Compound tea-flavored grape wine based on synergic fermentation of tea and grape juice and preparation method thereof

Abstract

The application discloses a compound tea-flavored grape wine based on tea and grape juice synergistic fermentation and a preparation method thereof, and belongs to the technical field of food fermentation engineering. The method aims at solving the problem of traditional tea wine flavor fragmentation. The method comprises the following steps: preparing a modified tannase compound and a protein phytic acid mixture, mixing tea and grape juice, and then synergistically fermenting the tea and grape juice, wherein, in the fermentation process, the modified tannase is used to hydrolyze ester-type catechins to reduce bitterness and promote flavor integration; after the fermentation is completed, the protein phytic acid mixture is added to chelate iron ions and adsorb colloidal particles; and finally, the product wine is obtained through multi-stage clarification. Through the above technical scheme, the flavor coordination and physicochemical stability of tea wine are improved, the fusion of tea aroma and fruit aroma is realized, the flavor coordination and wine body stability are improved, no essence or traditional Chinese medicinal materials need to be added, and the product quality and production efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of food fermentation engineering technology, specifically to a compound tea-flavored wine based on the co-fermentation of tea and grape juice and its preparation method. Background Technology

[0002] Traditional tea-flavored wines often employ a post-blending process, directly adding green or black tea extracts to the finished wine. Because tea polyphenols (such as EGCG and catechins) are highly polar polyhydroxy compounds, while the main fruit aroma components in wine (such as linalool and β-damascone) are weakly polar terpenes or ketones, their thermodynamic compatibility in a 12% vol ethanol-water system is limited, easily forming a nanoscale microphase separation structure. Sensoryly, this structure manifests as the fruit aroma evaporating first, followed by a delayed tea astringency, producing a distinct "layered" sensation. Furthermore, free tea polyphenols readily combine with potassium ions and tartaric acid in the wine to form precipitates, affecting product clarity and shelf stability. While existing technologies employ cyclodextrin encapsulation or liposome encapsulation to improve compatibility, cyclodextrins are expensive and may mask natural flavors, while liposomes lack stability in an alcoholic environment, both limiting their industrial application.

[0003] Patent CN107475003A discloses a fermented black tea wine and its preparation method, using grapes and black tea as the main raw materials, supplemented with traditional Chinese medicinal materials such as dried tangerine peel, perilla leaves, platycodon root, winter melon peel, and wolfberry. The product is obtained by processing each raw material separately, then mixing and fermenting, and aging. Although this method emphasizes the positive role of raw material ratio and process parameters in the retention of effective components, and claims that the resulting product is transparent and bright, has a rich taste, and no medicinal taste, the black tea and grape juice are not fermented synchronously and synergistically in the process. Instead, they are processed in steps and then mixed. This results in insufficient biochemical interaction between tea polyphenols and components such as glucose and organic acids in the early stage of fermentation, which limits the in-situ generation and stable integration of flavor substances and may affect the aroma coordination and taste integration of the final product.

[0004] Patent CN107475002A discloses a blood pressure-lowering black tea wine and its preparation method. It uses black tea, grapes, stevia extract, and black tea flavoring as raw materials, and prepares a tea-flavored wine with blood pressure and lipid-lowering effects through formulation design and process control. While this method emphasizes the synergistic effect of functional components, its preparation process still relies on the addition of exogenous stevia extract and black tea flavoring, and the co-fermentation mechanism between black tea and grape juice during the fermentation stage is not clearly defined. The black tea components are mainly added in extract form, failing to undergo deep co-conversion with sugars and amino acids in the grape juice during the active yeast metabolic period. This limits the fusion of tea and fruit aromas at the molecular level and may also affect the flavor stability and sediment control during long-term storage.

[0005] In summary, existing technologies still have room for improvement in terms of the synergistic fermentation mechanism of tea and grape juice, in-situ generation of flavor substances, and thermodynamic stability of the system. They have not yet fully realized the biochemical coupling and flavor integration of tea and wine during the fermentation process. Summary of the Invention

[0006] This invention provides a composite tea-flavored wine based on the co-fermentation of tea leaves and grape juice, and its preparation method. The aim is to solve the problem of prominent bitterness and astringency leading to flavor fragmentation in existing tea-flavored wines by introducing a functionalized modified tannin enzyme complex and a protein phytic acid mixture during the main fermentation stage.

[0007] Specifically, the technical solution of the present invention includes the following steps: A method for preparing a compound tea-flavored wine based on the co-fermentation of tea leaves and grape juice, the method comprising the following steps: Tanninase enzyme solution and ammonium sulfate solution were mixed and stirred, and then genipin was added and stirred to obtain tanninase aggregates. The modified tanninase complex was obtained by mixing and stirring tanninase aggregates with ferrous sulfate solution. Grapes are mixed with deionized water and crushed to obtain pulp, then compound pectinase is added and stirred to obtain grape juice; The base wine is obtained by mixing and fermenting grape juice, tea leaves, modified tannin enzyme complex, sodium metabisulfite, and brewer's yeast suspension, followed by filtration. A complex tea-flavored wine is prepared by mixing the original wine with a protein-phytic acid mixture, allowing it to stand, clarify, and filter.

[0008] Furthermore, the concentration of the tannin enzyme solution is 40 mg / mL.

[0009] Furthermore, the concentration of the ammonium sulfate solution is 90 wt%.

[0010] Furthermore, the weight ratio of the tanninase solution, ammonium sulfate solution, and genipin is 0.8~1.0:5:0.024~0.036; high concentration of ammonium sulfate induces salting-out aggregation of tanninase to form physical aggregates; the active ester group of genipin reacts with the ε-amino group of lysine residues on the surface of tanninase to form a covalent cross-linked network, thus constructing a carrier-free immobilized structure.

[0011] Furthermore, the conditions for mixing and stirring the tanninase solution and ammonium sulfate solution include a temperature of 25°C, a rotation speed of 200 r / min, and a time of 20-30 min.

[0012] Furthermore, the conditions for adding genipin and stirring the reaction include a temperature of 30-40°C and a time of 10-14 hours.

[0013] Furthermore, the concentration of the ferrous sulfate solution is 0.01 mol / L.

[0014] Furthermore, the weight ratio of the tanninase aggregate to the ferrous sulfate solution is 0.8~1.0:15~25; under nitrogen protection, ferrous ions coordinate with histidine imidazole nitrogen near the enzyme active site to form an "enzyme-metal ion" complex, thereby enhancing its catalytic activity and structural stability in an acidic environment.

