A method for producing Liubao tea with rapid and directional aroma

Abstract

The present invention provides a method for producing Liubao tea with rapid and directional aroma, and belongs to the technical field of tea processing. The method for producing Liubao tea with rapid and directional aroma includes the steps of quantitative control of tea base internal quality, quantitative control of wet base moisture content, precise pile fermentation, impurity removal and hot pile baking, breaking up and heat dissipation, steaming to adjust moisture, and directional aging and aroma production. In the present invention, the above-mentioned various links and preparation parameters are closely linked and indispensable. The method provided by the present invention can produce three types of Liubao tea with aged aroma, betel nut aroma, and mushroom aroma in a directional and controllable manner within 2 years, with a stable aroma rate of 100%, a flowering rate of more than 95.5% for mushroom-aroma Liubao tea, and a greatly shortened overall aroma production time, which improves the economic benefits by more than 6,000 yuan / ton compared with traditional technologies, thus achieving cost savings and efficiency improvement.

Description

Technical Field

[0001] The invention relates to the technical field of tea processing, in particular to a method for producing Liubao tea with rapid and directional aroma. Background Art

[0002] Liubao tea is a traditional and historical tea with Guangxi characteristics and a national geographical indication product. It is deeply loved by consumers for its unique quality characteristics such as bright red soup, mellow and refreshing taste, and mellow aroma or betel nut aroma, mushroom aroma, and ginseng aroma. Among them, the aroma of stale, betel nut aroma, and mushroom aroma are the three major market-leading aroma types. In recent years, the hot sales of black tea at home and abroad have driven the development of the Liubao tea industry. The consumer demand for Liubao tea has risen rapidly. In 2019, the Guangxi Zhuang Autonomous Region included Liubao tea in the work report of the autonomous region government for the first time. As a 100 billion yuan tea industry that the regional government has focused on supporting and building, the Liubao tea industry has gained unprecedented development opportunities and has become one of the main industries that drive tea farmers to increase their income and become rich. However, as a traditional industry, Liubao tea also faces many problems in the process of rapid development. Among them, the processing of aroma is unstable and time-consuming, which leads to the prominent problem of high production costs and low profits of Liubao tea. Liubao tea is a traditional processing industry with a low degree of modernization. Most of them use natural fermentation and aging. At the same time, the entire processing process relies on the experience and judgment of tea masters, that is, the empirical "making tea by looking at tea". Many producers do not accurately grasp the inherent relationship between key factors such as raw material characteristics, fermentation degree, aging conditions and the formation of Liubao tea flavor. The formation mechanism of Liubao processing quality with different flavors is unclear, and key processing technical indicators lack scientific data support. Therefore, the production of traditional Liubao tea takes too long. It often takes 5 to 8 years or even longer from raw material pile fermentation to aging and fragrance. The fragrance is random, and sometimes even no fragrance, resulting in slow workshop turnover cycle, high enterprise storage costs, large investment cash flow, and excessive financial expenses, which is very unfavorable for the development and growth of enterprises. Therefore, the research and development of targeted, fast and stable fragrance production technology for Liubao tea with different flavors is an important support for promoting the transformation and upgrading of the characteristic Liubao tea industry to standardization and modernization. Summary of the invention

[0003] The purpose of the present invention is to provide a production method for rapid and directional aroma production of Liubao tea, so as to solve the problem that the traditional preparation process of Liubao tea takes a long time to produce aroma or even produces no aroma.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for producing Liubao tea with rapid and directional aroma, comprising the following steps:

[0006] S1. Blending different grades of Liubao tea raw materials to obtain dry tea leaves that meet the internal quality control standards, wherein the internal quality control standards are: water extract content of 36-44%, tea polyphenol content of 26-32%, and moisture ≤10%;

[0007] S2. The dry tea blank is mixed with water to obtain a wet blank having a moisture content of 20 to 27%; according to the moisture content of the wet blank, it is divided into two grades, the moisture content of the wet blank in grade A1 is 23 to 27%, and the moisture content of the wet blank in grade A2 is 20 to 22%;

[0008] S3. The wet dough is piled for fermentation. When the A1 wet dough is fermented to B1 or B2, the fermentation is stopped; when the A2 wet dough is fermented to B3, the fermentation is stopped; after the fermentation is completed, the dough is spread out and the moisture content is 19 to 21% before entering the next step;

[0009] The tea polyphenol content of the B1 grade is 20-21.9%, the tea polyphenol content of the B2 grade is 22-24%, and the tea polyphenol content of the B3 grade is 23-25%;

[0010] S4. Steaming the fermented tea for 2 to 4 minutes, and baking the steamed tea while hot for 15 to 20 hours;

[0011] S5. After the baking is completed, the tea is broken up and the moisture content is reduced to 16-18% to obtain semi-finished tea;

[0012] S6. The semi-finished tea is steamed again, the steaming time is 3 to 6 minutes, the moisture content after steaming is controlled between 20 and 23%, the semi-finished tea is pressed while hot after steaming, and then placed in a cool and ventilated place until the temperature of the semi-finished tea drops to room temperature and the moisture content drops to an appropriate level to enter the next step;

[0013] The suitable degree of moisture content is: the moisture content of the product with fermentation degree of B1 and B3 is controlled at 15-18%; the moisture content of the product with fermentation degree of B2 is controlled at 18-21%;

[0014] S7. Aging the semi-finished tea after steaming and air-drying in S6. After aging, it becomes Liubao finished tea.

[0015] Preferably, the aging method of the semi-finished tea of ​​B1 grade is as follows: in the first stage, the moisture content of the semi-finished tea is controlled at 15-18%, the temperature of the aging bin is 22-28°C, the relative humidity is 80-85%, and the aging time is 90-150 days; in the second stage, the moisture content of the semi-finished tea is controlled at 13-15%, the temperature of the aging bin is 20-30°C, the relative humidity is 70-75%, and the aging time is 90-180 days; in the third stage, the moisture content of the semi-finished tea is controlled at 10-12%, the temperature of the aging bin is 20-30°C, the relative humidity is 65-80%, and the aging time is 150-180 days.

