A quaternary ammonium cellulose / pectin / teaflavin compound, its preparation method and application

Abstract

The application belongs to the technical field of food processing and biological medicine, and particularly relates to a quaternary ammonium cellulose / pectin / teaflavin compound and a preparation method and application thereof. The quaternary ammonium cellulose / pectin / teaflavin compound takes quaternary ammonium cellulose and pectin as wall materials, and teaflavin as a loaded drug, and the three are self-assembled. Experimental results show that the obtained composite system has high encapsulation efficiency and loading capacity for teaflavin, the constructed quaternary ammonium cellulose / pectin / teaflavin compound has strong antioxidant performance and pH responsiveness, the strong antioxidant capacity effectively protects teaflavin from oxidative damage during delivery, and maintains the biological activity thereof; the pH responsiveness enables the compound to realize more efficient release of teaflavin in an acidic environment such as a tumor tissue or an inflammation site, thereby improving the targeting and treatment effect. Moreover, the preparation method of the compound is simple and has good repeatability, and is expected to provide a new reference method for the development of a drug delivery system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of food processing technology and biomedicine. More specifically, it relates to a quaternary ammonium cellulose / pectin / theaflavins complex, as well as its preparation method and application. BACKGROUND

[0002] Theaflavins (TFs), as an important component unique to black tea, have received extensive attention in the fields of food, cosmetics, medicine and health products in recent years due to their unique biological activity and pharmacological function. Theaflavins not only have significant antioxidant, anti-inflammatory, antibacterial and anticancer activities, but also exhibit various health benefits such as lowering blood lipids, reducing blood sugar, and protecting cardiovascular health. However, theaflavins also face problems such as poor chemical stability and low bioavailability in practical applications, which severely limits the full play of their efficacy.

[0003] To solve these problems, researchers have begun to explore the delivery system of theaflavins, aiming to improve their stability and bioavailability through scientific methods, so as to better realize their biological activity and pharmacological function. The design principles of the delivery system mainly include protecting theaflavins from environmental damage, controlling their release rate, and improving their absorption and distribution efficiency in the body.

[0004] In the research of theaflavins delivery system, various materials and technologies are widely used. For example, nanotechnology provides a new idea for the delivery of theaflavins. By preparing theaflavins nanoparticles or loading them into nanocarriers, the stability of theaflavins can be significantly improved, while their biological membrane permeability and cell uptake efficiency are also improved. However, most existing theaflavins delivery systems focus on the construction of single or binary complexes. For example, Chinese patent application CN117137142A discloses a theaflavins complex prepared by complexing theaflavins on beta-lactoglobulin through hydrogen bonds and hydrophobic interactions. This theaflavins complex can protect theaflavins from gastric acid, effectively ensuring the stability of theaflavins in the human gastrointestinal tract, and also can improve the biological activity of theaflavins and increase their bioavailability in the human body. However, most traditional binary complexes (such as the theaflavins complex of the above patent) still have obvious shortcomings in stability, encapsulation efficiency and loading capacity, which not only affect the physical stability of the complex, but also limit its application potential in the fields of antioxidant, drug delivery and functional food.

[0005] Therefore, there is an urgent need to construct a theaflavins delivery system with high stability, high encapsulation efficiency and high bioavailability. SUMMARY

[0006] The technical problem to be solved by the present application is to overcome the obvious deficiencies of the binary complex for theaflavin delivery in stability, encapsulation efficiency and loading capacity, which not only affects the physical stability of the complex, but also limits the application potential of the complex in the fields of antioxidant, drug delivery and functional food, and to provide a quaternized cellulose / pectin / theaflavin complex.

[0007] The present application aims to provide a preparation method of the quaternized cellulose / pectin / theaflavin complex.

[0008] Another object of the present application is to provide an application of the quaternized cellulose / pectin / theaflavin complex.

[0009] The above objects of the present application are achieved by the following technical solutions.

[0010] The present application protects a quaternized cellulose / pectin / theaflavin complex, which comprises quaternized cellulose, pectin and theaflavin, the quaternized cellulose / pectin / theaflavin complex takes quaternized cellulose and pectin as wall materials, and theaflavin as a loaded drug, and the three are formed by self-assembly.

[0011] The esterification degree of the pectin is > 50%. Compared with low-ester pectin (esterification degree < 50%), high-ester pectin can also maintain good solubility in a low-temperature environment. At the same time, under certain pH conditions, the complex prepared from high-ester pectin has a high zeta potential, which can maintain its stability.

[0012] Quaternized cellulose has a positive charge, while pectin and theaflavin usually have a negative charge. This charge difference enables them to be tightly combined through electrostatic interaction and other non-covalent bonds, forming a stable quaternized cellulose / pectin / theaflavin complex. The network structure formed by quaternized cellulose and pectin can effectively encapsulate theaflavin and slow down the release of theaflavin through electrostatic interaction and other non-covalent bonds and physical barrier effect. This slow-release mechanism is of great significance for prolonging the action time of theaflavin and improving its effect in specific applications.

[0013] Further, the self-assembly refers to the process of spontaneously assembling basic structural units (such as molecules, nanomaterials, micromaterials or larger scale substances) into polymers through the interaction of non-covalent bonds (such as electrostatic interaction force, hydrogen bond, van der Waals force, hydrophobic interaction, etc.).

[0014] Further, the quaternized cellulose / pectin / theaflavin complex further comprises a crosslinking agent. By adding a crosslinking agent, the stability of the complex can be further enhanced. The crosslinking agent can promote the non-covalent bonding between quaternized cellulose, pectin and theaflavin, thereby improving the structural strength of the obtained complex.

[0015] Preferably, the cross-linking agent comprises a sucrose-hydrogen peroxide solution, a sucrose-periodate solution or tannic acid.

[0016] Further, the preparation method of the sucrose-hydrogen peroxide solution comprises the following steps: reacting sucrose with a hydrogen peroxide solution (the concentration of the hydrogen peroxide solution is preferably 0.3-1.5 vol%) at a solid-liquid ratio of 1:(2.5-10) g / mL, and obtaining the sucrose-hydrogen peroxide solution after sufficient reaction.

[0017] Preferably, the time for the sufficient reaction is 12-72 h.

[0018] Specifically, the preparation method of the quaternary ammonium cellulose comprises the following steps: adding cellulose into a cellulose swelling promoter, filtering after sufficient soaking, adding a quaternary ammonization reagent into the filtrate, and obtaining the quaternary ammonium cellulose after sufficient reaction. By chemically modifying the cellulose, quaternary ammonium groups are introduced to enhance the positive charge. This step is crucial for the subsequent formation of stable complexes with the negatively charged pectin and theaflavins.

[0019] Preferably, the cellulose swelling promoter comprises one or more of sodium hydroxide, urea, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), tetraethylammonium hydroxide (TEAOH), aqueous ammonia, and potassium hydroxide.

[0020] Preferably, the quaternary ammonization reagent comprises one or more of 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTA), glycidyltrimethylammonium chloride (GTMAC), 2,3-epoxypropyltrimethylammonium chloride (GTAC), N,N,N',N'-tetramethyl-1,6-hexanediamine (TMHDA), triethylamine (TEA), and trimethylamine (TMA).

