Example 9. Comparative Example 5

[0045] The difference between this comparative example and Example 9 is that the three-layer microspheres do not include the outermost layer, while the other conditions are the same as in Example 9. Comparative Example 6

[0046] The difference between this comparative example and Example 11 is that the core particles of the three-layer microspheres are ordinary chitosan, while the other conditions are the same as in Example 11. Comparative Example 7

[0047] The difference between this comparative example and Example 11 is that the intermediate layer of the three-layer microspheres does not contain cellulase R-10 and tyrosinase, while the other conditions are the same as in Example 11. Comparative Example 8

[0048] The difference between this comparative example and Example 11 is that the intermediate layer of the three-layer microspheres does not contain the citric acid-tartaric acid complex acid, while the other conditions are the same as in Example 11. Comparative Example 9

[0049] The difference between this comparative example and Example 11 is that the three-layer microspheres do not contain an intermediate layer, while the other conditions are the same as in Example 11. Comparative Example 10

[0050] The difference between this comparative example and Example 11 is that the three-layer microspheres do not include the outermost layer, while the other conditions are the same as in Example 11.

[0051] The extraction rate of total anthocyanins, the conversion rate of flavonol glycosides, the depolymerization rate of proanthocyanidins, the retention rate of total anthocyanin activity, and the purity of the grape anthocyanins extracted in Examples 5-9 and Comparative Examples 1-5 were determined, and the results are shown in Table 2.

[0052] Table 2. Determination of relevant indicators of grape anthocyanins extracted in Examples 5-9 and Comparative Examples 1-5

[0053] The total anthocyanin extraction rate, flavonol glycoside conversion rate, proanthocyanidin depolymerization rate, total anthocyanin activity retention rate, and product purity of the blueberry anthocyanins extracted in Examples 10-12 and Comparative Examples 6-10 were determined, and the results are shown in Table 3.

[0054] Table 3. Determination of relevant indicators of blueberry anthocyanins extracted in Examples 10-12 and Comparative Examples 6-10

[0055] As can be seen from the data in Tables 2 and 3, the total anthocyanin content, total anthocyanin activity retention rate, and product purity of the fruit anthocyanins extracted by the method of the present invention are all maintained at a high level. Simultaneously, highly efficient flavonol glycoside conversion and proanthocyanidin depolymerization rates are achieved. The effects of the examples are significantly better than those of the comparative examples. Among them, Example 9 shows the best effect for grape anthocyanins, and Example 11 shows the best effect for blueberry anthocyanins. It is worth noting that in Comparative Examples 1 and 6, the core particles of the three-layer microspheres are ordinary chitosan and do not contain xylooligosaccharides, which weakens the binding force between the microspheres and the raw materials and reduces the degree of damage to the raw materials, thus hindering the dissolution of inherent anthocyanins and ultimately leading to a decrease in the total anthocyanin extraction rate. In Comparative Examples 2 and 7, the middle layer of the three-layer microspheres does not contain cellulase R-10 and tyrosinase, which cannot release bound and acylated anthocyanins, nor can it directionally catalyze the conversion of flavonol glycosides into anthocyanin analogs, thereby reducing the total anthocyanin extraction rate. In Comparative Examples 3 and 8, the middle layer of the three-layer microspheres does not contain citric acid- Tartaric acid complex acid prevents dimer / polymer proanthocyanidins from depolymerizing into active monomeric anthocyanins, resulting in a reduced anthocyanin extraction rate. Furthermore, the absence of tartaric acid, which also possesses antioxidant properties, leads to a decrease in the total anthocyanin activity retention rate and product purity. In Comparative Examples 4 and 9, the three-layered microspheres lacked an intermediate layer, and the dual absence of complex enzymes and complex acids significantly reduced the total anthocyanin extraction rate, flavonol glycoside conversion rate, proanthocyanidin depolymerization rate, total anthocyanin activity retention rate, and product purity. In Comparative Examples 5 and 10, the three-layered microspheres lacked an outermost layer, significantly affecting the total anthocyanin activity retention rate and product purity of the fruit anthocyanins.

