Preparation method of brand-new birch tea

Abstract

The invention discloses a preparation method of brand-new birch tea, and relates to the technical field of tea drink processing. According to the method, birch twigs and buds and phloem are used as raw materials, and low-temperature ultrasonic cleaning, sectional type gradient drying, ultrahigh-pressure low-temperature wall breaking, composite enzymolysis, low-temperature fermentation, supercritical CO2 extraction, microwave vacuum drying and the like are performed to prepare the birch health-care food. Through innovative process combination, active ingredients such as triterpenoids and flavonoids in birches are effectively reserved, the problems that traditional birch tea is heavy in bitter taste and low in effective ingredient utilization rate are solved, and the obtained birch tea is rich in nutrition and warm and moist in taste, has good anti-oxidation and immune regulation functions and is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of tea processing technology, specifically a novel method for preparing birch tea. Background Technology

[0002] Birch, a deciduous tree widely distributed in temperate regions, contains abundant bioactive components in its bark, branches, and leaves, including triterpenoids, flavonoids, polyphenols, amino acids, and various trace elements. These components possess various pharmacological effects, such as antioxidant, anti-inflammatory, and immune-boosting properties. There is a long-standing tradition of using parts of birch tree to make tea, believing it to have health benefits. However, the traditional method of simply drying the birch and then steeping it directly presents several problems.

[0003] First, traditional preparation methods are crude, typically involving only simple washing and natural drying. This makes it difficult to completely remove impurities from the raw materials, and the natural drying process makes them susceptible to microbial contamination, affecting product safety. Second, the active ingredients in birch raw materials are mostly encased in tough cell walls, which traditional methods cannot break down, resulting in poor dissolution of active ingredients and extremely low absorption rates by the human body. Furthermore, untreated birch raw materials contain high levels of tannins and volatile oils, which produce a distinctly bitter and pungent taste when brewed directly, severely impacting the drinking experience and limiting its promotion as a daily tea beverage.

[0004] While there are some studies on birch product processing in the existing technology, most focus on the extraction of single components, such as birch sap, with limited research on systematic preparation processes for birch tea. Some processes employ high-temperature drying, resulting in significant loss of heat-sensitive active ingredients; others attempt enzymatic hydrolysis, but inappropriate enzyme selection and poor control of processing conditions fail to effectively improve taste and increase component utilization. Furthermore, existing processes generally suffer from long production cycles, high energy consumption, and unstable product quality, making industrial-scale production difficult.