[0021] Preferably, the cellulose is selected from bacterial cellulose, plant cellulose or microcrystalline cellulose, and more preferably is bacterial cellulose. The quaternary ammonium cellulose obtained by quaternary ammonization of the above types of cellulose can be used to prepare a relatively stable ternary complex with high-ester pectin.

[0022] Preferably, the mass ratio of the quaternary ammonium cellulose, the pectin and the theaflavins is 1:(10-250):(1-120).

[0023] More preferably, the mass ratio of the quaternary ammonium cellulose, the pectin and the theaflavins is 1:(25-100):(5-100).

[0024] Further more preferably, the mass ratio of the quaternary ammonium cellulose, the pectin and the theaflavins is 1:(25-100):(10-100).

[0025] Further, the pectin is extracted from the pectin-rich raw material by acid extraction.

[0026] Specifically, the preparation method of the pectin comprises the following steps: mixing the pectin-rich raw material with the organic acid at a solid-liquid ratio of 1:(10-30) g / mL, fully extracting, filtering, mixing the filtrate with an ethanol solution, fully precipitating, filtering, and taking the precipitate for post-treatment.

[0027] Further, the pectin-rich raw material comprises one or more of pomelo sponge layer powder, potato peel, apple peel, and citrus peel. The pectin extracted from different sources is all high-ester pectin, and the prepared complex has basically the same effect.

[0028] Further, the pomelo sponge layer powder is obtained by crushing the white sponge layer (also known as the meridian or endothelium of pomelo) on the dried pomelo peel.

[0029] Further, the organic acid comprises one or more of citric acid, acetic acid, and tartaric acid.

[0030] Further, the concentration of the ethanol solution is 30-99.5 vol %.

[0031] Further, the mixing method is ultrasonic mixing.

[0032] The application also protects a preparation method of the quaternary ammonium cellulose / pectin / tea polyphenol complex, comprising the following steps:

[0033] S1. dispersing tea polyphenol and quaternary ammonium cellulose in water, fully mixing, and allowing the tea polyphenol to fully adsorb into the quaternary ammonium cellulose to obtain a tea polyphenol-quaternary ammonium cellulose complex;

[0034] S2. mixing the tea polyphenol-quaternary ammonium cellulose complex obtained in step S1 with a pectin solution, fully reacting, and obtaining the quaternary ammonium cellulose / pectin / tea polyphenol complex.

[0035] Further, as a preferred method, the preparation method of the quaternary ammonium cellulose / pectin / tea polyphenol complex comprises the following steps:

[0036] S1. dispersing tea polyphenol and quaternary ammonium cellulose in water, fully mixing, and allowing the tea polyphenol to fully adsorb into the quaternary ammonium cellulose to obtain a tea polyphenol-quaternary ammonium cellulose complex;

[0037] S2. mixing the tea polyphenol-quaternary ammonium cellulose complex obtained in step S1 with a pectin solution and a crosslinking agent, fully reacting, and obtaining the quaternary ammonium cellulose / pectin / tea polyphenol complex.

[0038] Further, in the above preparation method, a basic reagent, an acidic reagent or a buffer can be added to adjust the pH of the mixed system. The change of pH will affect the charge state of the quaternary ammonium cellulose, pectin and theaflavins, and further affect the interaction between them and the stability of the formed complex. Within a specific pH range, the charge state of these components is more conducive to the formation of stable complexes.

[0039] Further, the pH range is 2-8, preferably the pH range is 2-6, more preferably 2-4.

[0040] The above preparation can form quaternary ammonium cellulose / pectin / theaflavins complex with high encapsulation efficiency and loading capacity under a wide range of pH conditions. This high encapsulation efficiency and loading capacity can ensure that more TFs are successfully encapsulated and delivered to the target site, improving the therapeutic effect. Since theaflavins itself has better antioxidant capacity under acidic conditions, the antioxidant capacity of theaflavins solution alone decreases significantly as the pH increases. After encapsulation, theaflavins still has certain antioxidant capacity under alkaline conditions, and the decrease in antioxidant capacity is significantly reduced.

[0041] Further, the acidic reagent includes hydrochloric acid, sulfuric acid, acetic acid, citric acid.

[0042] Further, the basic reagent includes sodium hydroxide, potassium hydroxide, ammonium hydroxide, disodium hydrogen phosphate, ammonia.

[0043] Further, the buffer includes any one of acetate buffer (acetic acid-sodium acetate or acetic acid-ammonium acetate), citrate buffer (citric acid-sodium citrate), phosphate buffer (one or more of sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate), borate buffer (boric acid-potassium chloride, boric acid-calcium chloride, borax-calcium chloride or borax-sodium carbonate), disodium hydrogen phosphate-citric acid buffer, sodium carbonate-sodium bicarbonate buffer, potassium dihydrogen phosphate-sodium hydroxide buffer, PBS buffer (sodium chloride-disodium hydrogen phosphate-potassium dihydrogen phosphate).

[0044] Further, in the above preparation method of quaternary ammonium cellulose / pectin / theaflavins complex, the sufficient reaction time is 3-8h.

[0045] Preferably, the sufficient reaction temperature is 15°C or below to avoid oxidation of theaflavins during preparation.

[0046] Further, after sufficient reaction, ultrasonic treatment can be performed to further disperse the obtained complex, so as to obtain more uniform and smaller complex particles.

[0047] Preferably, the ultrasonic treatment time is 10-60min.

[0048] Preferably, in step S1, the concentration of theaflavins in the theaflavins-quaternized cellulose complex is 0.1-15 mg / mL (more preferably 0.5-10 mg / mL), and the concentration of the quaternized cellulose is 0.01-2 mg / mL (more preferably 0.05-1 mg / mL).

[0049] Preferably, in step S2, the concentration of the pectin solution is 5-15 mg / mL, more preferably 8-12 mg / mL.

[0050] Preferably, the amount of the crosslinking agent added is 10-20 vol% (more preferably 12-18 vol%) based on the volume percentage of the quaternized cellulose / pectin / theaflavins complex.

[0051] The application also protects the use of the quaternized cellulose / pectin / theaflavins complex in the preparation of a medicine, health product or cosmetic product.

[0052] Compared with the prior art, the application has the following beneficial effects:

[0053] The quaternized cellulose / pectin / theaflavins complex of the application uses quaternized cellulose and pectin as wall materials, and theaflavins as the loaded drug, and the three are self-assembled. Experimental results show that the obtained complex system has a high encapsulation rate and loading capacity for theaflavins, and the constructed quaternized cellulose / pectin / theaflavins complex has strong antioxidant properties and pH responsiveness. The strong antioxidant capacity effectively protects theaflavins from oxidative damage during delivery, thereby maintaining its biological activity. The pH responsiveness enables the complex to achieve more efficient release of theaflavins in an acidic environment such as a tumor tissue or an inflammation site, thereby improving the targeting and treatment effect of the treatment. Moreover, the preparation method of the complex is simple and has good repeatability, and is expected to provide a new reference method for the development of a drug delivery system. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 The appearance of CBC / TFs, PAPP / TFs and CBC / PAPP / TFs after fresh preparation (left) and 40 days of storage (right), respectively.

