Processing technology of floating beam green tea

Abstract

The present invention relates to a floating beam green tea processing technology, which comprises the steps of tedding, fixation, spreading for cooling, rolling and parching, the fixation is divided into three steps: first steam fixation is performed, the temperatures of the front, middle and rear sections in a cylinder are different, ozone water washing is performed after the first fixation, the second fixation adopts microwave fixation, and nitrogen-containing substances are supplemented and sprayed before the fixation. And finally, the floating beam green tea which is mellow in tea fragrance, green in leaf bottom and light green and bright in soup color is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of tea processing, and in particular relates to a processing technology for Fuliang green tea. Background Art

[0002] Fuliang Green Tea is produced in Fuliang County, Jingdezhen City, Jiangxi Province, and has a long history and rich cultural background. Fuliang County is located near 30 degrees north latitude and belongs to the remnant of Huangshan Mountain and Huaiyu Mountain. The territory is mainly composed of medium and low mountains and hills. The climate is mild and humid, with sufficient sunlight and abundant rainfall, providing unique natural conditions for the growth of tea.

[0003] Fuliang tea is famous for its "beautiful appearance, noble aroma, bright soup color, and mellow taste", and is known as the "treasure of tea". The production process of Fuliang tea has evolved over time, from the flake tea and cake tea of ​​the Tang Dynasty to the loose tea of ​​the late Southern Song Dynasty, and then to the green tea process that was initially finalized in the Yuan Dynasty, including picking, spreading leaves, killing green, rolling, re-firing, and frying and drying.

[0004] The process of tea leaf killing plays a vital role in tea processing. First, killing tea leaves destroys the enzyme activity in fresh leaves through high temperature treatment, inhibits the oxidation reaction of polyphenols, thereby preventing the tea leaves from continuing to ferment and maintaining the original color and aroma of the tea leaves. Secondly, killing tea leaves can remove the grassy smell in the tea leaves, exude a charming tea fragrance, and improve the quality of the tea leaves. In addition, killing tea leaves can also evaporate some water, making the tea leaves softer and easier to roll and shape. Different types of tea have different requirements during the killing process. For example, green tea requires a shorter killing time to maintain its bright green color, while Pu'er tea requires a longer killing time to form a unique aged fragrance. Therefore, mastering the time, temperature and method of killing tea leaves is crucial to the final quality of the tea leaves and is a key step in ensuring the quality and taste of the tea leaves.

[0005] Among them, microwave killing can effectively inhibit enzyme activity, but sometimes it will lead to the failure of the aroma to fully develop, resulting in high-fire smell and burnt smell. The finished tea processed by the drum killing machine has a strong and long aroma, but it is prone to defects such as red stems or burnt edges. Even if continuous killing can improve these problems, it may still cause problems such as uneven killing and incomplete killing.

[0006] Theanine is the main source of the fresh and refreshing taste of tea and is positively correlated with the quality of green tea. However, after the high-temperature withering process of tea leaves, the content of theanine in the tea leaves will decrease. Therefore, the present invention sprays certain nitrogen-containing substances on the surface of tea leaves to supplement the surface of tea leaves, thereby reducing the difference in theanine metabolism and the molecular mechanism of responding to nitrogen deficiency stress, thereby obtaining high-quality green tea with high theanine content. Summary of the invention

[0007] The purpose of the invention is to provide a processing technology for Fuliang green tea.

[0008] In order to solve the above technical problems, the specific process of the present invention is as follows:

[0009] A processing technology for Fuliang green tea, including spreading, killing, cooling, rolling, and baking, characterized in that: the killing is divided into three stages, the first stage is steam staged killing, the green leaves after spreading are put into a steam drum for killing, the leaf feeding amount is 150kg / h, the front, middle and rear stages are 280℃, 270℃ and 260℃ respectively, and each stage time is 5min; the second stage is putting it into ozone water for washing, the mass fraction of ozone in water is 0.09%, the ozone water is washed for 20min, and then washed twice with clean water, each time for 20min, and then dried at a speed of 800-1000RPM for 2-5min; the third stage is microwave secondary killing, the power is 700w, and the time is 150s.