[0056] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for extracting anthocyanins from fruits, characterized in that, Includes the following steps: S1: Raw material pretreatment Select fresh fruit, remove impurities, wash it clean, drain the surface water, crush it, then vacuum dry it at 40-50℃ for 3-5 hours, and finally pulverize it to 80-120 mesh to obtain fruit powder. S2: Extraction of three-layer microspheres Prepare an extraction base solution using the fruit powder prepared in S1, and add three layers of microspheres, wherein the amount of the three layers of microspheres added is 4-10% of the mass of the extraction base solution. Stir at 40-45℃ and 100-150 r / min for 8-12 min; maintain a speed of 100-150 r / min, set the power to 300W and the temperature to 42-45℃, and perform intermittent ultrasonic extraction for 4-6 min, with a pause of 1-2 min, for 3-4 h; after extraction, centrifuge the extract at 7000-9000 r / min and 2-6℃ for 10-15 min, and collect the supernatant to obtain the crude extract; S3: Obtain the final product, fruit anthocyanins. The crude extract was purified by filtration, adsorption, elution, concentration, and drying to obtain the fruit anthocyanins.

2. The method as described in claim 1, characterized in that, The fruits include grapes and blueberries.

3. The method as described in claim 1, characterized in that, The preparation method of the base solution for extraction in S2 is as follows: Mix the fruit powder and deionized water evenly according to the mass ratio of fruit powder to deionized water = 1:8-12, and adjust the pH to 4.5-4.8 to obtain the base solution for extraction.

4. The method as described in claim 1, characterized in that, The preparation steps of the three-layer microspheres in S2 are as follows: (1) Preparation of core particles Porous chitosan and xylooligosaccharides are added to deionized water and stirred at 180-220 rpm for 25-30 min. The pH is adjusted to 4.8-5.2 to form a uniform suspension. The suspension is sonicated for 12-18 min and then granulated by spray granulation. The inlet air temperature is set to 150-170℃, the outlet air temperature to 65-75℃, and the feed rate to 4-6 mL / min. The collected granules are dried in a vacuum drying oven at 40-50℃ for 1.5-2.5 h to obtain the core granules. (2) Wrap the middle layer Cellulase R-10 and tyrosinase were added to deionized water and stirred at 32-38℃ and 130-170 r / min for 15-25 min to prepare a composite enzyme solution. Citric acid and tartaric acid were added to deionized water and stirred until completely dissolved. The pH was adjusted to 3.0-3.5 to prepare a composite acid solution. The composite enzyme solution was slowly added to the core particles and stirred at 35-40℃ and 100-140 r / min for 45-60 min to adsorb the particles. The composite acid solution was then slowly added dropwise and stirred for 25-30 min. The particles were then dried in a vacuum drying oven at 38-42℃ for 1-2 h to form intermediate layer coated particles. (3) Cover the outermost layer Quaternized modified chitosan and hydroxypropyl methylcellulose were added to an ethanol solution with a concentration of 25-30% and stirred at 30-35℃ and 80-120 r / min for 35-45 min to prepare a coating solution. The intermediate layer coated particles were added to the coating solution, wherein the volume of the coating solution was 6-8 times the mass of the intermediate layer coated particles, and stirred at 60-100 r / min for 45-75 min to make the coating solution uniformly coat the particle surface. The particles were dried at -40℃ to -50℃ and a vacuum degree of 10-20 Pa for 3.5-4.5 h to obtain three-layer microspheres.

5. The method as described in claim 4, characterized in that, In step (1), the mass ratio of porous chitosan, xylooligosaccharide and deionized water is 7:3:50-80.

6. The method as described in claim 4, characterized in that, In step (2), the mass ratio of cellulase R-10, tyrosinase and deionized water is 2:1:30-45; the mass ratio of citric acid, tartaric acid and deionized water is 2:1:24-36; the amount of compound enzyme solution added is 4-6 times the mass of the core particles, and the amount of compound acid solution added is 2-3 times the mass of the core particles.

7. The method as described in claim 4, characterized in that, In step (3), the mass ratio of quaternized modified chitosan, hydroxypropyl methylcellulose and ethanol solution is 3:2:40-60.

8. The method as described in claim 1, characterized in that, The specific operation of S3 is as follows: The crude extract was vacuum filtered through a 0.45 μm polytetrafluoroethylene (PTFE) membrane. The filtrate was then passed through an HPD-600 macroporous adsorption resin for 1.5-2.5 h. After adsorption, impurities were removed by elution with deionized water, followed by elution with 40% ethanol solution. The eluent was collected and placed in a vacuum rotary evaporator under nitrogen protection. The eluent was concentrated at 50-60 °C and a vacuum of 0.07-0.09 MPa for 30-40 min to obtain a concentrated solution. The concentrated solution was then transferred to a vacuum freeze dryer and dried at -40 °C to -50 °C and a vacuum of 10-20 Pa for 1-2 h to obtain fruit anthocyanins.

9. Fruit anthocyanins prepared by the method according to any one of claims 1-8.

10. The use of the fruit anthocyanins as described in claim 9 in the preparation of food or cosmetics with antioxidant activity.

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