[0055] Figure 2 The infrared spectrograms of the self-made pectin of pomelo sponge layer (PAPP) and the commercial pectin (PT).

[0056] Figure 3 The appearance of CBC / PAPP / TFs prepared at different pH values.

[0057] Figure 4Statistical graphs of particle size (A), antioxidant capacity (B) and bioaccessibility (C) of CBC / PAPP / TFs prepared in Example 3 in simulated gastrointestinal fluid digestion environment. (Note: different lower case letters in the figure represent significant difference (p <0.05), the same letter or no letter represents no significant difference (p >0.05). DETAILED DESCRIPTION

[0058] The present application will be further described by the following description of the drawings and specific examples, but the examples do not limit the present application in any form. Unless otherwise specified, the reagents, methods and equipment used in the present application are conventional reagents, methods and equipment in the technical field.

[0059] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0060] Pomelo spongy layer powder: Take the white spongy layer (also known as the meridian or endothelium of pomelo) on the commercially available dried honey pomelo peel, crush it, and you get pomelo spongy layer powder.

[0061] Commercial pectin (PT) was purchased from Shanghai Yuan Ye Biotechnology Co., Ltd.

[0062] Bacterial cellulose was purchased from Hainan Yide Food Co., Ltd.

[0063] Example 1 Preparation of quaternary ammonium bacterial cellulose

[0064] (1) Quaternary ammonium treatment of bacterial cellulose: 0.06 g of bacterial cellulose was added to 300 mL of an aqueous solution containing 7 wt% NaOH and 12 wt% urea and subjected to 10000 rpm homogenization treatment for 2 min, followed by magnetic stirring for 1 h reaction, and then frozen for storage. After taking it out, continue magnetic stirring for 1.5-5 h reaction, centrifuge the suspension at 8000-10000 r / min for 10-20 min to achieve solid-liquid separation, and continue to repeat the above steps for the solid part; add CHPTAC (3-chloro-2-hydroxypropyltrimethylammonium chloride) to the clarified solution to make its concentration in the system 1 wt%, and continuously stir the mixture at 30°C for 24 h to complete the surface quaternization of nanocellulose, to obtain quaternary ammonium bacterial cellulose (CBC).

[0065] Example 2 Preparation of pomelo-derived pectin (esterification degree > 50%)

[0066] The pomelo peel sponge layer powder was mixed with a citric acid solution at a certain solid-liquid ratio (1 g:30 mL) for dilution, ultrasonic treatment for 10 min, stirring in a water bath at a certain temperature using a hot plate magnetic stirrer for 12 min, and solid-liquid separation by suction filtration to obtain a filtrate; 95% ethanol was mixed with the obtained filtrate at a volume ratio of 1:1 to obtain a mixture, and the obtained mixture was left to stand at room temperature for 4 h before solid-liquid separation; the precipitate was taken and washed with 45% ethanol for 3 times, the ethanol was removed, and vacuum freeze drying was performed to obtain pomelo peel-derived pectin (PAPP) with a degree of esterification >50%, which is a high-ester pectin.

[0067] Example 3 Preparation of quaternized bacterial cellulose / pectin / TFs complex CBC / PAPP / TFs

[0068] Preparation of PAPP solution: PAPP (prepared according to the method of Example 2) was dispersed in distilled water and stirred in a 30°C water bath for 12 h to ensure its dissolution to obtain a PAPP solution with a concentration of 1 wt% (i.e. 10 mg / mL).

[0069] Preparation of sucrose-hydrogen peroxide solution: 20 g of sucrose was added to 100 mL of 0.6 vol% hydrogen peroxide solution after reaction to obtain.

[0070] Preparation of quaternized bacterial cellulose / pectin / TFs complex CBC / PAPP / TFs: CBC (prepared according to the method of Example 1) and TFs (TFs) were weighed and dispersed in ultrapure water together, and stirred in a 15°C water bath for 2 h to obtain a TFs-CBC dispersion (the concentration of TFs was 2 mg / mL, and the concentration of CBC was 0.2 mg / mL), and then the TFs-CBC dispersion was added to the above PAPP solution at a volume ratio of 1:1 under continuous stirring, 15 vol% sucrose-hydrogen peroxide solution was added as a crosslinking agent, and the system was stirred in an ice water bath for 4 h after ultrasonic treatment (with an ice bag or ice to ensure a lower water temperature, at 15°C or below) for 15 min, and ultrasonic treatment for 30 min again to obtain quaternized bacterial cellulose / pectin / TFs complex CBC / PAPP / TFs (the pH of the system was 3.58).

[0071] After the above freshly prepared CBC / PAPP / TFs was placed under refrigeration conditions (4°C) for 40 days (d), the obtained complex CBC / PAPP / TFs was named as CBC / PAPP / TFs-40d.

[0072] Example 4 Preparation of quaternized bacterial cellulose / pectin / TFs complex CBC / PAPP / TFs under different pH conditions

[0073] Preparation of PAPP solution: PAPP (prepared according to the method of Example 2) was dispersed in phosphate-citric acid buffer at different pH (pH 2.2, 3.4, 4.0, 4.6, 5.2, 5.8, 7.0, 8.0) and stirred in a water bath at 30°C for 12 h to ensure its dissolution, obtaining PAPP solution at different pH with a concentration of 1 wt% (i.e. 10 mg / mL).

[0074] Preparation of sucrose-hydrogen peroxide solution: 20 g of sucrose was added to 100 mL of 0.6 vol% hydrogen peroxide solution after reaction.

[0075] Preparation of quaternized bacterial cellulose / pectin / TFs complex CBC / PAPP / TFs: CBC (prepared according to the method of Example 1) and TFs (TFs) were weighed and dispersed together in phosphate-citric acid buffer at different pH (pH 2.2, 3.4, 4.0, 4.6, 5.2, 5.8, 7.0, 8.0) and stirred in a water bath at 15°C for 2 h, obtaining TFs-CBC dispersion at different pH (the concentration of TFs was 2 mg / mL and the concentration of CBC was 0.2 mg / mL), then 15 wt% sucrose-hydrogen peroxide solution was added as a crosslinking agent, and the system was ultrasonically treated (with ice bag or ice to ensure low water temperature, at 15°C or below) for 15 min, then stirred in an ice water bath for 4 h, and ultrasonically treated again for 30 min, obtaining quaternized bacterial cellulose / pectin / TFs complex CBC / PAPP / TFs prepared at different pH.

[0076] Example 5 Preparation of quaternized bacterial cellulose / pectin / TFs complex CBC / PAPP / TFs loaded with different content of TFs

[0077] Preparation of PAPP solution: PAPP (prepared according to the method of Example 2) was dispersed in distilled water and stirred in a water bath at 30°C for 12 h to ensure its dissolution, obtaining PAPP solution with a concentration of 1 wt% (i.e. 10 mg / mL).

