Longnan white tea preparation method and device based on vacuum rocking process

Abstract

The invention discloses a preparation method and device of Longnan white tea based on a vacuum rocking process, and belongs to the technical field of tea processing. The technical key point of the invention is as follows: vacuum and green leaf rocking processes are combined, and the vacuum and green leaf rocking synergistic effect is used for production and preparation of white tea. The content of aroma substances is increased on the basis that the content of gamma-aminobutyric acid in the tea leaves is remarkably increased, the technical defect that the gamma-aminobutyric acid tea generates smoldering sour taste due to vacuum treatment is overcome, and a technical direction is provided for improving the overall quality of the gamma-aminobutyric acid tea. The Longnan white tea prepared by the method based on the vacuum rocking process retains nutritional ingredients and flavor substances of Longnan white tea as much as possible, and the prepared Longnan white tea is more sweet and mellow in taste and has higher aroma quality. The preparation process is simple and easy to operate, the matched all-in-one machine can simultaneously complete vacuum treatment, rocking, withering and drying in one processing bin, the process flow and the occupied manual field are saved, and the preparation method is suitable for large-scale production and application.

Description

Technical Field

[0001] The invention relates to a method and a device for preparing Longnan white tea based on a vacuum shaking process, and belongs to the technical field of tea processing. Background Art

[0002] White tea has attracted wide attention from consumers due to its simple processing technology, which retains the nutrients of tea to the maximum extent. It also has rich biological activities such as antioxidant and anti-inflammatory, especially in preventing chronic diseases. Tea polyphenols, caffeine and amino acids in white tea not only determine the taste of tea, but also directly affect the nutritional value and health care function of tea. Amino acids are one of the important nutrients in tea. They can not only increase the freshness of tea, but also have a variety of physiological functions. γ-aminobutyric acid (GABA) is a non-protein amino acid with a variety of health functions such as anti-diabetes, anti-hypertension, and sleep promotion. Generally, tea with a GABA content of more than 150mg / 100g is named GABA tea. The content of GABA green tea treated with nitrogen is 166.8mg / 100g dw, and the content of GABA white tea treated with vacuum can reach 192.79mg / 100g dw. The production process of GABA tea mainly controls fermentation and oxygen content, so that glutamate decarboxylase converts glutamate into GABA under anaerobic conditions, thereby significantly increasing the GABA content in tea.

[0003] Volatile components are the main source of tea aroma and an important factor in determining tea quality. To date, more than 600 volatile compounds have been identified in tea aroma, among which hexanal, linalool, (E)-2-hexenal, phenylethanol, benzaldehyde and methyl salicylate are the main volatile compounds that determine the aroma of white tea. However, anaerobic treatment during GABA tea processing will have an adverse effect on the aroma quality of tea. Fresh tea leaves show a pungent sour taste after anaerobic treatment, and this odor characteristic will intensify with the extension of anaerobic treatment time. In contrast, the shaking process will promote enzymatic reactions in tea leaves, increase the generation and release of aromatic substances in tea leaves, and thus improve the aroma quality of tea leaves. Studies have reported that extending the shaking time usually enhances the floral and fruity aroma of tea leaves, while may reduce the proportion of fresh grassy aroma; in addition, the length of shaking time will also affect the proportion of esters, alcohols and aldehyde compounds in tea leaves. Therefore, using shaking treatment to improve the aroma quality of tea leaves during GABA white tea processing is an important process step in white tea processing.

[0004] However, although there are many processing methods to improve the GABA content and aroma of white tea, the following problems still exist: adding vacuum and other processes to the white tea processing will have an adverse effect on the aroma of the tea, producing a stuffy and sour taste, causing the quality of the white tea to decline; spraying the tree with extracts and microwave irradiation and other technologies are costly.