[0010] Among them, baking includes primary baking and re-baking. Primary baking: the rolled tea leaves should be put into bamboo baking cage or fried in pot in time at a temperature of 100℃-110℃ for 20min, and the final moisture content should be 20-30%; re-baking: fry the green tea after primary baking in a cast iron pot at a temperature of 80℃-90℃ for 30min, until the moisture content is 6.0%-6.5%, pour it into bamboo plate, sieve out the powder after cooling, and then pack and store.

[0011] A processing technology for Fuliang green tea is carried out according to the following steps:

[0012] Spreading the leaves: After picking the first bud, second and third leaves, spread them on different bamboo trays according to the standard grades. The thickness should not exceed 3.5cm. The leaves should be spread for 4-10 hours, turning them over lightly in the middle.

[0013] Steam-staged killing: put the green leaves after spreading into the steam drum for killing, the leaf feeding amount is 150kg / h, the front, middle and back stages are 280℃, 270℃ and 260℃ respectively, and each stage lasts for 5min; ozone water washing: the mass fraction of ozone in water is 0.09%, ozone water washing for 20min, and then washing twice with clean water, each time for 20min, and then spin drying at 800-1000RPM speed for 2-5min;

[0014] Microwave secondary fixing: power 700w, time 150s.

[0015] Cooling: After the tea leaves are withered, spread them evenly on a bamboo tray immediately to allow them to emit heat and avoid stuffiness. Fold them several times in the bamboo tray to remove debris and dust. The time is 1 hour, and the moisture content is 40-45%.

[0016] Rolling and twisting: Rolling and twisting is to hold the tea leaves between the palms of both hands, rubbing them in one direction with light gestures, then shaking them and rubbing them again until the tea juice comes out. The time is 10-15 minutes, and the moisture content is 45-50%.

[0017] Initial baking: The rolled tea leaves should be promptly placed in a bamboo baking cage or fried in a pan at a temperature of 100-110°C for 20 minutes, and the final moisture content should be 20-30%.

[0018] Re-drying: Fry the green tea after the initial baking in a cast iron pan at 80℃-90℃ for 30 minutes until the moisture content is 6.0%-6.5%. Pour it into a bamboo plate, wait for it to cool, sieve out the powder, and then package and store.

[0019] Among them, before the withering step, a spraying treatment is also included, specifically: spraying 4-8% of a nitrogen-containing supplement liquid with a mass fraction of 0.4-0.8% on the surface of the tea leaves after spreading, and stirring evenly for subsequent withering.

[0020] Wherein, the nitrogen-containing supplement liquid is L-glutamic acid benzyl ester solution.

[0021] The beneficial effects of the present invention are:

[0022] 1. The invention adjusts the withering process to reduce the phenomenon of red stems, burnt edges, and incomplete withering of tea leaves during the withering process, thereby retaining the tea aroma and the nutrients therein to the greatest extent. In addition, spraying and supplementing a certain nitrogen-containing substance before withering can provide an additional nitrogen source, promote the synthesis of theanine, and alleviate the stress of tea leaves under high temperature environment, slowing down the negative impact of high temperature on theanine synthase activity and gene expression, thereby improving the quality of tea leaves, and obtaining Fuliang green tea with mellow tea aroma, green leaves, and bright green soup color.

[0023] 2. Therefore, the present invention first adopts steam to kill the green tea and is divided into the front and back middle sections. The hot and humid air drum to kill the green tea uses high temperature hot and humid air to preheat the fresh leaves, so that the tea leaves that have just entered the drum are quickly heated up and killed thoroughly. At the same time, the moisture of the tea leaves will not evaporate too quickly, reducing the loss of some ingredients in the tea leaves (such as vitamin C, amino acids, etc.), while improving the quality of the tea leaves and improving the production efficiency. The tea after killing has the advantages of the steam to kill the green tea, such as the complete leaf surface, green leaf bottom, and bright green soup color, and the advantages of the drum to kill the green tea with a high and long aroma and a strong and refreshing taste.

