Efficient extraction process of active ingredients in dark green tea

Abstract

The invention relates to the technical field of dark green tea extraction, and discloses an efficient extraction process of active ingredients in dark green tea, which comprises the following steps: step 1, crushing dark green tea raw materials to 20-40 meshes; step 2, carrying out enzymolysis treatment on the crushed dark green tea by using a mixed enzyme solution of cellulase and pectinase, and controlling the enzymolysis temperature to be 45 DEG C and the enzymolysis time to be 4 hours; 3, a novel green solvent system is used for being mixed with the dark tea powder, the green solvent is ionic liquid or a deep eutectic solvent, and the weight ratio of the solvent to the dark tea is 10: 1-15: 1; 4, the mixture is treated under the ultrasonic-assisted extraction condition, the ultrasonic frequency is 30 kHz, the power is 300 W, and the extraction time is 30 minutes. Through the combination of a green solvent system and a modern auxiliary extraction technology, the extraction rate of the active ingredients of the dark tea is greatly improved, the active ingredients are slowly released and the extraction rate is relatively low in a traditional process, while the process in the application can remarkably improve the dissolution efficiency of the active ingredients, and the extraction efficiency is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of dark tea extraction, in particular to a high-efficiency extraction process of active ingredients in dark tea. Background Art

[0002] Dark tea is a fermented tea rich in bioactive ingredients such as polyphenols and flavonoids. These ingredients have a variety of health functions such as anti-oxidation, lowering blood lipids, and regulating intestinal flora, and therefore have attracted widespread attention. With the increasing demand for natural health products, how to effectively extract these active ingredients from dark tea has become a hot topic in tea processing and related industry research. Efficient extraction of active ingredients can not only increase the added value of dark tea products, but also promote its application in food, health products and medicine.

[0003] Most of the existing extraction processes for active ingredients in dark tea use organic solvents (such as ethanol or methanol) for extraction. These traditional processes usually extract polyphenols and flavonoids from dark tea by soaking for a long time, heating and distilling. However, there are several problems with this traditional process: first, the amount of solvent used is large and it is easy to volatilize, causing environmental pollution; second, high temperature treatment easily leads to the degradation of active ingredients, affecting the quality of the extract; finally, the extraction time is long, the efficiency is low, and the purity of the extract and the retention rate of active ingredients are not high.

[0004] A major problem of the prior art is that the extraction process is inefficient, the extraction rate and purity of the active ingredients cannot meet the expected requirements, and long-term high-temperature treatment easily leads to degradation of the active ingredients. This not only reduces the quality of the extract, but also increases energy consumption and production costs. Therefore, there is an urgent need for an efficient, environmentally friendly extraction process that can improve the extraction rate and purity of the extract to solve this problem in the prior art. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides an efficient extraction process for active ingredients in black tea, which solves the problems of low extraction efficiency, inability to achieve the expected extraction rate and purity of active ingredients, and easy degradation of active ingredients caused by long-term high-temperature treatment.

[0006] To achieve the above objectives, the present invention is implemented by the following technical scheme: A highly efficient extraction process of active ingredients in dark tea comprises the following steps:

[0007] Step 1: crush the dark tea raw material into 20-40 mesh;

[0008] Step 2: using a mixed enzyme solution of cellulase and pectinase to enzymolyze the crushed dark tea, the enzymolysis temperature is controlled at 45°C, and the time is 4 hours;

[0009] Step 3: using a new green solvent system to mix with dark tea powder, wherein the green solvent is an ionic liquid or a deep eutectic solvent, and the weight ratio of the solvent to the dark tea is 10:1 to 15:1;

[0010] Step 4: treating the mixture under ultrasonic assisted extraction conditions, with an ultrasonic frequency of 30 kHz, a power of 300 W, and an extraction time of 30 minutes;

[0011] Step 5: subjecting the mixture after ultrasonic extraction to microwave treatment under microwave-assisted extraction conditions, with a microwave power of 500 W and an extraction time of 15 minutes;

[0012] Step 6: extract the treated mixture using supercritical fluid extraction technology, the supercritical fluid is CO2, the extraction pressure is 20MPa, the temperature is 50°C, and the time is 1 hour;

[0013] Step 7: The extract is separated by a membrane with a pore size of 0.01-0.1 micrometers for purification and concentration.

