Organic white tea processing technology and multi-stage circulating drying processing device thereof

Abstract

The invention discloses an organic white tea leaf processing technology and a multi-stage circulating drying processing device thereof, and relates to the technical field of tea leaf processing, the organic white tea leaf processing technology comprises the following steps: selecting tea tree variety fresh leaves passing organic certification, picking according to a picking standard of one bud and one leaf or one bud and two leaves for initial expansion, uniformly spreading the fresh leaves on a bamboo withering sieve, and withering for 20-30 minutes; the method comprises the following steps: naturally withering tea leaves for 8-12 hours under the conditions that the temperature is 18-22 DEG C and the relative humidity is 65-75%, then transferring the tea leaves into a withering chamber with the illumination intensity of 3000-5000l ux, controlling the temperature to be 25-28 DEG C and the humidity to be 50-60%, withering for 4-6 hours, primarily drying the tea leaves for 20-30 minutes at 70-75 DEG C by adopting hot air equipment, reducing the water content of the tea leaves to be 15-18%, adjusting the temperature to be 90-95 DEG C, and re-drying for 10-15 minutes until the final water content is less than or equal to 6%, so as to obtain the tea leaves. The finished tea is placed in a dark environment, the temperature is controlled to be 0-5 DEG C, the relative humidity is controlled to be 30% or below, sealing preservation is carried out, the temperature and humidity, the illumination intensity and the leaf spreading density are regulated and controlled in stages, periodic leaf turning operation is combined, uniform loss of moisture of fresh leaves and accurate regulation and control of enzymatic oxidation are achieved, and the unique taste and soup color of the white tea are formed.

Description

Technical Field

[0001] The present invention relates to the technical field of tea processing, and more specifically, to an organic white tea processing technology and its multi-stage cyclic drying processing device. Background Art

[0002] In the process of white tea processing, how to effectively control the withering and drying processes of fresh leaves to retain the natural flavor and nutritional components of tea, while improving the quality and taste of tea, has always been a technical problem in the tea processing field.

[0003] Traditional white tea processing technologies often have problems such as inaccurate temperature and humidity control, unreasonable light intensity, and inappropriate leaf spreading density, resulting in uneven water loss during the withering and drying processes of tea leaves, and it is difficult to precisely regulate the enzymatic oxidation reaction, affecting the taste and color of tea.

[0004] Based on this, we provide an organic white tea processing technology and its multi-stage cyclic drying processing device. Summary of the Invention

[0005] In order to solve the problems raised in the above background art, the present invention provides an organic white tea processing technology and its multi-stage cyclic drying processing device. By regulating the temperature, humidity, light intensity, and leaf spreading density in stages, combined with periodic leaf turning operations, uniform water loss of fresh leaves and precise regulation of enzymatic oxidation are achieved, forming the unique taste and color of white tea. In the initial drying stage, low-temperature slow drying is used to inactivate enzyme activity. In the re-drying stage, high-temperature rapid dehydration is carried out to promote the Maillard reaction and generate characteristic aromas. Subsequently, nitrogen filling packaging and low-temperature light-proof storage effectively block tea oxidation, photolysis, and microbial growth, greatly increasing the retention rate of thermosensitive components to more than 85%, and no chemical preservatives are required, fully meeting the natural and pure standards of organic products, providing a new solution for the quality preservation and aroma enhancement of white tea.

[0006] The organic white tea processing technology and its multi-stage cyclic drying processing device provided by the present invention adopt the following technical solutions:

[0007] An organic white tea processing technology and its multi-stage cyclic drying processing device include the following steps:

[0008] Step 1: Select fresh leaves of tea tree varieties certified as organic, and the picking standard is one bud with one leaf or the initial unfolding of one bud with two leaves;

[0009] Step 2: Evenly spread the fresh leaves on a bamboo withering sieve, and naturally wither for 8 - 12 hours under the conditions of a temperature of 18 - 22°C and a relative humidity of 65 - 75%. Then transfer them to a withering room with a light intensity of 3000 - 5000 lux, control the temperature at 25 - 28°C and the humidity at 50 - 60%, and wither for 4 - 6 hours;

[0010] Step 3: Use hot air equipment to initially dry the tea leaves at 70-75°C for 20-30 minutes to reduce the moisture content of the tea leaves to 15-18%. Adjust the temperature to 90-95°C and re-dry for 10-15 minutes to a final moisture content of ≤6%.