[0024] 3. After the first killing, the tea leaves are washed with ozone water, dried and then subjected to microwave killing for the second time. Certain washing treatments can improve the sensory quality of tea leaves, reduce the phenol-ammonia ratio, reduce agricultural residues and heavy metal pollution, and improve tea production efficiency and sanitary quality. In addition, ozone water washing can remove excess residues and help retain the natural antioxidant components and nutrients in tea leaves.

[0025] 4. Microwave heating can not only efficiently remove moisture from tea leaves, but also promote the conversion and retention of aroma substances, amino acids and polyphenols in tea leaves. Precise heating during the secondary microwave withering process can further enhance the taste of tea leaves, maintain their nutrients and enhance their antioxidant properties. Microwave heating is characterized by fast and uniform heating, which can not only avoid damage to tea leaves caused by high temperatures, but also shorten the overall withering time, which helps to reduce the time tea leaves are exposed to high temperatures, thereby better retaining the nutrients and volatile aroma substances in tea leaves, and enhancing the flavor and taste of tea leaves. It promotes the full release and conversion of different volatile aroma substances in tea leaves at a suitable temperature. This heating method can effectively promote the formation of some compounds with pleasant odors (such as alcohols, esters, terpene alcohols, etc.), forming the unique aroma characteristics of tea leaves.

[0026] 5. This combined withering process has strong thermal cracking and ester effects, the highest content of ester compounds, a strong floral and fruity aroma, and the highest tea aroma content.

[0027] 6. When a certain amount of L-glutamic acid benzyl ester is added to the surface of tea leaves, L-glutamic acid benzyl ester itself is an esterified derivative of L-glutamic acid. Due to the particularity of its structure, L-glutamic acid benzyl ester can enter the rhizome of tea leaves and be hydrolyzed into L-glutamic acid therein. L-Glutamic acid is a precursor for the synthesis of theanine, and one of the key pathways for theanine synthesis also involves the synthesis of ethylamine. L-glutamic acid benzyl ester on the surface of tea leaves can improve the synthesis efficiency of theanine by promoting the expression of genes related to theanine synthesis in tea leaves, especially the high level expression of the CsALT gene.

[0028] 7. The CsALT gene plays a key role in the synthesis of ethylamine. Ethylamine is an important intermediate in the synthesis of theanine, and the synthesis of ethylamine is regulated by the CsALT gene. When L-glutamic acid benzyl ester is sprayed on tea leaves, it indirectly promotes the high level of expression of the CsALT gene by changing the nitrogen metabolism pathway in tea leaves cells. This helps to increase the conversion rate of ethylamine, thereby improving the efficiency of theanine synthesis.

[0029] 8. After theanine is synthesized, it needs to be transported to other parts of the tea leaves (such as leaves and stems) through certain pathways to maintain its content in the tea leaves. L-Glutamic Acid Benzyl Ester indirectly promotes the transport process of theanine by regulating the nitrogen metabolism of tea plants and enhancing the synthesis of theanine.

[0030] 9. As water evaporates and the temperature rises, nitrogen metabolism is disturbed, the synthesis of theanine may be inhibited, and losses may occur in the process. Spraying L-glutamic acid benzyl ester not only provides an additional nitrogen source and promotes the synthesis of theanine, but also alleviates the stress of tea leaves in high temperature environments and slows down the negative effects of high temperature on theanine synthase activity and gene expression. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with the embodiments. The ozone generators in the following embodiments are all air-cooled ozone generators (Q1-8003K model) produced by Guangzhou Quanju Ozone Co., Ltd.

[0032] Example 1

[0033] Spreading the leaves: After picking the first bud, second bud, and third bud fresh leaves, spread them on different bamboo trays according to standard grades. The thickness should not exceed 3.5 cm. The fresh leaves should be spread for 7 hours, turning them over lightly halfway.

[0034] Spraying treatment: Spray 6% of 0.6% L-glutamic acid benzyl ester solution on the surface of the tea leaves after spreading, and stir evenly for subsequent withering.

[0035] Steam-staged killing: put the green leaves after spreading into the steam drum for killing, the leaf feeding rate is 150kg / h, the front, middle and back stages are 280℃, 270℃ and 260℃ respectively, and each stage lasts for 5 minutes;

[0036] Ozone water washing: The mass fraction of ozone in water is 0.09%. Wash with ozone water for 20 minutes, then wash twice with clean water, each time for 20 minutes, and then spin dry at 900RPM for 4 minutes;

[0037] Microwave secondary fixing: power 700w, time 150s.