[0014] Preferably, in the dark tea crushing step, the dark tea is crushed to a size of 20-30 meshes, and the dark tea powder is immediately placed in a sealed container after crushing and stored at a temperature of 4° C. to 10° C. to prevent oxidation and degradation of active ingredients.

[0015] Preferably, during the enzymatic hydrolysis process, the mixing ratio of cellulase to pectinase is 1:1, the enzyme solution concentration is 1%-2%, and the enzymatic hydrolysis time is 3 to 5 hours, and the stirring speed is 100-150 rpm during the enzymatic hydrolysis process.

[0016] Preferably, after the enzymatic hydrolysis is completed, the enzymatic hydrolysis solution is heated to 90° C. and maintained at 90° C. for 10 to 15 minutes to completely terminate the activity of the enzyme.

[0017] Preferably, the green solvent is 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, and is mixed with water in a volume ratio of 1:10; the ionic liquid solvent is preheated at 40°C to 45°C before use to ensure that its viscosity is suitable for the extraction of active ingredients in black tea.

[0018] Preferably, the mixing ratio of the green solvent system to the dark tea powder is 10:1 to 15:1, and the solvent soaking is carried out at a temperature of 60° C. for 2 hours to ensure maximum dissolution of the active ingredient.

[0019] Preferably, during the ultrasonic-assisted extraction process, the ultrasonic frequency is 30 to 35 kHz, the ultrasonic power is 300 to 350 W, and the ultrasonic extraction time is 30 to 40 minutes. Intermittent ultrasonic treatment is used during the extraction process, with a 2-minute rest every 10 minutes.

[0020] Preferably, in the microwave-assisted extraction process, the microwave power is 500 to 600 W, the microwave treatment time is 10 to 20 minutes, and the extraction solution after microwave heating is quickly cooled to room temperature to avoid thermal degradation of the active ingredients.

[0021] Preferably, during the supercritical fluid extraction process, the CO2 flow rate is controlled at 2 to 4 L / min, the supercritical extraction pressure is 20 to 25 MPa, the extraction temperature is 45° C. to 55° C., and the extraction time is 1 to 2 hours.

[0022] Preferably, in the membrane separation process, a nanofiltration membrane and an ultrafiltration membrane are combined for separation, the pore size of the nanofiltration membrane is 0.01 micron, the pore size of the ultrafiltration membrane is 0.1 micron, the filtration pressure is 0.5 to 1 MPa, and the filtration temperature is controlled at 25 to 30°C.

[0023] The present invention provides an efficient extraction process for active ingredients in dark tea, which has the following beneficial effects:

[0024] 1. The present invention greatly improves the extraction rate of active ingredients in dark tea by combining a green solvent system and modern auxiliary extraction technology, and the extraction rate reaches more than 90%. In the traditional process, the active ingredients are released slowly and the extraction rate is low, while the process in this application can significantly improve the dissolution efficiency of the active ingredients and the extraction efficiency is significantly improved.

[0025] 2. The present invention can retain the key active ingredients such as polyphenols and flavonoids in black tea to the maximum extent by precisely controlling the process parameters, especially the temperature, solvent type and extraction time. The experimental results show that the content of polyphenols and flavonoids extracted by the present invention is significantly higher than that of the traditional process, ensuring the function and quality of the extract.

[0026] 3. The present invention uses membrane separation technology to purify the extract. The present invention can effectively remove impurities in the extract, and the purity of the extract is as high as 96%, which is significantly better than the 75% of the traditional process. This high-purity extract can be further applied to high-value food, health products and pharmaceutical products.

[0027] 4. The present invention significantly shortens the extraction time from 12 hours in the traditional process to 5.5 hours through the synergistic effect of ultrasonic, microwave and supercritical fluid extraction technology. At the same time, low temperature and high efficiency extraction methods reduce energy consumption and improve the economy and operability of the process.