[0005] In addition, during the production process, vacuum bags are generally used for tea vacuum treatment. Although this reduces costs, it causes significant damage to the appearance of the tea leaves, especially when producing white tea, which requires the tea leaves to stretch naturally. After vacuum treatment, the tea leaves need to be taken out, withered and shaken, which consumes a lot of time and energy. In addition, most of the current processing equipment is decentralized, occupies a large area, and has insufficient space utilization. Summary of the invention

[0006] The purpose of the present invention is to solve the problems existing in the background technology. The purpose of the present invention is to provide a method and device for preparing high GABA Longnan white tea which combines vacuum and shaking processes, does not require additives, is easy to operate, has high production efficiency, and has high aroma quality.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for preparing Longnan white tea based on a vacuum shaking process comprises the following steps:

[0009] Step 1: Pre-treatment of fresh leaves: Select complete, fresh and clean leaves with one bud and one leaf or one bud and two leaves. The color should be green with a slight yellow or green color, the leaves should be soft and the tender stems should be easy to break. Remove the impurities and foreign matter mixed in and set aside.

[0010] Step 2: Vacuum shaking: vacuum treat the qualified Longnan white tea leaves for 10 to 14 hours, then shake them for the first time, and then wither them for the first time;

[0011] Step 3, shaking the tea leaves for the second time: After the first withering is completed, the tea leaves prepared in step 2 are directly shaken for the second time, withered again for 10 to 12 hours, and then sieved and dried twice to finally obtain the finished tea leaves.

[0012] Preferably, the tea leaves pretreated in step 1 have no deterioration or peculiar smell, no buds or leaves that have changed, no scales, fish leaves, diseased or insect-infested leaves, tea fruits and old branches and leaves, and no inclusions; and the fresh leaves used for processing in the same batch have the same tenderness, uniformity and freshness.

[0013] Preferably, the freshly picked tea leaves in step 1 are freshly picked tea leaves within 5 to 10 hours after picking, and are processed as soon as possible after picking to prevent the fresh leaves from deteriorating.

[0014] Preferably, the vacuum treatment in step 2 is carried out at a pressure of 0.04-0.1 MPa and a temperature of 20-30°C.

[0015] Preferably, the method of shaking the tea leaves for the first time and the second time in step 2 and step 3 is: start the shaking function of the all-in-one machine and gently shake the tea leaves 200 times.

[0016] Preferably, the double drying method described in step three is: the first drying temperature is 60° C. and the time is 50 minutes; the second drying temperature is 80° C. and the time is 20 minutes.

[0017] Another technical purpose of the present invention is to provide a matching Longnan white tea processing integrated machine based on the vacuum shaking process, including a vacuum pump station, a controller and a processing chamber, the vacuum pump station and the processing chamber are airtightly connected by a vacuum pipe; the processing chamber is a horizontal processing chamber, one side of which is provided with a transmission device, which is connected to the rotating motor; a sealed chamber door is provided on the other side of the processing chamber, and the sealed chamber door is fixedly connected by a hinge device; the processing chamber body includes an inner wall and an insulating outer wall, and a heating device is provided between the inner wall and the insulating outer wall.

[0018] Furthermore, the connected vacuum pump station and the vacuum pipeline of the processing chamber are provided with a pressure sensor and an electromagnetic valve, and the pressure sensor and the electromagnetic valve are electrically connected to the controller to achieve real-time control of the process parameters.

[0019] Furthermore, a heating device is provided between the inner wall and the heat-insulating outer wall, which is a flexible infrared heating plate.

[0020] Furthermore, the processing chamber is provided with a temperature sensor, and the temperature sensor is electrically connected to the controller.

[0021] The vacuum treatment step is to put the green tea into the material inner barrel, place it in the processing room, close the sealed compartment door, and start the vacuum pump station; set the control parameters through the controller, start the control program, enter the vacuum treatment stage, and start the vacuum treatment timing; the pressure sensor obtains the pressure sensor value, controls the opening and closing of the electromagnetic valve, and controls the pressure in the processing room at the target pressure value; when the vacuum treatment time reaches the target time, the vacuum is released, and the pressure is restored to normal pressure before entering the shaking stage.