[0038] Cooling: After the tea leaves are withered, spread them evenly and thinly on a bamboo tray immediately to allow them to emit heat and avoid stuffiness. Fold them several times in the bamboo tray to remove debris and dust. The time is 1 hour, and the moisture content is 42%:

[0039] Rolling and twisting: Rolling and twisting is to hold the tea leaves between the palms of both hands, rubbing them in one direction with light gestures, then shaking them and rubbing them again until the tea juice comes out. The time is 12 minutes and the moisture content is 48%.

[0040] Initial baking: The rolled tea leaves should be promptly placed in a bamboo baking cage or fried in a pan at 105°C for 20 minutes, with a final moisture content of 25%.

[0041] Re-drying: Fry the initially roasted green tea in a cast iron pan at 85°C for 30 minutes until the moisture content reaches 6.2%. Pour the mixture into a bamboo basket, wait for it to cool, sieve out the powder, and then package and store.

[0042] Example 2

[0043] Spreading the leaves: After picking the first bud, second and third leaves, spread them on different bamboo trays according to the standard grades. The thickness should not exceed 3.5cm. The leaves should be spread for 10 hours, turning them over lightly once in the middle.

[0044] Spraying treatment: Spray 4% of 0.8% L-glutamic acid benzyl ester solution on the surface of the tea leaves after spreading, and stir evenly for subsequent withering.

[0045] Steam-staged killing: put the green leaves after spreading into the steam drum for killing, the leaf feeding rate is 150kg / h, the front, middle and back stages are 280℃, 270℃ and 260℃ respectively, and each stage lasts for 5 minutes;

[0046] Ozone water washing: The mass fraction of ozone in water is 0.09%. Wash with ozone water for 20 minutes, then wash twice with clean water, each time for 20 minutes, and then spin dry at 1000RPM for 2 minutes;

[0047] Microwave secondary fixing: power 700w, time 150s.

[0048] Cooling: After the tea leaves are withered, spread them evenly and thinly on a bamboo tray immediately to allow them to emit heat and avoid stuffiness. Fold them several times in the bamboo tray to remove debris and dust. The time is 1 hour, and the moisture content is 45%:

[0049] Rolling and twisting: Rolling and twisting is to hold the tea leaves between the palms of your hands, rubbing them in one direction with light gestures, then shaking them and rubbing them again until the tea juice comes out. The time is 15 minutes and the moisture content is 50%.

[0050] Initial baking: The rolled tea leaves should be promptly placed in a bamboo baking cage or fried in a pan at 100°C for 20 minutes, with a final moisture content of 30%.

[0051] Re-drying: Fry the initially roasted green tea in a cast iron pan at 80°C for 30 minutes until the moisture content reaches 6.0%. Pour the mixture into a bamboo basket, wait for it to cool, sieve out the powder, and then package and store.

[0052] Example 3

[0053] Spreading the leaves: After picking the first bud, second bud, and third bud fresh leaves, spread them on different bamboo trays according to standard grades. The thickness should not exceed 3.5 cm. The fresh leaves should be spread for 4 hours, turning them over lightly in the middle.

[0054] Spraying treatment: Spray 8% of 0.4% L-glutamic acid benzyl ester solution on the surface of the tea leaves after spreading, and stir evenly for subsequent withering.

[0055] Steam-staged killing: put the green leaves after spreading into the steam drum for killing, the leaf feeding rate is 150kg / h, the front, middle and back stages are 280℃, 270℃ and 260℃ respectively, and each stage lasts for 5 minutes;

[0056] Ozone water washing: The mass fraction of ozone in water is 0.09%. Wash with ozone water for 20 minutes, then wash twice with clean water, each time for 20 minutes, and then spin dry at 800RPM for 5 minutes;

[0057] Microwave secondary fixing: power 700w, time 150s.

