Chitosan / beta-lactoglobulin nano composite material loaded with theaflavin and preparation method thereof

Abstract

The invention discloses a theaflavin-loaded chitosan / beta-lactoglobulin nano composite material and a preparation method thereof, and belongs to the technical field of tea and food processing. The method comprises the following steps: sequentially carrying out first mixing on theaflavin and a chitosan hydrochloride solution, carrying out second mixing on theaflavin and a carboxymethyl chitosan solution, carrying out third mixing on theaflavin and a beta-lactoglobulin solution, and carrying out centrifugal treatment on a mixed solution obtained by the third mixing to obtain the theaflavin-chitosan / beta-lactoglobulin nano composite material, the pH (Potential of Hydrogen) value of the carboxymethyl chitosan solution is 5.8 to 6.2. According to the method disclosed by the invention, the bio-accessibility and stability of theaflavin can be improved.

Description

Technical Field

[0001] This invention relates to a chitosan / β-lactoglobulin nanocomposite material loaded with theaflavins and its preparation method, belonging to the field of tea and food processing technology. Background Technology

[0002] Theaflavins (TFs) are important natural products found in tea, possessing a variety of bioactivities, including antioxidant properties, anti-aging effects, lipid-lowering and blood sugar-lowering effects, cardiovascular disease prevention, cancer prevention, and muscle health protection, and are currently widely used. However, TFs are sensitive to oxidants, radiation, temperature, and pH, and are prone to degradation. Studies have shown that the amount of TFs absorbed by the human body is only 0.001% of the ingested amount, and their activity during gastrointestinal digestion is affected by conditions such as temperature, pH, and enzymes, resulting in extremely low bioavailability.

[0003] In the delivery of natural active substances, reported delivery system types include, but are not limited to: colloidal, emulsion, liposome, hydrogel, multilayer particle, and nanocapsule types. Nanoemulsions have advantages such as uniform particle size and good dispersibility, but the surfactants used in their synthesis may have potential toxicity. Liposomes are considered safe and biodegradable, and liposome preparation techniques include hand-cranking, high-pressure homogenization, and thin-film hydration, but most of these methods are difficult to meet the requirements of large-scale industrial production and have significant solvent residues. Polysaccharides and proteins, as natural biopolymers, have natural economic and safety advantages in preparing highly biocompatible, non-toxic, and degradable polysaccharide-protein delivery systems.

[0004] Chinese Patent (CN104605228A) discloses an EGCG-chitosan / β-lactoglobulin composite nanoparticle and its preparation method. The preparation method is as follows: (1) Carboxymethyl chitosan and chitosan hydrochloride are dissolved in deionized water to prepare a solution with a mass concentration of 1-2%; (2) A certain amount of β-lactoglobulin and EGCG are added to the chitosan hydrochloride solution; (3) Under stirring conditions, carboxymethyl chitosan solution is added dropwise to the chitosan hydrochloride solution containing β-lactoglobulin and EGCG, so that carboxymethyl chitosan and chitosan hydrochloride crosslink with each other to form nanoparticles. At this time, the solution is opalescent; (4) Stirring is continued and the solution is heated to 70-85℃, kept for 30-60 min and then cooled to room temperature, so that β-lactoglobulin and EGCG form a stable, clear composite nano-dispersion with high drug loading; (5) The nanoparticle aqueous solution obtained in step (4) is centrifuged by a high-speed refrigerated centrifuge, the supernatant is discarded and freeze-dried to obtain the composite nanoparticles. However, the release of the composite nanoparticles prepared by this method into gastric juice is still relatively high, and the residence time of the encapsulated material in the small intestine is limited, so the overall sustained release rate still needs to be improved. In addition, the method also involves heating in step (4), and EGCG itself will undergo partial degradation at a temperature of 70-85℃, and this degradation is irreversible.

[0005] Therefore, developing effective TF encapsulation technologies to improve their stability and bioactivity is an important way to broaden their application in food. Summary of the Invention

[0006] To address the problems existing in the prior art, one of the objectives of this invention is to provide a method for encapsulating and releasing theaflavins using chitosan / β-lactoglobulin, which can improve the bioaccessibility and stability of theaflavins.

[0007] The second objective of this invention is to provide a theaflavin-chitosan / β-lactoglobulin nanocomposite material, which has a small particle size, high encapsulation efficiency and excellent stability.

