Method for extracting and detecting tea polyphenol in Liupao tea

Abstract

The invention relates to the technical field of extraction and detection of active ingredients of tea leaves, and discloses a method for extracting and detecting tea polyphenol in Liupao tea, which comprises the following steps: S1, carrying out crushing and drying pretreatment on a Liupao tea sample; s2, extracting tea polyphenol from the Liupu tea sample through a green extraction technology, wherein the green extraction technology comprises any one of a supercritical CO2 extraction method, a deep cosolvent system extraction method and a microwave-assisted extraction method; and S3, filtering and concentrating the extracted tea polyphenol. Through supercritical CO2, a deep cosolvent system and a microwave-assisted extraction technology, the extraction efficiency of the tea polyphenol is remarkably improved, and the extraction time is shortened; meanwhile, the use of an organic solvent is reduced, the environmental pollution is reduced, and green and environment-friendly effects are realized; in addition, degradation of tea polyphenol is effectively avoided through low-temperature extraction, and the purity and biological activity of the extract are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of extraction and detection of active components of tea, in particular to a method for extracting and detecting tea polyphenols in Liubao tea. Background Art

[0002] Liubao tea is a tea with unique flavor and rich functional ingredients. Tea polyphenols are the most important active ingredients, which have multiple biological activities such as antioxidant, antibacterial and anticancer. The technology of extracting and detecting tea polyphenols plays a key role in tea processing and quality control. With the increasing demand for functional tea products, how to extract tea polyphenols efficiently and environmentally friendly has become a hot topic of research.

[0003] In the prior art, the extraction of tea polyphenols mainly adopts traditional solvent extraction methods, such as hot reflux method, cold soaking method and room temperature stirring method, using organic solvents such as ethanol and methanol. During the extraction process, the tea sample is fully contacted with the solvent by heating and stirring, and then filtered and concentrated to obtain the tea polyphenol extract. However, this type of extraction method first has low extraction efficiency and long extraction time, which is difficult to meet the needs of large-scale industrial production; secondly, a large amount of organic solvents are used in the extraction process, which not only increases production costs, but also pollutes the environment, and the recovery and treatment of solvents are also relatively complicated; finally, high-temperature operation can easily lead to the degradation of tea polyphenols, affecting its biological activity, thereby reducing the functionality of the product. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a method for extracting and detecting tea polyphenols in Liubao tea, which solves the problems of low extraction efficiency, environmentally unfriendly use of solvents and degradation of tea polyphenols due to high temperature in the prior art.

[0005] To achieve the above objectives, the present invention is implemented by the following technical scheme: A method for extracting and detecting tea polyphenols in Liubao tea, comprising the following steps:

[0006] S1, crushing and drying the Liubao tea sample for pretreatment;

[0007] S2. Extracting tea polyphenols from the Liubao tea sample by green extraction technology, wherein the green extraction technology includes any one of supercritical CO2 extraction, deep co-solvent system extraction, and microwave-assisted extraction;

[0008] S3, filtering and concentrating the extracted tea polyphenols;

[0009] S4. Use high performance liquid chromatography or liquid chromatography-mass spectrometry to conduct qualitative and quantitative detection of the extracted tea polyphenols.

[0010] Preferably, the pretreatment step of the Liubao tea sample includes crushing the Liubao tea sample to 60 meshes and adjusting the water content of the sample to 8%-10%.

[0011] Preferably, the steps of the supercritical CO2 extraction method include:

[0012] (1) placing the Liubao tea sample in a supercritical CO2 extraction device at a pressure of 15-30 MPa and a temperature of 35-50°C;

[0013] (2) selectively adding ethanol as a co-solvent, with the solvent ratio being 5% to 15% of the sample weight;

[0014] (3) The extraction time is 30-60 minutes. CO2 is recovered by reducing pressure and cooling, and the extract is collected.

[0015] Preferably, the steps of the deep co-solvent system extraction method include:

[0016] (1) preparing a DES solvent, wherein the DES solvent is prepared by mixing ethylene glycol and choline chloride in a molar ratio of 1:1 to 1:4;

[0017] (2) 1 g of Liubao tea sample was mixed with 10 mL of DES solution and placed in an ultrasonic-assisted extraction device at a temperature of 40-50°C for 20-40 minutes;

[0018] (3) The extract is filtered and then processed.