[0011] Step 4: Place the finished tea in a dark environment, control the temperature to 0-5℃, and store the tea in a sealed container with a relative humidity below 30%.

[0012] Preferably, in step 2, the density of the leaves spread on the withering screen is 0.4-0.6 kg / m 2 , turn the leaves every 2 hours during the withering process.

[0013] Preferably, in step 2, full spectrum sunlight is used to simulate sunlight exposure, and the light intensity gradient is set to 5000 lux for the initial 2 hours and then decreases by 500 lux per hour.

[0014] Preferably, in step 4, the sealed storage is carried out using nitrogen-filled packaging, the oxygen concentration in the packaging is ≤0.5%, and the nitrogen purity is ≥99.95%.

[0015] A multi-stage circulating drying processing device comprises a drying box, a first conveyor belt, a second conveyor belt, a third conveyor belt and two toggle mechanisms; the first conveyor belt, the second conveyor belt and the third conveyor belt are sequentially arranged in the drying box from top to bottom, one of the toggle mechanisms is arranged on the second conveyor belt and the other of the toggle mechanisms is arranged on the third conveyor belt; the side end of the first conveyor belt is arranged outside the drying box and the side end of the third conveyor belt is arranged outside the drying box.

[0016] Preferably, the side of the drying box is provided with a gear 1 for rotation, a gear 2 is provided on a rotating shaft of the conveyor belt 2, the gear 1 is meshed with the gear 2, and the side end of the conveyor belt 1 is connected to the side end of the gear 2 through a transmission belt; the side of the drying box is provided with a gear 3 for rotation, the rotating shaft of the conveyor belt 3 is provided with a gear 4, the gear 4 is meshed with the gear 3, and the other rotating shaft of the conveyor belt 2 is connected to the side end of the gear 3 through a transmission belt; the side end of the conveyor belt 1 is provided with a motor.

[0017] Preferably, a heating element is provided inside the drying box.

[0018] Preferably, the toggle mechanism includes a horizontal plate arranged inside the drying box, a rotating rod is rotatably arranged on the side of the horizontal plate, a plurality of rotating sleeves are equidistantly arranged in the middle of the rotating rod, a plurality of rotating wheels are arranged on the top of the horizontal plate, the rotating sleeves are meshed and connected with the rotating wheels, and the rotating sleeves correspond to the rotating wheels one by one, a toggle rod is provided at the bottom of the rotating wheel, and the toggle rod is arranged at the bottom of the horizontal plate.

[0019] Preferably, the side end of the rotating rod is transmission-connected to the side end of the conveyor belt 1 via a transmission belt.

[0020] Preferably, the conveyor belt one, the conveyor belt two, and the conveyor belt three are all made of high-temperature resistant mesh structures.

[0021] In summary, the present invention has the following beneficial technical effects:

[0022] 1. By regulating temperature, humidity and light intensity in stages (natural withering → simulated sunlight gradient irradiation), combined with precise leaf density (0.4-0.6kg / m 2 ) and periodic leaf turning operations can simultaneously achieve uniform water loss from fresh leaves and regulation of enzymatic oxidation. Among them, the full-spectrum sunlight-simulating light gradient design (starting at 5000 lux and decreasing by 500 lux per hour) accurately simulates the photoperiodic changes in the tea tree's native environment, effectively activating the activity of polyphenol oxidase in tea leaves and promoting the moderate conversion of catechins into theaflavins and thearubigins. This not only avoids excessive chlorophyll degradation caused by traditional high temperature and strong light (preserving green and protecting the tea leaves), but also reduces the bitterness caused by excessive oxidation of catechins, ultimately forming the unique sweet and mellow taste and apricot-yellow translucent soup color of white tea.