[0008] To achieve the above objectives, a first aspect of the present invention provides a method for encapsulating sustained-release theaflavins using chitosan / β-lactoglobulin, the method comprising:

[0009] Theaflavins were first mixed with chitosan hydrochloride solution, then mixed with carboxymethyl chitosan solution, and then mixed with β-lactoglobulin solution. The mixture obtained from the third mixture was then centrifuged to obtain theaflavins-chitosan / β-lactoglobulin nanocomposite material.

[0010] The pH value of the carboxymethyl chitosan solution is 5.8~6.2.

[0011] This invention first utilizes the amphiphilic polymer characteristics of carboxymethyl chitosan solution and chitosan hydrochloride, which are two chitosan derivatives with complementary properties. Carboxymethyl chitosan hydrochloride is cationic, while carboxymethyl chitosan is anionic. They encapsulate theaflavins through an ionic cross-linking reaction. Secondly, a carboxymethyl chitosan solution with a pH of 5.8–6.2 is used. This enhances the solubility of chitosan and provides weakly acidic conditions for the encapsulation of theaflavins. Under these weakly acidic conditions, the phenolic hydroxyl groups of theaflavins dissociate and bind to the carboxyl groups of carboxymethyl chitosan and the amino groups of chitosan hydrochloride via hydrogen bonds. The TFs are encapsulated in the complex network, while the hydrophobic region of β-lactoglobulin is exposed. This hydrophobic region binds to the nonpolar structure of the TFs through hydrophobic interactions, further enhancing the encapsulation effect. β-lactoglobulin provides a hydrophobic core to protect the TFs, forming an outer barrier through electrostatic and hydrogen bonding interactions, jointly improving the stability and sustained-release performance of the TFs. The method provided by this invention improves the availability and practical value of TFs in the human digestive system.

[0012] As a preferred embodiment, the carboxymethyl chitosan solution has a pH of 6. The inventors have found that this preferred embodiment further reduces the particle size of the nanocomposite material and improves the bioaccessibility and stability of the TFs.

[0013] As a preferred embodiment, the mass ratio of the theaflavins to chitosan hydrochloride in the chitosan hydrochloride solution, carboxymethyl chitosan in the carboxymethyl chitosan solution, and β-lactoglobulin in the β-lactoglobulin solution is 1:1~3:1~3.5:9~15.

[0014] As a more preferred embodiment, the mass ratio of theaflavins to chitosan hydrochloride in the chitosan hydrochloride solution, carboxymethyl chitosan in the carboxymethyl chitosan solution, and β-lactoglobulin in the β-lactoglobulin solution is 1:1.4~2.2:1.4~2.8:10~13. When the amount of at least one of chitosan hydrochloride, carboxymethyl chitosan, and β-lactoglobulin in the system is too high, the complex will aggregate, resulting in a sharp increase in particle size; when the amount of at least one of chitosan hydrochloride, carboxymethyl chitosan, and β-lactoglobulin in the system is too low, the complex network cannot be sufficiently formed, resulting in a low encapsulation efficiency of TFs.

[0015] As a preferred embodiment, the concentration of the chitosan hydrochloride solution is 0.4~0.6 mg / mL.

[0016] As a preferred embodiment, the concentration of the carboxymethyl chitosan solution is 1.5~2 mg / mL.

[0017] As a preferred embodiment, the concentration of the β-lactoglobulin solution is 4~6 mg / mL.

[0018] The inventors discovered that when the concentration of at least one of the chitosan hydrochloride solution, carboxymethyl chitosan solution, and β-lactoglobulin solution in the system is too high, the complex will aggregate, resulting in a sharp increase in particle size; when the concentration of at least one of the chitosan hydrochloride solution, carboxymethyl chitosan solution, and β-lactoglobulin solution in the system is too low, the complex network cannot be sufficiently formed, resulting in a low encapsulation rate of TFs.

[0019] As a preferred embodiment, the conditions for the first mixing include: a temperature of 10~30℃, a time of 1.5~3h, and a rotation speed of 400~600rpm.

[0020] As a preferred embodiment, the conditions for the second mixing include: a temperature of 10~30℃, a time of 2~4h, and a rotation speed of 400~600rpm.

[0021] As a preferred embodiment, the conditions for the third mixing include: a temperature of 10~30℃, a time of 3~4.5h, and a rotation speed of 400~600rpm.