[0019] Preferably, the steps of the microwave-assisted extraction method include:

[0020] (1) Mix the Liubao tea sample with 70% ethanol solution in a ratio of 1:10;

[0021] (2) using microwave-assisted extraction equipment, with a microwave power of 450-600 W, an extraction time of 5-10 minutes, and an extraction temperature not exceeding 60°C;

[0022] (3) The extract is filtered and concentrated to collect the tea polyphenol extract.

[0023] Preferably, the post-treatment step of the tea polyphenols extract comprises:

[0024] (1) The extract was filtered through a 0.45 μm filter membrane to remove solid impurities;

[0025] (2) using a rotary evaporator to concentrate at a temperature below 40° C. to obtain a dry tea polyphenol extract;

[0026] (3) The extract was stored in brown bottles at a temperature below 4°C to prevent oxidative degradation caused by light and high temperature.

[0027] Preferably, the quantitative detection step of tea polyphenols includes using high performance liquid chromatography for detection, and the chromatographic conditions used include: a C18 reverse phase chromatographic column, a mobile phase of water and acetonitrile gradient elution, a flow rate of 1.0 mL / min, and a detection wavelength of 280 nm.

[0028] Preferably, the quantitative detection step of tea polyphenols comprises using liquid chromatography-mass spectrometry technology in an electrospray ionization mode and a multiple reaction monitoring mode, and detecting a mass-to-charge ratio in the range of 100-1000.

[0029] Preferably, the extraction rate calculation formula is:

[0030]

[0031] Among them, η 提取 is the extraction rate, m 提取物 is the mass of tea polyphenols extracted, m 茶叶样品 For the quality of the original Liubao tea sample.

[0032] Preferably, in the extraction technology, the main parameters of the extraction process are optimized by a multivariate optimization method, and the parameters include pressure, temperature, extraction time and solvent ratio, and variance analysis is used to evaluate the significant effect of each parameter on the extraction efficiency.

[0033] The present invention provides a method for extracting and detecting tea polyphenols in Liubao tea. It has the following beneficial effects:

[0034] 1. The present invention significantly shortens the extraction time by adopting supercritical CO2 extraction, deep co-solvent system extraction and microwave-assisted extraction, and realizes efficient extraction of tea polyphenols under relatively low temperature conditions. Compared with traditional solvent extraction methods, these green extraction technologies can extract more tea polyphenols in a shorter time, effectively improve the extraction efficiency and reduce energy consumption.

[0035] 2. The extraction method of the present invention uses the green technology of supercritical CO2 and DES co-solvent, which greatly reduces the use of organic solvents such as ethanol, reduces the cost of solvent recovery and treatment, and reduces environmental pollution. In addition, supercritical CO2 and DES co-solvent can be recycled, which meets the requirements of green chemical industry and embodies the concept of environmental protection and sustainable development.

[0036] 3. The present invention avoids thermal degradation of the active ingredients of tea polyphenols due to high temperature by using low-temperature extraction technology, such as supercritical CO2 and DES technology, thereby ensuring the purity and biological activity of the extract. Compared with the traditional high-temperature extraction method, the method of the present invention completes the extraction under mild conditions, ensuring the integrity of the tea polyphenols in Liubao tea, so that its functions in subsequent detection and application remain unchanged. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Please see attached Figure 1 , the embodiment of the present invention provides a method for extracting and detecting tea polyphenols in Liubao tea, which belongs to the technical field of extraction and detection of active ingredients in tea. In view of the problems of low efficiency, environmentally unfriendly use of solvents, and inaccurate detection in existing extraction processes, the present invention provides a green and efficient method for extracting and detecting tea polyphenols in Liubao tea. The method combines the green technologies of supercritical CO2 extraction, deep co-solvent system (DES) extraction, and microwave-assisted extraction, as well as high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) to perform qualitative and quantitative analysis of tea polyphenols, thereby achieving efficient extraction and accurate detection of tea polyphenols.

[0040] 2. Principle of the method

[0041] Tea polyphenols are the main active ingredients in Liubao tea. During the extraction process, polyphenols are easily degraded by factors such as high temperature, light, and oxygen, so a low-temperature and efficient extraction process is required. The present invention adopts three green extraction methods to optimize extraction conditions, improve extraction efficiency, and reduce the use of organic solvents. The extraction parameters are optimized by response surface methodology (RSM), and accurate analysis of tea polyphenols is achieved by combining HPLC and LC-MS technology.