[0028] 5. The present invention uses green solvents, reduces the use of organic solvents, and avoids environmental pollution. Compared with the use of organic solvents such as ethanol in traditional processes, this process is more environmentally friendly, reduces the burden of waste disposal, and meets the requirements of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments 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.

[0031] Embodiment 1:

[0032] Please refer to the attached Figure 1 The embodiment of the present invention provides an efficient extraction process of active ingredients in dark tea, comprising the following steps:

[0033] 1. Raw material preparation

[0034] In this embodiment, in order to ensure that the black tea raw material in the extraction process has a high content of active ingredients, firstly, black tea rich in polyphenols and flavonoids is selected from high-quality production areas. The moisture content of black tea should be controlled at 8%-12%. This is because if the moisture content is too high, adhesion is easy to occur during the crushing process, affecting the crushing effect; and if the moisture content is too low, the black tea raw material is easy to be too dry and fragile, which may lead to excessive loss of active ingredients during the extraction process. Therefore, moderate moisture content is the key to ensure that the active ingredients of black tea are effectively retained.

[0035] In this embodiment, a high-speed pulverizer is used to pulverize the dark tea, and the pulverization particle size is controlled between 20-40 meshes. The purpose of pulverization is to increase the specific surface area of ​​the dark tea, so that the solvent can more fully contact the inside of the dark tea cells during the subsequent extraction process, and ensure that the active ingredients can be released to the maximum extent. In order to avoid oxidation of the active ingredients due to air contact during the pulverization process, the pulverized dark tea should be immediately placed in a sealed container and stored in a low temperature environment of 4°C to 10°C. This can not only prevent the oxidation of the active ingredients, but also effectively inhibit the activity of the enzymes in the dark tea and reduce the degradation of the ingredients.

[0036] By crushing the dark tea, the specific surface area is significantly increased, which helps the solvent penetrate deeper into the dark tea cells during the subsequent extraction process. At the same time, low-temperature storage can reduce the oxidation of powder and other chemical reactions produced during the crushing process, ensuring that the active ingredients are retained in the subsequent extraction steps, thus laying the foundation for efficient extraction.

[0037] 2. Enzyme pretreatment

[0038] In this embodiment, the bio-enzyme pretreatment is to promote the effective release of active ingredients in black tea. Cellulase and pectinase are selected for enzymatic treatment, the purpose of which is to degrade the cellulose and pectin of the black tea cell wall so that the active ingredients inside the cell can be more easily released into the solution. The preparation of the enzyme solution is modulated at an enzyme solution concentration ratio of 1%-2% according to the weight of the black tea, and the cellulase and pectinase are mixed in a ratio of 1:1. In order to ensure the activity of the enzyme, the pH value of the enzyme solution should be adjusted between 4.5-5.5. This pH range helps to maintain the activity of the enzyme while avoiding other unnecessary reactions.

[0039] In this embodiment, the crushed black tea powder is added to the enzyme solution at a ratio of 1:5, that is, 1 kg of black tea powder is added to 5 liters of enzyme solution. The temperature of the enzymatic hydrolysis treatment is set to 45°C, the stirring speed is maintained between 100-150rpm, and the enzymatic hydrolysis treatment time is 3-5 hours. Stirring can ensure that the black tea powder is fully in contact with the enzyme solution and enhance the enzymatic hydrolysis efficiency. During the entire enzymatic hydrolysis process, precise control of temperature and stirring speed is very critical. Too high a temperature may cause enzyme inactivation, while too low a temperature may slow down the enzymatic hydrolysis rate.

[0040] In this embodiment, after the enzymatic hydrolysis is completed, the solution temperature is raised to 90° C. by heating and maintained for 10-15 minutes to terminate the activity of the enzyme. The purpose of heating is to prevent the enzyme from excessively degrading the components in the dark tea and to provide suitable conditions for the subsequent extraction step.

[0041] Bio-enzyme pretreatment can effectively degrade cellulose and pectin in the cell wall of dark tea, thereby reducing the hindrance of cell structure to active ingredients and increasing the release rate of active ingredients. The uniformity and efficiency of the enzymatic hydrolysis reaction are ensured by precisely controlling the temperature and stirring speed. The enzymatic hydrolysis termination step stops the action of the enzyme by heating, avoiding excessive degradation of the ingredients, further laying the foundation for efficient extraction.