[0078] Preparation of sucrose-hydrogen peroxide solution: 20 g of sucrose was added to 100 mL of 0.6 vol% hydrogen peroxide solution after reaction.

[0079] Preparation of quaternary ammonium bacterial cellulose / pectin / TFs composite CBC / PAPP / TFs: CBC (prepared according to the method of Example 1) and different amounts of TFs (TFs) were weighed and dispersed in ultrapure water, and stirred at 15°C for 2h to obtain TFs-CBC dispersion solutions with different TFs contents (the concentrations of TFs were 1, 2, 5, 10, and 20mg / mL, and the concentration of CBC was 0.2mg / mL), and then under continuous stirring, different TFs-CBC solutions with different TFs contents were added to the above PAPP solution (the final concentrations of TFs were 0.5, 1, 2.5, 5, and 10mg / mL, where the final concentration refers to the concentration of TFs in the system before the addition of the crosslinking agent) at a volume ratio of 1:1, 15vol% sucrose-hydrogen peroxide solution was added as a crosslinking agent, and the system was ultrasonically treated (with ice bags or ice to ensure low water temperature, at 15°C or below) for 15min, then the system was stirred in an ice water bath for 4h, and then ultrasonically treated for another 30min to obtain quaternary ammonium bacterial cellulose / pectin / TFs composite CBC / PAPP / TFs with different TFs contents.

[0080] Example 6 Preparation of quaternary ammonium bacterial cellulose / pectin / TFs composite CBC / PAPP / TFs with different wall material mass ratios

[0081] Preparation of PAPP solution: PAPP (prepared according to the method of Example 2) was weighed and dispersed in distilled water, and stirred at 30°C for 12h to ensure its dissolution, to obtain a PAPP solution with a concentration of 1wt% (i.e. 10mg / mL).

[0082] Preparation of sucrose-hydrogen peroxide solution: 20g of sucrose was added to 100mL of 0.6vol% hydrogen peroxide solution after reaction to obtain.

[0083] Preparation of quaternary ammonium bacterial cellulose / pectin / TFs composite CBC / PAPP / TFs: Different mass of CBC and TFs (TFs) were weighed and dispersed in ultrapure water, and stirred at 15 °C for 2 h to obtain different concentrations of TFs-CBC dispersion (the concentration of TFs was 2 mg / mL, and the concentration of CBC was 0.05, 0.1, 0.2, 0.4, and 0.8 mg / mL, respectively). Then, the above different concentrations of TFs-CBC solution were added to the PAPP solution in a volume ratio of 1:1, and 15 vol% sucrose-hydrogen peroxide solution was added as a crosslinking agent. After ultrasonic treatment (with ice bag or ice to ensure lower water temperature, at 15 °C or below) for 15 min, the system was stirred at ice water bath for 4 h, and then ultrasonic treatment was performed again for 30 min to obtain quaternary ammonium bacterial cellulose / pectin / TFs composite CBC / PAPP / TFs with different wall material mass ratios.

[0084] Preparation of PAPP / TFs composite of pectin / TFs

[0085] Preparation of PAPP solution: PAPP (prepared according to the method of Example 2) was dispersed in distilled water and stirred at 30 °C for 12 h to ensure its dissolution to obtain a PAPP solution with a concentration of 1 wt% (i.e., 10 mg / mL).

[0086] Preparation of sucrose-hydrogen peroxide solution: 20 g of sucrose was added to 100 mL of 0.6 vol% hydrogen peroxide solution after reaction to obtain.

[0087] Preparation of PAPP / TFs composite of pectin / TFs: TFs were dispersed in the PAPP solution and stirred at 15 °C for 2 h to obtain a TFs-PAPP dispersion (the concentration of TFs was 1 mg / mL, and the concentration of PAPP was 5 mg / mL). Then, 15 vol% sucrose-hydrogen peroxide solution was added as a crosslinking agent, and ultrasonic treatment (with ice bag or ice to ensure lower water temperature, at 15 °C or below) was performed for 15 min. After stirring at ice water bath for 4 h, the system was ultrasonically treated again for 30 min to obtain the PAPP / TFs composite of pectin / TFs.

[0088] After the above freshly prepared PAPP / TFs was placed in a refrigerated condition (4 °C) for 40 days, the obtained composite PAPP / TFs was named PAPP / TFs-40d.

[0089] Preparation of quaternary ammonium bacterial cellulose / TFs composite CBC / TFs

[0090] Preparation of sucrose-hydrogen peroxide solution: 20 g of sucrose was added to 100 mL of 0.6 vol% hydrogen peroxide solution to obtain after reaction.

[0091] Preparation of quaternized bacterial cellulose / tea polyphenols composite CBC / TFs: CBC and TFs were dispersed in ultrapure water and stirred for 2 h in a water bath at 15 °C to obtain a TFs-CBC dispersion (the concentration of TFs was 1 mg / mL and the concentration of CBC was 0.1 mg / mL). 15 vol% sucrose-hydrogen peroxide solution was added as a crosslinking agent. After ultrasonic treatment (with an ice bag or ice to ensure a lower water temperature, at 15 °C or below) for 15 min, the system was stirred in an ice water bath for 4 h. After ultrasonic treatment for 30 min again, quaternized bacterial cellulose / tea polyphenols composite CBC / TFs was obtained.

[0092] After the above freshly prepared CBC / TFs was placed in a refrigerated condition (4 °C) for 40 days, the obtained composite CBC / TFs was named CBC / TFs-40d.

[0093] Preparation of quaternized bacterial cellulose / chitosan / tea polyphenols composite CS / PAPP / TFs

[0094] The difference from Example 3 is that CBC is replaced with an equal amount of chitosan (CS) to obtain quaternized bacterial cellulose / chitosan / tea polyphenols composite CS / PAPP / TFs.

[0095] Other conditions and parameters are consistent with Example 3.

[0096] Preparation of bacterial cellulose / pectin / tea polyphenols composite BC / PAPP / TFs

[0097] The difference from Example 3 is that CBC is replaced with an equal amount of bacterial cellulose (BC) to obtain bacterial cellulose / pectin / tea polyphenols composite BC / PAPP / TFs.

[0098] Other conditions and parameters are consistent with Example 3.

[0099] Preparation of quaternized bacterial cellulose / carrageenan / tea polyphenols composite CBC / CG / TFs

[0100] The difference from Example 3 is that PAPP is replaced with an equal amount of carrageenan (CG) to obtain quaternized bacterial cellulose / carrageenan / tea polyphenols composite CBC / CG / TFs.

[0101] Other conditions and parameters are consistent with Example 3.

[0102] Preparation of quaternized bacterial cellulose / xanthan gum / tea flavonoid composite CBC / XG / TFs

[0103] The difference from Example 3 is that PAPP is replaced by an equal amount of xanthan gum (XG) to obtain quaternized bacterial cellulose / xanthan gum / tea flavonoid composite CBC / XG / TFs.

[0104] Other conditions and parameters are the same as in Example 3.

[0105] Preparation of quaternized bacterial cellulose / gellan gum / tea flavonoid composite CBC / GG / TFs

[0106] The difference from Example 3 is that PAPP is replaced by an equal amount of gellan gum (GG) to obtain quaternized bacterial cellulose / gellan gum / tea flavonoid composite CBC / GG / TFs.