[0023] 2. In the initial baking stage, slow baking at 70-75°C (20-30 minutes) is used to quickly inactivate enzyme activity and lock in the flavor substance foundation formed in the withering stage; in the re-baking stage, the temperature is increased to 90-95°C for short-term high-temperature treatment (10-15 minutes). While quickly removing moisture (water content ≤ 6%), the thermal synergy promotes the Maillard reaction between sugars and amino acids, generating characteristic aroma components such as caramel and honey. Combined with subsequent nitrogen-filled packaging (oxygen concentration ≤ 0.5%) and low-temperature, light-proof storage (0-5°C), it can completely block the oxidation of tea lipids, chlorophyll photolysis, and microbial growth pathways, thereby increasing the 18-month retention rate of heat-sensitive components in tea, such as vitamin C and tea polyphenols, to more than 85%. No chemical preservatives are added, which fully meets the core appeal of natural purity of organic products.

[0024] 3. Through the hierarchical distribution design of the three-level conveyor belt (conveyor belts one to three), combined with the different temperatures of each level (adaptable to the requirements of 70-75°C for initial drying and 90-95°C for re-drying in the white tea processing technology), segmented control of tea drying parameters is achieved. Among them, the toggle mechanism configured on conveyor belts two and three can periodically turn over the tea layer (simulating the manual drying action), breaking the problems of surface crusting and uneven internal moisture content caused by traditional static drying, and ensuring the synchronous dehydration of the inner and outer layers of the tea. At the same time, the closed structure of the drying box and the vertical layout of the multi-level conveyor belts (natural convection of heat from top to bottom) enable the high-temperature hot air to form a circulating vortex in the box, and the heat energy recycling rate is increased by more than 40%, avoiding the energy waste caused by frequent dehumidification of the single-stage drying device.

[0025] 4. The rotating rod drives each rotating sleeve to rotate, thereby causing the corresponding rotating wheel to rotate, thereby driving the corresponding toggle rod to rotate. The rotating toggle rod can flip and toggle the tea leaves on the conveyor belt, avoiding mechanical damage to the tea buds during the flipping process. At the same time, the multi-level drop design allows the tea leaves to fall naturally and loosely, effectively preventing the leaves from breaking.

[0026] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present invention will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a flow chart of an organic white tea processing process according to an embodiment of the present invention;

[0028] Figure 2 1 is a schematic structural diagram of a multi-stage circulating drying processing device according to an embodiment of the present invention;

[0029] Figure 3 It is a structural schematic diagram of the other side of a multi-stage circulating drying processing device according to an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the internal structure of a multi-stage circulating drying processing device according to an embodiment of the present invention;

[0031] Figure 5 2 is a schematic structural diagram of the toggle mechanism in an embodiment of the present invention.

[0032] Explanation of the accompanying reference numerals: 1. Drying box; 2. Conveyor belt 1; 3. Conveyor belt 2; 4. Conveyor belt 3; 5. Toggle mechanism; 500. Horizontal plate; 501. Rotating rod; 502. Rotating sleeve; 503. Rotating wheel; 504. Toggle rod; 6. Motor; 7. Heating element. DETAILED DESCRIPTION

[0033] The following is combined with Figures 1 to 5 The present invention is described in further detail.

[0034] It should be noted that the drawings are schematic and not drawn to scale. For clarity and convenience, the relative sizes and proportions of parts shown in the drawings may be exaggerated or reduced in size. Any dimensions are illustrative only and are not intended to be limiting. Identical structures, elements, or components appearing in two or more drawings are denoted by the same reference numerals to indicate similar features.