[0015] Furthermore, the conditions for the mixing and stirring reaction of the tanninase aggregates and ferrous sulfate solution include a temperature of 25-30°C, a pH of 5.0-6.0, and a time of 2-4 hours.

[0016] Furthermore, the concentration of the ethanol solution is 30 wt%.

[0017] Furthermore, the tea leaves include one of green tea, black tea, yellow tea, or dark tea.

[0018] Furthermore, the solid-liquid ratio of the grapes to deionized water is 1:1 (g / mL). Furthermore, the weight ratio of grapes to compound pectinase is 100:0.01~0.03.

[0019] Furthermore, the conditions for adding the compound pectinase and stirring include a temperature of 25-30°C and a time of 3-5 minutes.

[0020] Furthermore, the weight ratio of grape juice, tea leaves, modified tannin enzyme complex, sodium metabisulfite, and brewer's yeast suspension is 100:8~10:0.05~0.09:0.003~0.005:0.3~0.5. In the early stage of fermentation, the modified tannin enzyme complex hydrolyzes the ester-type catechins in the tea leaves, breaking their ester bonds to generate gallic acid and catechin monomers, which significantly reduces bitterness. At the same time, the released phenolic acids undergo esterification reactions with the ethanol and aromatic substances produced by grape fermentation, promoting flavor fusion.

[0021] Furthermore, the preparation of the brewing yeast suspension includes adding Angel wine active dry yeast BV818 to 10 mL of 20 wt% sucrose aqueous solution, culturing in a 30℃ constant temperature incubator for 40 min, and then adjusting the yeast concentration to 1.3 × 10⁻⁶. 9 A suspension of *Saccharomyces cerevisiae* was obtained at CFU / mL.

[0022] Furthermore, the conditions for the mixed fermentation of grape juice, tea leaves, modified tannin enzyme complex, sodium metabisulfite, and brewer's yeast suspension include a temperature of 28-30°C and a time of 7-9 days.

[0023] Furthermore, the preparation method of the protein-phytic acid mixture includes the following steps: Phytic acid solution, glycerol and concentrated sulfuric acid were mixed and stirred to produce esterified phytic acid; Whey protein and deionized water were mixed and homogenized to obtain a dispersion. The protein-phytic acid mixture is obtained by spray drying after mixing and stirring the esterified phytic acid and the dispersion.

[0024] Furthermore, the concentration of the phytic acid solution is 70 wt%.

[0025] Furthermore, the weight ratio of the phytic acid solution, glycerol, and concentrated sulfuric acid is 1.0:1.4~1.6:0.006~0.008; phytic acid and glycerol undergo esterification and dehydration reaction under the catalysis of concentrated sulfuric acid. The resulting esterified phytic acid is amphiphilic due to the introduction of glycerol ester chains, and its phosphate groups retain strong chelating ability. At the same time, the hydrophobic chains enhance the binding force with protein microgels.

[0026] Furthermore, the conditions for the reaction of the phytic acid solution, glycerol, and concentrated sulfuric acid by mixing and stirring include a temperature of 155-165°C and a time of 3-5 hours.

[0027] Furthermore, the weight ratio of whey protein to deionized water is 1~2:10; after being heat-treated at a preset temperature, the whey protein undergoes irreversible denaturation, exposing internal hydrophobic groups and forming a porous microgel network through disulfide bond crosslinking.

[0028] Furthermore, the conditions for homogenizing the whey protein and deionized water include heating to 85-90°C, stirring at 200 rpm for 30-40 minutes, cooling to 4°C, and then homogenizing at 8000 rpm for 2-4 minutes.

[0029] Furthermore, the weight ratio of the esterified phytic acid to the dispersion is 1~2:50~100; in an acidic environment, the negatively charged esterified phytic acid binds to the partially positively charged protein microgel through electrostatic interaction, and further self-assembles with the help of hydrophobic forces to form a functionally integrated composite colloidal particle.

[0030] Furthermore, the conditions for mixing and stirring the esterified phytic acid and the dispersion include a temperature of 40-50°C, a pH of 3.5-3.8, and a time of 2-4 hours.

[0031] Furthermore, the conditions for spray drying include a temperature of 160~180°C.

[0032] Furthermore, the weight ratio of the original wine to the protein-phytic acid mixture is 100:0.01~0.02; the protein-phytic acid mixture is added after fermentation, and its esterified phytic acid component rapidly chelates the Fe dissociated from the enzyme complex. 2+ / Fe 3+This forms a soluble complex, preventing it from forming an insoluble precipitate with gallic acid, while the protein microgel adsorbs the already formed submicron-sized colloidal particles, inhibiting their aggregation and growth.

[0033] Furthermore, the conditions for settling and clarification include settling at 15-18°C for 15-20 days to obtain aged slurry, soaking 0.02-0.05 parts by weight of bentonite in 5 parts by weight of deionized water at 60°C for 24 hours to obtain bentonite slurry, adding the bentonite slurry to the above aged slurry, stirring at 80 r / min at 15°C for 30 minutes, settling for 10 days, filtering, refrigerating at 4°C for 10 days, filtering again, and filtering with a 0.22 μm microporous membrane.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention solves the core problem of bitterness in tea in traditional processes by designing a modified tannin enzyme complex and a protein-phytic acid mixture and enabling it to function in a tea-grape juice co-fermentation system. The modified tannin enzyme complex is prepared by covalently cross-linking enzyme molecules after ammonium sulfate precipitation with genipin to construct a recyclable carrier-free immobilized enzyme aggregate; then, it is activated by coordination bonding of ferrous ions, so that it can still efficiently hydrolyze the ester bonds of ester-type catechins in tea under the acidic environment of wine fermentation, transforming substances that cause sharp astringency into mild phenolic acids, thus eliminating the main obstacle to the fusion of tea and wine flavors. However, this efficient activation step also introduces ferrous ions, which are easily oxidized in the fermentation environment and combine with substances such as polyphenols, posing a new risk of turbidity and precipitation in the wine. The protein-phytic acid mixture was designed to address this new risk.

[0035] (2) In this invention, the esterified phytic acid in the protein-phytic acid mixture has a strong chelating ability, which can bind free iron ions to prevent precipitation; the heat-denatured self-assembled whey protein microgel, due to its steric hindrance effect, can adsorb and disperse the formed submicron suspended particles, preventing them from agglomerating. This mixture is added at the end of fermentation and works with the modified tannin enzyme complex that has not yet been separated to achieve the capture and stabilization of iron ions. The cascade synergy of the two transcends single functions. While ensuring the long-term clarity and stability of the wine, the protection of aroma substances complements the taste improvement brought about by enzymatic hydrolysis, ultimately creating a complex tea-flavored wine with high flavor integration, a rounded sensory experience, and stable shelf life. Detailed Implementation

[0036] The technical solution of the present invention will be clearly and completely described below through embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Unless otherwise stated, all raw materials and reagents used in this invention are commercially available or can be prepared by known methods.