[0107] Other conditions and parameters are the same as in Example 3.

[0108] Preparation of quaternized bacterial cellulose / pectin / tea flavonoid composite CBC / PT / TFs

[0109] The difference from Example 3 is that PAPP is replaced by an equal amount of commercial pectin (PT, degree of esterification < 50%, which is a low-ester pectin) to obtain quaternized bacterial cellulose / pectin / tea flavonoid composite CBC / PT / TFs.

[0110] Other conditions and parameters are the same as in Example 3.

[0111] Preparation of quaternized bacterial cellulose / pectin / tea polyphenol composite CBC / PAPP / TPs

[0112] The difference from Example 3 is that TFs is replaced by an equal amount of tea polyphenol (TPs) to obtain quaternized bacterial cellulose / pectin / tea polyphenol composite CBC / PAPP / TPs.

[0113] Other conditions and parameters are the same as in Example 3.

[0114] Preparation of quaternized bacterial cellulose / pectin / proanthocyanidin composite CBC / PAPP / Pas

[0115] The difference from Example 3 is that TFs is replaced by an equal amount of proanthocyanidin (Pas) to obtain quaternized bacterial cellulose / pectin / proanthocyanidin composite CBC / PAPP / Pas.

[0116] Other conditions and parameters are the same as in Example 3.

[0117] Determination of physicochemical properties of the composite

[0118] 1. Experimental method

[0119] (1) Measurement of particle size and Zeta potential

[0120] The particle size, Zeta potential and PDI value (polydispersity index) of the complex solution were measured by using a nano particle size and Zeta potential instrument (Zetasizer nano ZS).

[0121] (2) Encapsulation rate and loading capacity of polyphenols

[0122] The amount of polyphenols in the complex was quantified using the Folin-phenol method, and taking theaflavins TFs as an example: 1 mL of TFs-loaded complex dispersion was centrifuged at 20,000 rpm for 20 min, 0.4 mL of supernatant, 0.2 mL of Folin-phenol reagent and 0.6 mL of sodium carbonate solution (20 wt%) were mixed, and the volume was made up to 10 mL, and the mixture was placed in a 30°C water bath in the dark for 0.5 h, and the absorbance at 765 nm was measured. The determination of the encapsulation rate and loading capacity of other polyphenols is basically the same as the above method, except that the polyphenol content is calculated using the corresponding standard curve.

[0123] Determination of polyphenol content standard curve: First, prepare a 50 mg / 10 mL theaflavins (or tea polyphenols, anthocyanins) solution (then take 50, 40, 30, 20, 10, 0 uL, and finally add water to make the system 1000 uL, then take 0.4 mL for testing), 0.2 mL of Folin-phenol reagent and 0.6 mL of sodium carbonate solution (20 wt%) are mixed, and the volume is made up to 10 mL, and the mixture is placed in a 30°C water bath in the dark for 0.5 h, and the absorbance at 765 nm is measured. The absorbance value is substituted into the y value of the standard curve to calculate the x value, which is the theaflavins (or tea polyphenols, anthocyanins) content (mg / 10 mL).

[0124] Tea polyphenol standard curve: y = 0.0909x - 0.0019, R 2 = 0.9955

[0125] Anthocyanin standard curve: y = 0.0599x - 0.0005, R 2 = 0.9998

[0126] Theaflavins standard curve: y = 0.1948x + 0.0046, R 2 = 0.9987

[0127] Encapsulation rate (%) = (total polyphenol addition amount - free polyphenol content in supernatant) / total polyphenol addition amount

[0128] x 100% formula (1)

[0129] Loading capacity (mg / mL) = Encapsulated polyphenol content (mg) / Complex dispersion liquid volume (mL) Formula (2)

[0130] Wherein, the encapsulated polyphenol content = total polyphenol addition amount - free polyphenol content in supernatant.

[0131] (3) Determination of antioxidant capacity (DPPH)

[0132] The complex dispersion liquid reference fruit juice, wine and other samples: according to the sample: nitrogen radical extraction liquid = 1:9 ratio of shaking mixed, 10000 rpm centrifugation for 10 min, take supernatant for standby, 4℃ preservation standby, specific test parameters refer to table 1.

[0133] Table 1 test parameters

[0134] Nitrogen radical extraction solution DPPH Sample supernatant Anhydrous ethanol Blank A0 25 uL 225 uL / / Sample A 样 ]] / 225 uL 25 uL - Control A 对 ]] / / 25 uL 225 uL

[0135] DPPH radical scavenging rate (%) = (A0- (A 样 -A 对 )) / A0×100% Formula (3)

[0136] The particle size, potential, PDI, encapsulation efficiency, loading capacity and antioxidant capacity of the complex particles obtained by the present application were determined according to the above method, and the results are shown in Tables 2-9.

[0137] 2. Experimental results

[0138] (1) Comparison of physicochemical properties of binary complex and ternary complex

[0139] Table 2 Determination results of physicochemical properties of binary complex and ternary complex

[0140]

[0141] Note: The same column on the same column with different lowercase letters indicates significant difference (p<0.05), and the same letter or no letter indicates no significant difference (p>0.05).

[0142] As can be seen from Table 2, the particle size (p<0.05), PDI and potential absolute value (p<0.05) of the ternary complex prepared on the same day are better than those of the two binary complexes.

[0143] For binary complex CBC / TFs: The particle size of the CBC / TFs complex prepared on the same day was measured to be 1461.00 ± 44.91 nm, showing a relatively large particle size. However, after 40 days of storage, its particle size was significantly reduced to 1197.00 ± 170.89 nm. This change is likely due to the significant depolymerization of the complex during storage. In addition, stratification of the dispersion was observed during long-term storage (see Figure 1 ), which is an intuitive evidence of depolymerization. Moreover, the PDI is still large, which reflects that during the depolymerization process, the particle size distribution is extensive, both a large number of small particles are generated, and there may be some large particles that are not completely depolymerized or newly formed aggregates.

[0144] For binary complex PAPP / TFs: The particle size of the complex prepared on the same day was 1105.40 ± 133.21 nm, which decreased to 844.75 ± 24.15 nm after 40 days, and the PDI increased from 0.500 ± 0.030 to 0.580 ± 0.050. This indicates that some large particles may have depolymerized, but at the same time, there is a particle aggregation phenomenon, and the particle distribution is uneven, leading to a decrease in particle size and an increase in PDI.

[0145] For ternary complex CBC / PAPP / TFs: The complex may have undergone slight aggregation during storage, resulting in a slight increase in particle size, but the increase is not significant, and the particle size is still at the nanometer level (<1000 nm), and the particle distribution is still relatively uniform (PDI <0.5), maintaining a low overall level.

[0146] The higher the absolute value of the zeta potential, the more stable the surface charge, which helps to prevent particle aggregation. In comparison, the absolute value of the zeta potential of CBC / PAPP / TFs is the largest (34.65 ± 2.24 mV to 30.60 ± 0.65 mV), which has good stability and is not prone to aggregation (see Figure 1 ).