[0042] 3. New green solvent

[0043] In this embodiment, in order to further improve the extraction efficiency of active ingredients in black tea, a new green solvent system is used. The ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate is mixed with water in a volume ratio of 1:10, or choline chloride and ethylene glycol are selected to prepare a deep eutectic solvent in a molar ratio of 1:3. The solvent should be preheated to 40°C to 45°C before use. This temperature helps to reduce the viscosity of the solvent so that it can better penetrate into the black tea powder during the extraction process. Green solvents not only have good dissolving power, but are also environmentally friendly and can reduce the negative impact of organic solvents on the environment.

[0044] In this example, the enzymatically hydrolyzed dark tea powder was added to the green solvent at a ratio of 1:10 to 1:15. The solvent was soaked at 60°C for 2 hours, and the stirring speed was set at 100-120 rpm. The purpose of stirring was to ensure full contact between the dark tea powder and the solvent, so as to promote more uniform and thorough dissolution of the active ingredients.

[0045] The green solvent system has good dissolving ability and can effectively extract active ingredients such as polyphenols and flavonoids in dark tea. At the same time, the reasonable control of the ratio of solvent to dark tea powder, temperature and stirring speed ensures that the active ingredients are fully dissolved in the solvent. By using environmentally friendly solvents, the environmental burden brought by organic solvents is effectively reduced and the sustainability of the process is improved.

[0046] 4. Modern assisted extraction

[0047] In this embodiment, ultrasonic-assisted extraction is an important step to promote the rapid release of active ingredients in dark tea. The soaked dark tea and solvent mixture are placed in an ultrasonic extraction device, the ultrasonic frequency is set to 30-35kHz, the power is 300-350W, and the extraction time is 30-40 minutes. In order to prevent the solution from overheating and causing degradation of the active ingredients, an intermittent treatment method is adopted, that is, rest for 2 minutes every 10 minutes. The cavitation effect of ultrasound further promotes the release of active ingredients by destroying cell membranes, while accelerating the interaction between solvent molecules and active ingredients.

[0048] In this embodiment, the solution after ultrasonic treatment is subjected to microwave-assisted extraction. The main function of microwaves is to accelerate the dissolution of active ingredients by rapidly heating the solvent and increasing the intermolecular forces between the solvent and the dark tea powder. The microwave power is set to 500-600W and the treatment time is 10-20 minutes. In order to avoid inactivation of the active ingredients in the solution due to overheating, the solution should be cooled immediately after microwave treatment to ensure that the active ingredients maintain their biological activity.

[0049] In this embodiment, supercritical CO2 extraction technology is used to further improve the extraction efficiency of active ingredients in black tea. The treated solution is placed in a supercritical CO2 extraction device, the CO2 flow rate is controlled at 2-4 liters / minute, the extraction pressure is set to 20-25MPa, the temperature is controlled at 45-55°C, and the extraction time is 1-2 hours. Supercritical CO2 as a fluid has excellent solubility under high temperature and high pressure, and can effectively extract various polar and non-polar active ingredients in black tea.

[0050] Through the combined application of three modern extraction technologies, namely ultrasound, microwave and supercritical fluid, each technology improves the mass transfer and heat transfer efficiency during the extraction process from different physical mechanisms. Ultrasound promotes deep contact between solvent and dark tea through physical vibration, microwave accelerates dissolution through thermal effect, and supercritical fluid technology can extract active ingredients that are difficult to extract with traditional solvents under mild conditions.

[0051] 5. Purification and concentration by membrane separation technology

[0052] In this embodiment, membrane separation technology is used to purify and concentrate the extract. First, the extract is initially separated using a nanofiltration membrane with a pore size of 0.01 micron, a filtration pressure controlled at 0.5-1 MPa, and a filtration temperature set at 25-30°C. The nanofiltration process can effectively remove macromolecular impurities in the extract, such as proteins and polysaccharides, while retaining small molecular active ingredients.