[0022] Furthermore, the present invention eliminates the need for further heating of the mixture obtained in the third mixing step, thus avoiding the aggregation of theaflavins-chitosan / β-lactoglobulin nanocomposite materials due to heating.

[0023] As a preferred embodiment, the second mixing method is dropwise addition, where the solution obtained from the first mixture is added dropwise to the carboxymethyl chitosan solution, or the carboxymethyl chitosan solution is added dropwise to the solution obtained from the first mixture. The dropwise addition rate is 4.5~5.5 mL / min. The second mixing time includes the dropwise addition time. Dropwise addition allows for more thorough mixing of the substances, resulting in nanocomposite materials with smaller particle sizes.

[0024] As a preferred embodiment, the third mixing method is dropwise addition, where the solution obtained from the second mixture is added dropwise to the β-lactoglobulin solution, or the β-lactoglobulin solution is added dropwise to the solution obtained from the second mixture. The dropwise addition rate is 4.5~5.5 mL / min. The third mixing time includes the dropwise addition time. Dropwise addition allows for more thorough mixing of the substances, resulting in nanocomposite materials with smaller particle sizes.

[0025] A second aspect of the present invention is to provide a theaflavin-chitosan / β-lactoglobulin nanocomposite material prepared by the method described in the first aspect above.

[0026] As a preferred embodiment, the particle size of the nanocomposite material is 150~400nm.

[0027] As a preferred embodiment, the centrifugation process is carried out at a speed of 9000~1100 rpm for a time of 20~40 min.

[0028] Compared with the prior art, the present invention has at least the following advantages:

[0029] The theaflavin-chitosan / β-lactoglobulin nanocomposite material provided by this invention has a small particle size, high encapsulation efficiency and excellent stability. Attached Figure Description

[0030] Figure 1 These are SEM and TEM images of the theaflavin-chitosan / β-lactoglobulin nanocomposite material prepared in Example 1;

[0031] Figure 2 The infrared spectra of Cs / β-lg, Cs, β-lg, TFs and the theaflavins-chitosan / β-lactoglobulin nanocomposite material (TFs-Cs / β-lg) prepared in Example 1 are shown.

[0032] Figure 3 The images show the XRD patterns of Cs / β-lg, Cs, β-lg, TFs, and the theaflavins-chitosan / β-lactoglobulin nanocomposite material (TFs-Cs / β-lg) prepared in Example 1.

[0033] Figure 4 Differential scanning calorimetry (DSC) images of Cs / β-lg, Cs, β-lg, TFs, and the theaflavin-chitosan / β-lactoglobulin nanocomposite material (TFs-Cs / β-lg) prepared in Example 1;

[0034] Figure 5 This is a graph showing the in vitro release curve results;

[0035] Figure 6 This is a graph showing the results of the stability experiment. Detailed Implementation

[0036] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0037] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments. Obviously, the embodiments described below are only a part of the embodiments, and all other embodiments obtained by those skilled in the art without creative effort are still within the scope of protection of the present invention.

[0038] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0039] Example 1

[0040] At room temperature, 4 mg of TFs (theaflavins, 57% purity) were dissolved in 15 mL of CHC (chitosan hydrochloride solution, 0.5 mg / mL), and the mixture was magnetically stirred at 500 rpm for 2 h until fully dissolved. Then, 5 mL of CMC (carboxymethyl chitosan solution, 1.5 mg / mL, pH=6) was added dropwise (at a rate of 5 mL / min), and the mixture was magnetically stirred at 500 rpm for 3 h. Next, 10 mL of β-lg (β-lactoglobulin solution, 4 mg / mL) was added dropwise (at a rate of 5 mL / min), and the mixture was magnetically stirred at 500 rpm for 3.5 h. After centrifugation at 10000 rpm, the supernatant was removed, and the theaflavins-chitosan / β-lactoglobulin nanocomposite material (TFs-Cs / β-lg) was prepared.

[0041] The encapsulation efficiency of TFs in the nanocomposite material prepared in this embodiment was 73.7% ± 1.1. After freeze-drying the nanocomposite material for 24 hours, its particle size was measured to be 201.5 ± 2.5 nm.