[0005] With increasing health awareness, the demand for natural health-promoting teas is growing. Developing a novel birch tea preparation method that effectively preserves the active ingredients of birch, improves taste, and is suitable for industrial production has significant practical importance and market value. This invention addresses the shortcomings of existing technologies by providing a birch tea preparation method that is technologically sound, highly innovative, and yields remarkable results. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention provides a novel method for preparing birch tea, which solves the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides a novel method for preparing birch tea, comprising the following specific steps: S1. Select healthy birch trees with a growth cycle of 3 to 5 years. Collect tender shoots with a diameter of 0.5 to 1.0 cm and phloem with a thickness of 0.3 to 0.5 cm in April and May each year. Cut the tender shoots into small segments with a length of 1 to 2 cm and slice the phloem into thin slices with an area of ​​2 to 3 cm². Mix them evenly to obtain a raw material mixture. The mass ratio of tender shoots to phloem in the raw material mixture is 3:2. S2. Place the raw material mixture in an ultrasonic cleaner, add purified water at a temperature of 4-6℃, with a material-to-liquid ratio of 1:8-1:10, turn on the ultrasonic cleaner, set the power to 200-250W, the frequency to 40kHz, and the cleaning time to 15-20 minutes. Change the purified water every 5 minutes during the cleaning process. After cleaning, remove the raw material and quickly dry the surface moisture with hot air at 30-40℃, controlling the moisture content of the raw material to 65%-70%. S3. Place the cleaned raw materials into a vacuum drying oven and use a segmented gradient drying method to reduce the moisture content of the raw materials to 15%–20%. The segmented gradient drying process is as follows: (1) Dry for 1.5 to 2 hours under vacuum of 0.06-0.07 MPa and temperature of 35-40℃; (2) Adjust the vacuum to 0.08-0.09 MPa and the temperature to 45-50℃, and continue drying for 1-1.5 hours; (3) Maintain the vacuum at 0.09 MPa, lower the temperature to 30-35℃, and dry for 30-40 min; S4. The dried raw material is fed into an ultra-high pressure processing device. Under the condition of -5 to 0℃, a pressure of 300-350MPa is applied and the pressure is maintained for 10 to 15 minutes. After depressurization, the raw material is taken out and immediately crushed and passed through an 80-100 mesh sieve to obtain birch powder. S5. Add 5-8 times the weight of deionized water to the birch powder, stir evenly, and adjust the pH to 4.5-5.0. Add 0.3%-0.5% of the weight of birch powder of a compound enzyme, which is composed of cellulase, pectinase, and protease in a mass ratio of 2:1:1. Incubate the enzyme in a constant temperature water bath at 45-50℃ for 2-2.5 hours, stirring once every 30 minutes for 2 minutes each time. After the enzymatic hydrolysis is completed, raise the temperature of the solution to 90-95℃ and keep it at that temperature for 10 minutes to deactivate the enzyme. S6. Cool the enzymatically hydrolyzed solution to 30-32℃, and inoculate it with 1%-2% of fermentation inoculum by weight. The fermentation inoculum is a mixed bacterial solution of Lactobacillus plantarum and Saccharomyces cerevisiae in a volume ratio of 1:1, with a bacterial concentration of 10. 8 -10 9CFU / mL; fermentation was carried out under sealed conditions in a fermentation chamber at 30-32℃ for 18-24 hours, with the relative humidity maintained at 60%-65% during the fermentation process. S7. Press and filter the fermented material to obtain filtrate and filter residue; put the filter residue into a supercritical extraction vessel and extract for 1.5 to 2 hours using CO2 as the extractant at an extraction pressure of 25-30 MPa, an extraction temperature of 40-45℃, and a CO2 flow rate of 20-25 L / h; collect the extract and mix it evenly with the above filtrate to obtain a mixture. S8. The mixture is fed into a microwave vacuum dryer. The vacuum degree is set to 0.08-0.09MPa, the microwave power is 600-700W, the drying temperature is controlled at 40-45℃, and the drying time is 40-50min. During the drying process, the mixture is stirred once every 10min. When the moisture content of the material drops to 5%-8%, the drying is stopped. The material is then removed, crushed, and passed through a 120-150 mesh sieve to obtain the finished birch tea product.

[0008] Optionally, in step S1, the collected tender shoots must be plump and free from pests and diseases, and the outer layer of the phloem must be removed, leaving only the inner phloem tissue.

[0009] Optionally, in step S2, the ultrasonic cleaner uses a multi-frequency ultrasonic generator to maintain a stable water temperature of 4-6℃ during the cleaning process, and temperature control is achieved through an external constant temperature cooling device.

[0010] Optionally, in step S3, the drying time, temperature, and vacuum parameters of the three stages of segmented gradient drying correspond sequentially, and the temperature adjustment rate does not exceed 5℃ / min when switching between each stage.

[0011] Optionally, in step S4, the pressurization rate of the ultra-high pressure treatment equipment is 50 MPa / min, and the depressurization rate is 30 MPa / min, to ensure that the raw material cells are uniformly broken under low temperature and high pressure.

[0012] Optionally, in step S5, the method of adding the complex enzyme is as follows: Dissolve the compound enzyme in a small amount of deionized water at 40°C to prepare an enzyme solution; slowly add it to the mixture of birch powder and deionized water while stirring.

[0013] Optionally, in step S6, the fermentation strain needs to be activated before inoculation, specifically as follows: The cryopreserved bacterial strain was inoculated into MRS liquid medium and cultured at 37°C for 18 hours. The culture was passaged twice, and the bacterial cells were collected by centrifugation, washed twice with sterile physiological saline, and adjusted to the required concentration.

[0014] Optionally, in step S7, the separation conditions for supercritical CO2 extraction are: The primary separation pressure is 8-10 MPa, and the temperature is 30-35℃. The secondary separation pressure is 5-6 MPa and the temperature is 25-30℃. The extract is collected from the primary separator.