[0022] In the shaking step, the control box controls the rotation motor to start, and the withering stage is carried out after the shaking is completed. Withering: open the sealed chamber door, and carry out the withering treatment at a standstill. After the withering is completed, a second shaking is carried out. In the secondary shaking step, the inner box of the material is placed in the processing room, and the sealed chamber door is closed. The control box controls the rotation motor to start, and a secondary withering is carried out after the second shaking is completed. In the secondary withering step, the sealed chamber door is opened, and the secondary withering treatment is carried out at a standstill. After the withering is completed, drying is carried out; in the drying step, the target heating temperature is set, the control box obtains the temperature value of the temperature sensor, and controls the surface temperature of the flexible infrared heating plate at the target temperature. After the drying is completed, the power is turned off.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention discloses a processing technology of Longnan white tea based on vacuum and shaking treatment. When vacuum and shaking treatment are added in the production process of Longnan white tea, the types and contents of biochemical components and volatile components thereof are greatly changed. In general, the present invention has the following advantages:

[0025] (1) The Longnan white tea prepared by the vacuum + shaking process of the present invention has a significantly increased GABA content in the tea leaves, a decreased content of catechins and free amino acids, a reduced bitter taste, and a sweeter taste; compared with the traditional white tea processing technology, the contents of alcohol substances such as nerol, trans-nerol and 1-penten-3-ol in the tea samples vacuumed first and then shaken are increased, the contents of volatile components such as difurfuryl disulfide and nonanal are reduced, the stuffy sour taste in the tea samples is reduced, and the sensory quality is better;

[0026] (2) Compared with the traditional floral scent white tea processing technology, the present invention adopts a processing technology of vacuuming first and then shaking the tea leaves, which not only significantly improves the aroma and taste, but also increases the content of biochemical components in tea leaves, thereby improving the quality of white tea; compared with the white tea preparation technology of spraying the extract, the present invention can not only better save costs, but also improve the aroma and quality of tea leaves; compared with the white tea preparation technology of vacuuming or shaking alone, the present invention can not only reduce the generation of sour and stuffy taste of tea leaves and enhance the aroma of tea leaves, but also increase the content of GABA in tea leaves, thereby improving the quality of tea leaves.

[0027] (3) The present invention uses a vacuum chamber for vacuum treatment, which can maintain the natural extension of the tea leaves. At the same time, the present invention is equipped with a vacuum pump station to provide a stable vacuum environment, sense the pressure in the processing room through a pressure sensor, and adjust the pressure in the processing room by controlling the opening and closing of the electromagnetic valve, which has a good energy-saving effect. The present invention adopts a radiation heating method, using an infrared plate for heating, which has high heat transfer efficiency, a certain penetrating heat transfer ability, a fast heating speed, and a small thermal inertia. The infrared heating component is equipped with a temperature sensor to accurately control the temperature of the heating surface to prevent the quality of the tea leaves from deteriorating and to make the drying process more uniform.

[0028] (4) The Longnan white tea processing device based on the vacuum shaking process of the present invention is an integrated machine, which can continuously complete a whole set of processing processes, greatly saving manpower. The integrated machine of the present invention can simultaneously complete vacuum treatment, shaking, withering and drying in one processing chamber, greatly saving space. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a process flow chart of the Longnan white tea preparation method based on the vacuum shaking process;

[0030] Figure 2 It is a cluster heat map comparing the types and relative contents of volatile components of Comparative Examples 1-2 and Example 2 of the present invention;

[0031] Figure 3 It is a structural schematic diagram of the Longnan white tea processing integrated machine based on the vacuum shaking process of the present invention;

[0032] Figure 4 A cross-sectional view of the processing chamber for processing Longnan white tea based on the vacuum shaking process invented.

[0033] In the figure: 1. Vacuum pump station; 2. Vacuum pipeline; 3. Pressure sensor; 4. Controller; 5. Solenoid valve; 6. Rotating bearing; 7. Processing chamber; 8. Sealed chamber door; 9. Base; 10. Rotating motor; 701. Temperature sensor; 702. Flexible infrared heating plate; 703. Material inner barrel; 704. Insulated outer wall. DETAILED DESCRIPTION

[0034] 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.