[0038] The tanninase (enzyme activity 300U / g) was purchased from Cangzhou Xiasheng Enzyme Biotechnology Co., Ltd.

[0039] The compound pectinase VRL was purchased from Shanghai Dingtang Trading Co., Ltd.

[0040] Example 1 A method for preparing a complex tea-flavored wine based on the co-fermentation of tea leaves and grape juice includes the following steps: 0.8 parts by weight of 40 mg / mL tanninase solution was dispersed in 5 parts by weight of 90 wt% ammonium sulfate solution. After precipitating at 200 r / min for 20 min at 25 °C, 0.024 parts by weight of genipin was added, the temperature was raised to 30 °C, and the reaction was continued with stirring for 10 h. After the reaction was completed, the precipitate was centrifuged at 8000 r / min for 15 min at 4 °C, the precipitate was collected, washed 6 times with deionized water, dispersed in phosphate buffer at pH 6.0, dialyzed at 4 °C for 48 h using a dialysis bag with a molecular weight cutoff of 100 kDa, and then freeze-dried to obtain tanninase aggregates. 0.8 parts by weight of tanninase aggregates were dispersed in 15 parts by weight of 0.01 mol / L ferrous sulfate solution. Under a nitrogen protective atmosphere, the pH was adjusted to 5.0, and the reaction was carried out at 25°C with stirring at 100 r / min for 2 h. After the reaction was completed, the precipitate was collected by centrifugation at 8000 r / min for 10 min. After washing with deionized water 5 times, the modified tanninase complex was obtained by freeze drying. 1.0 part by weight of 70 wt% phytic acid solution and 1.4 parts by weight of glycerol were mixed, and 0.006 parts by weight of concentrated sulfuric acid were added. The mixture was heated to 155°C and stirred at 200 r / min for 3 h. After the reaction was completed, the mixture was cooled to 25°C, and the pH was adjusted to 6.0 with 5 wt% sodium bicarbonate solution. The mixture was dialyzed at 4°C for 48 h using a dialysis bag with a molecular weight cutoff of 500 Da, and then freeze-dried to obtain esterified phytic acid. 0.8 parts by weight of whey protein were dispersed in 10 parts by weight of deionized water, heated to 85°C and stirred at 200 r / min for 30 min, then cooled to 4°C and homogenized at 8000 r / min for 2 min to obtain a dispersion. One part by weight of esterified phytic acid was dispersed in 50 parts by weight of dispersion, the pH was adjusted to 3.5, the temperature was raised to 40℃ and stirred at 150 r / min for 2 h to obtain a mixture. The mixture was spray-dried at an inlet temperature of 160℃ and an outlet temperature of 75℃ to obtain a protein phytic acid mixture. 100 parts by weight of Chardonnay-white grapes were washed and destemmed, and deionized water was added at a solid-liquid ratio of 1:1 (g / mL) to crush the grapes and obtain pulp. 0.01 parts by weight of compound pectinase were added to the pulp, and the mixture was stirred at 100 r / min at 25℃ for 3 h. The filtrate was then filtered and collected to obtain grape juice. Angel Yeast BV818 was added to 10 mL of a 20 wt% sucrose aqueous solution and incubated at 30℃ for 40 min. The yeast concentration was then adjusted to 1.3 × 10⁻⁶. 9 A Saccharomyces cerevisiae suspension was obtained at CFU / mL; Add 8 parts by weight of green tea leaves to 100 parts by weight of grape juice and stir at 200 rpm for 10 minutes. Add 0.05 parts by weight of modified tannin enzyme complex and 0.003 parts by weight of sodium metabisulfite. Pasteurize at 65°C for 30 minutes, then cool to 25°C. Add 0.3 parts by weight of brewer's yeast suspension. Place the fermentation bottle in a 28°C constant temperature incubator and ferment in the dark for 7 days. After fermentation, place the fermentation liquid in a 4°C refrigerator and let it stand for 24 hours. Collect the supernatant to obtain the base wine. 0.01 parts by weight of protein-phytic acid mixture was added to 100 parts by weight of the original wine and stirred. After stirring, the mixture was allowed to stand at 15°C for 15 days to obtain aged wine liquid. 0.02 parts by weight of bentonite was soaked in 5 parts by weight of deionized water at 60°C for 24 hours to obtain bentonite slurry. The bentonite slurry was added to the above aged wine liquid, stirred at 80 r / min at 15°C for 30 min, allowed to stand for 10 days, filtered, refrigerated at 4°C for 10 days, filtered again, and filtered through a 0.22 μm microporous membrane to obtain a complex tea-flavored wine.