[0015] Optionally, in step S8, the microwave vacuum dryer adopts a pulsed microwave output mode, operates for 5 minutes, pauses for 1 minute, and repeats this cycle until the desired moisture content is reached.

[0016] This invention provides a novel method for preparing birch tea, which has the following beneficial effects: This novel birch tea preparation method employs a series of advanced processes, including segmented gradient drying, ultra-high pressure low-temperature cell disruption, and supercritical CO2 extraction, which work synergistically to minimize the damage and loss of active ingredients. Specifically, the ultra-high pressure low-temperature cell disruption technology breaks down the cell walls of the raw materials under low-temperature conditions using high pressure, avoiding the impact of high temperatures on heat-sensitive components and increasing the dissolution rate of active ingredients by more than 40%. Supercritical CO2 extraction selectively extracts fat-soluble active ingredients, complementing water-soluble components and significantly enhancing the product's nutritional value. Secondly, this invention effectively improves the drinking taste of birch tea. Through the organic combination of compound enzymatic hydrolysis and low-temperature fermentation, the cellulase and pectinase in the compound enzymes can decompose the cellulose and pectin in the raw materials, reducing the crude fiber content. The protease can decompose some proteins into small molecule peptides and amino acids, improving the taste. The mixed fermentation of lactic acid bacteria and yeast can not only further decompose bitter substances, but also produce flavor substances such as organic acids and alcohols, giving the product a mellow and smooth taste and a unique aroma. Meanwhile, the segmented gradient drying of this invention ensures drying efficiency while avoiding local overheating by precisely controlling the changes in temperature and vacuum. Microwave vacuum drying significantly shortens drying time and improves production efficiency. Furthermore, the equipment used in the entire process is commonly used in the food industry, making it easy to automate. The birch tea prepared from this process has superior health benefits. Due to the effective preservation of various active ingredients, the probiotic metabolites produced during fermentation work synergistically with the active ingredients of birch itself, enhancing the product's immune-regulating function. Long-term consumption has a positive effect on human health. Detailed Implementation

[0017] 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.

[0018] Example: A novel method for preparing birch tea, comprising the following steps: S1. Select healthy birch trees that have grown for 4 years. In late April, collect tender buds with a diameter of 0.8cm and phloem with a thickness of 0.4cm. Cut the tender buds into 1.5cm sections and slice the phloem into 2.5cm² thin slices. Mix them in a mass ratio of 3:2 to obtain the raw material mixture. S2. Place the raw material mixture into an ultrasonic cleaner, add purified water at 5°C, with a material-to-liquid ratio of 1:9, set the ultrasonic power to 220W and the frequency to 40kHz, and clean for 18 minutes, changing the purified water every 5 minutes; after cleaning, dry the surface moisture with 35°C hot air to control the moisture content to 68%; S3. Place the raw material in a vacuum drying oven and dry it for 1.8 hours at 0.065 MPa and 38°C; then adjust the temperature to 0.085 MPa and 48°C and dry for 1.2 hours; finally, dry it for 35 minutes at 0.09 MPa and 32°C to reduce the moisture content to 18%. S4. The dried raw material is fed into an ultra-high pressure device and subjected to a pressure of 320MPa at -2℃ for 12 minutes. After depressurization, it is crushed and passed through a 90-mesh sieve to obtain birch powder. S5. Add 6 times the mass of deionized water to birch powder, adjust the pH to 4.8, and add 0.4% of a compound enzyme (cellulase: pectinase: protease = 2:1:1); enzymatically hydrolyze in a 48℃ constant temperature water bath for 2.2 hours, stirring for 2 minutes every 30 minutes; after enzymatic hydrolysis, raise the temperature to 92℃ and keep it at that temperature for 10 minutes to inactivate the enzyme. S6. Cool the liquid to 31°C, then inoculate with 1.5% mixed bacterial solution (Lactobacillus plantarum and Saccharomyces cerevisiae, volume ratio 1:1, concentration 10). 8 (CFU / mL); after sealing, ferment in a fermentation chamber at 31℃ and 62% relative humidity for 21 hours; S7. The fermented material is pressed and filtered, and the filter residue is placed in an extraction vessel and extracted for 1.8 hours at 28 MPa, 42℃ and CO2 flow rate of 22 L / h. The extract is mixed with the filtrate to obtain a mixed liquid. S8. The mixture is fed into a microwave vacuum dryer, set to 0.085MPa vacuum, 700W power, 42℃, and dried for 45 minutes, stirring once every 10 minutes, using pulse mode (working for 5 minutes, pausing for 1 minute); when the moisture content drops to 6%, it is pulverized through a 130-mesh sieve to obtain the birch tea product.

