Production method of green-keeping, bitter-reducing and freshness-increasing matcha

Abstract

The invention relates to the technical field of tea production and processing, in particular to a green-keeping, bitter-reducing and freshness-increasing matcha production method which comprises the following steps: selecting a tea tree variety for planting, performing compensation fertilization, and shading and covering in the growth process to obtain fresh tea leaves; the collected fresh tea leaves are sequentially subjected to steam fixation, cooling and scattering, segmented baking, stem and leaf separation, drying, aging and alcoholization, impurity separation, low-temperature grinding and refining, and then the green-keeping, bitter-reducing and freshness-increasing matcha is prepared. Wherein the step of shading and covering is that overhead type shading and covering are carried out when one bud and two leaves grow on a tea tree, gray and blue polyethylene fiber nets are selected, the shading rate is 90%-95%, and fresh tea leaves are picked in two weeks to three weeks from the beginning of shading and covering; wherein in the low-temperature grinding, graphite is adopted for grinding and refining at the indoor temperature of 20 DEG C or below and the relative humidity of 50% or below; the method disclosed by the invention can improve the contents of amino acid and chlorophyll in the matcha, reduce the content of tea polyphenol and improve the nori fragrance of the matcha.

Description

Technical Field

[0001] The invention relates to the technical field of tea production and processing, and in particular to a method for producing green matcha with the function of retaining greenness, reducing bitterness and increasing freshness. Background Art

[0002] Matcha is made from fresh tea leaves picked after covered cultivation, which are ground into ultrafine powder through steaming, drying and other processing steps. Matcha can better preserve the nutrients and active ingredients in tea, making it have high nutritional and health value. Because of its sweet taste and good color, matcha is often used as a healthy and harmless natural food additive and is widely used in the food industry. The sensory requirements of matcha are green color and fresh taste, which are reflected in the specific physical and chemical indicators, that is, "two highs and one low", that is, high chlorophyll, high theanine, and low tea polyphenols.

[0003] The quality of matcha is closely related to the cultivation technology, and the key cultivation technology is fertilization and covering technology. Matcha gardens have a large demand for nutrients. If the fertilization technology of conventional tea gardens is used, the annual nutritional needs of matcha gardens cannot be met, and the quality of fresh leaves will not be very high. The fresh leaves of tea trees covered with shade increase the amino acid components with umami flavor represented by theanine, increase the synthesis of chlorophyll, and form the bright green color of matcha. The special aroma of matcha, "covered fragrance" and seaweed flavor, are formed through this cultivation method. Traditional covering methods mainly include direct covering, elevated covering, simple arch shed covering, etc., and generally use black fiber nets with a shading rate of 70% to 90%. However, traditional black fiber nets have problems such as easy heat absorption. The fresh leaves after covering have a high content of tea polyphenols and a relatively heavy bitter taste. In the process of processing tea into matcha, grinding and crushing are the key processes. Commonly used crushing methods include graphite, ball milling and air flow crushing. Different conditions such as grinding time and grinding method will lead to differences in the physical properties of tea powder such as temperature and humidity, which may cause significant changes in the particle size, color, odor, endogenous biochemical composition, and functional quality components of the tea powder.

[0004] Therefore, the cultivation, covering and crushing carried out according to the current matcha production and processing technology standards cannot control the color, bitterness and umami intensity of matcha, and cannot achieve the best quality characteristics of the product after crushing, such as bright green, obvious covering fragrance, and strong fresh taste, and ensure its flavor stability. Summary of the invention

[0005] Aiming at the technical problems of the existing tea tree cultivation and management technology for matcha being extensive and the grinding technology being uncontrollable, which leads to the product flavor being not prominent and the quality being unstable, a matcha production method with green preservation, reduced bitterness and increased freshness is provided. High-quality fresh tea leaves are obtained through the special field management of the present invention, and the matcha is obtained through steam killing, cooling and breaking up, four-stage baking, stem and leaf separation, drying, rapid aging and alcoholization, separation of impurities, low-temperature grinding and refining in sequence. The matcha produced by the present invention has a unique flavor, green color, high fragrance and fresh taste.