[0035] Embodiment 1:

[0036] A method for preparing Longnan white tea based on a vacuum shaking process comprises the following steps:

[0037] Step 1: Pre-treatment of fresh leaves: Select complete, fresh and clean leaves with one bud and one leaf or one bud and two leaves for picking. The color should be green with a slight yellow or green color, the leaves should be soft and the tender stems should be easy to break. During the pre-treatment process, diseased and insect-infested leaves, dead branches and leaves, weeds and debris, and deteriorated red stems and red leaves should be removed. Send the leaves to the tea processing site as soon as possible within 5 hours after picking to prevent the fresh leaves from deteriorating.

[0038] Step 2, vacuum shaking: subject the pre-treated Longnan white tea leaves to vacuum treatment at 0.04Mpa pressure and 20°C for 10 hours, and then perform the first shaking, and after the shaking is completed, perform the first withering;

[0039] Step 3, shaking the tea leaves for the second time: After the first withering is completed, shaking the tea leaves for the second time, withering again for 10 hours, and drying them twice after sieving (the first drying temperature is 60°C and the time is 50 minutes; the second drying temperature is 80°C and the time is 20 minutes), and finally the finished tea leaves are obtained.

[0040] The Longnan white tea preparation method based on the vacuum shaking process of the present invention combines vacuum and shaking processes, and the "vacuum + shaking" synergistically acts on the production and preparation of white tea. The content of aroma substances is increased on the basis of significantly improving the GABA content in tea leaves, which overcomes the technical defect that GABA tea produces a stuffy sour taste due to vacuum treatment, and provides a technical direction for improving the overall quality of GABA tea. In order to cooperate with the preparation process to retain the nutritional components and flavor substances of Longnan white tea as much as possible, improve work efficiency and save space, the Longnan white tea processing integrated machine based on the vacuum shaking process is used for processing and preparation.

[0041] like Figure 3-4 As shown, a supporting Longnan white tea processing integrated machine based on vacuum shaking process includes a vacuum pump station 1, a controller 4 and a processing chamber 7, wherein the vacuum pump station 1 and the processing chamber 7 are airtightly connected through a vacuum pipe 2; the processing chamber 7 is a horizontal processing chamber, one side of which is provided with a transmission device, which is transmission-connected to a rotating motor 10; the other side of the processing chamber 7 is provided with a sealed chamber door 8, which is fixedly connected through a hinge device; the processing chamber 7 includes an inner wall and an insulating outer wall, and a heating device 6 is provided between the inner wall and the insulating outer wall 704. The heating device 6 provided between the inner wall and the insulating outer wall is a flexible infrared heating plate.

[0042] The vacuum pipeline 2 of the vacuum pump station 1 and the processing chamber 7 is provided with a pressure sensor 3 and an electromagnetic valve 5, and the pressure sensor 3 and the electromagnetic valve 5 are electrically connected to the controller 4 to achieve real-time control of the process parameters. The processing chamber 7 is provided with a temperature sensor, and the temperature sensor 701 is electrically connected to the controller 4.

[0043] like Figure 1 , 3As shown in Figure 4, the Longnan white tea vacuum processing step is performed using the Longnan white tea processing integrated machine based on the vacuum shaking process of the present invention. The tea leaves are placed in the material inner cylinder 703, placed in the processing room, the sealed compartment door 8 is closed, and the vacuum pump station 1 is started; the control parameters are set by the controller 4, the control program is started, the vacuum processing stage is entered, and the vacuum processing timing is turned on; the pressure sensor 3 obtains the pressure sensor value, controls the opening and closing of the electromagnetic valve 5, and controls the pressure in the processing room at the target pressure value; when the vacuum processing time reaches the target time, the vacuum is released, and the shaking stage is entered after the pressure is restored to normal pressure.