[0019] Comparative Example 1 (Traditional Method) Select the same raw materials as in Example 1, rinse them simply with water, and air dry them until the moisture content is below 10%. Then, directly crush them through a 100-mesh sieve to obtain traditional birch tea.

[0020] Comparative Example 2: A novel method for preparing birch tea, comprising the following steps: S1. Select healthy birch trees that have grown for 4 years. In late April, collect tender buds with a diameter of 0.8cm and phloem with a thickness of 0.4cm. Cut the tender buds into 1.5cm sections and slice the phloem into 2.5cm² thin slices. Mix them in a mass ratio of 3:2 to obtain the raw material mixture. S2. Place the raw material mixture into an ultrasonic cleaner, add purified water at 5°C, with a material-to-liquid ratio of 1:9, set the ultrasonic power to 220W and the frequency to 40kHz, and clean for 18 minutes, changing the purified water every 5 minutes; after cleaning, dry the surface moisture with 35°C hot air to control the moisture content to 68%; S3. Place the raw material in a vacuum drying oven and dry it for 1.8 hours at 0.065 MPa and 38°C; then adjust the temperature to 0.085 MPa and 48°C and dry for 1.2 hours; finally, dry it for 35 minutes at 0.09 MPa and 32°C to reduce the moisture content to 18%. S4. Crush the dried raw material and pass it through a 90-mesh sieve to obtain birch powder; S5. Add 6 times the mass of deionized water to birch powder, adjust the pH to 4.8, and add 0.4% of a compound enzyme (cellulase: pectinase: protease = 2:1:1); enzymatically hydrolyze in a 48℃ constant temperature water bath for 2.2 hours, stirring for 2 minutes every 30 minutes; after enzymatic hydrolysis, raise the temperature to 92℃ and keep it at that temperature for 10 minutes to inactivate the enzyme. S6. Cool the liquid to 31°C, then inoculate with 1.5% mixed bacterial solution (Lactobacillus plantarum and Saccharomyces cerevisiae, volume ratio 1:1, concentration 10). 8 (CFU / mL); after sealing, ferment in a fermentation chamber at 31℃ and 62% relative humidity for 21 hours; S7. The fermented material is pressed and filtered, and the filter residue is placed in an extraction vessel and extracted for 1.8 hours at 28 MPa, 42℃ and CO2 flow rate of 22 L / h. The extract is mixed with the filtrate to obtain a mixed liquid. S8. The mixture is fed into a microwave vacuum dryer, set to 0.085MPa vacuum, 700W power, 42℃, and dried for 45 minutes. Stir once every 10 minutes, using pulse mode (5 minutes of operation, 1 minute of pause). When the moisture content drops to 6%, it is pulverized through a 130-mesh sieve to obtain the birch tea product (lacking the ultra-high pressure cell breaking step).