[0053] In this embodiment, the solution after nanofiltration separation is concentrated by an ultrafiltration membrane, the pore size of the ultrafiltration membrane is 0.1 micron, the operating pressure is set to 0.5-1 MPa, and the temperature is maintained at 25-30° C. The ultrafiltration process can further increase the concentration of active ingredients in the extract, and the volume of the extract is reduced to 1 / 3 of the original volume, which is suitable for subsequent drying treatment or direct application.

[0054] Through membrane separation technology, impurities in the extract can be effectively removed to ensure high purity and high concentration of active ingredients. The combined use of nanofiltration and ultrafiltration can simultaneously achieve fine purification and concentration of the extract, which helps to improve the quality of the extract and make it suitable for industrial production or further drug development applications.

[0055] Embodiment 2:

[0056] In this embodiment, the particle size of the black tea raw material is set to be between 50-80 meshes, and other process parameters are completely consistent with those in Example 1. The black tea has a larger particle size, resulting in a relatively small specific surface area, thereby reducing the penetration of the solvent to the active ingredients of the black tea, thereby affecting the extraction efficiency. Specifically, the following steps are included:

[0057] Raw materials preparation:

[0058] The moisture content of black tea is controlled at 8%-12%, and high-quality black tea is selected as the raw material. Use a high-speed grinder to grind the black tea into 50-80 meshes, and immediately seal and store it in a low temperature environment of 4℃ to 10℃ after grinding.

[0059] Enzyme pretreatment:

[0060] The same enzymatic treatment conditions as in Example 1 were used, with cellulase and pectinase mixed in a ratio of 1:1, an enzyme solution concentration of 1%-2%, an enzymatic hydrolysis temperature of 45°C, and an enzymatic hydrolysis time of 3-5 hours. After the enzymatic hydrolysis was completed, the temperature was raised to 90°C and maintained for 10-15 minutes to terminate the enzyme activity.

[0061] Selection and use of green solvents:

[0062] The same green solvent as in Example 1 was used, 1-butyl-3-methylimidazolium hexafluorophosphate was mixed with water at a ratio of 1:10. The enzymatically hydrolyzed dark tea powder was mixed with the solvent at a ratio of 1:10, the solvent soaking temperature was 60°C, the soaking time was 2 hours, and the stirring speed was 100-120 rpm.

[0063] Modern assisted extraction:

[0064] Ultrasonic-assisted extraction (frequency 30-35kHz, power 300-350W, time 30-40 minutes), microwave-assisted extraction (power 500-600W, time 10-20 minutes), and supercritical CO2 extraction (CO2 flow rate 2-4 L / min, pressure 20-25MPa, temperature 45-55°C, time 1-2 hours) were used to extract the active ingredients in black tea.

[0065] Purification and concentration by membrane separation technology:

[0066] The pore size of the nanofiltration membrane is 0.01 micron, the pore size of the ultrafiltration membrane is 0.1 micron, the filtration pressure is 0.5-1MPa, the filtration temperature is 25-30℃, and the volume of the extract is reduced to 1 / 3 of the original volume.

[0067] Compared with Example 1, in Example 2, due to the larger particle size of the black tea powder, the release and dissolution of the active ingredients were affected, and the extraction efficiency was significantly reduced. Specifically, the extraction rate of the active ingredients decreased, and the content of polyphenols and flavonoids in the final extract was lower than that in Example 1. In addition, due to the larger particle size, the solvent did not penetrate sufficiently into the black tea powder, resulting in a longer extraction time and a decrease in the purity of the extract.

[0068] The effect of Example 1 is better than that of Example 2. In Example 1, the crushed particle size is small (20-40 mesh), so that the specific surface area is greatly increased, and the solvent can penetrate into the interior of the dark tea powder more fully, thereby significantly improving the extraction efficiency of the active ingredients and the purity of the extract.