[0035] Example 1

[0036] The embodiment of the present invention discloses a process for processing organic white tea.Figure 1 , an organic white tea processing process, comprising the following steps:

[0037] Step 1: Select fresh leaves from organically certified tea varieties, picking them with one bud and one leaf or one bud and two leaves beginning to unfold;

[0038] Step 2: Spread the fresh leaves evenly on a bamboo withering screen and wither naturally for 8-12 hours at a temperature of 18-22°C and a relative humidity of 65-75%. Then transfer them to a withering room with a light intensity of 3000-5000 lux, control the temperature at 25-28°C and the humidity at 50-60%, and wither for 4-6 hours.

[0039] Step 3: Use hot air equipment to initially dry the tea leaves at 70-75°C for 20-30 minutes to reduce the moisture content of the tea leaves to 15-18%. Adjust the temperature to 90-95°C and re-dry for 10-15 minutes to a final moisture content of ≤6%.

[0040] Step 4: Place the finished tea in a dark environment, control the temperature to 0-5℃, and store the tea in a sealed container with a relative humidity below 30%.

[0041] This processing technology achieves uniform moisture loss from fresh leaves and precise control of enzymatic oxidation by regulating temperature, humidity, light intensity and leaf density in stages, combined with periodic leaf turning operations, thus forming the unique taste and soup color of white tea. The low-temperature slow baking in the initial baking stage inactivates enzyme activity, while the high-temperature rapid dehydration in the re-baking stage promotes Maillard reaction and generates characteristic aroma. The subsequent nitrogen-filled packaging and low-temperature, light-proof storage effectively block the oxidation, photolysis and microbial growth of tea leaves, significantly increasing the retention rate of heat-sensitive components to over 85%. Without the need for chemical preservatives, it fully meets the natural and pure standards of organic products, providing a new solution for the preservation and aroma enhancement of white tea.

[0042] Specifically, in step 2, the density of the leaves spread on the withering screen is 0.4-0.6 kg / m 2 , turn the leaves every 2 hours during the withering process.

[0043] Specifically, in step 2, full spectrum sunlight is used to simulate sunlight exposure, and the light intensity gradient is set to 5000 lux for the initial 2 hours and then decrease by 500 lux per hour.

[0044] Specifically, in step 4, the sealed storage is carried out using nitrogen-filled packaging, the oxygen concentration in the packaging is ≤0.5%, and the nitrogen purity is ≥99.95%.

[0045] Through this process:

[0046] 1. By regulating temperature, humidity and light intensity in stages (natural withering → simulated sunlight gradient irradiation), combined with precise leaf density (0.4-0.6kg / m 2) and periodic leaf turning operations can simultaneously achieve uniform water loss from fresh leaves and regulation of enzymatic oxidation. Among them, the full-spectrum sunlight-simulating light gradient design (starting at 5000 lux and decreasing by 500 lux per hour) accurately simulates the photoperiodic changes in the tea tree's native environment, effectively activating the activity of polyphenol oxidase in tea leaves and promoting the moderate conversion of catechins into theaflavins and thearubigins. This not only avoids excessive chlorophyll degradation caused by traditional high temperature and strong light (preserving green and protecting the tea leaves), but also reduces the bitterness caused by excessive oxidation of catechins, ultimately forming the unique sweet and mellow taste and apricot-yellow translucent soup color of white tea.

[0047] 2. In the initial baking stage, slow baking at 70-75°C (20-30 minutes) is used to quickly inactivate enzyme activity and lock in the flavor substance foundation formed in the withering stage; in the re-baking stage, the temperature is increased to 90-95°C for short-term high-temperature treatment (10-15 minutes). While quickly removing moisture (water content ≤ 6%), the thermal synergy promotes the Maillard reaction between sugars and amino acids, generating characteristic aroma components such as caramel and honey. Combined with subsequent nitrogen-filled packaging (oxygen concentration ≤ 0.5%) and low-temperature, light-proof storage (0-5°C), it can completely block the oxidation of tea lipids, chlorophyll photolysis, and microbial growth pathways, thereby increasing the 18-month retention rate of heat-sensitive components in tea, such as vitamin C and tea polyphenols, to more than 85%. No chemical preservatives are added, which fully meets the core appeal of natural purity of organic products.

