Method for efficiently extracting tea polyphenol and tea polysaccharide and application

Abstract

The invention provides a method for efficiently extracting tea polyphenol and tea polysaccharide and application, and belongs to the technical field of plant extraction.The extraction method comprises the following steps that tea leaves are pre-cooled and rolled and cut to obtain pretreated tea leaves, then the pretreated tea leaves are added into water to be mixed, biological enzyme is added for ultrasonic enzymolysis, filtering is conducted, and filtrate and tea residues are obtained; adding tea residues into water, mixing, adding an auxiliary agent, and carrying out low-temperature plasma treatment and filtration to obtain a filtrate; combining the filtrates, concentrating, precipitating, centrifuging, and collecting precipitate and supernate; washing and drying the precipitate to obtain a tea polysaccharide extract; and concentrating, extracting, adsorbing, eluting, re-concentrating and drying the supernate to obtain the tea polyphenol extract. The extraction method disclosed by the invention can be used for efficiently extracting the tea polyphenol and the tea polysaccharide in the tea leaves, the product yield and purity are high, and the tea polyphenol and the tea polysaccharide can be used for preparing health-care products for relieving diabetes and polyuria.

Description

Technical Field

[0001] This invention belongs to the field of plant extraction technology, and particularly relates to a method and application for the efficient extraction of tea polyphenols and tea polysaccharides. Background Technology

[0002] Tea is widely loved for its various health benefits, including antioxidant properties, lipid-lowering effects, and energizing properties. It is rich in bioactive substances, with tea polyphenols and tea polysaccharides being the core functional components. Tea polyphenols are a class of polyphenolic compounds with excellent antioxidant capabilities, able to scavenge free radicals, delay aging, and potentially prevent cardiovascular diseases, diabetes, and other chronic diseases. Tea polysaccharides are water-soluble polysaccharides, and studies have reported their ability to regulate blood sugar metabolism and enhance immunity, particularly showing significant effects in alleviating polyuria in diabetic patients. Furthermore, the synergistic effect of tea polyphenols and tea polysaccharides can further enhance their bioactivity, leading to their widespread application in the food and health product industries, including functional beverages, blood sugar-lowering meal replacements, and anti-aging skincare products. However, traditional tea extraction processes suffer from low efficiency and low purity, limiting their in-depth development in high-end products such as health supplements. Therefore, a more efficient and convenient extraction method is urgently needed to meet these application requirements.

[0003] Currently, methods for extracting tea polyphenols and polysaccharides from tea mainly include solvent extraction, ultrasound-assisted extraction, microwave-assisted extraction, and supercritical fluid extraction. Solvent extraction is simple to operate but requires large amounts of organic solvents, posing risks of pollution and residue, and has high energy consumption. Ultrasonic and microwave-assisted extraction can shorten extraction time and improve efficiency, but controlling the stability of heat-sensitive components is difficult. Supercritical fluid extraction, while environmentally friendly, requires large equipment investments and is relatively complex, making large-scale promotion difficult. Furthermore, existing methods generally rely on column chromatography or resin adsorption in the separation and purification stages, which are cumbersome and prone to introducing impurities, making it difficult to balance the purity and yield of the final product. For example, some processes can damage the structure of tea polyphenols when removing caffeine, or easily lose the activity of tea polysaccharides during decolorization. Therefore, existing technologies still have significant shortcomings in extraction efficiency, component retention rate, and industrial adaptability, making it difficult to meet the needs of large-scale production of high-quality functional components.