[0058] Cooling: After the tea leaves are withered, spread them evenly and thinly on a bamboo tray immediately to allow them to emit heat and avoid stuffiness. Fold them several times in the bamboo tray to remove debris and dust. The time is 1 hour, and the moisture content is 40%:

[0059] Rolling and twisting: Rolling and twisting is to hold the tea leaves between the palms of both hands, rubbing them in one direction with light gestures, then shaking them and rubbing them again until the tea juice comes out. The time is 10-15 minutes, and the moisture content is 45%.

[0060] Initial baking: The rolled tea leaves should be promptly put into a bamboo baking cage for baking or fried in a pan at a temperature of 110°C for 20 minutes, and the final moisture content should be 20%.

[0061] Re-drying: Fry the green tea after the initial baking in a cast iron pan at 80℃-90℃ for 30 minutes until the moisture content reaches 6.5%. Pour it into a bamboo plate, wait for it to cool, sieve out the powder, and then package and store.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 is that this comparative example does not undergo spraying treatment, and the rest is the same as Example 1.

[0064] Comparative Example 2

[0065] The difference between this comparative example and Example 1 is that the L-glutamic acid benzyl ester solution is a glutamic acid solution, and the rest is the same as Example 1.

[0066] Comparative Example 3

[0067] The difference between this comparative example and Example 1 is that the content of L-glutamate benzyl ester solution in this comparative example is different. The specific spraying treatment is as follows: 12% of a 0.6% L-glutamate benzyl ester solution by mass is sprayed on the surface of the tea leaves after spreading, and the tea leaves are stirred evenly for subsequent withering; the rest is the same as Example 1.

[0068] Comparative Example 4

[0069] The difference between this comparative example and Example 1 is that the content of L-glutamate benzyl ester solution in this comparative example is different. The specific spraying treatment is as follows: 2% of L-glutamate benzyl ester solution with a mass fraction of 0.6% is sprayed on the surface of the tea leaves after spreading, and the tea leaves are stirred evenly for subsequent withering; the rest is the same as Example 1.

[0070] Comparative Example 5

[0071] The difference between this comparative example and Example 1 is that the killing process in this comparative example is a single steam-stage killing process, without ozone water cleaning and secondary microwave killing process, and the rest is the same as Example 1.

[0072] Comparative Example 6

[0073] The difference between this comparative example and Example 1 is that the microwave sterilization in this comparative example is one-time microwave sterilization, and the specific microwave sterilization is: power 700w, time 150s; the rest is the same as Example 1.

[0074] Comparative Example 7

[0075] The difference between this comparative example and Example 1 is that the killing process in this comparative example is a single steam killing process, and the killing temperature is fixed. The specific steam killing process is: the green leaves after spreading are put into the steam drum for killing, the leaf feeding amount is 150kg / h, the temperature is 270°C, and the time is 15min; the rest is the same as Example 1.

[0076] Comparative Example 8

[0077] The difference between this comparative example and Example 1 is that the killing of green leaves in this comparative example is steam-stage killing of green leaves, rinsing with clean water, and finally microwave killing of green leaves, specifically: steam-stage killing of green leaves: the green leaves after spreading are put into the steam drum for killing, the leaf feeding amount is 150kg / h, the front, middle and rear sections are 280℃, 270℃ and 260℃ respectively, and the time of each section is 5min; then rinse with clean water twice, each time for 20min, and then spin dry at 900RPM for 4min; microwave secondary killing of green leaves: power is 700w, time is 150s; the rest is the same as Example 1.

[0078] Test 1: Tea ingredient detection

[0079] (1) Sample pretreatment: Take 2 g of green tea and put it into a 10 mL extraction bottle, seal it, and place it in a water bath at 80°C for 10 min. Insert a 65 μm PDMS / DVB extraction head that had been pre-aged for 45 min into the top of the extraction bottle. After extraction for 60 min, take it out and immediately insert it into the chromatograph injection port for desorption for 5 min. At the same time, start the instrument to collect data.