[0042] 3. Specific implementation steps

[0043] 3.1 Pretreatment of Liubao tea samples

[0044] First, the Liubao tea samples were pretreated:

[0045] The Liubao tea samples were crushed to 60 meshes to increase the specific surface area, which was beneficial for the full contact between the solvent and the sample in the subsequent extraction process;

[0046] The moisture content of the sample was controlled at 8%-10% to avoid the sample being too dry or too wet, which would affect the extraction efficiency.

[0047] 3.2 Green extraction process

[0048] The extraction process of the present invention selects any one of three green extraction methods: supercritical CO2 extraction, deep co-solvent system (DES) extraction or microwave-assisted extraction. The optimal extraction conditions are determined by multivariate optimization.

[0049] 3.2.1 Supercritical CO2 extraction method

[0050] Supercritical CO2 extraction technology utilizes the special fluid properties of CO2 under critical temperature and pressure conditions to efficiently dissolve the tea polyphenols in Liubao tea at low temperatures, ensuring the integrity of the active ingredients.

[0051] step:

[0052] The pretreated Liubao tea samples were placed in a supercritical CO2 extraction device;

[0053] By controlling the pressure of the equipment at 15-30MPa, the temperature at 35-50°C, and setting the CO2 flow rate at 5mL / min;

[0054] Add ethanol as a co-solvent at a ratio of 5%-15% of the sample mass to enhance the solubility of CO2 on tea polyphenols;

[0055] The extraction time is set to 30-60 minutes, and CO2 is recovered by reducing pressure and cooling to obtain tea polyphenol extract.

[0056] Extraction principle: CO2 has both gas diffusion and liquid solubility in the supercritical state. By adding ethanol as a co-solvent, CO2's solubility for polar substances such as tea polyphenols is further enhanced, and efficient extraction can be achieved at a lower temperature, avoiding the degradation of polyphenols in a high temperature environment.

[0057] 3.2.2 Deep co-solvent system (DES) extraction method

[0058] The DES extraction method is a low melting point co-solvent system based on hydrogen bond donors and hydrogen bond acceptors, which has the characteristics of low toxicity, environmental protection and high solubility. By adjusting the ratio of co-solvents, the dissolution efficiency of tea polyphenols can be improved.

[0059] step:

[0060] Preparation of DES solvent: mixing ethylene glycol and choline chloride in a molar ratio of 1:1 to 1:4, heating in a water bath at 80°C until the mixture is uniformly mixed, and cooling to room temperature to obtain a DES solution;

[0061] 1 g of Liubao tea sample was mixed with 10 mL of DES solution and placed in an ultrasonic-assisted extraction device;

[0062] The extraction temperature was controlled at 40-50°C and the ultrasonic time was 20-40 minutes;

[0063] After extraction, the solution was filtered through a 0.45 μm filter membrane to obtain a tea polyphenol extract.

[0064] Extraction principle: DES enhances the solubility of polar compounds (such as tea polyphenols) through hydrogen bonding. Compared with traditional organic solvents, it is more environmentally friendly and can achieve efficient extraction at a lower temperature.

[0065] 3.2.3 Microwave-assisted extraction

[0066] Microwave-assisted extraction technology uses microwaves to heat the vibrations of water molecules, achieving rapid heating of samples, thereby enhancing extraction efficiency and significantly shortening the extraction time.

[0067] step:

[0068] The Liubao tea sample was mixed with 70% ethanol at a ratio of 1:10;

[0069] The mixture was placed in a microwave-assisted extraction device, the microwave power was set to 450-600W, the extraction time was 5-10 minutes, and the extraction temperature was controlled not to exceed 60°C;

[0070] The extract is filtered and concentrated to dryness to obtain a tea polyphenol extract.

[0071] Extraction principle: Microwaves quickly heat and destroy cell structures, enhancing the contact between the solvent and the sample, allowing tea polyphenols to be released from the sample faster, while effectively shortening the extraction time and reducing the amount of solvent used.

[0072] 3.3 Extract handling and storage

[0073] Filtration: The extract is filtered through a 0.45μm filter membrane to remove solid impurities and ensure that subsequent testing equipment is not blocked.