[0147] The encapsulation efficiency and loading capacity of all complexes decreased after storage, but the decrease in CBC / PAPP / TFs was the smallest, and from Figure 1 it can be seen that the complex system has a good embedding effect on theaflavins, and after long-term storage, neither stratification nor obvious discoloration of the complex system occurred, indicating that it has good long-term stability, can effectively protect theaflavins, and avoid their oxidation and discoloration. Although the encapsulation efficiency and loading capacity of the binary complex CBC / TFs before and after storage did not differ significantly from those of the ternary complex CBC / PAPP / TFs, from Figure 1It can be seen that the obvious stratification phenomenon appeared after a period of storage, which indicated that the embedding system was unstable and could not achieve the stable encapsulation of theaflavins. In addition, the encapsulation efficiency and loading capacity of the binary complex PAPP / TFs decreased significantly after storage, and the color of the system became significantly darker, which indicated that more theaflavins were released from the embedding system, and the long-term stability of the complex system was poor.

[0148] In summary, the CBC / PAPP / TFs complex showed better performance in uniformity, stability, encapsulation efficiency and loading capacity, which was due to the complex structure composed of CBC, PAPP and TFs, which could better protect theaflavins from environmental factors.

[0149] (2) Performance comparison of ternary complexes prepared from different esterification degree pectins

[0150] The Fourier transform infrared spectroscopy (FT-IR) instrument was set to a wave number range of 4000 to 500 cm -1 . The esterification degree (DM) was calculated by integrating the area of the corresponding wave number range:

[0151] DM = A 1740 / (A 1630-1600 -A 1740 )*100%

[0152] Table 3 Determination results of CBC / PAPP / TFs and CBC / PT / TFs ternary complexes prepared from pectins with different esterification degrees

[0153]

[0154] Note: The same column indicates significant difference (p < 0.05) between different lowercase letters, and the same or no letters indicate no significant difference (p > 0.05).

[0155] Through FT-IR determination and comparison of the corresponding infrared spectra of self-made PAPP and commercial PT, it was found that the spectrum peaks of the two pectins near 1740 cm -1 and 1630-1600 cm -1 were different. Figure 2) Area integration was performed to obtain the esterification degree of PAPP as 54.55%, i.e. high ester pectin (DM>50%); while the esterification degree of commercial PT was 15.36%, i.e. low ester pectin (DM<50%). Meanwhile, from Table 3, it can be seen that the comparison of the prepared complexes of the two kinds of pectin shows that the CBC / PAPP / TFs prepared based on high ester pectin has smaller particle size (672.00±68.38 nm), PDI (0.404±0.012) and larger absolute value of Zeta potential (-34.65±2.24 mV), indicating that the CBC / PAPP / TFs prepared based on high ester pectin has better uniformity and stability. The absolute value of the potential of CBC / PT / TFs prepared based on low ester pectin is lower than 15 mV, and the PDI value is also higher, and the uniformity and stability are poor, and it is easy to stratify or aggregate, which is not conducive to long-term storage and subsequent further use.

[0156] (3) Comparison of physicochemical properties of ternary complexes prepared using BC, CS and CBC

[0157] Table 4 Determination results of physicochemical properties of ternary complexes prepared using BC, CS and CBC

[0158] Group Complex Size (nm) PDI Zeta (mV) Encapsulation efficiency (%) Loading capacity (mg / mL) Example 3 CBC / PAPP / TFs 672.00 ± 68.38 b ]] 0.404 ± 0.012 b ]] -34.65 ± 2.24 a ]] 83.41 ± 2.85 a ]] 0.7252 ± 0.0248 a ]] Comparative Example 3 CS / PAPP / TFs 776.00 ± 3.07 a ]] 0.527 ± 0.017 a ]] -26.65 ± 0.60 b ]] 73.79 ± 0.78 b ]] 0.6417 ± 0.0069 b ]] Comparative Example 4 BC / PAPP / TFs 792.60 ± 15.06 a ]] 0.435 ± 0.004 b ]] -24.10 ± 0.77 b ]] 74.03 ± 0.03 b ]] 0.6437 ± 0.0003 b ]]

[0159] Note: Different lower-case letters on the same column indicate significant difference (p<0.05), and the same letter or no letter indicates no significant difference (p>0.05).

[0160] The data of the three complexes (CS / PAPP / TFs, BC / PAPP / TFs, CBC / PAPP / TFs) can be analyzed from the aspects of particle size, polydispersity index (PDI), Zeta potential, encapsulation efficiency and loading capacity, and the results are shown in Table 4.

[0161] From the particle size and PDI data, the PDI value of CS / PAPP / TFs is the highest (0.527±0.017), indicating that its particle size distribution is relatively wide, and its stability and uniformity are poor. The PDI values of BC / PAPP / TFs and CBC / PAPP / TFs are lower and similar (0.435±0.004 and 0.404±0.012, respectively), indicating that their particle size distribution is relatively more uniform, and they have better stability and consistency.

[0162] From the zeta potential data, the absolute value of the zeta potential of CBC / PAPP / TFs was the largest (34.65±2.24 mV), which was significantly higher than that of BC / PAPP / TFs and CBC / PAPP / TFs, indicating that CBC / PAPP / TFs had better charge stability and more significant electrostatic interaction, which helped to prevent the aggregation between particles and thus maintained the stable dispersion state of the complex.

[0163] CBC / PAPP / TFs showed the highest encapsulation efficiency (83.41±2.85%) and loading level, which indicated its excellent ability to encapsulate target substances, while the loading capacity of CS / PAPP / TFs and BC / PAPP / TFs was relatively low.

[0164] In summary, TFs-CBC-PAPP showed better performance in terms of particle size distribution uniformity, potential stability, encapsulation efficiency, and loading capacity, and was a more advantageous complex for loading teaflavins.

[0165] (4) Comparison of physicochemical properties of ternary complexes prepared under different anionic polysaccharides

[0166] Table 5 Determination results of physicochemical properties of ternary complexes prepared under different anionic polysaccharides

[0167]

[0168]

[0169] Note: Different lower case letters on the same column indicate significant differences (p<0.05), and the same letters or no letters indicate no significant differences (p>0.05).

[0170] The physicochemical properties of ternary complexes prepared under different anionic polysaccharides are shown in Table 5. The particle size of CBC / PAPP / TFs prepared from self-made pectin (PAPP) was the smallest (672.00±68.38 nm), and the absolute value of the zeta potential was 34.65±2.24 mV (the absolute value of the zeta potential >25), indicating that it had good stability and uniformity. Although the zeta potential values of gellan gum (GG), carrageenan (CG), and xanthan gum (XG) were higher, their particle sizes were larger and / or the PDI values were >0.5, which was not conducive to the digestion and absorption of the complex particles in the gastrointestinal tract of the human body.