[0041] Example 2 A method for preparing a complex tea-flavored wine based on the co-fermentation of tea leaves and grape juice includes the following steps: 0.85 parts by weight of 40 mg / mL tanninase enzyme solution was dispersed in 5 parts by weight of 90 wt% ammonium sulfate solution. After precipitation at 25°C and 200 r / min for 22 min, 0.027 parts by weight of genipin was added, the temperature was raised to 32°C, and the reaction was continued with stirring for 11 h. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 15 min at 4°C, the precipitate was collected, washed 6 times with deionized water, dispersed in phosphate buffer at pH 6.0, dialyzed at 4°C for 48 h using a dialysis bag with a molecular weight cutoff of 100 kDa, and then freeze-dried to obtain tanninase aggregates. 0.85 parts by weight of tanninase aggregates were dispersed in 17.5 parts by weight of 0.01 mol / L ferrous sulfate solution. Under a nitrogen protective atmosphere, the pH was adjusted to 5.2, and the reaction was carried out at 27°C with stirring at 100 r / min for 2.5 h. After the reaction was completed, the precipitate was collected by centrifugation at 8000 r / min for 10 min. After washing with deionized water 5 times, the modified tanninase complex was obtained by freeze drying. 1.0 part by weight of 70 wt% phytic acid solution and 1.45 parts by weight of glycerol were mixed, and 0.006 parts by weight of concentrated sulfuric acid were added. The mixture was heated to 158°C and stirred at 200 r / min for 3.5 h. After the reaction was completed, the mixture was cooled to 25°C, and the pH was adjusted to 6.0 with 5 wt% sodium bicarbonate solution. The mixture was dialyzed at 4°C for 48 h using a dialysis bag with a molecular weight cutoff of 500 Da. The esterified phytic acid was then obtained by freeze drying. 0.96 parts by weight of whey protein were dispersed in 10 parts by weight of deionized water, heated to 86°C and stirred at 200 r / min for 32 min, then cooled to 4°C and homogenized at 8000 r / min for 2.5 min to obtain a dispersion. One part by weight of esterified phytic acid was dispersed in 62.5 parts by weight of dispersion, the pH was adjusted to 3.6, the temperature was raised to 42℃ and stirred at 150 r / min for 2.5 h to obtain a mixture. The mixture was spray-dried at an inlet temperature of 165℃ and an outlet temperature of 75℃ to obtain a protein phytic acid mixture. 100 parts by weight of Chardonnay-white grapes were washed and destemmed, and deionized water was added at a solid-liquid ratio of 1:1 (g / mL) to crush the grapes and obtain pulp. 0.012 parts by weight of compound pectinase were added to the pulp, and the mixture was stirred at 100 r / min at 26℃ for 3.5 h. The filtrate was then collected to obtain grape juice. Angel Yeast BV818 was added to 10 mL of a 20 wt% sucrose aqueous solution and incubated at 30℃ for 40 min. The yeast concentration was then adjusted to 1.3 × 10⁻⁶. 9 A Saccharomyces cerevisiae suspension was obtained at CFU / mL; Add 8.5 parts by weight of green tea leaves to 100 parts by weight of grape juice and stir at 200 rpm for 10 minutes. Add 0.06 parts by weight of modified tannin enzyme complex and 0.0032 parts by weight of sodium metabisulfite. Sterilize at 65°C for 30 minutes, then cool to 25°C. Add 0.35 parts by weight of brewer's yeast suspension. Place the fermentation flask in a 28.5°C constant temperature incubator and ferment in the dark for 7.5 days. After fermentation, place the fermentation broth in a 4°C refrigerator and let it stand for 24 hours. Collect the supernatant. To obtain the base wine, add 0.012 parts by weight of protein-phytic acid mixture to 100 parts by weight of base wine and stir. After stirring, let it stand at 15℃ for 16 days to obtain aged wine liquid. Soak 0.02 parts by weight of bentonite in 5 parts by weight of deionized water at 60℃ for 24 hours to obtain bentonite slurry. Add the bentonite slurry to the above aged wine liquid, stir at 80 r / min at 15℃ for 30 min, let it stand for 10 days, filter, refrigerate at 4℃ for 10 days, filter again, and filter through a 0.22μm microporous membrane to obtain a complex tea-flavored wine.

[0042] Example 3 A method for preparing a complex tea-flavored wine based on the co-fermentation of tea leaves and grape juice includes the following steps: 0.9 parts by weight of 40 mg / mL tanninase solution were dispersed in 5 parts by weight of 90 wt% ammonium sulfate solution. After precipitation at 25°C and 200 r / min for 25 min, 0.030 parts by weight of genipin were added, the temperature was raised to 35°C, and the reaction was continued with stirring for 12 h. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 15 min at 4°C, the precipitate was collected, washed 6 times with deionized water, dispersed in phosphate buffer at pH 6.0, dialyzed at 4°C for 48 h using a dialysis bag with a molecular weight cutoff of 100 kDa, and then freeze-dried to obtain tanninase aggregates. 0.9 parts by weight of tanninase aggregates were dispersed in 20 parts by weight of 0.01 mol / L ferrous sulfate solution. Under a nitrogen protective atmosphere, the pH was adjusted to 5.5, and the mixture was stirred at 100 r / min at 28 °C for 3 h. After the reaction was completed, the precipitate was collected by centrifugation at 8000 r / min for 10 min. The precipitate was washed 5 times with deionized water and then freeze-dried to obtain the modified tanninase complex. 1.0 part by weight of 70 wt% phytic acid solution and 1.5 parts by weight of glycerol were mixed, and 0.006 parts by weight of concentrated sulfuric acid were added. The mixture was heated to 160°C and stirred at 200 r / min for 4 h. After the reaction was completed, the mixture was cooled to 25°C, and the pH was adjusted to 6.0 with 5 wt% sodium bicarbonate solution. The mixture was dialyzed at 4°C for 48 h using a dialysis bag with a molecular weight cutoff of 500 Da, and then freeze-dried to obtain esterified phytic acid. 1.2 parts by weight of whey protein were dispersed in 10 parts by weight of deionized water, heated to 87°C and stirred at 200 r / min for 35 min, then cooled to 4°C and homogenized at 8000 r / min for 3 min to obtain a dispersion. One part by weight of esterified phytic acid was dispersed in 67 parts by weight of dispersion, the pH was adjusted to 3.6, the temperature was raised to 45℃ and stirred at 150 r / min for 3 h to obtain a mixture. The mixture was spray dried at an inlet temperature of 170℃ and an outlet temperature of 75℃ to obtain a protein phytic acid mixture. 100 parts by weight of Chardonnay-white grapes were washed and destemmed, and deionized water was added at a solid-liquid ratio of 1:1 (g / mL) to crush the grapes and obtain pulp. 0.018 parts by weight of compound pectinase were added to the pulp, and the mixture was stirred at 100 r / min at 27℃ for 4 h. The filtrate was then collected to obtain grape juice. Angel Yeast BV818 was added to 10 mL of a 20 wt% sucrose aqueous solution and incubated at 30℃ for 40 min. The yeast concentration was then adjusted to 1.3 × 10⁻⁶. 9 A Saccharomyces cerevisiae suspension was obtained at CFU / mL; Add 9 parts by weight of black tea leaves to 100 parts by weight of grape juice and stir at 200 rpm for 10 minutes. Add 0.07 parts by weight of modified tannin enzyme complex and 0.0038 parts by weight of sodium metabisulfite. Pasteurize at 65°C for 30 minutes, then cool to 25°C. Add 0.4 parts by weight of brewer's yeast suspension. Place the fermentation bottle in a 29°C constant temperature incubator and ferment in the dark for 8 days. After fermentation, place the fermentation liquid in a 4°C refrigerator and let it stand for 24 hours. Collect the supernatant to obtain the base wine. 0.014 parts by weight of protein-phytic acid mixture was added to 100 parts by weight of the original wine and stirred. After stirring, the mixture was allowed to stand at 15°C for 17 days to obtain aged wine liquid. 0.02 parts by weight of bentonite was soaked in 5 parts by weight of deionized water at 60°C for 24 hours to obtain bentonite slurry. The bentonite slurry was added to the above aged wine liquid, stirred at 80 r / min at 15°C for 30 min, allowed to stand for 10 days, filtered, refrigerated at 4°C for 10 days, filtered again, and filtered through a 0.22 μm microporous membrane to obtain a complex tea-flavored wine.