[0016] Preferably, the aging method for the semi-finished tea of Grade B2 is as follows: in the first stage of aging, the moisture content of the semi-finished tea is controlled at 18-20%, the temperature of the aging warehouse is 22-26°C, the relative humidity is 75-85%, and the aging time is 10-20 days; in the second stage of aging, the moisture content is controlled at 15-18%, the temperature of the aging warehouse is 22-28°C, the relative humidity is 80-85%, and the aging time is 90-120 days; in the third stage of aging, the moisture content is controlled at 10-12%, the temperature of the aging warehouse is 20-30°C, the relative humidity is 70%-75%, and the aging is carried out for 90-180 days.

[0017] Preferably, the aging method for the semi-finished tea with a fermentation degree of Grade B3 is as follows: in the first stage of aging, the moisture content of the semi-finished tea is controlled at 15-18%, the temperature of the aging warehouse is 22-28°C, the relative humidity is 80-85%, and the aging time is 150-180 days; in the second stage of aging, the moisture content of the semi-finished tea is controlled at 13-15%, the temperature of the aging warehouse is 20-30°C, the relative humidity is 70-75%, and the aging time is 90-180 days; in the third stage of aging, the moisture content is controlled at 10-12%, the temperature of the aging warehouse is 20-30°C, the relative humidity is 65-80%, and the aging is carried out for 150-180 days.

[0018] Preferably, the environmental temperature for the piling fermentation is 25-35°C, the humidity is 80-95%, and the temperature inside the pile is controlled at 45-55°C.

[0019] Preferably, the wet blanks are piled into blocks or strips, and the height of the pile is 80-100 cm.

[0020] Preferably, the height of the pile during baking is 60-120 cm.

[0021] Preferably, during aging, the semi-finished tea is placed in bamboo baskets according to the specification of 15-45 kg, and the bamboo baskets are stacked in a "pin" shape, and the positions are regularly changed up and down and left and right every 20-30 days.

[0022] The present invention also provides Liubao tea prepared by the production method described above.

[0023] By adopting the above technical solutions, the present invention has the following beneficial effects: The production method for rapid and directional aroma release of Liubao tea in the present invention includes steps such as quantitative control of the internal quality of the tea blanks, quantitative control of the moisture content of the wet blanks, piling fermentation, impurity removal and baking, loosening and heat dissipation, steam distillation for moisture adjustment, and directional aging and aroma release. In the present invention, the above-mentioned various links and preparation parameters are closely linked and indispensable. It is possible to produce Liubao tea with three aroma types of aged aroma, betel nut aroma, and mushroom aroma in a directional and controllable manner within 2 years. The aroma release stability rate is 100%, and the flower formation rate of the mushroom aroma type Liubao tea is more than 95.5%. The overall aroma release time is greatly shortened, and the economic benefit is increased by more than 6,000 yuan / ton compared with the traditional technology, achieving cost reduction and efficiency increase. Specific embodiments

[0024] The present invention provides 1. a method for producing Liubao tea with rapid and directional aroma, comprising the following steps:

[0025] S1. Blending different grades of Liubao tea raw materials to obtain dry tea leaves that meet the internal quality control standards, wherein the internal quality control standards are: water extract content of 36-44%, tea polyphenol content of 26-32%, and moisture ≤10%;

[0026] S2. The dry tea blank is mixed with water to obtain a wet blank having a moisture content of 20 to 27%; according to the moisture content of the wet blank, it is divided into two grades, the moisture content of the wet blank in grade A1 is 23 to 27%, and the moisture content of the wet blank in grade A2 is 20 to 22%;

[0027] S3. The wet dough is piled for fermentation. When the A1 wet dough is fermented to B1 or B2, the fermentation is stopped; when the A2 wet dough is fermented to B3, the fermentation is stopped; after the fermentation is completed, the dough is spread out and the moisture content is 19 to 21% and the next step is entered;

[0028] The tea polyphenol content of the B1 grade is 20-21.9%, the tea polyphenol content of the B2 grade is 22-24%, and the tea polyphenol content of the B3 grade is 23-25%;

[0029] S4. Steaming the fermented tea for 2 to 4 minutes, and baking the steamed tea while hot for 15 to 20 hours;

[0030] S5. After the baking is completed, the tea is broken up and the moisture content is reduced to 16-18% to obtain semi-finished tea;

[0031] S6. The semi-finished tea is steamed again, the steaming time is 3 to 6 minutes, the moisture content after steaming is controlled between 20 and 23%, the semi-finished tea is pressed while hot after steaming, and then placed in a cool and ventilated place until the temperature of the semi-finished tea drops to room temperature and the moisture content drops to an appropriate level to enter the next step;

[0032] The suitable degree of moisture content is: the moisture content of the product with fermentation degree of B1 and B3 is controlled at 15-18%; the moisture content of the product with fermentation degree of B2 is controlled at 18-21%;

[0033] S7. Aging the semi-finished tea after steaming and air-drying in S6. After aging, it becomes Liubao finished tea.

[0034] The main technical solutions of the present invention are as follows:

[0035] Raw material screening and grading: Select the raw Liubao tea with rich internal materials, remove impurities and dust, and then use shaking screens, round screens, winnowing machines, etc. to screen, winnow, pick, and remove stems. According to the group standard T / GXAS 311-2022, the raw Liubao tea is graded to obtain raw tea of ​​various grades with basically the same appearance.