[0171] (5) Comparison of physicochemical properties of ternary complexes loaded with different polyphenols

[0172] Table 6 Determination results of physicochemical properties of ternary complexes loaded with different polyphenols

[0173] Group Complex Size (nm) PDI Zeta (mV) Encapsulation efficiency (%) Loading capacity (mg / mL) Example 3 CBC / PAPP / TFs 672.00 ± 68.38 b ]] 0.404 ± 0.012 b ]] -34.65 ± 2.24 a ]] 83.41 ± 2.85 a ]] 0.7252 ± 0.0248 a ]] Comparative Example 9 CBC / PAPP / TPs 772.70 ± 17.31 c ]] 0.424 ± 0.002 a ]] -27.40 ± 0.00 b ]] 46.52 ± 0.89 b ]] 0.4652 ± 0.0067 b ]] Comparative Example 10 CBC / PAPP / Pas 864.50 ± 24.76 a ]] 0.435 ± 0.014 a ]] -26.10 ± 0.55 c ]] 34.57 ± 0.56 b ]] 0.3748 ± 0.0043 b ]]

[0174] Note: Different lowercase superscript letters in the same column indicate significant differences (p<0.05), while identical letters or no letters indicate no significant differences (p>0.05).

[0175] Table 6 shows that the CBC / PAPP / TFs particle size is 672.00±68.38 nm, the Zeta potential is 34.65±2.24 mV, the encapsulation efficiency reaches 83.41±2.85%, and the loading capacity reaches 0.7252±0.0248 mg / mL, exhibiting good potential stability, not easily agglomerating, and good encapsulation ability for TFs. In the CBC / PAPP composite system, the encapsulation efficiency and loading capacity of CBC / PAPP / TFs are significantly better than those of the other two polyphenols, TPs (tea polyphenols) or Pas (proanthocyanidins), indicating that the CBC / PAPP composite system is suitable for encapsulating theaflavins, but less effective for encapsulating other types of polyphenols.

[0176] (6) Determination of encapsulation efficiency and loading capacity of CBC / PAPP / TFs on TFs under different pH conditions

[0177] Table 7. Results of CBC / PAPP / TFs encapsulation efficiency and loading capacity of TFs under different pH conditions.

[0178]

[0179]

[0180] Note: Different lowercase superscript letters in the same column indicate significant differences (p<0.05), while identical letters or no letters indicate no significant differences (p>0.05).

[0181] Table 7 shows that the ternary complexes CBC / PAPP / TFs prepared at different pH values ​​(their appearance is shown in the figure) Figure 3 The encapsulation efficiency and loading capacity (as shown) are above 76% and 0.66 mg / mL, respectively, and the encapsulation efficiency and loading capacity are good over a wide pH range.

[0182] The results of the antioxidant performance test show that the ternary complex CBC / PAPP / TFs exhibits extremely strong antioxidant capacity in an acidic environment (especially at pH 2.2), which can protect TFs from oxidative damage. The DPPH clearance rate reaches 86.46±1.20% within 30 minutes, and increases to 93.16±1.50% after 12 hours. With the increase of pH value, the antioxidant performance gradually decreases. At pH 7.0 and 8.0, the antioxidant performance significantly decreases, and even negative clearance rate appears (at pH 8.0, the DPPH clearance rate within 30 minutes is -11.57±0.21%). At the same time, compared with the antioxidant capacity of the theaflavins aqueous solution, the ternary complex CBC / PAPP / TFs has a long-lasting (12h) antioxidant capacity under the same pH conditions.

[0183] (7) Determination results of physicochemical properties of ternary complexes loaded with different contents of TFs (Example 5)

[0184] Table 8 Determination results of physicochemical properties of ternary complexes loaded with different contents of TFs

[0185]

[0186]

[0187] Note: Different lower-case letters on the same column indicate significant differences (p<0.05), and the same letters or no letters indicate no significant differences (p>0.05).

[0188] As can be seen from Table 8, with the increase of the concentration of TFs, the particle size changes, but still belongs to a smaller particle size. When the concentration of theaflavins is 1 mg / mL, the particle size is the smallest (672.00±68.38 nm). The Zeta potential at all concentrations is negative, and the absolute value fluctuates between 30 and 35 mV, indicating that the increase of the concentration has no significant effect on the Zeta potential, indicating that the CBC / PAPP / TFs with different contents of TFs all have good stability.

[0189] In addition, the encapsulation efficiency and the loading capacity significantly increase with the increase of the concentration, from 68.11±0.00% and 0.2973±0.0000 mg / mL at 0.5 mg / mL to 96.40±0.06% and 8.3825±0.0051 mg / mL at 10 mg / mL. This directly reflects that the CBC / PAPP complex system has a good encapsulation effect on TFs, and the encapsulation efficiency and the loading capacity are improved with the increase of the concentration of TFs.

[0190] (8) Determination of physicochemical properties of ternary complexes with different mass ratios of wall materials

[0191] Table 9 Determination results of physicochemical properties of ternary composites with different mass ratios of wall materials

[0192]

[0193] Note: Different lower-case letters in the same column indicate significant differences (p < 0.05), and the same letters or no letters indicate no significant differences (p > 0.05).

[0194] As can be seen from Table 9, the particle size of the composites changes with the change of the mass ratio of the wall material, but the overall particle size is still at a relatively small level. The absolute value of the Zeta potential at all concentrations is greater than 25 mV (it is generally considered that the absolute value of the potential of the composite particle system > 25 mV has good charge stability), and all have good charge stability. Among them, when the mass ratio of CBC to PAPP is 1:25 and 1:50, the system is the most stable, and the absolute value of the potential is 34.00 ± 2.24 mV and 34.08 ± 1.27 mV, respectively.

[0195] When the mass ratio is 1:50, the composite has the largest encapsulation efficiency (83.41 ± 2.85%) and loading capacity (0.7252 ± 0.0248 mg / mL). With the decrease of the mass ratio of CBC to PAPP, the encapsulation efficiency and loading capacity of each composite show a trend of first increasing and then decreasing, but the overall difference is not significant. This result shows that the change of the mass ratio of the wall material has limited effect on the encapsulation effect of TFs, that is, the ternary composites prepared at different mass ratios all have good encapsulation efficiency and loading capacity.

[0196] Experimental Example 2 Exploration of in vitro release and bioavailability of CBC / PAPP / TFs ternary composites

[0197] 1. Experimental method

[0198] The CBC / PAPP / TFs ternary composite prepared in Example 3 was taken as a representative test object to explore the in vitro release and bioavailability.

[0199] (1) Preparation of TFs aqueous solution

[0200] An appropriate amount of TFs was dispersed in ultrapure water and stirred at 15°C for 2 h. The obtained TFs aqueous solution was ultrasonically treated (with ice bag or ice to ensure low water temperature, at 15°C or below) for 15 min. After stirring in an ice water bath for 4 h, the system was ultrasonically treated again for 30 min to obtain a TFs aqueous solution with a concentration of 1 mg / mL.