[0006] In order to achieve the above objectives, the present invention is implemented by the following technical solutions:

[0007] A method for producing green matcha with reduced bitterness and increased freshness comprises the following steps:

[0008] Select tea tree varieties for planting, apply compensatory fertilization, and shade and cover during the growth process to obtain fresh tea leaves;

[0009] The collected fresh tea leaves are sequentially subjected to steam killing, cooling and breaking, segmented baking, stem and leaf separation, drying, aging and alcoholization, impurity separation, low-temperature grinding, and refining to obtain green-retaining, bitter-reducing, and fresh-enhancing matcha;

[0010] The compensatory fertilization is: every 667m 2 The amount of fertilizer used in the tea garden is 25kg-30kg of pure nitrogen fertilizer for every 100kg of matcha produced, and phosphorus and potassium fertilizers are applied according to the weight ratio of N:P2O5:K20 (3.5-4):1:(1.2-1.5);

[0011] The shading covering is to carry out elevated shading covering when the tea tree grows one bud and two leaves, with a shading rate of 90%-95%, and fresh tea leaves are picked two to three weeks after the shading covering begins;

[0012] The low temperature grinding is grinding and refining by using a graphite grinder at a room temperature below 20° C. and a relative humidity below 50%.

[0013] Furthermore, the tea tree variety is selected from one of Longjing 43, E-tea No. 1, and Zhongcha 108; the planting method is double-row strip planting, the row spacing is 1.8m-2m, the plant spacing is 0.4m-0.6m, and the fertilization method is trenching and covering the soil for fertilization. A trench is dug 10cm away from the crown of the tree, the trench is 10-20cm deep and 15-20cm wide, and the soil is covered in time after fertilization.

[0014] Furthermore, the shade covering adopts an elevated film covering. When the tea tree grows one bud and two leaves, a gray shade net with a shading rate of 90%-95% is first used to cover for 10 days, and then a blue shade net with a shading rate of 90%-95% is used to cover for 8 to 10 days. The height of the elevated film covering is 1.6m-1.8m, and the shade net is a polyethylene fiber net. The gray RGB variation range of the gray shade net is: RGB (150, 150, 150)-RGB (180, 180, 180), and the blue color of the blue shade net corresponds to a wavelength of 500nm-400nm in the air, or RGB (0, 0, 255)-RGB (0, 0, 150), or RGB (0, 0, 255)-RGB (50, 50, 255).

[0015] Furthermore, the temperature of the steam killing is 114° C.-116° C., and the killing time is 12 seconds to 15 seconds. The seaweed needs to be killed thoroughly and evenly so that the grass smell disappears and the seaweed fragrance is revealed.

[0016] Furthermore, the cooling and breaking up is done by blowing with a blower, lifting and lowering the particles several times in a cooling net at a height of 6m-8m, with a cooling time of 8min-10min, to break them up, cool them, remove surface moisture, and deposit them on a conveyor belt at a speed of 160g / m 2 -180g / m 2 The amount of loose tea.

[0017] Furthermore, the temperature of the first stage of the segmented baking is set at 150°C-160°C, the temperature of the second stage is set at 100°C-110°C, the temperature of the third stage is set at 80°C-90°C, and the temperature of the fourth stage is set at 70°C-80°C, which takes a total of 25min-30min.

[0018] Furthermore, the drying is to separately dry the stems and leaves obtained after the stem-leaf separation, using a chain plate dryer, with a hot air temperature of 70°C-90°C, repeated drying 2-3 times, a total time of 70min-90min, and controlling the moisture content of the leaves and stems after drying to be below 4wt%.

[0019] Furthermore, the aging and alcoholization is carried out in a temperature- and humidity-controlled artificial climate chamber, the aging and alcoholization temperature is 10°C-15°C, the time is 60 days-80 days, the relative humidity is 40%-45%, and the water content is less than 4.5wt% at the end of the aging and alcoholization.

[0020] Beneficial technical effects:

[0021] The present invention aims to make matcha products unique in flavor, green in color, fragrant and delicious, and affordable. By improving and optimizing traditional cultivation, production and processing technology, and controlling key process parameters, the internal quality and flavor are improved. The characteristics of the present invention are specifically embodied in:

[0022] (1) Applying special fertilizer for matcha gardens with a reasonable ratio of nitrogen, phosphorus and potassium through compensatory fertilization technology can effectively increase the content of amino acids and chlorophyll in matcha, reduce the content of tea polyphenols, and improve the seaweed aroma of matcha;

[0023] (2) By precisely controlling light, the color and internal components of fresh leaves are regulated to achieve rapid directional transformation of internal components, thus accumulating a rich material basis for the presentation of green color and fresh taste;

[0024] (3) The temperature of steam increases after secondary heating. Superheated steam can improve penetration and reduce the possibility of steam condensation, thereby improving thermal efficiency and enhancing the greenness and aroma of the withered leaves.