[0044] In the shaking step, the control box controls the rotating motor to start, and the withering stage is carried out after the shaking is completed. Withering: open the sealed compartment door 8, and perform the withering treatment at a standstill. After the withering is completed, a second shaking is carried out. In the secondary shaking step, the inner box of the material is placed in the processing room, and the sealed compartment door 8 is closed. The control box controls the rotating motor to start, and a secondary withering is carried out after the second shaking is completed. In the secondary withering step, the sealed compartment door 8 is opened, and the secondary withering treatment is performed at a standstill. After the withering is completed, drying is carried out; in the drying step, the target heating temperature is set, the control box obtains the temperature value of the temperature sensor, and controls the surface temperature of the flexible infrared heating plate at the target temperature. After the drying is completed, the power is turned off.

[0045] Embodiment 2:

[0046] A method for preparing Longnan white tea based on a vacuum shaking process comprises the following steps:

[0047] Step 1: Pre-treatment of fresh leaves: Select complete, fresh and clean leaves with one bud and one leaf or one bud and two leaves for picking. The color should be green with a slight yellow or green color, the leaves should be soft and the tender stems should be easy to break. During the pre-treatment process, diseased and insect-infested leaves, dead branches and leaves, weeds and debris, and deteriorated red stems and red leaves should be removed. Send the leaves to the tea processing site as soon as possible within 7 hours after picking to prevent the fresh leaves from deteriorating.

[0048] Step 2, vacuum shaking: subject the qualified pre-treated Longnan white tea leaves to vacuum treatment at 0.09Mpa pressure and 25°C for 12 hours, and then perform the first shaking, and after the shaking is completed, perform the first withering;

[0049] Step 3, shaking the tea leaves for the second time: After the first withering is completed, shaking the tea leaves for the second time, withering again for 11 hours, and drying them twice after sieving (the first drying temperature is 60°C and the time is 50 minutes; the second drying temperature is 80°C and the time is 20 minutes), and finally the finished tea leaves are obtained.

[0050] Its application equipment and application method are the same as those in Example 1 and will not be described in detail here.

[0051] Embodiment 3:

[0052] A method for preparing Longnan white tea based on a vacuum shaking process comprises the following steps:

[0053] Step 1: Pretreatment of fresh leaves: Select complete, fresh and clean leaves with one bud and one leaf or one bud and two leaves for picking. The color should be green with a slight yellow or green color, the leaves should be soft and the tender stems should be easy to break. During the pretreatment process, diseased and insect-infested leaves, dead branches and leaves, weeds and debris, and deteriorated red stems and red leaves should be removed. Send the leaves to the tea processing site as soon as possible within 10 hours after picking to prevent the fresh leaves from deteriorating.

[0054] Step 2: vacuum shaking: subject the qualified pre-treated Longnan white tea leaves to vacuum treatment at 0.1Mpa pressure and 30°C for 14 hours, and then perform the first shaking, and after the shaking is completed, perform the first withering;

[0055] Step 3, shaking the tea leaves for the second time: After the first withering is completed, shaking the tea leaves for the second time, withering for another 12 hours, and drying them twice after sieving (the first drying temperature is 60°C and the time is 50 minutes; the second drying temperature is 80°C and the time is 20 minutes), and finally the finished tea leaves are obtained.

[0056] Its application equipment and application method are the same as those in Example 1 and will not be described in detail here.

[0057] Comparative Example 1

[0058] The screening and pretreatment of tea leaves are the same as those in Example 2, except that the withering treatment is only performed at room temperature, followed by drying to finally obtain finished tea leaves.

[0059] Comparative Example 2

[0060] The screening and pretreatment of tea leaves are the same as those in Example 2, except that withering is performed immediately after vacuum treatment: vacuum treatment is performed at a pressure of 0.09 MPa and 25°C for 12 hours, followed by withering for 11 hours, and finally the finished tea leaves are obtained after screening and drying.

[0061] Performance Test:

[0062] 1. Test indicators and methods

[0063] The tea samples (Implementation 1-3, Comparative Example 1-2) that had been pretreated and prepared by different processing methods were tested.