[0201] (2) In vitro digestion experiment

[0202] a) Preparation of 3.2 mg / mL pepsin solution 10 mL (i.e. 32 mg pepsin / 10 mL artificial gastric juice, collectively referred to as SGF solution)

[0203] b) Preparation of 0.8 mg / mL trypsin solution 10 mL (i.e. 8 mg trypsin / 10 mL artificial intestinal juice, collectively referred to as SIF solution)

[0204] c) Simulated gastric digestion: The ternary complex solution of Example 3 (or TFs aqueous solution) was mixed with the SGF solution at a volume ratio of 1:1, stirred in a 37°C water bath, and 2.5 mL was taken at 0, 30, 60, 90 min for determination of particle size and antioxidant capacity.

[0205] d) Simulated intestinal digestion: The mixed solution of the ternary complex CBC / PAPP / TFs of Example 3 (or TFs aqueous solution) and SGF solution was adjusted to pH 6.80±0.02, mixed with the SIF solution at a volume ratio of 1:1, stirred in a 37°C water bath, and 2.5 mL was taken at 120, 150, 180 and 210 min for determination of particle size and antioxidant capacity.

[0206] e) After the digestion was completed, the total theaflavins content in the simulated intestinal juice was determined, and the bioavailability was calculated according to the following formula:

[0207] Bioavailability = m / m0x 100% Formula (4)

[0208] In the formula, m is the theaflavins content in the intestinal juice after simulated gastrointestinal digestion, mg; m0is the theaflavins content in the complex before digestion, mg.

[0209] 2. Experimental results

[0210] In order to explore the stability of nanoparticles in the gastrointestinal environment, the changes of the ternary complex CBC / PAPP / TFs and TFs were compared in the simulated gastrointestinal juice digestion environment, and the results are shown in Figure 4 Figure 4 ​As shown in Figure (A), after 90 minutes of digestion in simulated gastric juice, the average particle size of CBC / PAPP / TFs decreased from 672.00±68.38 nm to 524.35±3.46 nm, while the average particle size of the TFs aqueous solution increased from 267.65±3.89 nm to 1539.00±0.00 nm. This indicates that TFs exhibited a certain degree of flocculation and aggregation in gastric juice, while CBC / PAPP / TFs showed good stability. This suggests that the CBC / PAPP / TF complex can effectively resist harsh conditions such as gastric acid, protecting TFs from damage or aggregation. After 120 minutes of further digestion in simulated intestinal juice (i.e., 210 minutes of gastrointestinal digestion), the average particle size of both decreased significantly. This is due to the action of digestive enzymes such as pancreatic enzymes causing the complex to dissociate and release TFs for intestinal absorption.

[0211] The bioavailability of bioactive compounds in the gut is a key factor determining whether they can be effectively utilized by the body. Figure 4 As shown in Figure (C), the bioavailability of the ternary complex CBC / PAPP / TFs (38.55%) increased by 18.52% compared to the bioavailability of unencapsulated TFs (20.03%). This is because using CBC and PAPP as carriers to encapsulate TFs not only enhances their resistance to the gastrointestinal environment but also promotes their release and absorption in the intestine, thereby improving overall bioavailability. Higher bioavailability means that more active ingredients can be absorbed and utilized by the body, which is crucial for improving the effectiveness of drugs or nutritional supplements. This implies that the CBC / PAPP / TFs complex can effectively carry and protect TFs, preventing them from being prematurely decomposed in the stomach and allowing for greater absorption in the intestine, thus improving the stability and bioavailability of TFs.

[0212] Depend on Figure 4 As shown in Figure (B), the comparative experiment on the DPPH free radical scavenging capacity of the ternary complex CBC / PAPP / TFs and TFs in the gastrointestinal environment demonstrates that the CBC / PAPP / TFs complex maintains high antioxidant activity throughout the digestion process, while TFs significantly decrease after entering the intestinal environment. This further confirms the protective effect of the CBC / PAPP / TFs complex on TFs and its ability to exert biological activity at different stages of digestion. This means that it can carry more TFs into the stomach. As the gastric juice gradually dissolves or degrades the complex, the encapsulated TFs can be slowly released for further absorption in the stomach and small intestine. Because the CBC / PAPP / TFs complex has good stability in an acidic environment, it can maintain its structure well in the gastric environment and gradually release TFs.

[0213] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above embodiments, and any changes, modifications, substitutions, combinations, simplifications, etc. made without departing from the spirit and principles of the present application should be equivalent replacement manners and should be included in the protection scope of the present application.

Claims

1. A quaternized cellulose / pectin / theaflavin complex, characterized in that, The quaternary ammonium cellulose / pectin / tea polyphenol complex comprises quaternary ammonium cellulose, pectin and tea polyphenol as wall materials, and tea polyphenol as a loaded drug, and is formed by self-assembly. The esterification degree of the pectin is greater than 50%.

2. The quaternary ammonium cellulose / pectin / theaflavin complex according to claim 1, characterized in that, The quaternary ammonium cellulose / pectin / tea polyphenol complex further comprises a crosslinking agent.

3. The quaternary ammonium cellulose / pectin / theaflavin complex according to claim 1, characterized in that, The preparation method of the quaternary ammonium cellulose comprises the following steps: adding cellulose into a cellulose swelling promoter, filtering after sufficient soaking, adding a quaternary ammonium reagent into the filtrate, and performing sufficient reaction to obtain quaternary ammonium cellulose.

4. The quaternary ammonium cellulose / pectin / theaflavin complex according to claim 3, characterized in that, The cellulose swelling promoter comprises one or more of sodium hydroxide, urea, 1,8-diazabicyclo[5.4.0]undec-7-ene, tetraethylammonium hydroxide, ammonia water and potassium hydroxide.

5. The quaternary ammonium cellulose / pectin / theaflavin complex according to claim 3, characterized in that, The quaternary ammonium reagent comprises one or more of 3-chloro-2-hydroxypropyl-trimethylammonium chloride, glycidyltrimethylammonium chloride, 2,3-epoxypropyltrimethylammonium chloride, N,N,N',N'-tetramethyl-1,6-hexanediamine, triethylamine and trimethylamine.

6. The quaternary ammonium cellulose / pectin / theaflavin complex according to claim 3, characterized in that, The cellulose is selected from bacterial cellulose, plant cellulose or microcrystalline cellulose.

7. The quaternary ammonium cellulose / pectin / theaflavin complex according to claim 1, characterized in that, The mass ratio of the quaternary ammonium cellulose, pectin and tea polyphenol is 1:(10-250):(1-120).

8. The quaternary ammonium cellulose / pectin / theaflavin complex according to claim 1, characterized in that, The pectin is obtained by acid extraction from a pectin-rich raw material.

9. A process for the preparation of the quaternary ammonium cellulose / pectin / theaflavin complex according to any one of claims 1 to 8, characterized in that, The preparation method comprises the following steps: S1. dispersing tea polyphenol and quaternary ammonium cellulose in water, mixing uniformly, and obtaining a tea polyphenol-quaternary ammonium cellulose complex; S2. mixing the tea polyphenol-quaternary ammonium cellulose complex obtained in step S1 with a pectin solution, and performing sufficient reaction to obtain the quaternary ammonium cellulose / pectin / tea polyphenol complex.

10. Use of the quaternary ammonium cellulose / pectin / tea polyphenol complex according to any one of claims 1-8 in the preparation of a drug, health product or cosmetic.

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