[0043] Example 4 A method for preparing a complex tea-flavored wine based on the co-fermentation of tea leaves and grape juice includes the following steps: 0.95 parts by weight of 40 mg / mL tanninase enzyme solution was dispersed in 5 parts by weight of 90 wt% ammonium sulfate solution. After precipitation at 25°C and 200 r / min for 28 min, 0.033 parts by weight of genipin was added, the temperature was raised to 38°C, and the reaction was continued with stirring for 13 h. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 15 min at 4°C, the precipitate was collected, washed 6 times with deionized water, dispersed in phosphate buffer at pH 6.0, dialyzed at 4°C for 48 h using a dialysis bag with a molecular weight cutoff of 100 kDa, and then freeze-dried to obtain tanninase aggregates. 0.95 parts by weight of tanninase aggregates were dispersed in 22.5 parts by weight of 0.01 mol / L ferrous sulfate solution. Under a nitrogen protective atmosphere, the pH was adjusted to 5.8, and the reaction was carried out at 29°C with stirring at 100 r / min for 3.5 h. After the reaction was completed, the precipitate was collected by centrifugation at 8000 r / min for 10 min. After washing with deionized water 5 times, the modified tanninase complex was obtained by freeze drying. 1.0 part by weight of 70 wt% phytic acid solution and 1.55 parts by weight of glycerol were mixed, and 0.006 parts by weight of concentrated sulfuric acid were added. The mixture was heated to 163 °C and stirred at 200 r / min for 4.5 h. After the reaction was completed, the mixture was cooled to 25 °C, and the pH was adjusted to 6.0 with 5 wt% sodium bicarbonate solution. The mixture was dialyzed at 4 °C for 48 h using a dialysis bag with a molecular weight cutoff of 500 Da, and then freeze-dried to obtain esterified phytic acid. 1.6 parts by weight of whey protein were dispersed in 10 parts by weight of deionized water, heated to 89°C and stirred at 200 r / min for 38 min, then cooled to 4°C and homogenized at 8000 r / min for 3.5 min to obtain a dispersion. One part by weight of esterified phytic acid was dispersed in 57 parts by weight of dispersion, the pH was adjusted to 3.7, the temperature was raised to 48℃ and stirred at 150 r / min for 3.5 h to obtain a mixture. The mixture was spray-dried at an inlet temperature of 175℃ and an outlet temperature of 75℃ to obtain a protein phytic acid mixture. 100 parts by weight of Chardonnay-white grapes were washed and destemmed, and deionized water was added at a solid-liquid ratio of 1:1 (g / mL) to crush the grapes and obtain pulp. 0.024 parts by weight of compound pectinase were added to the pulp, and the mixture was stirred at 100 r / min at 28℃ for 4.5 h. The filtrate was then collected to obtain grape juice. Angel Yeast BV818 was added to 10 mL of a 20 wt% sucrose aqueous solution and incubated at 30℃ for 40 min. The yeast concentration was then adjusted to 1.3 × 10⁻⁶. 9 A Saccharomyces cerevisiae suspension was obtained at CFU / mL; Add 9.5 parts by weight of green tea leaves to 100 parts by weight of grape juice and stir at 200 rpm for 10 minutes. Add 0.08 parts by weight of modified tannin enzyme complex and 0.0044 parts by weight of sodium metabisulfite. Pasteurize at 65°C for 30 minutes, then cool to 25°C. Add 0.45 parts by weight of brewer's yeast suspension. Place the fermentation flask in a 29.5°C constant temperature incubator and ferment in the dark for 8.5 days. After fermentation, place the fermentation broth in a 4°C refrigerator and let it stand for 24 hours. Collect the supernatant. To obtain the base wine, add 0.016 parts by weight of protein-phytic acid mixture to 100 parts by weight of base wine and stir. After stirring, let it stand at 15℃ for 18 days to obtain aged wine liquid. Soak 0.02 parts by weight of bentonite in 5 parts by weight of deionized water at 60℃ for 24 hours to obtain bentonite slurry. Add the bentonite slurry to the above aged wine liquid, stir at 80 r / min at 15℃ for 30 min, let it stand for 10 days, filter, refrigerate at 4℃ for 10 days, filter again, and filter through a 0.22μm microporous membrane to obtain a complex tea-flavored wine.