[0036] Quantitative control of tea base internal quality: quantitative analysis of water extract and tea polyphenols, the main internal quality components of Liubao tea raw materials of different origins and batches, and sensory evaluation of aroma, taste and other indicators, and blending of raw materials of different grades based on the internal quality detection and sensory evaluation results of different origins and batches. The internal quality control standards of raw materials after blending are as follows: water extract content of 36-44%, more preferably 38-42%, more preferably 40%; tea polyphenol content of 26-32%, more preferably 28-30%, more preferably 29%; water content ≤10%, and dry tea base with distinct grades that meet the internal quality requirements is obtained. The present invention does not use mixed-grade tea as raw material, because mixed grades are prone to uneven fermentation, affecting the fermentation effect and the quality of finished tea.

[0037] Quantitative control of moisture content of tea leaves: In the present invention, water is added to the blended dry tea leaves and stirred to make the moisture content of the tea leaves evenly distributed, thereby obtaining wet leaves. The moisture content of the wet leaves is quantitatively controlled and is specifically divided into two levels. The moisture content of the wet leaves in level A1 is 23-27%, more preferably 24-26%, and more preferably 25%; the moisture content of the wet leaves in level A2 is 20-22%, and more preferably 21%.

[0038] The pile fermentation of Liubao tea is a process of drastic physical and chemical changes and material transformation under the combined effects of microorganisms, moisture, heat, and enzymes. Water is a key factor in the formation of various chemical changes, microbial metabolism, and moisture and heat conditions. The inventors learned through experiments that if the water content is too high, when it is greater than 30%, it will cause hypoxia in the tea pile and a large number of anaerobic microorganisms will multiply, causing the tea leaves to become sour and rancid; and if the water content is too low, when it is less than 16%, the tea leaves will be too dry, the moisture and heat environment will take a long time to form, the activity of microorganisms will increase slowly, various physical and chemical changes will occur slowly, the pile fermentation time will be long, and the material transformation will be insufficient. The present invention studies the influence of the moisture content of tea leaves on the fermentation effect, and finally determines that the moisture content of the tea leaves in the heap fermentation stage of Liubao tea is preferably 20-27%. At the same time, by combining and comparing the influence of different fermentation degrees on the formation of tea quality in the later stage, it is found that compared with the Liubao teas of aged fragrance and mushroom fragrance, the formation of the Liubao tea of ​​betel nut fragrance needs lighter fermentation in the heap fermentation link, that is, the fermentation intensity needs to be better controlled during the heap fermentation, and a slightly lower moisture content of the tea leaves within an appropriate range is more conducive to controlling the fermentation degree and the direction of material conversion. Therefore, it is finally determined that the control of moisture content is as follows: when producing and processing the Liubao tea of ​​betel nut fragrance, the moisture content of the tea leaves is preferably 20-22%, and combined with the fermentation efficiency and the direction of material conversion, it is more appropriate to control the moisture content of the tea leaves of aged fragrance and mushroom fragrance at 23-27%.

[0039] Pile fermentation: The present invention piles the prepared wet tea leaves for fermentation, and the piles are piled into blocks or strips, with a pile height of 80 to 100 cm, more preferably 85 to 95 cm, and more preferably 90 cm. The temperature of the fermentation environment is 25 to 35°C, more preferably 27 to 32°C, and more preferably 30°C; the relative humidity is 80 to 95%, more preferably 85 to 90%, and more preferably 88%; the temperature in the fermentation pile is controlled at 45 to 55°C, more preferably 48 to 52°C, and more preferably 50°C. When the pile temperature rises to above 55°C, the pile is turned over to dissolve the blocks and dissipate heat, and then the pile fermentation is continued, and the tea at the edge of the pile is covered on the center of the pile, and the tea at the center of the pile is turned to the edge of the pile, so that the whole pile of tea leaves changes evenly, and this is alternated 3 to 4 times, during which the moisture content of the tea leaves is monitored, and when the moisture content of the tea leaves is less than 20%, the moisture is replenished in time. From the 10th day of pile fermentation, monitor the changes of tea polyphenols in the products every 2 days (tea polyphenols are used to characterize the fermentation degree). When the tea polyphenol content in the products degrades to the requirements of each level, the pile fermentation can be completed. The pile fermentation can be stopped when the tea polyphenol content in the products with A1 moisture level degrades to B1 level, that is, the fermentation degree is 20-21.9% (fermentation degree) or B2 level: 22-24% (fermentation degree). The pile fermentation can be stopped when the tea polyphenol content in the products with A2 moisture level degrades to B3 level: 23-25% (fermentation degree). After the pile fermentation is completed, spread out to cool down and release moisture. When it drops to room temperature and the released moisture content is about 20%, enter the next process.

[0040] Hot-baking pile for removing impurities: the tea after piling is steamed by a tea steaming device (to achieve the purpose of removing impurities, quickly forming an environmental condition in which heat and humidity dominate the tea pile, and promoting the transformation of alkaloids), the steaming time is 2 to 4 minutes, more preferably 2.5 to 3.5 minutes, and more preferably 3 minutes; the steamed tea is pressed and baked while hot, and the pile height is 60 to 120 cm, more preferably 80 to 100 cm, and more preferably 90 cm; the baking time is 15 to 20 hours, more preferably 17 to 19 hours, and more preferably 18 hours.

[0041] In the present invention, in order to further promote the formation of the flavor quality of the product, the hot steaming method is used to quickly remove the stuffy smell generated by long-term pile fermentation, reduce the microorganisms generated during the pile fermentation process, and reduce the metabolic effect of the microorganisms. At the same time, the temperature of the product is quickly increased by steaming, and moist heat conditions are formed efficiently and quickly. Under the conditions dominated by moist heat, the continued transformation and change of the substances contained in the product is promoted, especially the caffeine substances in tea are relatively stable. The heat created in this step promotes the changes of alkaloids such as caffeine. Experimental results show that adding a short-term steaming and baking for 15 to 20 hours after pile fermentation is beneficial to improving the mellowness of the later taste. If the time is too long, the substances will be excessively transformed, affecting the direction of aroma formation. If the time is too short, the cost of the later transformation time is too high.