[0048] Example 2

[0049] The embodiment of the present invention discloses a multi-stage circulation drying processing device. Figures 2 to 5 A multi-stage circulating drying processing device includes a drying box 1, a conveyor belt 1 2, a conveyor belt 2 3, a conveyor belt 3 4 and two toggle mechanisms 5; the conveyor belt 1 2, the conveyor belt 2 3, and the conveyor belt 3 4 are arranged in the drying box 1 from top to bottom, one toggle mechanism 5 is arranged on the conveyor belt 2 3, and the other toggle mechanism 5 is arranged on the conveyor belt 3 4; the side end of the conveyor belt 1 2 is arranged outside the drying box 1, and the side end of the conveyor belt 3 4 is arranged outside the drying box 1.

[0050] Specifically, the semi-finished white tea to be dried is transported by conveyor belt 1 2 and dried by drying box 1. After drying for a certain period of time, it is transported to conveyor belt 2 3 by conveyor belt 1 2 and dried for a period of time. Then, it is transported to conveyor belt 3 4 by conveyor belt 2 3 and dried for a period of time. Finally, it is transported and discharged by conveyor belt 3 4. Through this structural design, the tea leaves can be dried in multiple stages, and the heat can be retained in the drying box 1 to achieve cyclic drying.

[0051] like Figure 3As shown, the side of the drying box 1 is provided with a gear 1 for rotation, and a gear 2 is provided on a rotating shaft of the conveyor belt 2 3. The gear 1 is meshed with the gear 2, and the side end of the conveyor belt 1 2 is connected to the side end of the gear 2 through a transmission belt; the side of the drying box 1 is provided with a gear 3 for rotation, and the rotating shaft of the conveyor belt 3 4 is provided with a gear 4. The gear 4 is meshed with the gear 3, and the other rotating shaft of the conveyor belt 2 3 is connected to the side end of the gear 3 through a transmission belt; the side end of the conveyor belt 1 2 is provided with a motor 6.

[0052] Specifically, the motor 6 drives the conveyor belt 1 2 to rotate, thereby causing the transmission belt to drive gear 1 to rotate, thereby rotating gear 2, thereby causing the conveyor belt 2 3 to rotate, the rotation of the conveyor belt 2 3 causes the transmission belt to drive gear 3 to rotate, the rotation of gear 3 causes gear 4 to rotate, thereby rotating the conveyor belt 3 4, completing the transportation and delivery of tea leaves.

[0053] like Figure 4 As shown, a heating element 7 (which may be an electric drying machine, an electric baking cage, a mesh belt electric drying machine, a far infrared electric drying machine, etc.) is provided inside the drying box 1.

[0054] Through the hierarchical distribution design of the three-level conveyor belt (conveyor belts one to three), combined with the different temperatures of each level (adaptable to the requirements of initial drying at 70-75°C and re-drying at 90-95°C in the white tea processing technology), segmented control of tea drying parameters is achieved.

[0055] Among them, the toggle mechanism 5 configured on the conveyor belt 2 3 and the conveyor belt 3 4 can periodically turn over the tea layer (simulating the manual spreading action), breaking the problems of surface crusting and uneven internal moisture content caused by traditional static drying, and ensuring the synchronous dehydration of the inner and outer layers of the tea.

[0056] At the same time, the closed structure of the drying box 1 and the vertical layout of the multi-stage conveyor belt (heat naturally convects from top to bottom) enable the high-temperature hot air to form a circulating vortex in the box, increasing the heat energy recycling rate by more than 40%, avoiding energy waste caused by frequent dehumidification in a single-stage drying device.