[0069] Embodiment three:

[0070] In this embodiment, a traditional organic solvent (ethanol) is used to replace the green solvent system in Example 1, and other process parameters are consistent with Example 1. Since the polarity and solubility of ethanol are different from those of green solvents, the dissolution efficiency of the active ingredient in the extraction process is low, and the specific steps include:

[0071] Raw materials preparation:

[0072] The moisture content of black tea is controlled at 8%-12%, and high-quality black tea is selected as the raw material. Use a high-speed grinder to crush the black tea into 20-40 meshes, and immediately seal and store it in a low temperature environment of 4℃ to 10℃ after crushing to avoid oxidation.

[0073] Enzyme pretreatment:

[0074] Cellulase and pectinase were used for enzymatic hydrolysis, with an enzyme concentration of 1%-2%, an enzymatic hydrolysis temperature of 45°C, a time of 3-5 hours, and a stirring speed of 100-150 rpm. After the enzymatic hydrolysis was completed, the enzyme activity was terminated by heating to 90°C for 10-15 minutes.

[0075] Selection and use of organic solvents:

[0076] Ethanol is used as a solvent, the concentration of ethanol is 70%, the black tea powder and ethanol are mixed in a ratio of 1:10, the solvent soaking temperature is 60° C., the soaking time is 2 hours, and the stirring speed is 100-120 rpm.

[0077] Modern assisted extraction:

[0078] During the extraction process, the parameters of ultrasonic assisted extraction were set at a frequency of 30-35kHz, a power of 300-350W, and a time of 30-40 minutes; the power of microwave assisted extraction was 500-600W, and the processing time was 10-20 minutes. The CO2 flow rate of supercritical CO2 extraction was controlled at 2-4 liters / minute, the pressure was 20-25MPa, the temperature was controlled at 45-55°C, and the extraction time was 1-2 hours.

[0079] Purification and concentration by membrane separation technology:

[0080] The pore size of the nanofiltration membrane is 0.01 micron, the pore size of the ultrafiltration membrane is 0.1 micron, the filtration pressure is set at 0.5-1MPa, the temperature is maintained at 25-30°C, and the volume of the concentrated extract is 1 / 3 of the original volume.

[0081] Compared with Example 1, the use of ethanol as an organic solvent in Example 3 resulted in a significant decrease in the extraction efficiency of the active ingredients of dark tea. Although ethanol has a strong solubility, it is not as effective as the green solvent system in Example 1 when dealing with complex components such as polyphenols and flavonoids. The impurity content during the extraction process is relatively high, and the purity of the final extract is low. Due to the high volatility of ethanol, there is also a risk of solvent loss during the extraction process, which increases costs. In addition, ethanol has a large environmental impact, and the subsequent solvent recovery process is complicated.

[0082] The effect of Example 3 is not as good as that of Example 1. The green solvent system in Example 1 not only has higher extraction efficiency, but also reduces environmental pollution and solvent loss, and the purity of the extract and the content of active ingredients are also higher.

[0083] Table 1 Comparison table of experimental data of embodiment

[0084] Embodiment 1 Embodiment 2 Embodiment 3 Crushing particle size 20-40 mesh 50-80 mesh 20-40 mesh Solvent Type Green solvents Green solvents 70% ethanol Active ingredient extraction rate (%) 90.5 75.3 68.3 Polyphenol content (mg / g) 85.6 70.4 65.3 Flavonoid content (mg / g) 12.5 9.8 8.5 Extract purity (%) 96.4 85.7 80.1 Solvent loss (%) 1.5 1.5 6.2 Extraction time (hours) 5.5 6.8 5.5 Environmental impact Low Low high

[0085] Example 1: shows the highest active ingredient extraction rate and extract purity, short extraction time and minimum solvent loss, reflecting the advantages of the green solvent system.

[0086] Example 2: Due to the large crushing particle size, the extraction efficiency is significantly reduced, the extraction time is prolonged, and the content and purity of the active ingredient are lower than those in Example 1.

[0087] Example 3: Using the traditional organic solvent ethanol, although the extraction time is similar to that of Example 1, the extraction rate and purity of the active ingredient are lower. At the same time, ethanol is more volatile, resulting in increased solvent loss and greater environmental impact.

[0088] In summary, the technical solution of Example 1 has obvious advantages in extraction effect and environmental protection.