[0004] To address the shortcomings of existing technologies, researchers have attempted to improve extraction efficiency by optimizing solvent systems, introducing synergistic extraction techniques such as ultrasound-microwave combined extraction, and developing novel green solvents such as ionic liquids. For example, low-temperature dynamic countercurrent extraction can reduce the oxidative loss of heat-sensitive components, while enzymatic pretreatment helps to disrupt cell wall structures and increase the release rate of target components. However, these methods still face challenges such as high energy consumption and difficulty in standardizing process parameters. Existing technologies have limited ability to remove trace impurities from the extract, affecting the stability and functionality of the final product. Therefore, there is an urgent need for a highly efficient method for extracting tea polyphenols and tea polysaccharides to promote the high-value utilization of active ingredients in tea. Summary of the Invention

[0005] The purpose of this invention is to provide a method for efficiently extracting tea polyphenols and tea polysaccharides. By pre-treating the tea leaves with pre-cooling, rolling and cutting, and then combining ultrasonic enzymatic hydrolysis and low-temperature plasma extraction, the yield and purity of tea polyphenols and tea polysaccharides are further improved.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for efficiently extracting tea polyphenols and tea polysaccharides, comprising the following steps:

[0008] Step 1: Pre-cool the tea leaves, then place them in a rolling and cutting machine for rolling and cutting to obtain pre-treated tea leaves; add the pre-treated tea leaves to water and mix evenly, then add biological enzymes, sonicate to hydrolyze, inactivate the enzymes, cool to room temperature, filter, and obtain filtrate A and tea residue;

[0009] Step 2: Add the tea dregs to water and mix well. Then add the additives and place the mixture in a low-temperature plasma reaction chamber for treatment. Filter to obtain filtrate B. Combine filtrate A and filtrate B for later use.

[0010] Step 3: Concentrate the filtrate by rotary evaporation, cool to room temperature, add anhydrous ethanol to precipitate, centrifuge, and collect the precipitate and supernatant; wash the precipitate with ethanol solution, dry, and obtain tea polysaccharide extract;

[0011] Step 4: Concentrate the supernatant by rotary evaporation, cool to room temperature, extract with ethyl acetate, collect the extract layer, remove the solvent by rotary evaporation, dilute with water, adsorb using a macroporous resin chromatography column, elute the adsorbed macroporous resin with ethanol solution, collect the eluent, concentrate and dry to obtain tea polyphenol extract.

[0012] First, this invention pre-cools and rolls the tea leaves before subsequent extraction. The pre-cooling process deeply inhibits the activity of polyphenol oxidase, blocking the enzymatic oxidation pathway of tea polyphenols, while reducing cellular metabolic energy consumption and minimizing the degradation of heat-sensitive components. The rolling process breaks down the cell wall structure through mechanical stress, increasing the dissociation degree of the cellulose-pectin complex and forming mass transfer channels. Moreover, the humid and hot environment promotes pectin swelling and releases intracellular esterases, which catalyze the stabilization of ester-type tea polyphenols in situ. The cell sap induced by rolling and squeezing seeps out onto the surface of the tea leaves, forming a natural antioxidant film, improving the activity retention rate, and reducing the resistance to dissolution of tea polysaccharides, thus facilitating the subsequent extraction process.

[0013] Next, this invention achieves efficient extraction of tea polysaccharides and tea polyphenols through the synergistic effect of ultrasonic enzymatic hydrolysis and low-temperature plasma. Cellulase targets and hydrolyzes β-1,4-glycosidic bonds in the cell wall, while pectinase cleaves α-1,4-galacturonic acid chains, forming a highly efficient enzymatic hydrolysis system. Simultaneously, the ultrasonic cavitation effect generates microjets that impact the cell wall, increasing the enzyme-substrate contact area and improving the hydrolysis rate. The cavitation heat effect also helps maintain the uniformity of the system's temperature field, preventing localized overheating and inactivation. Nitrogen dielectric barrier discharge excites high-density active nitrogen particles, bombarding the cell wall to produce a non-thermal plasma etching effect, forming a three-dimensional nanoporous network. This significantly improves the penetration efficiency of the adjuvants, and nitrogen free radicals quench the phenolic oxygen free radicals in tea polyphenols, reducing the oxidation loss rate. Therefore, the yield and purity of tea polysaccharides and tea polyphenols in the product are significantly improved.

[0014] Preferably, the pre-cooling treatment in step one is performed at a temperature of 8-12°C for 4-6 hours.

[0015] Preferably, the temperature of the kneading and cutting process in step one is 35-40℃, the pressure is 160-200Pa, and the processing time is 70-90min.