[0042] Example 2

[0043] At room temperature, 4 mg of TFs (theaflavins, 57% purity) were dissolved in 15 mL of CHC (chitosan hydrochloride solution, 0.5 mg / mL), and the mixture was magnetically stirred at 500 rpm for 2 h until fully dissolved. Then, 5 mL of CMC (carboxymethyl chitosan solution, 2 mg / mL, pH=6) was added dropwise (at a rate of 5 mL / min), and the mixture was magnetically stirred at 500 rpm for 3 h. Next, 10 mL of β-lg (β-lactoglobulin solution, 5 mg / mL) was added dropwise (at a rate of 5 mL / min), and the mixture was magnetically stirred at 500 rpm for 3.5 h. After centrifugation at 10000 rpm, the supernatant was removed, and the theaflavins-chitosan / β-lactoglobulin nanocomposite material was prepared.

[0044] The encapsulation efficiency of TFs in the nanocomposite material prepared in this embodiment was 71.9% ± 1.4. After freeze-drying the nanocomposite material for 24 hours, its particle size was measured to be 306.3 ± 1.9 nm.

[0045] Example 3

[0046] At room temperature, 5 mg of TFs (theaflavins, 57% purity) were dissolved in 15 mL of CHC (chitosan hydrochloride solution, 0.5 mg / mL), and the mixture was magnetically stirred at 500 rpm for 2 h until fully dissolved. Then, 5 mL of CMC (carboxymethyl chitosan solution, 1.5 mg / mL, pH=6) was added dropwise (at a rate of 5 mL / min), and the mixture was magnetically stirred at 500 rpm for 3 h. Next, 10 mL of β-lg (β-lactoglobulin solution, 5 mg / mL) was added dropwise (at a rate of 5 mL / min), and the mixture was magnetically stirred at 500 rpm for 3.5 h. After centrifugation at 10000 rpm, the supernatant was removed, and the theaflavins-chitosan / β-lactoglobulin nanocomposite material was prepared.

[0047] The encapsulation efficiency of TFs in the nanocomposite material prepared in this embodiment was 71.3% ± 1.1. After freeze-drying the nanocomposite material for 24 hours, its particle size was measured to be 162.9 ± 3.8 nm.

[0048] Example 4

[0049] At room temperature, 6 mg of TFs (theaflavins, 57% purity) were dissolved in 15 mL of CHC (chitosan hydrochloride solution, 0.5 mg / mL), and the solution was magnetically stirred at 500 rpm for 2 h until fully dissolved. Then, 5 mL of CMC (carboxymethyl chitosan solution, 1.5 mg / mL, pH=6) was added dropwise (at a rate of 5 mL / min), and the solution was magnetically stirred at 500 rpm for 3 h. Then, 10 mL of β-lg (β-lactoglobulin solution, 5 mg / mL) was added dropwise (at a rate of 5 mL / min), and the solution was magnetically stirred at 500 rpm for 3.5 h. After centrifugation at 10000 rpm, the supernatant was removed, and the theaflavins-chitosan / β-lactoglobulin nanocomposite material was prepared.

[0050] The encapsulation efficiency of TFs in the nanocomposite material prepared in this embodiment was 62.3% ± 1.0. After freeze-drying the nanocomposite material for 24 hours, its particle size was measured to be 179.1 ± 4.5 nm.

[0051] Example 5

[0052] This embodiment is carried out using a method similar to that of Example 1, except that the concentration of the chitosan hydrochloride solution is adjusted to 0.75 mg / mL and the volume is adjusted to 10 mL.

[0053] The encapsulation efficiency of TFs in the nanocomposite material prepared in this embodiment is 62.2%-65.7%. After freeze-drying the nanocomposite material for 24 hours, its particle size was measured to be 403-442 nm.

[0054] Comparative Example 1

[0055] This comparative example was conducted using a method similar to that of Example 1, except that the pH value of the carboxymethyl chitosan solution was not adjusted (the natural pH value is 6.9).

[0056] The encapsulation efficiency of TFs in the nanocomposite material prepared in this comparative example was 52.6% ± 1.0. After freeze-drying the nanocomposite material for 24 hours, its particle size was measured to be 485 nm.