[0057] The three-stage conveyor belt is arranged end to end (feeding at the 2nd side of the conveyor belt and discharging at the 3rd side of the conveyor belt) to realize the continuous operation of the entire process from initial drying to re-drying of white tea, reducing the manual intervention time by 40% compared with intermittent drying equipment.

[0058] Example 3

[0059] This embodiment is further optimized based on the above embodiment 2, and the parts that are the same as the above technical solutions will not be repeated here. Figure 5As shown, in order to better realize the present invention, the following setting is particularly adopted: in this embodiment, the toggle mechanism 5 includes a horizontal plate 500 arranged inside the drying box 1, and a rotating rod 501 is rotatably arranged on the side of the horizontal plate 500, and a plurality of rotating sleeves 502 are equidistantly arranged in the middle of the rotating rod 501, and a plurality of rotating wheels 503 are arranged on the top of the horizontal plate 500, and the rotating sleeves 502 are meshed and connected with the rotating wheels 503, and the rotating sleeves 502 correspond to the rotating wheels 503 one by one, and a toggle rod 504 is provided at the bottom of the rotating wheel 503, and the toggle rod 504 is arranged at the bottom of the horizontal plate 500.

[0060] Specifically, the rotating rod 501 drives each rotating sleeve 502 to rotate, thereby causing the corresponding rotating wheel 503 to rotate, thereby driving the corresponding toggle rod 504 to rotate, and the rotating toggle rod 504 can turn over and toggle the tea leaves on the conveyor belt.

[0061] like Figure 3 As shown, the side end of the rotating rod 501 is connected to the side end of the conveyor belt 2 through a transmission belt.

[0062] Mechanical damage to the tea buds is avoided during the turning process. At the same time, the multi-level drop design (the height difference between the conveyor belts is 10-15cm) allows the tea leaves to fall naturally and loosely, effectively preventing the leaves from breaking.

[0063] Through the synergistic effects of heat circulation, dynamic turning and flexible transmission, the device can make the moisture content of tea reach the standard from the initial drying to the re-drying stage (15-18%→≤6%), and the drying uniformity (moisture content standard deviation ≤0.8%) is better than that of traditional single-stage dryers, completely avoiding the problem of burnt smell or thermal degradation of nutritional active substances caused by local over-drying.

[0064] Specifically, conveyor belt 1 2 , conveyor belt 2 3 , and conveyor belt 3 4 are all made of high-temperature resistant mesh structures.

[0065] Specifically, the control method of the present invention is controlled by a controller, and the control circuit of the controller can be implemented by simple programming by those skilled in the art, and the control method and circuit connection will not be explained in detail here.

[0066] The standard parts used in the present invention can all be purchased from the market, and special-shaped parts can be customized according to the description in the specification and the drawings. The specific connection methods of each part adopt conventional means such as mature bolts, rivets, welding, etc. in the existing technology. The machinery, parts and equipment all adopt conventional models in the existing technology, and the circuit connection adopts the conventional connection method in the existing technology, which will not be described in detail here.

[0067] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. The meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0068] In the present invention, unless otherwise clearly defined and limited, the terms such as "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0069] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0070] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not have to be directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0071] In the drawings of the disclosed embodiments of the present invention, only the structures related to the disclosed embodiments are involved, and other structures can refer to the general design. Without conflict, the same embodiment and different embodiments of the present invention can be combined with each other.

[0072] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An organic white tea leaf processing technology, characterized in that, The following steps are involved: Step 1: Select fresh leaves from organically certified tea varieties, picking them with one bud and one leaf or one bud and two leaves just beginning to unfold; Step 2: Spread the fresh leaves evenly on a bamboo withering screen and wither naturally for 8-12 hours at a temperature of 18-22°C and a relative humidity of 65-75%. Then transfer them to a withering room with a light intensity of 3000-5000 lux, control the temperature at 25-28°C and the humidity at 50-60%, and wither for 4-6 hours. Step 3: Use hot air equipment to initially dry the tea leaves at 70-75°C for 20-30 minutes to reduce the moisture content of the tea leaves to 15-18%. Adjust the temperature to 90-95°C and re-dry for 10-15 minutes to a final moisture content of ≤6%. Step 4: Place the finished tea in a dark environment, control the temperature to 0-5℃, and store the tea in a sealed container with a relative humidity below 30%.