[0042] Scattered heat dissipation: After the baking pile is completed, the tea pile is shoveled and scattered to dissipate heat, and the moisture is dissipated to 16-18%, further preferably 16.5-17.5%, and more preferably 17%.

[0043] Steam adjustment of moisture: The semi-finished tea after the baking pile is scattered is steamed again. The purpose is to soften the semi-finished tea and quickly increase the moisture content of the semi-finished tea. The steaming time is 3-6 minutes, further preferably 4-5 minutes, and more preferably 4.5 minutes. After steaming, the moisture is controlled at 20-23%, further preferably 21-22%, and more preferably 21.5%. After steaming, it is quickly packed into a bamboo basket and compacted while it is hot. The in-process products packed in the baskets are placed in a clean, cool, ventilated environment without strange odors for airing. During the airing process, high temperature and high humidity are prohibited. Wait until the temperature of the semi-finished tea drops to room temperature and the moisture content drops to an appropriate level to enter the next process. The appropriate level of the moisture content is: for the in-process products with fermentation degrees of B1 and B3, the moisture content is controlled at 15-18%, further preferably 16-17%, and more preferably 16.5%; for the in-process products with a fermentation degree of B2, the moisture content is controlled at 18-21%, further preferably 19-20%, and more preferably 19.5%.

[0044] Directed aging for aroma formation: The above-mentioned well-aired semi-finished tea is placed in a bamboo basket, and the mass of the semi-finished tea in each bamboo basket is 15-45 kg, further preferably 20-40 kg, and more preferably 30 kg; then it is put into the aging warehouse for aging. The bamboo baskets are stacked in a "pin" shape, and the upper and lower, left and right positions are regularly changed every 20-30 days.

[0045] The aging conditions and process for the semi-finished products with a fermentation degree of B1 are as follows:

[0046] In the first stage of aging, the moisture of the semi-finished products is controlled at 15-18%, further preferably 16-17%, and more preferably 16.5%; the temperature of the aging warehouse is 22-28°C, further preferably 24-26°C, and more preferably 25°C; the relative humidity is 80-85%, further preferably 81-84%, and more preferably 83%; the aging time is 90-150 days, further preferably 110-130 days, and more preferably 120 days.

[0047] In the second stage of aging, the moisture is controlled at 13-15%, further preferably 13.5-14.5%, and more preferably 14%; the temperature of the aging warehouse is 20-30°C, further preferably 22-28°C, and more preferably 25°C; the relative humidity is 70-75%, further preferably 71-74%, and more preferably 73%; the aging time is 90-180 days, further preferably 120-150 days, and more preferably 135 days.

[0048] In the third stage of aging, the moisture content is controlled at 10-12%, more preferably 10.5-11.5%, and more preferably 11%; the temperature of the aging bin is 20-30°C, more preferably 23-27%, and more preferably 25%; the humidity is 65-80%, more preferably 70-75%, and more preferably 72%; the aging period is 150-180 days, more preferably 160-170 days, and more preferably 165 days.

[0049] The aging conditions and process of semi-finished products with B2 fermentation degree are as follows:

[0050] In the first stage, the moisture content of the semi-finished product is controlled at 18-20%, more preferably 18.5-19.5%, more preferably 19%; the temperature of the aging bin is 22-26°C, more preferably 23-25°C, more preferably 24°C; the relative humidity is 75-85%, more preferably 78-82%, more preferably 80%, and the aging time is 10-20 days, more preferably 12-18 days, more preferably 15 days.

[0051] In the second stage of aging, the moisture content is controlled at 15-18%, more preferably 16-17%, and more preferably 16.5%; the temperature of the aging bin is 22-28°C, more preferably 24-26°C, and more preferably 25°C; the relative humidity is 80-85%, more preferably 81-84%, and more preferably 83%; the aging time is 90-120 days, more preferably 100-110 days, and more preferably 105 days.

[0052] In the third stage of aging, the moisture content is controlled at 10-12%, more preferably 10.5-11.5%, and more preferably 11%; the temperature of the aging bin is 20-30°C, more preferably 22-28°C, and more preferably 25°C; the humidity is 70-75%, more preferably 71-74%, and more preferably 73%; and the aging is for 90-180 days.

[0053] The aging conditions and process of semi-finished products with B3 fermentation degree are as follows: the moisture content of the semi-finished products in the first stage of aging is controlled at 15-18%, more preferably 16-17%, and more preferably 16.5%; the temperature of the aging bin is 22-28°C, more preferably 24-26°C, and more preferably 25°C; the relative humidity is 80-85%, more preferably 82-84%, and more preferably 83%; the aging time is 150-180 days, more preferably 160-170 days, and more preferably 165 days.

[0054] In the second stage of aging, the moisture content is controlled at 13-15%, more preferably 13.5-14.5%, and more preferably 14%; the temperature of the aging bin is 20-30°C, more preferably 22-27°C, and more preferably 25°C; the relative humidity is 70-75%, more preferably 71-73%, and more preferably 72%; the aging time is 90-180 days, more preferably 120-150 days, and more preferably 130 days.

[0055] In the third stage of aging, the moisture content is controlled at 10-12%, preferably 10.5-11.5%, and more preferably 11%; the temperature of the aging chamber is 20-30°C, preferably 23-27%, and more preferably 25%; the humidity is 65-80%, preferably 70-76%, and more preferably 73%; the aging is 150-180 days, preferably 160-170 days, and more preferably 165 days. After the aging is completed, it is the finished Liubao tea.