[0057] Comparative Example 2

[0058] At room temperature, 4 mg of TFs (theaflavins, 57% purity) were dissolved in 15 mL of CHC (chitosan hydrochloride solution, 0.5 mg / mL), and the solution was magnetically stirred at 500 rpm for 2 h until fully dissolved. Then, 5 mL of CMC (carboxymethyl chitosan solution, 2 mg / mL, pH=6) was added dropwise (at a rate of 5 mL / min), and the solution was magnetically stirred at 500 rpm for 3 h. Then, 10 mL of β-lg (β-lactoglobulin solution, 5 mg / mL) was added dropwise (at a rate of 5 mL / min), and the solution was magnetically stirred at 500 rpm for 3.5 h. The resulting mixture was then stirred at 80 °C for 1 h, centrifuged at 10,000 rpm, and the supernatant was removed to prepare the theaflavins-chitosan / β-lactoglobulin nanocomposite material.

[0059] The encapsulation efficiency of TFs in the nanocomposite material prepared in this comparative example was 55%. Furthermore, after heating at 80℃, β-lactoglobulin deformed, leading to aggregation of the nanocomposite material.

[0060] Test Example 1

[0061] The theaflavin-chitosan / β-lactoglobulin nanocomposite material prepared in Example 1 was tested by SEM, TEM, FTIR and XRD.

[0062] Figure 1 SEM and TEM images of the theaflavin-chitosan / β-lactoglobulin nanocomposite material prepared in Example 1. Figure 1 The top center is the SEM image. Figure 1 The image below is a TEM image. It can be seen from the image that TFs-Cs / β-lg exhibits a relatively smooth spherical shape, a compact structure, and a particle size of about 200 nm.

[0063] Figure 2The images show the infrared spectra of Cs / β-lg, Cs, β-lg, TFs, and the theaflavin-chitosan / β-lactoglobulin nanocomposite material (TFs-Cs / β-lg) prepared in Example 1. As can be seen from the images, TFs-Cs / β-lg is formed by non-covalent interactions such as hydrogen bonding, electrostatic interactions, and hydrophobic interactions between TFs, Cs, and β-lg.

[0064] Figure 3 The figures show the XRD patterns of Cs / β-lg, Cs, β-lg, TFs, and the theaflavins-chitosan / β-lactoglobulin nanocomposite material (TFs-Cs / β-lg) prepared in Example 1. The figures show that TFs exhibits sharp crystalline peaks at 2θ of 28.4° and 31.9°, and broad diffuse peaks at 2θ of 8.5° and 19.3°. The diffuse and crystalline peaks of TFs are not observed in TFs-Cs / β-lg, and no new crystalline peaks appear in TFs-Cs / β-lg, indicating that TFs are dispersed in an amorphous state in Cs / β-lg.

[0065] Figure 4 Differential scanning calorimetry (DSC) curves of Cs / β-lg, Cs, β-lg, TFs, and the theaflavin-chitosan / β-lactoglobulin nanocomposite material (TFs-Cs / β-lg) prepared in Example 1 are shown. The curves reveal that TFs-Cs / β-lg, through steric hindrance and molecular encapsulation, delays the degradation of TFs by heating.

[0066] Test Example 2

[0067] (1) An in vitro release experiment was conducted on the theaflavins-chitosan / β-lactoglobulin nanocomposite material and theaflavins prepared in Example 1. The specific method was as follows: 2.5 mL of free theaflavins and the theaflavins-chitosan / β-lactoglobulin nanocomposite material were added to 6 mL of simulated gastric juice, the pH of the mixture was adjusted to 2.0, and dialyzed at 37°C for 6 h. Then, 6 mL of intestinal juice and 3 mL of bile were added, the pH of the mixture was adjusted to 7.0, and dialyzed at 37°C for 14 h.

[0068] Figure 5 This is a graph showing the in vitro release curves. The graph shows that the cumulative release rates of TFs and TFs-Cs / β-lg in simulated gastric fluid after 6 hours of dialysis were 79.1% and 21.2%, respectively. In simulated intestinal fluid, the cumulative release rates were 95.9% and 82.4%, respectively. By 20 hours of digestion, the cumulative release rates of both TFs and TFs-Cs / β-lg were above 99%. Furthermore, when the cumulative release rates of TFs-Cs / β-lg and TFs reached 99%, the release time of TFs-Cs / β-lg was 6 hours longer than that of TFs.