[0016] Preferably, the solid-liquid ratio of the pretreated tea leaves to water in step one is 1kg:10-40L.

[0017] Preferably, the solid-liquid ratio of the pretreated tea leaves to water in step one is 1 kg: 15-25 L. Preferably, the amount of bio-enzyme added in step one is 0.1-0.15% of the mass of the pretreated tea leaves.

[0018] Preferably, the bio-enzyme in step one is composed of cellulase and pectinase, and the mass ratio of cellulase to pectinase is 3:1-3.

[0019] Preferably, the ultrasonic enzymatic hydrolysis in step one is performed at a temperature of 45-50°C, an ultrasonic frequency of 35-45kHz, and a pH of 5.0-6.0.

[0020] Preferably, the enzyme inactivation temperature in step one is 90-100℃ and the time is 15-25 min.

[0021] Preferably, the solid-liquid ratio of tea residue to water in step two is 1kg:10-40L.

[0022] Preferably, the solid-liquid ratio of tea residue to water in step two is 1kg:15-25L.

[0023] Preferably, the amount of the additive added in step two is 60-75% of the mass of the tea residue.

[0024] Preferably, the auxiliary agent in step two is composed of glycerol and citric acid, wherein the mass ratio of glycerol to citric acid is 2-4:1.

[0025] In this invention, during the low-temperature plasma treatment process, an auxiliary agent composed of glycerol and citric acid is added. Glycerol acts as a penetrant to further disrupt the hydrogen bond network of the cell wall, reducing the resistance to polysaccharide dissolution. Citric acid chelates metal ions to inhibit the oxidation of tea polyphenols. At the same time, the buffer system stabilizes the appropriate pH, reducing the degradation of heat-sensitive components. The highly reactive nitrogen species excited by the plasma bombard the cell wall to form nanopores, which promotes the penetration depth of the auxiliary agent and activates glycerol to enhance interfacial mass transfer. The carboxyl groups of citric acid competitively bind to the calcium bridges of polysaccharides, breaking the pectin-metal cross-linking structure and increasing the release rate of bound polysaccharides, ultimately improving the product yield and purity.

[0026] Preferably, the discharge form of the low-temperature plasma in step two is dielectric barrier discharge, the working voltage is 20-30kV, the processing time is 2-3min, and the working gas is at least one of nitrogen, argon, and helium.

[0027] Preferably, the temperature for rotary evaporation concentration in step three is 40-55℃, with a preferred range of 45-50℃; the volume is concentrated to 1 / 6-1 / 5 of the original volume.

[0028] Preferably, the conditions for ethanol precipitation in step three are: adding anhydrous ethanol until the final ethanol concentration reaches 75-85 wt%.

[0029] Preferably, the washing conditions in step three are: washing 2-3 times with a 75-85 wt% ethanol solution.

[0030] Preferably, the temperature for rotary evaporation concentration in step four is 40-55℃ or 40-45℃; the volume is concentrated to 1 / 5-1 / 4 of the original volume.

[0031] Preferably, the conditions for ethyl acetate extraction in step four are: adding 1-2 times the volume of ethyl acetate and extracting 2-3 times.

[0032] Preferably, the temperature of rotary evaporation of the extraction layer in step four is 40-45℃.

[0033] Preferably, in step four, the water is diluted to a 2-4 wt% solution.

[0034] Preferably, the macroporous resin in step four is at least one of macroporous resin LX-8, macroporous resin DM130, and macroporous resin HZ-818.

[0035] Preferably, the adsorption flow rate in step four is 1-3 mL / min.

[0036] Preferably, the elution in step four uses a 25-35 wt% ethanol solution.

[0037] The present invention also provides a tea polyphenol extract and a tea polysaccharide extract, which are prepared by the above method.

[0038] This invention also provides the application of the above-mentioned tea polyphenol extract and tea polysaccharide extract in the preparation of health products; the application includes, but is not limited to, alleviating diabetes, polyuria, etc.