[0074] Concentration: The filtered extract is placed in a rotary evaporator and concentrated below 40°C to prevent degradation of tea polyphenols due to high temperature, so as to obtain a dry tea polyphenol extract.

[0075] Storage: Store the dried extract in a brown bottle below 4°C. To further avoid oxidative degradation, 0.02% vitamin C or gallic acid can be added to the extract as an antioxidant.

[0076] 3.4 Qualitative and quantitative detection of tea polyphenols

[0077] According to the properties of the extract, appropriate detection technology is selected for qualitative and quantitative analysis, mainly through high performance liquid chromatography (HPLC) or liquid chromatography-mass spectrometry (LC-MS).

[0078] 3.4.1 High performance liquid chromatography (HPLC) detection

[0079] step:

[0080] The concentrated tea polyphenol extract was dissolved in an appropriate amount of methanol, filtered through a 0.45 μm filter membrane, and then injected into the HPLC system;

[0081] A C18 reverse phase column was used, the mobile phase was water (containing 0.1% phosphoric acid) and acetonitrile, gradient elution was adopted, the flow rate was 1.0 mL / min, and the detection wavelength was 280 nm;

[0082] The content of tea polyphenols was calculated by establishing a standard curve with standard substances (such as catechins and gallic acid).

[0083] Quantitative formula:

[0084] Through the linear relationship between peak area and concentration, the content of tea polyphenols was calculated using the following formula:

[0085]

[0086] in:

[0087] C 样品 is the concentration of tea polyphenols in the sample;

[0088] A 样品 is the peak area of ​​the sample;

[0089] k and b are the regression coefficient and intercept of the standard curve.

[0090] 3.4.2 Liquid chromatography-mass spectrometry (LC-MS) detection

[0091] step:

[0092] The extract was dissolved and injected into the LC-MS system after filtering;

[0093] Electrospray ionization (ESI) mode was used, and the multiple reaction monitoring (MRM) mode was set to detect the mass-to-charge ratio (m / z) range of 100-1000;

[0094] By comparing the mass-to-charge ratio with that of the standard, the structural composition of tea polyphenols was qualitatively analyzed, and quantitative analysis was performed based on the mass spectrum peak area.

[0095] 3.5 Data processing and optimization

[0096] Calculation of extraction rate: The extraction efficiency is calculated by the following formula:

[0097]

[0098] in:

[0099] η 提取 is the extraction rate;

[0100] m 提取物 is the quality of tea polyphenols extract obtained by extraction;

[0101] m 茶叶样品 For the quality of the original Liubao tea sample.

[0102] Optimization: Multi-factor optimization was performed by response surface methodology (RSM), and the optimized parameters included extraction time, solvent ratio, temperature and pressure, etc. The significant effect of each factor on the extraction rate was evaluated by analysis of variance (ANOVA) to determine the optimal extraction conditions.

[0103] Example 1: Supercritical CO2 extraction method

[0104] step:

[0105] Sample pretreatment:

[0106] The Liubao tea samples were crushed to 60 mesh and the moisture content was controlled at 8%.

[0107] Supercritical CO2 extraction:

[0108] Extraction equipment: Supercritical CO2 extraction equipment (SFE-500 model).

[0109] Extraction parameters: pressure 20 MPa, temperature 40°C.

[0110] 5% ethanol was added as a co-solvent and the CO2 flow rate was 5 mL / min.

[0111] Extraction time: 40 minutes.

[0112] Post-processing:

[0113] After the extraction is completed, CO2 is recovered by reducing pressure and cooling.

[0114] The extract is filtered and concentrated by rotary evaporation to finally obtain the tea polyphenol extract.

[0115] Extraction efficiency: The extraction rate is calculated by the formula.

[0116] Comparative Example 1: Traditional solvent extraction method (thermal reflux method)

[0117] step:

[0118] Sample pretreatment:

[0119] The Liubao tea samples were crushed to 60 mesh and the moisture content was controlled at 8%.

[0120] Hot reflux extraction:

[0121] Solvent: 70% ethanol solution.

[0122] Extraction equipment: conventional heat reflux device.

[0123] Extraction conditions: reflux temperature of 80°C and time of 120 minutes.

[0124] Post-processing:

[0125] The extract was filtered through a 0.45 μm filter membrane and concentrated by rotary evaporation to obtain the tea polyphenol extract.