[0064] (1) Tea polyphenols and six catechins: the determination method refers to GB / T 8313-2018 “Determination method for tea polyphenols and catechins in tea”;

[0065] (2) GABA: in accordance with GB 5009.124-2016 “Determination of Amino Acids in Foods”;

[0066] (3) Volatile components: Determination was performed using a comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometer. The specific method was to weigh 1 g of tea powder and 2 mL of saturated sodium chloride solution in a 20 mL headspace bottle, add 2 μL of ethyl decanoate (1000 mg / kg) and furfurylthiol (2000 mg / kg) respectively, seal the bottle, quickly insert the SPME extraction head into the headspace bottle, place the headspace bottle in a 100 °C constant temperature controller for 30 min, remove the extraction head after the end, quickly insert it into the GC syringe, and desorb at 270 °C for 5 min with a split ratio of 10:1. Carrier gas: high-purity helium, flow rate 1.4 mL / min. The injection port and transfer line temperatures were set to 270 °C and 280 °C, respectively. The temperature program was as follows: the initial temperature was 40 °C, increased to 200 °C at a rate of 7 °C / min, maintained for 2 min, and then further increased to 280 °C at a rate of 20 °C / min and maintained for 3 min. The temperature of the two-dimensional column was set 5°C higher than that of the one-dimensional column, the modulator temperature was always 15°C higher than the column temperature of the two-dimensional column, the modulation period was 3s, and a 0.6-second thermal pulse was generated. The mass spectrometry parameters were set as follows: solvent delay 60s; acquisition rate 100 spectra / s; detector voltage 1450V; electron bombardment source 70eV; ion source temperature 250°C, and the acquisition mass range 35-550amu.

[0067] 2. Measured data of samples prepared in Examples 1-3 and Comparative Examples 1-2

[0068] Table 1: Comparison of biochemical components

[0069]

[0070] Table 2: Comparison of relative contents of key volatile components OAV values

[0071]

[0072]

[0073] 3. Related data analysis

[0074] (1) From the analysis results of the content of white tea polyphenols and catechins in Table 1, it can be seen that compared with comparative examples 1-2, the contents of ester-type and non-ester-type catechins in Examples 1-3 decreased, especially the contents of EGCG and ECG. The above changes indicate that the bitterness of Examples 1-3 is significantly reduced and the taste is better.

[0075] (2) From the analysis results of the content of GABA and total free amino acids in white tea in Table 2, it can be seen that compared with Comparative Example 1, GABA in Examples 1-3 and Comparative Example 2 was upregulated. The above changes suggest that vacuum treatment can significantly increase the GABA content.

[0076] (3) The relative content OAV value test results of key volatile compounds in white tea processed by different methods in Table 2 and the types and relative contents of volatile components in Comparative Examples 1-2 and Example 2 are compared in the cluster heat map (see Appendix Figure 2 ) It can be seen that the content of dimethyl sulfide and difurfuryl disulfide in Comparative Example 2 increased significantly, giving the vacuum group white tea a pungent smell. In Examples 1-3, the content of alcohol substances such as nerol and 1-pentene-3-ol increased, and the content of volatile components such as difurfuryl disulfide decreased, showing a stronger fruity aroma and a sweeter taste. The above changes indicate that vacuum treatment increases the pungent smell of white tea, but after adding the shaking process, the pungent smell is reduced, and the fruity aroma is increased, which improves the aroma quality of GABA white tea.

[0077] In summary, the present invention utilizes vacuum and shaking technology to not only increase the GABA content of Longnan white tea, but also improves the aroma quality of Longnan white tea, and obtains Longnan white tea with high GABA and sweet taste. Compared with traditional white tea, the present invention adds vacuum and shaking technology to the original process, and the quality and aroma of Longnan white tea are greatly improved; at the same time, compared with floral white tea, the white tea of ​​the present invention can better save costs, reduce waste of resources, and better retain the aroma of the tea leaves themselves, and improve the biochemical components of tea leaves; compared with the single processing method of vacuum or shaking, the present invention can better reduce the sourness of tea leaves and increase the GABA content of tea leaves. Therefore, the present invention breaks the single processing method, and uses the processing method of vacuum and shaking to process, which greatly improves the aroma quality of white tea while improving the quality of tea leaves.