[0039] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0040] 1. This invention provides a highly efficient method for extracting tea polyphenols and tea polysaccharides. By optimizing the pretreatment and extraction steps, the tea leaves are first pretreated by pre-cooling and rolling, and then extracted using ultrasonic enzymatic hydrolysis and low-temperature plasma, further improving the yield and purity of tea polyphenols and tea polysaccharides in the product. Furthermore, water is used as the main extraction solvent in the process, eliminating the introduction of harmful reagents, making it environmentally friendly and with excellent application prospects.

[0041] 2. This invention pre-cools and rolls tea leaves. Pre-cooling deeply inhibits polyphenol oxidase activity, blocking the enzymatic oxidation pathway of tea polyphenols, while reducing cell metabolic energy consumption and minimizing the degradation of heat-sensitive components. Rolling breaks down the cell wall structure through mechanical stress, increasing the dissociation of the cellulose-pectin complex and forming mass transfer channels. Furthermore, the humid and hot environment promotes pectin swelling and releases intracellular esterases, catalyzing the stabilization of ester-type tea polyphenols in situ. The cell sap induced by rolling and squeezing seeps out onto the tea leaf surface to form a natural antioxidant film, improving the activity retention rate and reducing the resistance to tea polysaccharide dissolution.

[0042] 3. This invention utilizes a combined ultrasonic enzymatic hydrolysis and low-temperature plasma extraction. Cellulase targets and hydrolyzes β-1,4-glycosidic bonds in the cell wall, while pectinase cleaves α-1,4-galacturonic acid chains, forming a highly efficient enzymatic hydrolysis system. Simultaneously, the ultrasonic cavitation effect generates microjets that impact the cell wall, increasing the enzyme-substrate contact area and improving the hydrolysis rate. The nitrogen-mediated barrier discharge of the low-temperature plasma excites high-density reactive nitrogen particles, bombarding the cell wall to produce a non-thermal plasma etching effect, forming a three-dimensional nanoporous network. This further improves the permeability of the adjuvants. Nitrogen free radicals quench the phenolic oxygen free radicals in tea polyphenols, reducing the oxidation loss rate. The synergistic effect of ultrasonic enzymatic hydrolysis and low-temperature plasma achieves highly efficient extraction of tea polysaccharides and tea polyphenols. Detailed Implementation

[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0044] The following is a description of some of the raw materials used in the examples and comparative examples:

[0045] Tea raw materials: produced in Luoshan County, Xinyang, Henan Province (harvested in summer and autumn).

[0046] Cellulase: Brand name: Xiasheng FDY-2243, enzyme activity: 11000u / mL, purchased from Xiasheng (Beijing) Biotechnology Development Co., Ltd.

[0047] Pectinase: Brand name: Xiasheng FFY-0654, enzyme activity: 10000u / mL, purchased from Xiasheng (Beijing) Biotechnology Development Co., Ltd.

[0048] Macroporous resin LX-8: Product number HA-0949-500g, purchased from Beijing Ruida Heng Hui Technology Development Co., Ltd.

[0049] Example 1

[0050] This embodiment provides a method for efficiently extracting tea polyphenols and tea polysaccharides, including the following steps:

[0051] Step 1: Pre-cool freshly picked tea leaves at 10℃ for 5 hours, then place them in a rolling and cutting machine and roll and cut them at 37℃ and 180Pa for 80 minutes to obtain pre-treated tea leaves. Add the pre-treated tea leaves to water at a solid-liquid ratio of 1kg:20L and mix well. Then add 0.12% of the pre-treated tea leaves' mass of a biological enzyme, which is composed of cellulase and pectinase at a mass ratio of 3:2 and the pH is adjusted to 5.5. Perform ultrasonic enzymatic hydrolysis at 48℃ and 40kHz for 65 minutes, then raise the temperature to 95℃ to inactivate the enzyme for 20 minutes. Cool to room temperature and filter to obtain filtrate A and tea residue.

[0052] Step 2: Add tea residue to water at a solid-liquid ratio of 1kg:20L and mix thoroughly. Then add an auxiliary agent equal to 70% of the tea residue mass. The auxiliary agent consists of glycerol and citric acid in a mass ratio of 3:1. Place the mixture in a low-temperature plasma reaction chamber for 2.5 minutes, filter, and obtain filtrate B. Combine filtrate A and filtrate B for later use. The low-temperature plasma discharge mode is dielectric barrier discharge, the working voltage is 25kV, and the working gas is nitrogen.