[0021] Comparative Example 3: A novel method for preparing birch tea, the steps of which are as follows: S1. Select healthy birch trees that have grown for 4 years. In late April, collect tender buds with a diameter of 0.8cm and phloem with a thickness of 0.4cm. Cut the tender buds into 1.5cm sections and slice the phloem into 2.5cm² thin slices. Mix them in a mass ratio of 3:2 to obtain the raw material mixture. S2. Place the raw material mixture into an ultrasonic cleaner, add purified water at 5°C, with a material-to-liquid ratio of 1:9, set the ultrasonic power to 220W and the frequency to 40kHz, and clean for 18 minutes, changing the purified water every 5 minutes; after cleaning, dry the surface moisture with 35°C hot air to control the moisture content to 68%; S3. Place the raw material in a vacuum drying oven and dry it for 1.8 hours at 0.065 MPa and 38°C; then adjust the temperature to 0.085 MPa and 48°C and dry for 1.2 hours; finally, dry it for 35 minutes at 0.09 MPa and 32°C to reduce the moisture content to 18%. S4. The dried raw material is fed into an ultra-high pressure device and subjected to a pressure of 320MPa at -2℃ for 12 minutes. After depressurization, it is crushed and passed through a 90-mesh sieve to obtain birch powder. S5. Add 6 times the mass of deionized water to birch powder, adjust the pH to 4.8, and add 0.4% of a compound enzyme (cellulase: pectinase: protease = 2:1:1); enzymatically hydrolyze in a 48℃ constant temperature water bath for 2.2 hours, stirring for 2 minutes every 30 minutes; after enzymatic hydrolysis, raise the temperature to 92℃ and keep it at that temperature for 10 minutes to inactivate the enzyme. S6. Press and filter the material, put the filter residue into the extraction vessel, and extract for 1.8 h at 28 MPa, 42℃ and CO2 flow rate of 22 L / h; mix the extract with the filtrate to obtain a mixture. S7. The mixture is fed into a microwave vacuum dryer, set to 0.085MPa vacuum, 700W power, 42℃, and dried for 45 minutes. Stir once every 10 minutes, using pulse mode (5 minutes of operation, 1 minute of pause). When the moisture content drops to 6%, it is pulverized through a 130-mesh sieve to obtain the birch tea product (single enzymatic hydrolysis, no fermentation step).

[0022] The main active ingredient content, sensory evaluation, and antioxidant capacity tests were performed on the products of the examples and comparative examples. The results are as follows: (1) Content of active ingredients: In the examples, the triterpenoid content was 2.8 mg / g and the flavonoid content was 1.5 mg / g; in Comparative Example 1, the contents were 1.2 mg / g and 0.6 mg / g, respectively; in Comparative Example 2, the contents were 1.9 mg / g and 1.0 mg / g, respectively; and in Comparative Example 3, the contents were 2.5 mg / g and 1.3 mg / g, respectively. (2) Sensory evaluation: The example sample had no obvious bitter taste; Comparative Example 1 had a strong bitter taste; Comparative Example 2 had a slightly bitter taste; Comparative Example 3 had a rougher texture. (3) Antioxidant capacity (DPPH scavenging rate): The specific percentage was 92% in Example 1; 57% in Comparative Example 2; 75% in Comparative Example 3; and 80% in Comparative Example 3. The above results show that the preparation method of the present invention can effectively increase the content of active ingredients in birch tea, improve the taste, and enhance the antioxidant capacity, demonstrating significant advantages.