[0056] Water is a key medium for chemical changes in substances and the growth and metabolism of microorganisms. The inventors have found through research that in order to process Liubao tea products with different aromas, in addition to mastering the appropriate fermentation degree of raw materials, the moisture content of Liubao tea in the aging stage, the temperature and humidity conditions of aging, and the length of aging time are all key factors affecting the later aging effect and the formation trend of the aroma. The inventors have found through experiments that the alternating conditions of different aging humidity are conducive to the formation of the taste and aroma of Liubao tea. Compared with the other two types of Liubao tea, the mushroom-flavored Liubao tea requires a relatively high moisture content in the first two stages of golden flower. Through a large number of experimental studies, it is determined that the moisture content in the first two stages is 18-20% and 15-18% respectively. Too low or too high is not conducive to flower. The moisture content required in the first two stages of the two aromas of Chenxiang and Areca Nut is slightly lower, and 15-18% and 13-15% are the most suitable, respectively. Different temperatures and aging conversion times can effectively control the material conversion pathway of the finished product, and finally form Chenxiang and Areca Nut fragrance.

[0057] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0058] Example 1

[0059] 1. Raw material screening and grading: Select the raw materials of Liubao tea with rich internal substances, remove impurities and dust, and then use shaking screens, round screens, wind separators, etc. to screen, winnow, pick, and remove stems, etc. to obtain raw tea of ​​various grades with basically the same appearance.

[0060] 2. Quantitative control of the inner quality of the tea base: Quantitatively analyze the main inner quality components of the raw materials of Liubao tea of different grades from different origins and batches, namely water extract and tea polyphenols, and conduct sensory evaluation on indicators such as aroma and taste. Based on the inner quality detection and sensory evaluation results of different origins and batches, blend the raw materials of each grade. After blending, the control standards for the inner quality of the raw materials are that the water extract content is 36%, the tea polyphenol content is 26%, and the moisture content ≤ 10%, obtaining dry tea bases that meet the inner quality requirements and are clearly graded.

[0061] 3. Quantitative control of the moisture content of the tea base: Add water to the above-mentioned blended dry tea base and stir to make the moisture content of the tea base evenly distributed, obtaining a wet base with a moisture content of 21.5% (Grade A2).

[0062] 4. The prepared wet base is piled up for pile fermentation. The pile height is 80 cm, piled into strips. The temperature of the pile fermentation environment is 25 - 35 °C, and the relative humidity is 80 - 95%. The temperature inside the fermentation pile is controlled at 45 - 55 °C. When the pile temperature rises above 55 °C, turn the pile, break up the lumps and dissipate heat. Cover the tea on the edge of the pile on the center of the pile, and turn the tea in the center of the pile to the edge of the pile to make the whole pile of tea change evenly. Alternate like this 4 times. During this period, monitor the moisture content of the tea base. When the moisture content of the tea base is less than 20%, replenish water in time. Starting from the 10th day of pile fermentation, monitor the change of tea polyphenols in the in-process products every 2 days (using tea polyphenols to characterize the degree of fermentation). When the tea polyphenol content in the in-process products degrades to 24.8%, the pile fermentation ends (Grade B3). After the pile fermentation ends, spread it out to cool down and dissipate moisture. When it drops to room temperature and the moisture content dissipates to 20%, enter the next process.

[0063] 5. Remove impurities and conduct hot baking in a pile: The tea after pile fermentation is steamed through a tea steaming device to achieve the purpose of removing miscellaneous odors and quickly forming a dominant environment condition of heat and humidity inside the tea pile, and at the same time promoting the transformation of alkaloid substances. The steaming time is 2.5 minutes. After steaming, the in-process tea products are tightly pressed while they are still hot for baking in a pile. The pile height is 60 cm, and the baking time in a pile is 15 hours.

[0064] 6. Break up and dissipate heat: After the baking in a pile ends, break up the tea pile and dissipate heat and moisture to 16%.

[0065] 7. Steam to adjust moisture: The semi-finished products after breaking up and baking in a pile are steamed again. The main purpose is to soften the semi-finished tea leaves and quickly increase their moisture content. The steaming time is 3 minutes. After steaming, the moisture content is controlled at 20%. After steaming, pack it tightly into bamboo baskets while it is still hot. Place the in-process products packed in baskets in a clean, cool and ventilated (avoiding high temperature and high humidity), and odor-free environment for airing. Wait until the temperature of the semi-finished products drops to room temperature and the moisture content drops to 15% before entering the next process (Grade B3).

[0066] 8. Directed aging to produce aroma: Pack the above-mentioned aired semi-finished tea into bamboo baskets according to the specification of 15 kg, and place them in the aging warehouse for aging. Stack the bamboo baskets in a "pin" shape, and change the up and down, left and right positions every 30 days.

[0067] The aging conditions and process of semi-finished products with B3 fermentation degree are as follows: the moisture content of semi-finished products in the first stage is controlled at 15%, the temperature of the aging warehouse is 28℃, the relative humidity is 85%, and the aging time is 180 days; the moisture content of semi-finished products in the second stage is controlled at 15%, the temperature of the aging warehouse is 28℃, the relative humidity is 70%, and the aging time is 90 days; the moisture content of semi-finished products in the third stage is controlled at 10%, the temperature of the aging warehouse is 25℃, the humidity is 70%, and the aging time is 180 days. After the aging, the semi-finished products are betel nut flavored Liubao finished tea with a strong taste.

[0068] Example 2

[0069] 1. Raw material screening and grading: Select the raw materials of Liubao tea with rich internal substances, remove impurities and dust, and then use shaking screens, round screens, wind separators, etc. to screen, winnow, pick, and remove stems, etc. to obtain raw tea of ​​various grades with basically the same appearance.

[0070] 2. Quantitative control of the internal quality of tea leaves: Quantitative analysis is conducted on the main internal components of water extracts and tea polyphenols in various grades of Liubao tea raw materials from different origins and batches, and sensory evaluation is conducted on indicators such as aroma and taste. Raw materials of various grades are blended based on the internal quality detection and sensory evaluation results of different origins and batches. The internal quality control standards for the raw materials after blending are water extract content of 41.6%, tea polyphenols content of 28%, and moisture content ≤10%, so as to obtain dry tea leaves with distinct grades that meet the internal quality requirements.