[0053] Step 3: Concentrate the filtrate to 1 / 5 of its original volume by rotary evaporation at 50°C, cool to room temperature, add anhydrous ethanol to a final ethanol concentration of 80 wt%, precipitate the polysaccharides, centrifuge, and collect the precipitate and supernatant; wash the precipitate twice with 80 wt% ethanol solution, dry, and obtain tea polysaccharide extract.

[0054] Step 4: Concentrate the supernatant to 1 / 4 of its original volume by rotary evaporation at 40℃, cool to room temperature, extract twice with 1 volume of ethyl acetate, collect the extract layer, remove the solvent by rotary evaporation at 40℃, dilute with water to a 3wt% solution, and adsorb onto a macroporous resin LX-8 column at a flow rate of 2mL / min. Elute the adsorbed macroporous resin with 30wt% ethanol solution, collect the eluent, concentrate and dry to obtain the tea polyphenol extract.

[0055] Example 2

[0056] This embodiment provides a method for efficiently extracting tea polyphenols and tea polysaccharides, including the following steps:

[0057] Step 1: Pre-cool freshly picked tea leaves at 8℃ for 4 hours, then place them in a rolling and cutting machine and roll and cut them at 35℃ and 160Pa for 90 minutes to obtain pre-treated tea leaves. Add the pre-treated tea leaves to water at a solid-liquid ratio of 1kg:15L and mix evenly. Then add 0.1% of the pre-treated tea leaves' mass of a biological enzyme, which is composed of cellulase and pectinase at a mass ratio of 3:1 and the pH is adjusted to 5.0. Perform ultrasonic enzymatic hydrolysis at 45℃ and 35kHz for 70 minutes, then raise the temperature to 90℃ to inactivate the enzyme for 25 minutes. Cool to room temperature and filter to obtain filtrate A and tea residue.

[0058] Step 2: Add tea residue to water at a solid-liquid ratio of 1kg:15L and mix thoroughly. Then add an auxiliary agent of 60% of the tea residue mass, which is composed of glycerol and citric acid in a mass ratio of 2:1. Place the mixture in a low-temperature plasma reaction chamber for 2 minutes, filter, and obtain filtrate B. Combine filtrate A and filtrate B for later use. The discharge mode of the low-temperature plasma is dielectric barrier discharge, the working voltage is 30kV, and the working gas is nitrogen.

[0059] Step 3: Concentrate the filtrate to 1 / 5 of its original volume by rotary evaporation at 45°C, cool to room temperature, add anhydrous ethanol to a final ethanol concentration of 75 wt%, precipitate the polysaccharides, centrifuge, and collect the precipitate and supernatant; wash the precipitate three times with 75 wt% ethanol solution, dry, and obtain tea polysaccharide extract.

[0060] Step 4: Concentrate the supernatant to 1 / 4 of its original volume by rotary evaporation at 40℃, cool to room temperature, extract three times with 1 volume of ethyl acetate, collect the extract, remove the solvent by rotary evaporation at 40℃, dilute with water to a 2wt% solution, and adsorb onto a macroporous resin LX-8 column at a flow rate of 1 mL / min. Elute the adsorbed macroporous resin with 25wt% ethanol solution, collect the eluent, concentrate and dry to obtain the tea polyphenol extract.

[0061] Example 3

[0062] This embodiment provides a method for efficiently extracting tea polyphenols and tea polysaccharides, including the following steps:

[0063] Step 1: Pre-cool freshly picked tea leaves at 12℃ for 6 hours, then place them in a rolling and cutting machine and roll and cut them at 40℃ and 200Pa for 70 minutes to obtain pre-treated tea leaves. Add the pre-treated tea leaves to water at a solid-liquid ratio of 1kg:25L and mix evenly. Then add 0.15% of the pre-treated tea leaves' mass of a biological enzyme, which is composed of cellulase and pectinase in a mass ratio of 3:3 and the pH is adjusted to 6.0. Perform enzymatic hydrolysis at 50℃ and 45kHz for 60 minutes, then raise the temperature to 100℃ to inactivate the enzyme for 15 minutes. Cool to room temperature and filter to obtain filtrate A and tea residue.