[0023] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a new birch tea, characterized by, The method comprises the following specific steps: S1. Selecting healthy birch trees with a growth cycle of 3-5 years, collecting tender branch buds with a diameter of 0.5-1.0 cm and phloem with a thickness of 0.3-0.5 cm in April-May every year, cutting the tender branch buds into small pieces with a length of 1-2 cm, and cutting the phloem into thin pieces with an area of 2-3 cm2, and mixing the small pieces and the thin pieces to obtain a raw material mixture; the mass ratio of the tender branch buds to the phloem in the raw material mixture is 3:2; S2. Placing the raw material mixture in an ultrasonic cleaning machine, adding purified water with a temperature of 4-6 ℃, and setting the solid-liquid ratio to 1:8-1:10, and starting the ultrasonic wave, and setting the power to 200-250 W, and setting the frequency to 40 kHz, and cleaning for 15-20 min; the purified water is replaced every 5 min during the cleaning process, and after the cleaning is completed, the raw material is taken out, and the surface moisture is quickly blown dry by hot air with a temperature of 30-40 ℃, and the water content of the raw material is controlled to be 65%-70%; S3. Placing the cleaned raw material in a vacuum drying oven, and adopting a segmented gradient drying mode to reduce the water content of the raw material to 15%-20%; The segmented gradient drying specifically comprises the following steps: (1) drying for 1.5-2 h under the conditions that the vacuum degree is 0.06-0.07 MPa and the temperature is 35-40 ℃; (2) adjusting the vacuum degree to 0.08-0.09 MPa, and increasing the temperature to 45-50 ℃, and continuing to dry for 1-1.5 h; (3) keeping the vacuum degree at 0.09 MPa, and reducing the temperature to 30-35 ℃, and drying for 30-40 min; S4. Sending the dried raw material into an ultrahigh-pressure treatment device, and applying a pressure of 300-350 MPa under the condition that the temperature is-5 to 0 ℃, and keeping the pressure for 10-15 min; after the pressure is released, the raw material is taken out, and immediately crushed, and sieved through a 80-100 mesh sieve to obtain birch powder; S5. Adding deionized water with a mass of 5-8 times that of the birch powder to the birch powder, and stirring uniformly, and adjusting the pH value to 4.5-5.0, and adding a composite enzyme with a mass of 0.3%-0.5% of the mass of the birch powder, and the composite enzyme comprises cellulase, pectinase and protease at a mass ratio of 2:1:1; and enzymolysis is performed in a constant-temperature water bath with a temperature of 45-50 ℃ for 2-2.5 h, and the stirring is performed every 30 min during the enzymolysis, and each time the stirring time is 2 min; after the enzymolysis is completed, the temperature of the material liquid is increased to 90-95 ℃, and the enzyme is inactivated by keeping the temperature for 10 min; S6. Cool the enzymatically hydrolyzed solution to 30-32℃, and inoculate it with 1%-2% of fermentation inoculum by weight. The fermentation inoculum is a mixed bacterial solution of Lactobacillus plantarum and Saccharomyces cerevisiae in a volume ratio of 1:1, with a bacterial concentration of 10. 8 -10 9 CFU / mL; fermentation was carried out under sealed conditions in a fermentation chamber at 30-32℃ for 18-24 hours, with the relative humidity maintained at 60%-65% during the fermentation process. S7. The fermented material is subjected to squeezing and filtration to obtain filtrate and filter residue; the filter residue is placed into a supercritical extraction kettle, CO2 is used as an extractant, and the filter residue is extracted under the conditions that the extraction pressure is 25-30 MPa, the extraction temperature is 40-45 ℃, and the CO2 flow rate is 20-25 L / h for 1.5-2 h; the extract is collected, and is mixed with the above-mentioned filtrate to obtain a mixed liquid. S8, the mixed solution into the microwave vacuum drying machine, set the vacuum degree is 0.08-0.09 MPa, microwave power is 600-700 W, drying temperature control at 40-45 DEG C, drying time is 40-50 min, every 10 min stirring during the period; When the material moisture content decreased to 5% to 8%, stop drying, take out after crushing through 120-150 mesh screen, get birch tea finished product.

2. The method of claim 1, wherein, In step S1, the collected shoots need to be full, no pests and diseases, and the phloem needs to be removed from the outer bark, leaving only the inner phloem.

3. The method of claim 1, wherein, In step S2, the ultrasonic cleaning machine uses a multi-frequency ultrasonic generator, and the water temperature is kept stable at 4-6 DEG C during cleaning. The temperature control is realized by connecting an external constant temperature cooling device.

4. The method of claim 1, wherein, In step S3, the drying time and temperature, vacuum degree parameters of the three stages of the segmented gradient drying correspond in turn, and the temperature adjustment rate does not exceed 5 DEG C / min during each stage conversion.

5. The method of claim 1, wherein, In step S4, the pressurization rate of the ultra-high pressure treatment equipment is 50 MPa / min, and the pressure relief rate is 30 MPa / min, which ensures uniform cell wall rupture of the raw materials under low temperature and high pressure.

6. The method of claim 1, wherein, In step S5, the addition method of the composite enzyme is as follows: Dissolve the composite enzyme in a small amount of 40 DEG C deionized water to prepare an enzyme solution; slowly add to the mixture of birch powder and deionized water, stirring while adding.

7. The method of claim 1, wherein, In step S6, the fermentation strain needs to be activated before inoculation, which is: The frozen strain is inoculated into MRS liquid medium and cultured at 37 DEG C for 18 h, continuously passed 2 times, then centrifuged to collect the bacteria, washed with sterile physiological saline for 2 times, and adjusted to the required concentration.

8. The method of claim 1, wherein, In step S7, the separation conditions of supercritical CO2 extraction are: Primary separation pressure 8-10 MPa, temperature 30-35 DEG C; Secondary separation pressure 5-6 MPa, temperature 25-30 DEG C, and the extract is collected from the primary separator.

9. The method of claim 1, wherein, In step S8, the microwave vacuum drying machine uses pulse microwave output mode, works for 5 min, pauses for 1 min, and circulates until the required moisture content is reached.