[0080] (2) Gas chromatography (GC) conditions: chromatographic column: CD-WAX flexible quartz capillary column (30 m x 25 mm x 25 μm); injection port temperature: 240 °C; flow rate: 0.98 m / min; splitless injection; carrier gas: He; heating program: initial temperature: 60 °C, hold for 2 min; increase the temperature to 180 °C at 4 °C / min, hold for 10 min; increase the temperature to 220 °C at 10 °C / min, hold for 5 min; increase the temperature to 240 °C at 15 °C / min, hold for 5 min.

[0081] (3) Mass spectrometry (MS) conditions: ion source as source; electron energy 70 eV; ion source temperature 200 °C, interface temperature 220 °C, scanning range 45-500 (m / z).

[0082] The results are shown in Table 1.

[0083] Table 1

[0084]

[0085] Test 2: Color test

[0086] The color difference determination is as follows: weigh 5g of tea sample, grind it with a tea grinder for 40s to make the powder uniform, mix it and place it in a colorimetric box to determine the color difference value. The colorimeter uses D65 light source and adopts the CIE (International Commission on Illumination) 1976 (L*, a*, b*) colorimetric method. The measuring head contacts the tea steadily, adopts the 5-point colorimetric method, and records the L*, a*, and b* values.

[0087] L represents brightness, the larger the value, the higher the brightness; a* represents the red-green tone, if a* is a negative value, the object color is green, and if a* is a positive value, the color is reddish; b* represents the yellow-blue tone, if b* is a negative value, the object color is blue, and if b* is a positive value, the object color is yellowish.

[0088] The results are shown in Table 2 below.

[0089] Table 2

[0090]

Claims

1. A processing technology for Fuliang green tea, comprising spreading, killing, cooling, rolling, and roasting, characterized in that: The killing green leaves is divided into three stages. The first stage is steam-stage killing green leaves. The green leaves after spreading are put into a steam drum for killing green leaves. The leaf feeding amount is 150kg / h. The front, middle and rear stages are 280°C, 270°C and 260°C respectively, and each stage lasts for 5 minutes. The second stage is washing them in ozone water. The mass fraction of ozone in water is 0.09%. The ozone water is washed for 20 minutes, and then washed twice with clean water, each time for 20 minutes, and then dried at a speed of 800-1000RPM for 2-5 minutes. The third stage is microwave secondary killing with a power of 700w and a time of 150s.

2. The processing technology of Fuliang green tea as claimed in claim 1, characterized in that: The baking includes primary baking and secondary baking. Primary baking: the rolled tea leaves should be promptly put into a bamboo baking cage for baking or put into a pot for frying at a temperature of 100-110°C for 20 minutes, and the final moisture content is 20-30%; secondary baking: the green tea leaves after primary baking are fried in a cast iron pot at a temperature of 80-90°C for 30 minutes until the moisture content is 6.0%-6.5%, then poured into a bamboo plate, sieved to remove powder after cooling, and then packaged and stored.

3. The processing technology of Fuliang green tea according to claim 1, characterized in that: Proceed as follows: Spreading: After picking the first bud, second and third leaves, spread them on different bamboo trays according to the standard grades. The thickness should not exceed 3.5cm. Spread the leaves for 4-10 hours, turning them over once in the middle. The tea leaves after spreading are subjected to steam-assisted segmented de-greening and microwave-assisted secondary de-greening; Cooling: After the tea leaves are withered, spread them evenly on a bamboo tray immediately to allow them to emit heat and avoid stuffiness. Fold them several times in the bamboo tray to remove debris and dust. The time is 1 hour, and the moisture content is 40-45%. Rolling: Rolling means holding the tea leaves between the palms of your hands, rubbing them in one direction with light gestures, then shaking them loose and rubbing them again until the tea juice comes out. The time is 10-15 minutes, and the moisture content is 45-50%; Then carry out initial baking and re-baking.

4. The processing technology of Fuliang green tea as claimed in claim 1, characterized in that: The step of withering also includes spraying treatment, specifically: spraying 4-8% of a nitrogen-containing supplement liquid with a mass fraction of 0.4-0.8% on the surface of the tea leaves after spreading, and stirring evenly for subsequent withering.

5. The processing technology of Fuliang green tea as claimed in claim 1, characterized in that: The nitrogen-containing supplementing liquid is L-glutamic acid benzyl ester solution.

Images