[0064] Step 2: Add tea residue to water at a solid-liquid ratio of 1kg:25L and mix thoroughly. Then add an auxiliary agent (75% by weight of tea residue), which is composed of glycerol and citric acid in a mass ratio of 4:1. Place the mixture in a low-temperature plasma reaction chamber for 3 minutes, filter, and obtain filtrate B. Combine filtrate A and filtrate B for later use. The low-temperature plasma discharge mode is dielectric barrier discharge, the working voltage is 20kV, and the working gas is nitrogen.

[0065] Step 3: Concentrate the filtrate to 1 / 6 of its original volume by rotary evaporation at 50°C, cool to room temperature, add anhydrous ethanol to a final ethanol concentration of 85 wt%, precipitate the polysaccharides, centrifuge, and collect the precipitate and supernatant; wash the precipitate twice with 85 wt% ethanol solution, dry, and obtain tea polysaccharide extract.

[0066] Step 4: Concentrate the supernatant to 1 / 5 of its original volume by rotary evaporation at 45℃, cool to room temperature, extract twice with 2 times its volume of ethyl acetate, collect the extract, remove the solvent by rotary evaporation at 45℃, dilute with water to a 4wt% solution, and adsorb onto a macroporous resin LX-8 column at a flow rate of 3mL / min. Elute the adsorbed macroporous resin with 35wt% ethanol solution, collect the eluent, concentrate and dry to obtain the tea polyphenol extract.

[0067] Comparative Example 1

[0068] The difference between this comparative example and Example 1 is that step one of the method for efficiently extracting tea polyphenols and tea polysaccharides is different, as follows: Freshly picked tea leaves are placed in a rolling and cutting machine and rolled and cut for 80 minutes at a temperature of 37°C and a pressure of 180Pa to obtain pretreated tea leaves; the pretreated tea leaves are added to water at a solid-liquid ratio of 1kg:20L and mixed evenly, and then 0.12% of the mass of the pretreated tea leaves of a biological enzyme is added. The biological enzyme is composed of cellulase and pectinase at a mass ratio of 3:2 and the pH is adjusted to 5.5. The enzyme is enzymatically hydrolyzed by ultrasound at a temperature of 48°C and an ultrasonic frequency of 40kHz for 65 minutes, then heated to 95°C to inactivate the enzyme for 20 minutes, cooled to room temperature, and filtered to obtain filtrate A and tea residue.

[0069] Comparative Example 2

[0070] The difference between this comparative example and Example 1 is that step one in the method for efficient extraction of tea polyphenols and tea polysaccharides is different, as follows: Freshly picked tea leaves are crushed and sieved through an 80-mesh sieve to obtain pretreated tea leaves; the pretreated tea leaves are added to water at a solid-liquid ratio of 1kg:20L and mixed evenly, and then 0.12% of the mass of the pretreated tea leaves of a biological enzyme is added. The biological enzyme consists of cellulase and pectinase in a mass ratio of 3:2, the pH is adjusted to 5.5, and the enzyme is enzymatically hydrolyzed by ultrasonication at a temperature of 48℃ and an ultrasonic frequency of 40kHz for 65 minutes. The temperature is then raised to 95℃ to inactivate the enzyme for 20 minutes, cooled to room temperature, and filtered to obtain filtrate A and tea residue.