[0126] Extraction efficiency: Calculate the extraction rate using the same formula.

[0127] Example 2: Deep co-solvent system (DES) extraction method

[0128] step:

[0129] Sample pretreatment:

[0130] The Liubao tea samples were crushed to 60 mesh and the moisture content was controlled at 8%.

[0131] DES preparation and extraction:

[0132] DES solvent: Ethylene glycol and choline chloride were mixed in a molar ratio of 1:2 and heated at 80°C until the mixture was uniform.

[0133] Extraction equipment: Ultrasonic assisted extractor (KQ-500DE model).

[0134] Extraction conditions: temperature was 45°C and ultrasonic time was 30 min.

[0135] Post-processing:

[0136] The extract was filtered through a 0.45 μm filter membrane and concentrated by rotary evaporation to finally obtain the tea polyphenol extract. Extraction efficiency: The extraction rate was calculated by the formula.

[0137] Comparative Example 2: Ethanol Cold Soaking Method

[0138] step:

[0139] Sample pretreatment:

[0140] The Liubao tea samples were crushed to 60 mesh and the moisture content was controlled at 8%.

[0141] Ethanol cold soak extraction:

[0142] Solvent: 70% ethanol solution.

[0143] Extraction equipment: ordinary container for static soaking.

[0144] Extraction conditions: Soak at room temperature for 24 hours.

[0145] Post-processing:

[0146] The extract was filtered through a 0.45 μm filter membrane and concentrated by rotary evaporation to obtain the tea polyphenol extract. Extraction efficiency: The extraction rate was calculated using the same formula.

[0147] Example 3: Microwave Assisted Extraction

[0148] step:

[0149] Sample pretreatment:

[0150] The Liubao tea samples were crushed to 60 mesh and the moisture content was controlled at 8%.

[0151] Microwave assisted extraction:

[0152] Solvent: 70% ethanol.

[0153] Extraction equipment: microwave-assisted extractor (MARS240).

[0154] Extraction conditions: microwave power 600W, extraction time 8 minutes, temperature not exceeding 60°C. Post-processing:

[0155] The extract was filtered, concentrated by rotary evaporation, and tea polyphenol extract was obtained.

[0156] Extraction efficiency: The extraction rate is calculated by the formula.

[0157] Comparative Example 3: Normal Temperature Stirring Extraction Method

[0158] step:

[0159] Sample pretreatment:

[0160] The Liubao tea samples were crushed to 60 mesh and the moisture content was controlled at 8%.

[0161] Normal temperature stirring extraction:

[0162] Solvent: 70% ethanol solution.

[0163] Extraction equipment: magnetic stirrer.

[0164] Extraction conditions: Stir at room temperature for 6 hours.

[0165] Post-processing:

[0166] The extract was filtered through a 0.45 μm filter membrane and concentrated by rotary evaporation to obtain the tea polyphenol extract.

[0167] Extraction efficiency: Calculate the extraction rate using the same formula.

[0168] Comparative experiments and results

[0169] In order to verify the superiority of the three extraction methods in the present invention, a comparative experiment was designed, and the same detection method (HPLC) was used to compare the extraction effects of the embodiments and the comparative examples. The tea polyphenol content (mg / g) in the extract was calculated using the standard curve. The experimental data are shown in the following table:

[0170]

[0171]

[0172] By comparing the experimental data, combined with the extraction time, temperature, tea polyphenols content and extraction rate, the method of the present invention (Examples 1-3) has significant advantages over the traditional extraction method (Comparative Examples 1-3):

[0173] 1. Extraction time: The three green extraction methods in the examples significantly shorten the extraction time, especially the microwave-assisted extraction method, which takes only 8 minutes to complete, while the hot reflux method used in the comparative example takes 120 minutes and the ethanol cold soaking method takes up to 24 hours, which is extremely inefficient.

[0174] 2. Extraction efficiency: The tea polyphenol content and extraction rate of the three methods in the embodiment are significantly higher than those in the comparative example. For example, the tea polyphenol content of the supercritical CO2 extraction method is 142.3 mg / g, and the extraction rate reaches 12.5%, while the extraction rate of the conventional heat reflux method is only 8.9%.