[0069] (2) Temperature stability experiments were conducted on the theaflavins-chitosan / β-lactoglobulin nanocomposite material and theaflavins prepared in Example 1: TFs-Cs / β-lg and TFs were stored at 80 degrees Celsius in the dark for 2 h and their retention rates were measured; TFs-Cs / β-lg and TFs were stored at 10-30 degrees Celsius in the dark for 90 days and their retention rates were measured; TFs-Cs / β-lg and TFs were stored at 4 degrees Celsius in the dark for 120 days and their retention rates were measured.

[0070] Figure 6 The figure shows the results of the stability experiment. It can be seen from the figure that the TFs-Cs / β-lg nanocomposite material can significantly improve the thermal stability of TFs.

[0071] Note: In Figures 1-6 In the accompanying figure, TFs-Cs / β-lg refers to the theaflavins-chitosan / β-lactoglobulin nanocomposite material prepared in Example 1, Cs refers to chitosan, β-lg refers to β-lactoglobulin, and TFs refers to theaflavins.

[0072] The preparation method of Cs / β-lg is as follows: At room temperature, 15 mL of CHC (chitosan hydrochloride solution, 0.5 mg / mL) and 5 mL of CMC (carboxymethyl chitosan solution, 2 mg / mL, pH=6) are mixed and magnetically stirred at 500 rpm for 3 h. Then, 10 mL of β-lg (β-lactoglobulin solution, 4 mg / mL) is added dropwise (dropping rate is 5 mL / min), and magnetically stirred at 500 rpm for 3.5 h. After centrifugation at 10000 rpm, the supernatant is removed to prepare Cs / β-lg.

[0073] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for encapsulating and releasing theaflavins using chitosan / β-lactoglobulin, characterized in that: The method includes: Theaflavins were first mixed with chitosan hydrochloride solution, then mixed with carboxymethyl chitosan solution, and then mixed with β-lactoglobulin solution. The mixture obtained from the third mixture was then centrifuged to obtain theaflavins-chitosan / β-lactoglobulin nanocomposite material. The pH value of the carboxymethyl chitosan solution is 5.8~6.

2.

2. The method for encapsulating and releasing theaflavins using chitosan / β-lactoglobulin according to claim 1, characterized in that: The pH value of the carboxymethyl chitosan solution is 6.

3. A method for encapsulating and releasing theaflavins using chitosan / β-lactoglobulin according to claim 1 or 2, characterized in that: The mass ratio of theaflavins to chitosan hydrochloride in the chitosan hydrochloride solution, carboxymethyl chitosan in the carboxymethyl chitosan solution, and β-lactoglobulin in the β-lactoglobulin solution is 1:1~3:1~3.5:9~15.

4. The method for encapsulating and releasing theaflavins using chitosan / β-lactoglobulin according to claim 3, characterized in that: The mass ratio of theaflavins to chitosan hydrochloride in the chitosan hydrochloride solution, carboxymethyl chitosan in the carboxymethyl chitosan solution, and β-lactoglobulin in the β-lactoglobulin solution is 1:1.4~2.2:1.4~2.8:10~13.

5. A method for encapsulating and releasing theaflavins using chitosan / β-lactoglobulin according to claim 1 or 2, characterized in that: The concentration of the chitosan hydrochloride solution is 0.4~0.6 mg / mL.

6. A method for encapsulating and releasing theaflavins using chitosan / β-lactoglobulin according to claim 1 or 2, characterized in that: The concentration of the carboxymethyl chitosan solution is 1.5~2 mg / mL.

7. A method for encapsulating and releasing theaflavins using chitosan / β-lactoglobulin according to claim 1 or 2, characterized in that: The concentration of the β-lactoglobulin solution is 4~6 mg / mL.

8. A method for encapsulating and releasing theaflavins using chitosan / β-lactoglobulin according to claim 1 or 2, characterized in that: The conditions for the first mixing include: a temperature of 10~30℃, a time of 1.5~3h, and a rotation speed of 400~600rpm; And / or, the conditions for the second mixing include: a temperature of 10~30℃, a time of 2~4h, and a rotation speed of 400~600rpm; And / or, the conditions for the third mixing include: a temperature of 10~30℃, a time of 3~4.5h, and a rotation speed of 400~600rpm.

9. The theaflavin-chitosan / β-lactoglobulin nanocomposite material prepared by the method according to any one of claims 1 to 8.

10. The chitosan / β-lactoglobulin nanocomposite material loaded with theaflavins according to claim 9, characterized in that: The particle size of the nanocomposite material is 150~400nm.

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