[0071] Comparative Example 3

[0072] The difference between this comparative example and Example 1 is that steps one and two of the method for efficiently extracting tea polyphenols and tea polysaccharides are different (ultrasonic enzymatic hydrolysis is omitted). Specifically, the following steps are taken: Freshly picked tea leaves are pre-cooled at 10°C for 5 hours, and then placed in a rolling and cutting machine for 80 minutes at 37°C and 180Pa to obtain pre-treated tea leaves; the pre-treated tea leaves are added to water at a solid-liquid ratio of 1kg:20L and mixed evenly, and then 70% of the mass of the pre-treated tea leaves is added as an auxiliary agent, which is composed of glycerol and citric acid at a mass ratio of 3:1. The mixture is then placed in a low-temperature plasma reaction chamber for 2.5 minutes, filtered, and the filtrate is obtained; the discharge form of the low-temperature plasma is dielectric barrier discharge, the working voltage is 25kV, and the working gas is nitrogen.

[0073] Comparative Example 4

[0074] The difference between this comparative example and Example 1 is that steps one and two of the method for efficiently extracting tea polyphenols and tea polysaccharides are different (the low-temperature plasma process is omitted). Specifically, the following steps are taken: Freshly picked tea leaves are pre-cooled at 10°C for 5 hours, and then placed in a rolling and cutting machine for 80 minutes at 37°C and 180Pa to obtain pre-treated tea leaves. The pre-treated tea leaves are added to water at a solid-liquid ratio of 1 kg: 20 L and mixed evenly. Then, 0.12% of the mass of the pre-treated tea leaves is added with a biological enzyme composed of cellulase and pectinase at a mass ratio of 3:2 and the pH is adjusted to 5.5. The enzyme is enzymatically hydrolyzed by ultrasound at 48°C and 40 kHz for 65 minutes, then heated to 95°C to inactivate the enzyme for 20 minutes. After cooling to room temperature, the mixture is filtered to obtain the filtrate.

[0075] Comparative Example 5

[0076] The difference between this comparative example and Example 1 is that step two in the method for efficient extraction of tea polyphenols and tea polysaccharides is different, as follows: tea residue is added to water at a solid-liquid ratio of 1kg:20L and mixed evenly. Then, 70% of the mass of the tea residue is added as an auxiliary agent, namely glycerol. The mixture is then placed in a low-temperature plasma reaction chamber for 2.5 minutes and filtered to obtain filtrate B. Filtrate A and filtrate B are combined and set aside. The discharge form of the low-temperature plasma is dielectric barrier discharge, the working voltage is 25kV, and the working gas is nitrogen.

[0077] Comparative Example 6

[0078] The difference between this comparative example and Example 1 is that step two in the method for efficient extraction of tea polyphenols and tea polysaccharides is different, as follows: tea residue is added to water at a solid-liquid ratio of 1kg:20L and mixed evenly. Then, 70% of the mass of the tea residue is added as an auxiliary agent, namely citric acid. The mixture is then placed in a low-temperature plasma reaction chamber for 2.5 minutes and filtered to obtain filtrate B. Filtrate A and filtrate B are combined and set aside. The discharge form of the low-temperature plasma is dielectric barrier discharge, the working voltage is 25kV, and the working gas is nitrogen.

[0079] Performance testing

[0080] The purity and yield of tea polysaccharides and tea polyphenols obtained in Examples 1-3 and Comparative Examples 1-6 were determined, with yields calculated based on the weight of fresh leaves. The content of tea polyphenols was determined using the spectrophotometric method according to the national standard GB / T8313-2018, and the purity and yield were calculated. The content of tea polysaccharides was determined using the anthrone-sulfuric acid method, and the purity and yield were calculated. The test results are shown in Table 1.

[0081] Table 1: Purity and Yield of Tea Polysaccharides and Tea Polyphenols

[0082]

[0083] As shown in Table 1, the extraction methods described in Examples 1-3 can improve the yield and purity of tea polysaccharides and tea polyphenols, especially the extraction method described in Example 1, which yields the highest yield and purity of tea polysaccharides and tea polyphenols. This is because Examples 1-3 of this invention optimize and improve the tea extraction process by adding pre-cooling and rolling pretreatment to the tea leaves, and using a combination of ultrasonic enzymatic hydrolysis and low-temperature plasma extraction, which further improves the yield and purity of tea polyphenols and tea polysaccharides in the product. In contrast, Comparative Examples 1-6 did not use the necessary technical solutions, resulting in significantly lower yields and purity of the products obtained compared to Examples 1-3. Specifically, Comparative Examples 1-2 did not use pre-cooling and rolling treatment, Comparative Examples 3-4 did not use a combination of ultrasonic enzymatic hydrolysis and low-temperature plasma extraction, and Comparative Examples 5-6 did not use an adjuvant composed of glycerol and citric acid during low-temperature plasma treatment. The results show that this leads to a decrease in the yield and purity of tea polyphenols and tea polysaccharides in the product. The above experimental results further demonstrate the importance of the technical solutions defined in this invention for its technical effect.