[0025] (4) Through the staged baking technology, first high temperature and then low temperature, the color is further fixed, the bitterness is reduced, and the aroma components are enriched;

[0026] (5) It combines low-temperature graphite technology to fix and highlight the green color and fresh taste. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a flow chart of the production process of matcha with green preservation, bitterness reduction and freshness enhancement according to the present invention;

[0028] Figure 2 Comparison of the chemical composition of matcha produced by some treatments. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments of the present invention are within the scope of protection of the present invention.

[0030] Unless otherwise specifically stated, the numerical value set forth in these embodiments does not limit the scope of the present invention. The technology and method known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology and method should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values.

[0031] The experimental methods in the following examples without specifying specific conditions are usually measured in accordance with national standards; if there is no corresponding national standard, they are carried out in accordance with general standard requirements or general methods.

[0032] Example 1

[0033] A method for producing and processing green matcha with reduced bitterness and increased freshness. In this case, Longjing 43 tea tree variety is selected for planting, compensatory fertilization is carried out, and fresh tea leaves are obtained by shading and covering during the growth process; the collected fresh tea leaves are sequentially subjected to steam withering, cooling and breaking up, segmented baking, stem and leaf separation, drying, aging and alcoholization, separation of impurities, low-temperature grinding, and refining to obtain green matcha with reduced bitterness and increased freshness.

[0034] The general process flow is as follows Figure 1 As shown, the specific steps include:

[0035] (1) The tea tree variety for fresh leaves is Longjing 43. The tea trees are planted in double rows with a row spacing of 1.8 m and a plant spacing of 0.4 m. The fertilization method is to dig trenches and cover the soil for fertilization. A trench is dug 10 cm away from the tree crown with a depth of 15 cm and a width of 15-20 cm. The soil is covered in time after fertilization.

[0036] (2) Compensatory fertilization, every 667m 2 Fertilizer dosage in tea garden: 30kg nitrogen fertilizer (pure) for every 100kg of tea produced, and phosphorus and potassium fertilizers according to the weight ratio of N:P2O5:K20 of 4:1:1.5;

[0037] The tea garden produces 1,000 kg of fresh leaves in spring, summer and autumn, and produces about 150 kg of ground tea. Therefore, the actual yield per 667m 2 45kg of nitrogen fertilizer, 11.3kg of phosphorus fertilizer and 16.9kg of potassium fertilizer were applied in the tea garden.

[0038] (3) When the tea tree grows one bud and two leaves, shade covering is carried out using an elevated covering system at a height of 1.8 m. First, a gray shade net with a shading rate of 95% is used to cover the tree for 10 days (gray RGB (160,160,160)), and then a blue shade net with a shading rate of 95% is used to cover the tree for 10 days (blue RGB (0,0,255)). The shade nets are all made of polyethylene fiber nets. Finally, fresh tea leaves with one bud and four leaves are harvested.

[0039] (4) The collected fresh tea leaves are withered by a steam withering machine, and steam is used for secondary heating. The temperature after heating is 115° C., and the withering time is 15 seconds. The tea leaves are withered thoroughly and evenly, the grass smell disappears, and the seaweed fragrance is revealed.

[0040] (5) The liquid is quickly blown up by a blower and raised and lowered several times in a cooling net 8m high for 10 minutes to disperse, cool and remove surface moisture; the liquid is then blown up on a conveyor belt at a pressure of 180 g / m 2 The amount of loose tea.

[0041] (6) The initial baking is carried out in a tea-grinding furnace, and the baking process is carried out in four stages. The temperature of the first stage is set at 160°C, the temperature of the second stage is set at 100°C, the temperature of the third stage is set at 80°C, and the temperature of the fourth stage is set at 70°C, which takes a total of 30 minutes.

[0042] (7) Use a stem-leaf separator to separate the leaves and tea stems and remove impurities at the same time. The stem-leaf separation is performed three times and the stem content of the leaves is less than 1%.

[0043] (8) The tea stems and leaves are dried separately in a chain plate dryer at a hot air temperature of 80°C for two times for a total of 70 minutes. The moisture content of the leaves and stems after drying is controlled to be below 4%.

[0044] (9) Aging and aging is carried out in an artificial climate room with controllable temperature and humidity, at a temperature of 10°C, for 60 days and a relative humidity of 40%.