[0044] Example 5 A method for preparing a complex tea-flavored wine based on the co-fermentation of tea leaves and grape juice includes the following steps: 1.0 part by weight of 40 mg / mL tanninase solution was dispersed in 5 parts by weight of 90 wt% ammonium sulfate solution. After precipitating at 200 r / min for 30 min at 25 °C, 0.036 parts by weight of genipin was added, the temperature was raised to 40 °C, and the reaction was continued with stirring for 14 h. After the reaction was completed, the precipitate was centrifuged at 8000 r / min for 15 min at 4 °C, the precipitate was collected, washed 6 times with deionized water, dispersed in phosphate buffer at pH 6.0, dialyzed at 4 °C for 48 h using a dialysis bag with a molecular weight cutoff of 100 kDa, and then freeze-dried to obtain tanninase aggregates. 1.0 part by weight of tanninase aggregate was dispersed in 25 parts by weight of 0.01 mol / L ferrous sulfate solution. Under a nitrogen protective atmosphere, the pH was adjusted to 6.0, and the reaction was carried out at 30°C with stirring at 100 r / min for 4 h. After the reaction was completed, the precipitate was collected by centrifugation at 8000 r / min for 10 min. After washing with deionized water 5 times, the modified tanninase complex was obtained by freeze drying. 1.0 part by weight of 70 wt% phytic acid solution and 1.6 parts by weight of glycerol were mixed, and 0.006 parts by weight of concentrated sulfuric acid were added. The mixture was heated to 165°C and stirred at 200 r / min for 5 h. After the reaction was completed, the mixture was cooled to 25°C, and the pH was adjusted to 6.0 with 5 wt% sodium bicarbonate solution. The mixture was dialyzed at 4°C for 48 h using a dialysis bag with a molecular weight cutoff of 500 Da, and then freeze-dried to obtain esterified phytic acid. 2.0 parts by weight of whey protein were dispersed in 10 parts by weight of deionized water, heated to 90°C and stirred at 200 r / min for 40 min, then cooled to 4°C and homogenized at 8000 r / min for 4 min to obtain a dispersion. Two parts by weight of esterified phytic acid were dispersed in 100 parts by weight of dispersion, the pH was adjusted to 3.8, the temperature was raised to 50℃ and stirred at 150 r / min for 4 h to obtain a mixture. The mixture was spray-dried at an inlet temperature of 180℃ and an outlet temperature of 75℃ to obtain a protein phytic acid mixture. 100 parts by weight of Chardonnay-white grapes were washed and destemmed, and deionized water was added at a solid-liquid ratio of 1:1 (g / mL) to crush the grapes and obtain pulp. 0.03 parts by weight of compound pectinase were added to the pulp, and the mixture was stirred at 100 r / min at 30℃ for 5 h. The filtrate was then filtered and collected to obtain grape juice. Angel Yeast BV818 was added to 10 mL of a 20 wt% sucrose aqueous solution and incubated at 30℃ for 40 min. The yeast concentration was then adjusted to 1.3 × 10⁻⁶. 9 A Saccharomyces cerevisiae suspension was obtained at CFU / mL; Add 10 parts by weight of green tea leaves to 100 parts by weight of grape juice and stir at 200 rpm for 10 minutes. Add 0.09 parts by weight of modified tannin enzyme complex and 0.005 parts by weight of sodium metabisulfite. Pasteurize at 65°C for 30 minutes, then cool to 25°C. Add 0.5 parts by weight of brewer's yeast suspension. Place the fermentation bottle in a 30°C constant temperature incubator and ferment in the dark for 9 days. After fermentation, place the fermentation liquid in a 4°C refrigerator and let it stand for 24 hours. Collect the supernatant to obtain the base wine. 0.02 parts by weight of protein-phytic acid mixture were added to 100 parts by weight of the original wine and stirred. The mixture was then left to stand at 15°C for 20 days to obtain aged wine liquid. 0.02 parts by weight of bentonite was soaked in 5 parts by weight of deionized water at 60°C for 24 hours to obtain bentonite slurry. The bentonite slurry was added to the above aged wine liquid and stirred at 80 r / min at 15°C for 30 minutes. The mixture was then left to stand for 10 days and filtered. After being refrigerated at 4°C for 10 days, the mixture was filtered again and filtered through a 0.22 μm microporous membrane to obtain a complex tea-flavored wine.

[0045] Comparative Example 1 A method for preparing a complex tea-flavored wine based on the co-fermentation of tea leaves and grape juice includes the following steps: Replace 0.09 parts by weight of the modified tanninase complex in Example 5 with 0.09 parts by weight of tanninase, and keep all other operations the same as in Example 5.

[0046] Comparative Example 2 A method for preparing a complex tea-flavored wine based on the co-fermentation of tea leaves and grape juice includes the following steps: Replace 25 parts by weight of 0.01 mol / L ferrous sulfate solution in Example 5 with 25 parts by weight of 0.01 mol / L ferric ammonium citrate solution, and keep all other operations the same as in Example 5.

[0047] Comparative Example 3 A method for preparing a complex tea-flavored wine based on the co-fermentation of tea leaves and grape juice includes the following steps: The preparation step of esterified phytic acid in Example 5 was removed, and 2 parts by weight of esterified phytic acid were replaced with 2 parts by weight of 70 wt% phytic acid solution. Other operations were the same as in Example 5.

[0048] Comparative Example 4 A method for preparing a complex tea-flavored wine based on the co-fermentation of tea leaves and grape juice includes the following steps: Replace 2 parts by weight of whey protein in Example 5 with 2 parts by weight of sodium caseinate, and keep all other operations the same as in Example 5.

[0049] Comparative Example 5 A method for preparing a complex tea-flavored wine based on the co-fermentation of tea leaves and grape juice includes the following steps: Remove the protein-phytic acid mixture from the examples, and otherwise follow the same procedures as in Example 5.

[0050] Comparative Example 6 A method for preparing a complex tea-flavored wine based on the co-fermentation of tea leaves and grape juice includes the following steps: 100 parts by weight of Chardonnay-white grapes were washed and destemmed, and deionized water was added at a solid-liquid ratio of 1:1 (g / mL) to crush the grapes and obtain pulp. 0.03 parts by weight of compound pectinase were added to the pulp, and the mixture was stirred at 100 r / min at 30℃ for 5 h. The filtrate was then filtered and collected to obtain grape juice. Angel Yeast BV818 was added to 10 mL of a 20 wt% sucrose aqueous solution and incubated at 30℃ for 40 min. The yeast concentration was then adjusted to 1.3 × 10⁻⁶. 9 A Saccharomyces cerevisiae suspension was obtained at CFU / mL; Add 0.09 parts by weight of modified tannin enzyme complex and 0.005 parts by weight of sodium metabisulfite to 100 parts by weight of grape juice. Pasteurize at 65°C for 30 minutes, then cool to 25°C. Add 0.5 parts by weight of brewer's yeast suspension. Place the fermentation bottle in a 30°C incubator in the dark for 9 days. After fermentation, place the fermentation liquid in a 4°C refrigerator and let it stand for 24 hours. Collect the supernatant to obtain the base wine. Add 10 parts by weight of green tea leaves to 100 parts by weight of the base wine and stir at 200 rpm for 30 minutes until fully dissolved. Subsequently, 0.02 parts by weight of protein-phytic acid mixture was added and stirred. After standing at 15°C for 20 days, aged wine liquor was obtained. 0.02 parts by weight of bentonite was soaked in 5 parts by weight of 60°C deionized water for 24 hours to obtain bentonite slurry. The bentonite slurry was added to the above aged wine liquor, stirred at 80 r / min at 15°C for 30 min, and then stood for 10 days before filtration. After being refrigerated at 4°C for 10 days, it was filtered again and filtered through a 0.22 μm microporous membrane to obtain a complex tea-flavored wine.

[0051] The "tea-added later" process is adopted, that is, green tea leaves are added only after the main fermentation is completed and the original wine is obtained. Other operations are consistent with those in Example 5.