[0084] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for efficiently extracting tea polyphenols and tea polysaccharides, characterized in that, Includes the following steps: Step 1: Pre-cool the tea leaves, then place them in a rolling and cutting machine to roll and cut them, thus obtaining pre-treated tea leaves; Pretreated tea leaves are added to water and mixed evenly. Then, biological enzymes are added, and the mixture is subjected to ultrasonic enzymatic hydrolysis, enzyme inactivation, cooling, and filtration to obtain filtrate A and tea residue. Step 2: Add the tea dregs to water and mix well. Then add the additives and place the mixture in a low-temperature plasma reaction chamber for treatment. Filter to obtain filtrate B. Combine filtrate A and filtrate B for later use. Step 3: Concentrate the filtrate by rotary evaporation, cool it, add anhydrous ethanol to precipitate it, centrifuge it, and collect the precipitate and supernatant; wash the precipitate with ethanol solution, dry it, and obtain the tea polysaccharide extract; Step 4: Concentrate the supernatant by rotary evaporation, cool, extract with ethyl acetate, collect the extract, remove the solvent by rotary evaporation, dilute with water, adsorb and elute using a macroporous resin chromatography column, collect the eluent, concentrate and dry to obtain the tea polyphenol extract.

2. The method for efficiently extracting tea polyphenols and tea polysaccharides according to claim 1, characterized in that, The pre-cooling treatment in step one is carried out at a temperature of 8-12℃ and a treatment time of 4-6 hours; the kneading and cutting treatment in step one is carried out at a temperature of 35-40℃, a pressure of 160-200Pa, and a treatment time of 70-90 minutes.

3. The method for efficiently extracting tea polyphenols and tea polysaccharides according to claim 1, characterized in that, The bio-enzyme mentioned in step one consists of cellulase and pectinase; the amount of the bio-enzyme added is 0.1-0.15% of the mass of the pretreated tea leaves.

4. The method for efficiently extracting tea polyphenols and tea polysaccharides according to claim 1, characterized in that, The ultrasonic enzymatic hydrolysis in step one is performed at a temperature of 45-50℃, an ultrasonic frequency of 35-45kHz, and a pH of 5.0-6.

0.

5. The method for efficiently extracting tea polyphenols and tea polysaccharides according to claim 1, characterized in that, The auxiliary agent mentioned in step two is composed of glycerol and citric acid; the amount of the auxiliary agent added is 60-75% of the mass of tea residue.

6. The method for efficiently extracting tea polyphenols and tea polysaccharides according to claim 1, characterized in that, The discharge form of the low-temperature plasma in step two is dielectric barrier discharge, with a working voltage of 20-30 kV, a processing time of 2-3 min, and a working gas of at least one of nitrogen, argon, and helium.

7. The method for efficiently extracting tea polyphenols and tea polysaccharides according to claim 1, characterized in that, In step four, the macroporous resin is at least one of macroporous resin LX-8, macroporous resin DM130, and macroporous resin HZ-818, and the adsorption flow rate is 1-3 mL / min.

8. The method for efficiently extracting tea polyphenols and tea polysaccharides according to claim 1, characterized in that, The temperature for rotary evaporation in steps three and four is 40-55℃.

9. A tea polyphenol extract and a tea polysaccharide extract, characterized in that, Prepared by the method according to any one of claims 1-8.

10. The application of the tea polyphenol extract and tea polysaccharide extract according to claim 9 in the preparation of health products for relieving diabetes and polyuria.

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