[0175] 3. Temperature control: Both supercritical CO2 and DES extraction methods achieve efficient extraction at low temperatures, avoiding the degradation of tea polyphenols at high temperatures. In contrast, the hot reflux method operates at 80°C for a long time, which may cause some tea polyphenols to degrade.

[0176] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for extracting and detecting tea polyphenols in Liubao tea, characterized in that: The following steps are involved: S1, crushing and drying the Liubao tea sample for pretreatment; S2. Extracting tea polyphenols from the Liubao tea sample by green extraction technology, wherein the green extraction technology includes any one of supercritical CO2 extraction, deep co-solvent system extraction, and microwave-assisted extraction; S3, filtering and concentrating the extracted tea polyphenols; S4. Use high performance liquid chromatography or liquid chromatography-mass spectrometry to conduct qualitative and quantitative detection of the extracted tea polyphenols.

2. The method for extracting and detecting tea polyphenols in Liubao tea according to claim 1, characterized in that: The pretreatment step of the Liubao tea sample includes crushing the Liubao tea sample to 60 meshes and adjusting the water content of the sample to 8%-10%.

3. The method for extracting and detecting tea polyphenols in Liubao tea according to claim 1, characterized in that: The steps of the supercritical CO2 extraction method include: (1) placing the Liubao tea sample in a supercritical CO2 extraction device at a pressure of 15-30 MPa and a temperature of 35-50°C; (2) selectively adding ethanol as a co-solvent, with the solvent ratio being 5% to 15% of the sample weight; (3) The extraction time is 30-60 minutes. CO2 is recovered by reducing pressure and cooling, and the extract is collected.

4. The method for extracting and detecting tea polyphenols in Liubao tea according to claim 1, characterized in that: The steps of the deep co-solvent system extraction method include (1) preparing a DES solvent, wherein the DES solvent is prepared by mixing ethylene glycol and choline chloride in a molar ratio of 1:1 to 1:4; (2) 1 g of Liubao tea sample was mixed with 10 mL of DES solution and placed in an ultrasonic-assisted extraction device at a temperature of 40-50°C for 20-40 minutes; (3) The extract is filtered and then processed.

5. The method for extracting and detecting tea polyphenols in Liubao tea according to claim 1, characterized in that: The steps of the microwave-assisted extraction method include: (1) Mix the Liubao tea sample with 70% ethanol solution in a ratio of 1:10; (2) using microwave-assisted extraction equipment, with a microwave power of 450-600 W, an extraction time of 5-10 minutes, and an extraction temperature not exceeding 60°C; (3) The extract is filtered and concentrated to collect the tea polyphenol extract.

6. The method for extracting and detecting tea polyphenols in Liubao tea according to claim 1, characterized in that: The post-treatment step of the tea polyphenols extract comprises: (1) The extract was filtered through a 0.45 μm filter membrane to remove solid impurities; (2) using a rotary evaporator to concentrate at a temperature below 40° C. to obtain a dry tea polyphenol extract; (3) The extract was stored in brown bottles at a temperature below 4°C to prevent oxidative degradation caused by light and high temperature.

7. The method for extracting and detecting tea polyphenols in Liubao tea according to claim 1, characterized in that: The quantitative detection step of tea polyphenols includes using high performance liquid chromatography for detection, and the chromatographic conditions used include: C18 reverse phase chromatographic column, mobile phase of water and acetonitrile gradient elution, flow rate of 1.0 mL / min, and detection wavelength of 280 nm.

8. The method for extracting and detecting tea polyphenols in Liubao tea according to claim 1, characterized in that: The quantitative detection step of tea polyphenols includes using liquid chromatography-mass spectrometry technology, adopting electrospray ionization mode, multiple reaction monitoring mode, and detecting a mass-to-charge ratio range of 100-1000.

9. The method for extracting and detecting tea polyphenols in Liubao tea according to claim 1, characterized in that: The extraction rate calculation formula is: Among them, η 提取 is the extraction rate, m 提取物 is the mass of tea polyphenols extracted, m 茶叶样品 For the quality of the original Liubao tea sample.

10. The method for extracting and detecting tea polyphenols in Liubao tea according to claim 1, characterized in that: In the extraction technology, the main parameters in the extraction process are optimized by a multivariate optimization method, and the parameters include pressure, temperature, extraction time and solvent ratio. Variance analysis is used to evaluate the significant effect of each parameter on the extraction efficiency.

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