[0045] (10) Impurities are separated by using machines with functions such as wind sorting, color sorting, electrostatic stem picking, and metal removal to sort and remove non-tea foreign matter, while separating leaf stems, leaf veins, coarse leaves, and other impurities.

[0046] (11) Low temperature grinding: Grind the green tea with a low temperature electric graphite grinder at a room temperature below 20°C and a relative humidity below 50% to obtain ground green tea.

[0047] (12) Refining the ground matcha: Put it into the iron removal device and screening machine in sequence, pass it through an 80-mesh stainless steel sieve, and remove foreign matter on the surface. Then turn on the metal detector and pass the sieved matcha through the metal detector. Finally, the matcha after impurities are removed is put into an aluminum foil bag to obtain refined matcha powder.

[0048] Comparative Example

[0049] In this case, the following multiple different production conditions are set up as a comparative test. Except for the following different production conditions, other production conditions are the same as those in Example 1:

[0050] Treatment 1: no shading and covering + conventional fertilization;

[0051] Treatment 2: shade coverage with black shade netting with a shading rate of 95% + conventional fertilization + ball milling;

[0052] Treatment 3: shade cover with black shade net with 95% shading rate + compensatory fertilization + ball milling;

[0053] Treatment 3-1: Shade coverage with black shade net with 95% shading rate + compensatory fertilization + air flow crushing;

[0054] Treatment 3-2: Shading with a black shading net with a shading rate of 95% + compensatory fertilization + low-temperature graphite grinding (same as step 11 in Example 1);

[0055] Treatment 4: shade coverage with a blue shade net with a shading rate of 95% + compensatory fertilization + ball milling;

[0056] Treatment 5: shading coverage with red shading netting with a shading rate of 95% + compensatory fertilization + ball milling;

[0057] Treatment 6: shade coverage with gray shade netting with a shading rate of 95% + compensatory fertilization + ball milling;

[0058] Treatment 7: Shading was first covered with a black shading net with a shading rate of 95%, then with a blue shading net with a shading rate of 95% + ball milling;

[0059] Treatment 8: Shade cover first with a gray shade net with a shading rate of 95%, and then switch to a blue shade net with a shading rate of 95% + ball mill.

[0060] The specific process parameters of ball milling in the above treatment are: 20kg-25kg of tea raw materials are put in each time, and the rotation time is 20h-22h. The specific process parameters of air flow crushing in the above treatment are: the air flow mill equipment has continuous feeding and discharging during the grinding process, and the processing volume can be greatly adjusted. The single cycle (feeding to discharging) takes 1.5min-2min, and the processing capacity of each equipment is 50kg / h-150kg / h; the specific process parameters of graphite are: the electric stone mill continuously feeds and discharges, and the processing capacity of each stone mill is 40g / h-50g / h.

[0061] The shade mesh colors involved in the above processing are: gray RGB (160,160,160), blue RGB (0,0,255), red RGB (255,0,0), and black RGB (0,0,0).

[0062] The sensory quality of the matcha produced by the above treatment was evaluated in accordance with the "GB / T 23776-2018 Sensory Evaluation Method for Tea". The specific results are shown in Table 1 below.

[0063] Table 1 Sensory quality evaluation results of matcha produced by different treatments

[0064]

[0065]

[0066] As shown in Table 1, the sensory quality score of the matcha produced by treatment 1 of no covering + conventional fertilization + ball milling is the lowest, and the sensory quality score of the matcha produced by embodiment 1 of gray net first and then blue net covering + compensatory fertilization + low temperature grinding is the highest. Treatment 2 of black net covering + conventional fertilization + ball milling is a traditional production mode, and the sensory total score of the matcha produced is 88.65; the aroma and taste of the matcha produced by treatment 3 of black net covering + compensatory fertilization + ball milling are improved, and its sensory quality is improved by 1.325 points; treatments 4-6 replace the shade net on the basis of treatment 3, and the matcha treated by blue net shading has a greener color and a higher fresh and mellow taste, the matcha treated by gray net shading has a greener color and a higher covering fragrance intensity, and the aroma, taste and soup color of the matcha treated by red net shading are poor. It can be seen that the sensory quality of the matcha treated by blue net or gray net shading is one level higher than that of traditional matcha.