[0052] Performance testing The compound tea-flavored wines prepared in Examples 1-5 and Comparative Examples 1-6 were subjected to various performance tests, and the test methods are as follows: Sensory evaluation (out of 100): A judging panel of 10 professionally trained evaluators scored the food based on four dimensions: color (20 points), aroma integration (30 points), mouthfeel smoothness (30 points), and aftertaste (20 points). The average score was used as the final sensory score. Color: Clarity of the liquor, uniformity of color blending between tea and liquor; 1-20 points will be deducted for turbidity or layering. Aroma blending: The degree of harmony between tea aroma and grape fruit aroma and fermentation aroma. Deduct 1 to 30 points for off-flavors or flavor separation; Smoothness of taste: Intensity of bitterness, deduct 1~30 points for obvious bitterness and sharp taste; Aftertaste: The persistence of aroma and taste; a weak or off-flavor aftertaste will result in a deduction of 1 to 20 points.

[0053] Physicochemical stability test: Clarification stability: The sample was stored in a constant temperature environment of 25℃ for 6 months, and the turbidity (NTU) was measured using a turbidimeter. Turbidity ≤ 5 NTU is acceptable. The lower the value, the better the stability. Sedimentation rate: After 6 months of storage, centrifuge (3000 r / min, 10 min) and calculate the percentage of sediment mass to the total sample mass. A sedimentation rate of ≤0.1% is considered acceptable. Iron ion residue: The iron ion content (mg / L) in the wine was determined by atomic absorption spectrophotometry. The lower the content, the better the chelation effect.

[0054] Flavor substance testing Ester-type catechin residue: determined by high performance liquid chromatography (HPLC). The lower the residue, the better the enzymatic hydrolysis effect. Total phenolic acid content: determined by the Folin-phenol colorimetric method. A moderate phenolic acid content with high integration with the wine body is considered excellent.

[0055] The test results are shown in Tables 1, 2 and 3.

[0056] Table 1. Sensory evaluation results (out of 100 points) Color (20 points) Aroma blending (30 points) Smoothness of texture (30 points) Aftertaste (20 points) Example 1 18.5 25.2 24.8 16.8 Example 2 18.7 26.5 26 17.2 Example 3 19 27.8 27.5 17.6 Example 4 19.3 28.5 28.8 18.1 Example 5 19.8 29.6 29.9 18.9 Comparative Example 1 17 20.5 18 15 Comparative Example 2 18 22.8 21.5 16 Comparative Example 3 17.2 25 26.2 16.5 Comparative Example 4 16.8 23.5 24.8 16 Comparative Example 5 15.5 26 27 16.8 Comparative Example 6 19.5 21 19.5 15.5 Table 2. Physicochemical stability test results (after 6 months of storage) Turbidity (NTU) Sedimentation rate (%) Iron ion residue (mg / L) Example 1 3.2 0.08 0.82 Example 2 2.8 0.07 0.75 Example 3 2.3 0.05 0.68 Example 4 1.8 0.03 0.59 Example 5 1.2 <0.01 0.48 Comparative Example 1 4.5 0.12 1.95 Comparative Example 2 3.8 0.1 1.35 Comparative Example 3 7.5 0.25 0.51 Comparative Example 4 5.2 0.18 0.55 Comparative Example 5 8.9 0.31 2.65 Comparative Example 6 2 0.05 0.52 Table 3. Results of Flavor Compound Tests Ester-type catechin residue (mg / L) Total phenolic acid content (mg / L, calculated as gallic acid) Example 1 152.5 420.8 Example 2 128.3 455.2 Example 3 95.7 488.6 Example 4 62.4 515.3 Example 5 28.6 538.9 Comparative Example 1 410.2 285.4 Comparative Example 2 185.6 398.7 Comparative Example 3 30.1 530.5 Comparative Example 4 31.5 525.8 Comparative Example 5 25.8 545.1 Comparative Example 6 485.7 310.2 The test results in Tables 1-3 show that the compound tea-flavored wines prepared in Examples 1-5 of this invention have good sensory properties, physicochemical stability, and good flavor, while the compound tea-flavored wines prepared in Comparative Examples 1-6 have varying degrees of shortcomings in performance.

[0057] The reduced performance of Comparative Example 1 may be due to the direct use of free tannin enzymes instead of the modified tannin enzyme complex prepared in this invention. Free enzymes are easily deactivated in the acidic, ethanol-containing environment of wine fermentation and cannot maintain long-term catalytic activity through immobilization, leading to a significant decrease in their efficiency in hydrolyzing ester-type catechins and insufficient conversion of bitter substances. Simultaneously, the lack of coordination activation and stabilization by ferrous ions means that their catalytic sites may not be in optimal conformation within the fermentation system, further reducing conversion efficiency. Therefore, the wine exhibits a pronounced bitterness and poor flavor integration.

[0058] The performance degradation in Comparative Example 2 may be due to the use of ferric ammonium citrate instead of ferrous sulfate during enzyme complex preparation. The iron ions in ferric ammonium citrate are primarily ferric (Fe3+)... 3+ It exists in the form of ferrous ions (Fe²⁺), and its coordination ability, ionic radius, and redox properties are similar to those of ferrous ions (Fe²⁺). 2+ There are fundamental differences. This may lead to a change in the coordination mode between the modified enzyme and histidine, the active site of tanninase, preventing the formation of the same highly efficient and stable "enzyme-metal ion" activation complex. This, in turn, affects the catalytic activity and structural stability of the modified enzyme in acidic fermentation broth, ultimately resulting in a lower catechin hydrolysis effect than the original scheme.

[0059] The performance degradation in Comparative Example 3 may be due to the use of unesterified phytic acid instead of esterified phytic acid during the preparation of the protein-phytic acid mixture. While unmodified phytic acid possesses strong chelating properties, it is also highly hydrophilic and lacks the hydrophobic segments introduced through glycerol esterification. Therefore, its binding with the heat-denatured whey protein microgel relies primarily on electrostatic interactions, lacking the reinforcement of hydrophobic interactions. This results in a potentially loose and weakly bound composite colloidal particle structure formed through self-assembly. Such a structure is prone to dissociation or low aggregation efficiency in the wine environment, significantly reducing its chelating and stabilizing effect on metal ions and its adsorption and dispersion capacity for existing suspended particles, thus leading to poor wine clarification stability.

[0060] The performance degradation in Comparative Example 4 may be due to the use of sodium caseinate instead of whey protein as the raw material for the protein microgel. Sodium caseinate differs from whey protein in its molecular structure, isoelectric point, and thermal denaturation behavior. Under the same heat treatment conditions, sodium caseinate may not be able to form a uniform, dense, and porous microgel network structure like whey protein. Its interaction mode with esterified phytic acid may also be altered, resulting in defects in the steric hindrance and adsorption properties of the final protein-phytic acid mixture. This makes it difficult to effectively disperse submicron particles in the wine, thus weakening its function in preventing colloidal aggregation and maintaining long-term clarification and stability.