[0078] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing Longnan white tea based on vacuum shaking process, characterized in that The steps include: Step 1: Pre-treatment of fresh leaves: Select freshly picked, complete, clean one bud and one leaf or one bud and two leaves for picking. The selected tea leaves are green with a slightly yellowish or green color, with soft leaves and tender stems that are easy to break. Remove impurities and foreign matter from the freshly picked tea leaves and set aside. Step 2, vacuum shaking: subject the Longnan white tea leaves pretreated in step 1 to vacuum treatment for 10 to 14 hours, and then perform the first shaking, and after the shaking is completed, perform the first withering, and set aside; Step 3, shaking the tea leaves twice: After the first withering is completed, the tea leaves prepared in step 2 are shaken twice, and then withered for a second time for 10 to 12 hours, and then sieved and dried twice to finally obtain the finished tea leaves.

2. The method for preparing Longnan white tea based on vacuum shaking process according to claim 1, characterized in that: After the pretreatment in step 1, the fresh tea leaves have no deterioration or peculiar smell, no mutated buds and leaves, no scales, fish leaves, diseased and insect-infested leaves, tea fruits and old branches and leaves, and no other debris; the fresh tea leaves used for processing in the same batch have the same tenderness, uniformity and freshness.

3. The method for preparing Longnan white tea based on vacuum shaking process according to claim 1, characterized in that: The freshly picked tea leaves in step 1 are newly picked tea leaves within 5 to 10 hours after picking.

4. The method for preparing Longnan white tea based on vacuum shaking process according to claim 1, characterized in that: The vacuum treatment described in step 2 is carried out at a pressure of 0.04-0.1 MPa and a temperature of 20-30°C.

5. The method for preparing Longnan white tea based on vacuum shaking process according to claim 1, characterized in that: The method of the first shaking and the second shaking of the tea leaves described in step 2 and step 3 is: gently shake the vacuum-treated tea leaves 200 times.

6. The method for preparing Longnan white tea based on vacuum shaking process according to claim 1, characterized in that: The double drying method described in step 3 is as follows: the first drying temperature is 60° C. and the time is 50 minutes; the second drying temperature is 80° C. and the time is 20 minutes.

7. The Longnan white tea processing integrated machine based on vacuum shaking process used in the Longnan white tea preparation method based on vacuum shaking process according to claim 1 is characterized in that: The invention comprises a vacuum pump station (1), a controller (4) and a processing chamber (7), wherein the vacuum pump station (1) and the processing chamber (7) are hermetically connected via a vacuum pipe (2); the processing chamber (7) is a horizontal processing chamber, one side of which is provided with a transmission device, which is transmission-connected to a rotating motor (10); the other side of the processing chamber (7) is provided with a sealed chamber door (8), and the sealed chamber door (8) is fixedly connected via a hinge device; the chamber body of the processing chamber (7) comprises an inner wall and a heat-insulating outer wall, and a heating device (6) is provided between the inner wall and the heat-insulating outer wall (704).

8. The Longnan white tea processing integrated machine based on vacuum shaking process according to claim 7 is characterized in that: A pressure sensor (3) and an electromagnetic valve (5) are provided on the vacuum pipeline (2) of the connected vacuum pump station (1) and the processing chamber (7), and the pressure sensor (3) and the electromagnetic valve (5) are electrically connected to the controller (4).

9. The Longnan white tea processing integrated machine based on vacuum shaking process according to claim 7, characterized in that: A heating device (6) is provided between the inner wall and the heat-insulating outer wall and is a flexible infrared heating plate.

10. The Longnan white tea processing integrated machine based on vacuum shaking process according to claim 7, characterized in that: The processing chamber (7) is provided with a temperature sensor (701), and the temperature sensor (701) is electrically connected to the controller (4).

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