[0067] Treatment 7, based on Treatment 3, first used a black net and then a blue net combined with shading treatment, and the sensory quality of the matcha produced therefrom did not change significantly compared with the single light treatment; while Treatment 8, based on Treatment 3, first used a gray net and then a blue net combined with shading treatment, and the sensory quality of the matcha reached 92.8 points compared with the single light treatment; the matcha of Example 1 was first covered with a gray net and then a blue net + compensatory fertilization + low-temperature graphite grinding, and its color and covering aroma were further improved.

[0068] In addition, under the same conditions of black net covering + compensatory fertilization, the effects of different powder making methods on matcha in treatment 3, treatment 3-1, and treatment 3-2 were compared. The color, aroma, and taste of matcha produced by the airflow milling method were poor, and the sensory quality score was the lowest, while the color, aroma, and taste of matcha produced by the low-temperature graphite grinding method were better, and the sensory quality score was the highest.

[0069] In summary, the color, aroma and taste of matcha produced by the present invention using gray nets and then blue nets for combined shading, combined with on-demand compensatory fertilization and low-temperature graphite grinding is the best.

[0070] The quality components in fresh tea leaves, such as amino acids, catechins, tea polyphenols, and flavonoid glycosides, are the material basis for the formation of the quality characteristics of tea making. Amino acids are an important component of the flavor of green tea and an important substance for improving the freshness of tea. Theanine is a characteristic amino acid substance and the main substance for the formation of the freshness of tea. The content of tea polyphenols determines the concentration and thickness of the tea soup to a certain extent, and makes an important contribution to the bitterness of the taste. Catechins are the main component of polyphenols and the main substance for the formation of the bitterness of tea. The phenol-ammonia ratio can reflect the flavor quality of the tea soup and is negatively correlated with the freshness of the tea soup. Chlorophyll is the main substance for the formation of the appearance and bottom color of green tea. It is the main contributor to the green color of tea and gives green tea its unique bright green color. Therefore, the chemical composition of the above-treated matcha was analyzed, and the results are shown in Tables 2 and Figure 2 .

[0071] Table 2 Chemical composition of matcha produced by each treatment

[0072]

[0073] As shown in Table 2, the total catechins, total flavonoid glycosides, tea polyphenols and phenol-amine ratio of the matcha produced by treatment 1 without coverage were the highest, while the total amount of amino acids, theanine and chlorophyll were the lowest; the total catechins, total flavonoid glycosides, tea polyphenols and phenol-amine ratio of the matcha produced by treatment 2 traditional method and treatment 5 red net coverage were higher, second only to the matcha produced by treatment 1 without coverage. Figure 2 It can be seen that compared with the traditional matcha in treatment 2, the total catechins, total flavonoid glycosides, tea polyphenols and phenol-amine ratio of matcha produced by treatment 3 (black net covering + compensatory fertilization + ball milling) decreased by 6.03%, 17.31%, 5.05% and 29.34%, respectively, while the total amount of amino acids, theanine and chlorophyll increased by 34.36%, 23.97% and 39.26%, respectively; the total catechins, total flavonoid glycosides, tea polyphenols and phenol-amine ratio of matcha produced by treatment 4 (blue net covering + compensatory fertilization + ball milling) decreased by 12.17%, 24.17%, 11.85% and 36.63%, respectively. .23%, while the total amount of amino acids, theanine and chlorophyll increased by 38.22%, 27.40% and 43.8% respectively; the chemical composition of matcha made by treatment 7 with black net first + blue net covering + compensatory fertilization + ball milling was similar to that of single blue net or black net treatment. Compared with the traditional matcha in treatment 2, its total catechins, total flavonoid glycosides, tea polyphenols and phenol-ammonia ratio decreased by 18.59%, 36.47%, 16.34% and 44.3% respectively, while the total amount of amino acids, theanine and chlorophyll increased by 50.19%, 39.04% and 66.53% respectively. Compared with the traditional matcha in treatment 2, the chemical composition of the matcha prepared in treatment 8 with gray net first + blue net covering + compensatory fertilization + ball milling changed significantly, and its total catechins, total flavonoid glycosides, tea polyphenols and phenol-amine ratio decreased by 27.76%, 58.66%, 24.95% and 56.52%, respectively, while the total amount of amino acids, theanine and chlorophyll increased by 72.59%, 63.01% and 135.12%, respectively; the chemical composition of the matcha prepared in Example 1 changed most significantly, and its total catechins, total flavonoid glycosides, tea polyphenols and phenol-amine ratio decreased by 34.72%, 63.6%, 34% and 65.04%, respectively, while the total amount of amino acids, theanine and chlorophyll increased by 88.8%, 76.03% and 161.57%, respectively. Therefore, the high content of total amino acids, theanine and chlorophyll, and the lower content of total catechins, total flavonoid glycosides, tea polyphenols and phenol-amino ratio in the embodiments of the present invention are the important material basis for the green color, low bitterness and fresh taste of matcha.