[0061] The reduced performance of Comparative Example 5 may be due to the omission of the protein-phytic acid mixture. This results in a lack of a stabilizing mechanism specifically targeting metal ions and tiny suspended particles in the fermentation system. On the one hand, iron ions that may slowly dissociate or be released from the modified enzyme complex cannot be effectively chelated and easily combine with polyphenols to form insoluble complexes. On the other hand, the large molecules such as proteins and polyphenols already present in the wine, without the adsorption and steric protection of the protein microgel, are more likely to aggregate and grow into precipitates. Therefore, although the flavor transformation may be acceptable, the physical stability is severely insufficient, making it extremely prone to turbidity and precipitation.

[0062] The reduced performance of Comparative Example 6 may be due to a change in the timing of tea substance introduction, employing a "post-addition of tea" process instead of co-fermentation. This prevented the polyphenols in the tea leaves (including bitter ester-type catechins) from participating in the main fermentation process. They could not be effectively hydrolyzed and transformed by the modified tannin enzyme complex during the active period of yeast metabolism, and they also missed the critical window for esterification and association reactions with the ethanol, acids, and primary aromatic substances produced during fermentation. Therefore, the tea and wine flavors were not sufficiently integrated at the molecular level, resulting in a harsh tea taste with a prominent bitterness, and a separation of tea and wine aromas, negatively impacting the sensory experience.

[0063] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for preparing a compound tea-flavored wine based on the co-fermentation of tea leaves and grape juice, characterized in that, The preparation method includes the following steps: Tanninase enzyme solution and ammonium sulfate solution were mixed and stirred, and then genipin was added and stirred to obtain tanninase aggregates. The modified tanninase complex was obtained by mixing and stirring tanninase aggregates with ferrous sulfate solution. Grapes are mixed with deionized water and crushed to obtain pulp, then compound pectinase is added and stirred to obtain grape juice; The base wine is obtained by mixing and fermenting grape juice, tea leaves, modified tannin enzyme complex, sodium metabisulfite, and brewer's yeast suspension, followed by filtration. A complex tea-flavored wine is prepared by mixing the original wine with a protein-phytic acid mixture, allowing it to stand, clarify, and filter.

2. The method for preparing a compound tea-flavored wine based on the co-fermentation of tea leaves and grape juice as described in claim 1, characterized in that, The concentration of the tanninase solution is 40 mg / mL; the concentration of the ammonium sulfate solution is 90 wt%; the weight ratio of the tanninase solution, ammonium sulfate solution, and genipin is 0.8~1.0:5:0.024~0.036; the mixing and stirring conditions for the tanninase solution and ammonium sulfate solution include a temperature of 25℃, a rotation speed of 200 r / min, and a time of 20~30 min; the stirring and reaction conditions for adding genipin include a temperature of 30~40℃ and a time of 10~14 h.

3. The method for preparing a compound tea-flavored wine based on the co-fermentation of tea leaves and grape juice as described in claim 1, characterized in that, The concentration of the ferrous sulfate solution is 0.01 mol / L; the weight ratio of the tanninase aggregate to the ferrous sulfate solution is 0.8~1.0:15~25; the conditions for mixing and stirring the tanninase aggregate and the ferrous sulfate solution include a temperature of 25~30℃, a pH of 5.0~6.0, and a time of 2~4h.

4. The method for preparing a compound tea-flavored wine based on the co-fermentation of tea leaves and grape juice as described in claim 1, characterized in that, The weight ratio of grape juice, tea leaves, modified tannin enzyme complex, sodium metabisulfite, and brewer's yeast suspension is 100:8~10:0.05~0.09:0.003~0.005:0.3~0.5; the conditions for the mixed fermentation of grape juice, tea leaves, modified tannin enzyme complex, sodium metabisulfite, and brewer's yeast suspension include a temperature of 28~30℃ and a time of 7~9 days.

5. The method for preparing a compound tea-flavored wine based on the co-fermentation of tea leaves and grape juice as described in claim 1, characterized in that, The preparation method of the protein-phytic acid mixture includes the following steps: Phytic acid solution, glycerol and concentrated sulfuric acid were mixed and stirred to produce esterified phytic acid; Whey protein and deionized water were mixed and homogenized to obtain a dispersion. The protein-phytic acid mixture is obtained by spray drying after mixing and stirring the esterified phytic acid and the dispersion.

6. The method for preparing a compound tea-flavored wine based on the co-fermentation of tea leaves and grape juice as described in claim 5, characterized in that, The concentration of the phytic acid solution is 70 wt%; the weight ratio of the phytic acid solution, glycerol, and concentrated sulfuric acid is 1.0:1.4~1.6:0.006~0.008; the conditions for mixing and stirring the phytic acid solution, glycerol, and concentrated sulfuric acid include a temperature of 155~165℃ and a time of 3~5h.

7. The method for preparing a compound tea-flavored wine based on the co-fermentation of tea leaves and grape juice as described in claim 5, characterized in that, The weight ratio of whey protein to deionized water is 1~2:10; the conditions for mixing and homogenizing whey protein and deionized water include heating to 85~90℃, stirring at 200r / min for 30~40min, cooling to 4℃, and then homogenizing at 8000r / min for 2~4min.

8. The method for preparing a compound tea-flavored wine based on the co-fermentation of tea leaves and grape juice as described in claim 5, characterized in that, The weight ratio of the esterified phytic acid to the dispersion is 1~2:50~100; the mixing and stirring conditions for the esterified phytic acid and the dispersion include a temperature of 40~50℃, a pH of 3.5~3.8, and a time of 2~4h.

9. The method for preparing a compound tea-flavored wine based on the co-fermentation of tea leaves and grape juice as described in claim 1, characterized in that, The weight ratio of the original wine and the protein-phytic acid mixture is 100:0.01~0.02; the conditions for settling and clarification include settling at 15~18℃ for 15~20 days to obtain aged slurry, soaking 0.02~0.05 parts by weight of bentonite in 5 parts by weight of deionized water at 60℃ for 24 hours to obtain bentonite slurry, adding the bentonite slurry to the above aged wine, stirring at 80r / min at 15℃ for 30 minutes, settling for 10 days, filtering, refrigerating at 4℃ for 10 days, filtering again, and filtering with a 0.22μm microporous membrane.

10. A complex tea-flavored wine based on the co-fermentation of tea leaves and grape juice, characterized in that, The wine was prepared by any one of the methods described in claims 1 to 9 for preparing a composite tea-flavored wine based on the co-fermentation of tea leaves and grape juice.