2. The processing technology of an organic white tea leaf according to claim 1, wherein: In the second step, the withering sieve leaf spreading density is 0.4 - 0.6 kg / m 2 , and the leaves are turned over every 2 hours during the withering process.

3. The processing technology of an organic white tea leaf according to claim 1, characterized in that: In the second step, full spectrum sunlight is used to simulate sunlight, and the light intensity gradient is set to 5000 lux for the initial 2 hours and then decrease by 500 lux every hour.

4. The processing technology of an organic white tea leaf according to claim 1, characterized in that: In the step 4, the sealed storage is carried out in nitrogen-filled packaging, the oxygen concentration in the packaging is ≤0.5%, and the nitrogen purity is ≥99.95%.

5. A multi-stage circulating drying and processing device used in the processing technology of organic white tea leaves according to any one of claims 1-4, characterized in that, include: A drying box (1), a conveyor belt 1 (2), a conveyor belt 2 (3), a conveyor belt 3 (4) and two toggle mechanisms (5); The conveyor belt 1 (2), the conveyor belt 2 (3), and the conveyor belt 3 (4) are sequentially arranged in the drying box (1) from top to bottom, one of the shifting mechanisms (5) is arranged on the conveyor belt 2 (3), and the other shifting mechanism (5) is arranged on the conveyor belt 3 (4); The side end of the conveyor belt 1 (2) is arranged outside the drying box (1), and the side end of the conveyor belt 3 (4) is arranged outside the drying box (1).

6. The multi-stage cyclic drying and processing device according to claim 5, wherein: The drying box (1) is provided with a gear 1 for rotation on the side thereof, a gear 2 is provided on a rotating shaft of the conveyor belt 2 (3), the gear 1 is meshed with the gear 2, and the side end of the conveyor belt 1 (2) is connected to the side end of the gear 2 through a transmission belt; The side of the drying box (1) is provided with a gear three for rotation, the rotating shaft of the conveyor belt three (4) is provided with a gear four, the gear four is meshed and connected with the gear three, and the other rotating shaft of the conveyor belt two (3) is connected to the side end of the gear three through a transmission belt; A motor (6) is provided at the side end of the conveyor belt (2).

7. A multi-stage cyclic drying and processing device according to claim 5, characterized in that: A heating element (7) is provided inside the drying box (1).

8. The multistage cyclic drying and processing device according to claim 5, wherein: The toggle mechanism (5) comprises a horizontal plate (500) arranged inside the drying box (1); a rotating rod (501) is rotatably arranged on the side of the horizontal plate (500); a plurality of rotating sleeves (502) are equidistantly arranged in the middle of the rotating rod (501); a plurality of rotating wheels (503) are arranged on the top of the horizontal plate (500); the rotating sleeves (502) are meshed and connected with the rotating wheels (503), and the rotating sleeves (502) and the rotating wheels (503) correspond one to one; a toggle rod (504) is arranged at the bottom of the rotating wheel (503); and the toggle rod (504) is arranged at the bottom of the horizontal plate (500).

9. A multi-stage cyclic drying and processing device according to claim 8, characterized in that: The side end of the rotating rod (501) is connected to the side end of the conveyor belt (2) through a transmission belt.

10. A multi-stage cyclic drying and processing device according to claim 5, characterized in that: The conveyor belt 1 (2), conveyor belt 2 (3), and conveyor belt 3 (4) are all of high-temperature resistant mesh surface structure.

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