[0074] The present invention significantly improves the color, flavor and aroma quality of matcha by controlling the conditions of key production, cultivation and crushing processes of matcha, increases the added value of the product, and obtains a matcha product with better quality, bright green color and mellow flavor, which has broad application prospects.

[0075] The above description 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 producing green tea with reduced bitterness and increased freshness, characterized in that: The steps include: Select tea tree varieties for planting, apply compensatory fertilization, and shade and cover during the growth process to obtain fresh tea leaves; The collected fresh tea leaves are sequentially subjected to steam killing, cooling and breaking, segmented baking, stem and leaf separation, drying, aging and alcoholization, impurity separation, low-temperature grinding, and refining to obtain green-retaining, bitter-reducing, and fresh-enhancing matcha; The compensatory fertilization is: every 667m 2 The amount of fertilizer used in the tea garden is 25kg-30kg of pure nitrogen fertilizer for every 100kg of matcha produced, and phosphorus and potassium fertilizers are applied according to the weight ratio of N:P2O5:K20 (3.5-4):1:(1.2-1.5); The shading covering is to carry out elevated shading covering when the tea tree grows one bud and two leaves, with a shading rate of 90%-95%, and fresh tea leaves are picked two to three weeks after the shading covering begins; The low temperature grinding is grinding and refining by using a graphite grinder at a room temperature below 20° C. and a relative humidity below 50%.

2. The method for producing green tea with reduced bitterness and increased freshness according to claim 1, characterized in that: The tea tree variety is selected from one of Longjing 43, E-tea No. 1, and Zhongcha 108; the planting method is double-row strip planting, the row spacing is 1.8m-2m, the plant spacing is 0.4m-0.6m, and the fertilization method is trenching and covering the soil for fertilization. A trench is dug 10cm away from the tree crown, the trench is 10-20cm deep and 15-20cm wide, and the soil is covered in time after fertilization.

3. The method for producing green tea with reduced bitterness and increased freshness according to claim 1, characterized in that: The shading covering is to first use a gray shading net with a shading rate of 90%-95% to cover it for 10 days when the tea tree grows one bud and two leaves, and then use a blue shading net with a shading rate of 90%-95% to cover it for 8 to 10 days. The height of the elevated covering is 1.6m-1.8m, and the shading net is a polyethylene fiber net.

4. The method for producing green tea with reduced bitterness and increased freshness according to claim 1, characterized in that: The steam killing temperature is 114° C.-116° C., and the killing time is 12 seconds to 15 seconds.

5. The method for producing green tea with reduced bitterness and increased freshness according to claim 1, characterized in that: The cooling and breaking up is done by blowing with a blower, lifting and lowering for several times in a cooling net at a height of 6m-8m, with a cooling time of 8min-10min, in order to break up, cool, and remove surface moisture, and then the particles are transported on a conveyor belt at a speed of 160g / m 2 -180g / m 2 The amount of loose tea.

6. The method for producing green tea with reduced bitterness and increased freshness according to claim 1, characterized in that: The first stage temperature of the segmented baking is set at 150°C-160°C, the second stage temperature is set at 100°C-110°C, the third stage temperature is set at 80°C-90°C, and the fourth stage temperature is set at 70°C-80°C, which takes a total of 25 minutes to 30 minutes.

7. The method for producing green tea with reduced bitterness and increased freshness according to claim 1, characterized in that: The drying is to separately dry the stems and leaves obtained after the stem-leaf separation, using a chain plate dryer, with a hot air temperature of 70°C-90°C, repeated drying 2-3 times, a total time of 70min-90min, and controlling the moisture content of the leaves and stems after drying to be below 4wt%.

8. The method for producing green tea with reduced bitterness and increased freshness according to claim 1, characterized in that: The aging and alcoholization is carried out in a temperature- and humidity-controlled artificial climate room, the aging and alcoholization temperature is 10° C.-15° C., the time is 60 days-80 days, the relative humidity is 40%-45%, and the water content is lower than 4.5wt% at the end of the aging and alcoholization.

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