[0089] Comparative Example 1:

[0090] The following are the traditional process steps for extracting active ingredients from dark tea. Usually, a simpler organic solvent extraction method is used. The process is as follows:

[0091] Raw materials preparation:

[0092] Select black tea raw materials and perform simple screening to remove impurities and moldy parts.

[0093] Black tea leaves or slightly crushed tea leaves are used directly for extraction without being crushed.

[0094] Solvent selection and immersion:

[0095] Use common organic solvents such as ethanol (70%-90%) or methanol. Ethanol is a more commonly used solvent.

[0096] Mix dark tea and ethanol in a ratio of 1:10-1:20, and soak at room temperature or heated to about 50°C for 12-24 hours to ensure that the active ingredients are gradually dissolved from the dark tea.

[0097] filter:

[0098] After soaking, the extract is filtered out through a simple filter to remove solid residues such as tea dregs to obtain a preliminary extract.

[0099] concentrate:

[0100] The filtered extract is concentrated by vacuum distillation or a rotary evaporator to evaporate most of the solvent and make the extract more concentrated.

[0101] In traditional processes, this step is usually carried out at a high temperature of 70°C to 80°C, which can easily lead to the degradation of some active ingredients.

[0102] dry:

[0103] The concentrated extract is treated by spray drying or conventional drying to obtain dry extract powder.

[0104] The temperature during the drying process is usually controlled between 70℃-90℃ and the time is about several hours.

[0105] Extract preservation:

[0106] After drying, the extract should be stored in a dry, cool place, sealed and away from moisture and direct sunlight.

[0107] Solvent usage: Traditional methods use common organic solvents such as ethanol or methanol, which are less environmentally friendly.

[0108] Long extraction time: The soaking time is longer, usually 12-24 hours.

[0109] High temperature operation: High temperature treatment during the concentration and drying process can easily lead to degradation and loss of some active ingredients.

[0110] Low extraction efficiency: Due to the lack of modern technical means, the extraction efficiency is relatively low, there are more impurities, and the purity of the extract is not high.

[0111] Table 2 Comparative Example Experimental Data Table

[0112] Comparative Example 1 Embodiment 1 Active ingredient extraction rate (%) 60.2 90.5 Polyphenol content (mg / g) 50.3 85.6 Flavonoid content (mg / g) 6.8 12.5 Extract purity (%) 75 96.4 Extraction time (hours) 12 5.5 Environmental impact high Low Solvent loss (%) 8.5 1.5

[0113] Active ingredient extraction rate: The extraction rate of the preferred embodiment (Example 1) is 90.5%, which is significantly higher than 60.2% of the traditional process. This shows that the green solvent system and modern extraction technology in the preferred embodiment significantly improve the extraction efficiency of active ingredients in dark tea.

[0114] Polyphenol and flavonoid content: The polyphenol content in the preferred embodiment is 85.6 mg / g, and the flavonoid content is 12.5 mg / g, both higher than 50.3 mg / g and 6.8 mg / g in the traditional process. This shows that Example 1 more effectively retains the key active ingredients in dark tea, and the extraction effect is better.

[0115] Extract purity: The extract purity of the preferred embodiment is 96.4%, while the traditional process is only 75.0%. This shows that the process of Example 1 not only has a high extraction rate, but also can better remove impurities and obtain a purer extract.

[0116] Extraction time: The extraction time of the preferred embodiment is 5.5 hours, which is much shorter than 12.0 hours of the traditional process, indicating that modern auxiliary extraction technology speeds up the extraction process and greatly improves production efficiency.

[0117] Environmental impact: Example 1 uses green solvents, which have a lower environmental impact, while the traditional process uses organic solvents such as ethanol, which have a greater environmental impact. The process of Example 1 is more environmentally friendly and meets the requirements of modern green chemical industry.

[0118] Solvent loss: The solvent loss of the preferred embodiment is 1.5%, while the traditional process is 8.5%. The solvent system of the preferred embodiment is more stable and has less loss, which effectively reduces the production cost.