[0071] 3. Quantitative control of the moisture content of tea leaves: Add water to the blended dry tea leaves and stir to make the moisture content of the tea leaves evenly distributed, thereby obtaining wet tea leaves with a moisture content of 25.5% (A1 grade).

[0072] 4. The prepared wet blanks are piled up for fermentation. The pile height is 90 cm and the pile is in block shape. The fermentation environment temperature is 25-35°C and the relative humidity is 80-95%. The temperature in the fermentation pile is controlled at 45-55°C. When the pile temperature rises to above 55°C, the pile is turned over to dissipate heat. The edge tea is covered on the center of the pile, and the center tea is turned over to the edge of the pile to make the whole pile of tea change evenly. This is alternated 4 times. During this period, the moisture content of the tea blank is monitored. When the moisture content of the tea blank is less than 20%, the water is replenished in time. From the 10th day of the pile fermentation, the changes of tea polyphenols in the finished product are monitored every 2 days (the degree of fermentation is characterized by tea polyphenols). When the content of tea polyphenols in the finished product is degraded to 22.6, the pile fermentation ends (B2 gear). After the pile fermentation ends, it is spread out to cool down and dissipate moisture. When it drops to room temperature and the moisture content is dissipated to 20%, it enters the next process.

[0073] 5. Hot-baking pile for removing impurities: The tea after piling is steamed in a tea steaming device to remove impurities and quickly form a dominant environment in the tea pile with heat and moisture, while promoting the transformation of alkaloids. The steaming time is 3 minutes. The steamed tea is pressed and baked while hot, with a pile height of 80 cm and a baking time of 18 hours.

[0074] 6. Loosening for heat dissipation: After the piling-up process, the tea pile is spread out to dissipate heat and moisture until the moisture content reaches 17%.

[0075] 7. Steam conditioning for moisture adjustment: The semi-finished product after the piling-up and loosening process is steamed again. The main purpose is to soften the semi-finished tea leaves and quickly increase their moisture content. The steaming time is 4 minutes, and the moisture content after steaming is controlled at 22%. After steaming, it is immediately packed tightly into bamboo baskets while it is still hot. The in-process products packed in baskets are placed in a clean, cool, and well-ventilated environment (avoiding high temperature and high humidity, and no abnormal odors) for airing. After the temperature of the semi-finished product drops to room temperature and the moisture content drops to 20%, it enters the next process (B2 grade).

[0076] 8. Directed aging for aroma development: The semi-finished tea prepared above is packed in bamboo baskets at a specification of 25 kg each and placed in an aging warehouse for aging. The bamboo baskets are stacked in a "pin" shape, and the positions are changed up and down and left and right every 25 days.

[0077] The aging conditions and process for the semi-finished product with a fermentation degree of B2 grade are as follows: In the first stage of aging, the moisture content of the semi-finished product is controlled at 20%, the temperature of the aging warehouse is 24 °C, the relative humidity is 80%, and the aging time is 15 days; in the second stage of aging, the moisture content is controlled at 16%, the temperature of the aging warehouse is 28 °C, the relative humidity is 80%, and the aging time is 90 days; in the third stage of aging, the moisture content is controlled at 11%, the temperature of the aging warehouse is 26 °C, and the humidity is 70%, and the aging lasts for 90 days to obtain the mushroom-aroma Liubao tea with a mellow taste.

[0078] Example 3

[0079] 1. Screening and grading of raw materials: Select Liubao rough tea raw materials rich in internal substances, remove impurities and dust, and then perform screening, air separation, sorting, and stem removal through vibrating sieves, circular sieves, air separators, etc. to obtain rough teas of each grade with basically the same appearance.

[0080] 2. Quantitative control of the internal quality of the tea blank: Quantitative analysis is carried out on the main internal quality components of the rough teas of each grade from different origins and batches, including water extract and tea polyphenols, and sensory evaluation is carried out on indicators such as aroma and taste. Based on the internal quality detection and sensory evaluation results of different origins and batches, the raw materials of each grade are blended. After blending, the control standards for the internal quality of the raw materials are that the water extract content is 44%, the tea polyphenol content is 32%, and the moisture content ≤ 10%, obtaining dry tea blanks that meet the internal quality requirements and are clearly graded.

[0081] 3. Quantitative control of the moisture content of the tea blank: The blended dry tea blanks are added with water and stirred to make the moisture content of the tea blanks evenly distributed, obtaining wet blanks with a moisture content of 23% (A1 grade).

[0082] 4. The prepared wet tea blanks are piled up for piling fermentation. The pile height is 100 cm, and it is piled into strips. The temperature of the piling fermentation environment is 25 - 35 °C, and the relative humidity is 80 - 95%. The temperature inside the fermentation pile is controlled at 45 - 55 °C. When the pile temperature rises above 55 °C, turn the pile and break up the lumps to dissipate heat. Cover the tea at the edge of the pile on the center of the pile, and turn the tea in the center of the pile to the edge, so that the whole pile of tea changes evenly. Alternate like this 3 times. During this period, monitor the moisture content of the tea blanks. When the moisture content of the tea blanks is less than 20%, replenish water in time. Since the 10th day of piling, monitor the change of tea polyphenols in the in-process products every 2 days (using tea polyphenols to characterize the fermentation degree). When the content of tea polyphenols in the in-process products degrades to 20.5, the piling ends (Grade B1). After the piling ends, spread it out to cool down and dissipate moisture. When it drops to room temperature and the moisture content dissipates to 20%, enter the next process.

[0083] 5. Debloating and heat-baking pile: The tea after piling is steamed by a tea steaming device to achieve the purpose of removing miscellaneous flavors and quickly forming a dominant environment condition of heat and humidity inside the tea pile. At the same time, it promotes the transformation of alkaloid substances. The steaming time is 3.5 minutes. After steaming, the in-process tea products are tightly pressed while they are hot for baking pile. The pile height is 120 cm, and the baking pile time is 20 hours.

[0084] 6. Loosen and dissipate heat: After the baking pile ends, break up the tea pile to loosen and dissipate heat and dissipate moisture to 18%.

[0085] 7. Steam to adjust moisture: The semi-finished products after baking pile and loosening are steamed again. The main purpose is to soften the semi-finished tea leaves and quickly increase their moisture content. The steaming time is 5 minutes. After steaming, the moisture is controlled at 22%. After steaming, pack it tightly into bamboo baskets while it is hot. Place the in-process products packed in baskets in a clean, cool and ventilated (avoid high temperature and high humidity), odorless environment to air dry. When the temperature of the semi-finished products drops to room temperature and the moisture content drops to 16%, enter the next process (Grade B1).

[0086] 8. Directed aging and aroma formation: Pack the air-dried semi-finished tea in the above-mentioned specifications of 45 kg into bamboo baskets, put them into the aging warehouse for aging. The bamboo baskets are stacked in a "pin" shape, and the upper and lower, left and right positions are changed every 20 days.

[0087] The aging conditions and process of the semi-finished products with Grade B1 fermentation degree are as follows: In the first stage of aging, the moisture content of the semi-finished products is controlled at 16%, the temperature of the aging warehouse is 26 °C, the relative humidity is 82%, and the aging time is 90 days. In the second stage of aging, the moisture content is controlled at 14%, the temperature of the aging warehouse is 28 °C, the relative humidity is 73%, and the aging time is 90 days; In the third stage of aging, the moisture content is controlled at 12%, the temperature of the aging warehouse is 26 °C, the humidity is 70%, and the aging is 180 days to obtain aged-flavor Liubao tea with mellow taste.

[0088] Experimental Example 1. Influence of Different Inner Substances on the Quality of Finished Tea

[0089] Liubao raw tea with different contents was used as raw material, water was added to prepare wet blanks with a water content of about 25%, and Liubao tea was processed according to the preparation method of B1 grade tea in Example 1.

[0090] The B1 grade finished tea was evaluated with reference to the national standard “GB / T 23776 Evaluation Method for Chinese Dark Tea”. The evaluation was completed by professional tea reviewers. The evaluation results are shown in Table 1.

[0091] Table 1 Evaluation results of Liubao tea with different treatments

[0092]

[0093] Table 1 shows that when the water extract of the raw materials is greater than 36% and the tea polyphenols are greater than 26%, the finished tea after pile fermentation and aging can show the quality characteristics of Liubao tea in terms of soup color, taste and aroma, which is "red, strong, aged and mellow". When the internal content is too low, the taste is bland, the soup color is not red enough, and the aroma is especially low, failing to have the typical aroma and flavor of Liubao tea.

[0094] Liubao tea is a deep fermented tea, which requires a sufficient amount of internal substances as a basis, especially higher phenolic substances can lay the foundation for later fermentation, aging and quality formation. Table 1 shows that raw materials with too low internal substances, especially too low phenolic substances, are degraded after pile fermentation, and then after aging and transformation, the final finished product has a bland taste, the soup color is not red, and often cannot form the unique aged aroma and rhyme of Liubao tea, that is, the problem of no fragrance. Traditional Liubao tea focuses on the appearance grade factors such as length, thickness, etc. in the raw material blending link, and does not control the internal quality, which is also one of the reasons why it often does not produce fragrance and taste bland during processing. The present invention uses the total amount of water extract and tea polyphenols as the main internal quality indicators, and quantitatively controls the internal quality in the raw material blending link. The internal quality of the raw materials after blending must meet the requirements of 36-44% water extract content and 26-32% tea polyphenol content, ensuring that the raw materials have sufficient material basis, which can provide reliable guarantee for the quality formation of later processing.

[0095] Experimental Example 2. Effects of different fermentation degrees on tea aroma substances

[0096] The traditional Liubao tea production relies on manual smelling, touching, and looking to judge the fermentation degree of the product, which is not only inaccurate, but also requires a high level of technical skills from the tea master. Compared with the traditional Liubao tea production method, the present invention uses the key chemical component tea polyphenols as the fermentation degree characterization quantity, accurately controls the fermentation degree of the product during the pile fermentation process, and provides support for the directional production of different flavors of Liubao tea in the later stage. Through research, the inventor found that different fermentation degrees have a huge impact on the aroma of the product and the aroma of the finished tea in the later stage. Using raw tea leaves with an initial tea polyphenol content of 28.35% as raw material, water was added to make a wet leaf with a moisture content of about 23.5%, and pile fermentation was carried out. During the fermentation process, the fermentation degree (tea polyphenol content) of the finished product was monitored. Samples were taken at fermentation degree 1 (fermentation degree 26-27%, average 26.5%), fermentation degree 2 (fermentation degree 23-25%, average 24%), and fermentation degree 3 (fermentation degree 20-23%, average 21.5%) to detect and analyze the aroma of the tea leaves in the product. The results are shown in Table 2.