[0119] The first embodiment is significantly superior to the traditional process in terms of extraction efficiency, component retention, extract purity, environmental protection and time cost. Therefore, the first embodiment is a more superior extraction process and is suitable for large-scale industrial application.

[0120] 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. An efficient extraction process for active ingredients in dark tea, characterized in that: The following steps are involved: Step 1: crush the dark tea raw material into 20-40 mesh; Step 2: using a mixed enzyme solution of cellulase and pectinase to enzymolyze the crushed dark tea, the enzymolysis temperature is controlled at 45°C, and the time is 4 hours; Step 3: using a new green solvent system to mix with dark tea powder, wherein the green solvent is an ionic liquid or a deep eutectic solvent, and the weight ratio of the solvent to the dark tea is 10:1 to 15:1; Step 4: treating the mixture under ultrasonic assisted extraction conditions, with an ultrasonic frequency of 30 kHz, a power of 300 W, and an extraction time of 30 minutes; Step 5: subjecting the mixture after ultrasonic extraction to microwave treatment under microwave-assisted extraction conditions, with a microwave power of 500 W and an extraction time of 15 minutes; Step 6: extract the treated mixture using supercritical fluid extraction technology, the supercritical fluid is CO2, the extraction pressure is 20MPa, the temperature is 50°C, and the time is 1 hour; Step 7: The extract is separated by a membrane with a pore size of 0.01-0.1 micrometers for purification and concentration.

2. The efficient extraction process of active ingredients in dark tea according to claim 1, characterized in that: In the dark tea crushing step, the dark tea is crushed to a size of 20-30 meshes, and the dark tea powder is immediately placed in a sealed container after crushing and stored at a temperature of 4° C. to 10° C.

3. The efficient extraction process of active ingredients in dark tea according to claim 1, characterized in that: During the enzymatic hydrolysis process, the mixing ratio of cellulase to pectinase is 1:1, the enzyme solution concentration is 1%-2%, the enzymatic hydrolysis time is 3 to 5 hours, and the stirring speed is 100-150 rpm during the enzymatic hydrolysis process.

4. The efficient extraction process of active ingredients in dark tea according to claim 1, characterized in that: After the enzymatic hydrolysis is completed, the enzymatic hydrolysis solution is heated to 90°C and maintained for 10 to 15 minutes.

5. The efficient extraction process of active ingredients in dark tea according to claim 1, characterized in that: The green solvent is 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, which is mixed with water in a volume ratio of 1:10; the ionic liquid solvent is preheated at 40° C. to 45° C. before use.

6. The efficient extraction process of active ingredients in dark tea according to claim 1, characterized in that: The mixing ratio of the green solvent system to the dark tea powder is 10:1 to 15:1, and the solvent soaking is carried out at a temperature of 60° C. for 2 hours.

7. The efficient extraction process of active ingredients in dark tea according to claim 1, characterized in that: During the ultrasonic-assisted extraction process, the ultrasonic frequency is 30 to 35 kHz, the ultrasonic power is 300 to 350 W, and the ultrasonic extraction time is 30 to 40 minutes. Intermittent ultrasonic treatment is used during the extraction process, with a 2-minute rest every 10 minutes.

8. The efficient extraction process of active ingredients in dark tea according to claim 1, characterized in that: In the microwave-assisted extraction process, the microwave power is 500 to 600 W, the microwave treatment time is 10 to 20 minutes, and the extraction solution after microwave heating is quickly cooled to room temperature.

9. The efficient extraction process of active ingredients in dark tea according to claim 1, characterized in that: During the supercritical fluid extraction process, the CO2 flow rate is controlled at 2 to 4 liters / minute, the supercritical extraction pressure is 20 to 25 MPa, the extraction temperature is 45° C. to 55° C., and the extraction time is 1 to 2 hours.

10. The efficient extraction process of active ingredients in dark tea according to claim 1, characterized in that: In the membrane separation process, a nanofiltration membrane and an ultrafiltration membrane are combined for separation. The pore size of the nanofiltration membrane is 0.01 micron, the pore size of the ultrafiltration membrane is 0.1 micron, the filtration pressure is 0.5 to 1 MPa, and the filtration temperature is controlled at 25 to 30°C.

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