[0097] Table 2 Effects of different fermentation degrees on tea aroma substances

[0098]

[0099]

[0100]

[0101] As can be seen from Table 2, with the increase of fermentation degree, the contents of fresh and floral substances such as indole, α-farnesene, nerolidol, 4-propylguaiacol, etc. are greatly reduced, and the contents of lily of the valley aroma β-linalool, wintergreen oil aroma methyl salicylate, α-terpineol, α-cedarol, cis-linalool II oxide (furan type) and other woody aroma substances and 1,2-dimethoxy-4-methylbenzene, 1,2-dimethoxybenzene and other aged aromas are greatly increased. When the fermentation degree is 23-25%, the contents of α-terpineol, cis-linalool II oxide (furan type) and methoxybenzene substances are higher, which lays a material foundation for the formation of the "betel nut aroma" type Liubao tea in the later stage; when the fermentation degree is 20-23%, the contents of β-linalool, α-cedarol and methyl salicylate are higher, which lays a material foundation for the formation of the "aged aroma" type Liubao tea. The aroma of tea is often the result of the combined effects of several key aroma substances. The aroma of tea is significantly different when the key substances are in different proportions. After further fermentation with raw materials with an initial content of 28.35% of tea polyphenols, the effects of different fermentation degrees on the aroma of Liubao tea were explored in conjunction with the subsequent steaming-baking-steaming-aging process. The results are shown in Table 3:

[0102] Table 3 Effects of different pile fermentation degrees on the aroma of Liubao tea in the later stage

[0103]

[0104]

[0105] It can be seen from Table 3 that the suitable fermentation degree of betel nut aroma Liubao tea is 23-25%, the suitable fermentation degree of aged aroma Liubao tea is 20-23%, and the mushroom aroma Liubao tea needs to promote flowering, which involves more complex microbial formation. Combined with the research on later flowering conditions, it is finally determined that the fermentation degree that is conducive to the formation of mushroom aroma should be controlled at 22-24%, which overlaps with the suitable fermentation degrees of aged aroma and betel nut aroma, and requires higher and more precise flowering moisture and temperature and humidity conditions.

[0106] Traditional Liubao tea is processed extensively. Generally, the raw tea is blended mainly for appearance, and the internal quality requirements are not controlled. After blending, water is added to pile, and steaming and airing are performed indiscriminately. The whole processing process relies on human experience and sensory judgment, and it often takes 5 to 6 years to produce fragrance, and the fragrance is random or even no fragrance. The preparation process of Liubao tea with directional fragrance of the present invention accurately controls each stage from raw materials to pile fermentation and aging, and at the same time adds the impurity removal and hot baking pile link on the basis of the traditional Liubao process. The elements of each link are closely linked and indispensable. According to the production method of the present invention, three types of Liubao tea with fragrance of Chenxiang, betel nut fragrance and mushroom fragrance can be produced in a directional and controllable manner within 2 years, and the fragrance stability rate is 100%, the flowering rate of mushroom-flavored Liubao tea is more than 95.5%, and the overall fragrance time is greatly shortened. Compared with the traditional Liubao tea preparation process, the cost is saved and the efficiency is increased by more than 6,000 yuan / ton. In the same production cycle, the output of this technology can be doubled compared with the traditional technology.

[0107] Table 4 Comparison of production costs between traditional technology and this technology (yuan)

[0108]

[0109] As can be seen from Table 4, the method of the present invention can save costs = 60675.49-54465.64 = 6209.85 yuan / ton when preparing Liubao tea; increase efficiency = 6209.85 / 60675.49 = 10.23%; the traditional technology takes 5 to 6 years to produce fragrance, while the method of the present invention takes about 2 years to produce fragrance, which saves time and achieves cost saving and efficiency improvement.

[0110] As can be seen from the above embodiments, the present invention provides a method for producing Liubao tea with rapid directional aroma. According to the method of the present invention, Liubao tea with three aroma types, namely, aged aroma, betel nut aroma, and mushroom aroma, can be produced in a directional and controllable manner within 2 years, with an aroma stability rate of 100%, a flower rate of mushroom-aroma Liubao tea of ​​more than 95.5%, and a greatly shortened overall aroma time, which improves the economic benefits by more than 6,000 yuan / ton compared with the traditional technology, thus achieving cost saving and efficiency improvement.

[0111] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for producing Liubao tea with rapid and directional aroma, characterized in that: The following steps are involved: S1. Blending different grades of Liubao tea raw materials to obtain dry tea leaves that meet the internal quality control standards, wherein the internal quality control standards are: water extract content of 36-44%, tea polyphenol content of 26-32%, and moisture ≤10%; S2. The dry tea blank is mixed with water to obtain a wet blank having a moisture content of 20 to 27%; according to the moisture content of the wet blank, it is divided into two grades, the moisture content of the wet blank in grade A1 is 23 to 27%, and the moisture content of the wet blank in grade A2 is 20 to 22%; S3. The wet dough is piled for fermentation. When the wet dough A1 is fermented to B1 or B2, the fermentation is stopped; when the wet dough A2 is fermented to B3, the fermentation is stopped; after the fermentation is completed, the dough is spread out and the moisture content is 19 to 21% before entering the next step; The tea polyphenol content of the B1 grade is 20-21.9%, the tea polyphenol content of the B2 grade is 22-24%, and the tea polyphenol content of the B3 grade is 23-25%; S4. Steaming the fermented tea for 2 to 4 minutes, and baking the steamed tea while hot for 15 to 20 hours; S5. After the baking is completed, the tea is broken up and the moisture content is reduced to 16-18% to obtain semi-finished tea; S6. The semi-finished tea is steamed again, the steaming time is 3 to 6 minutes, the moisture content after steaming is controlled between 20 and 23%, the semi-finished tea is pressed while hot after steaming, and then placed in a cool and ventilated place until the temperature of the semi-finished tea drops to room temperature and the moisture content drops to an appropriate level to enter the next step; The suitable degree of moisture content is: the moisture content of the product with fermentation degree of B1 and B3 is controlled at 15-18%; the moisture content of the product with fermentation degree of B2 is controlled at 18-21%; S7. Aging the semi-finished tea after steaming and air-drying in S6. After aging, it becomes Liubao finished tea.

2. The production method according to claim 1, characterized in that The aging method of the semi-finished tea of ​​B1 grade is as follows: in the first stage, the moisture content of the semi-finished tea is controlled at 15-18%, the temperature of the aging warehouse is 22-28°C, the relative humidity is 80-85%, and the aging time is 90-150 days; in the second stage, the moisture content of the semi-finished tea is controlled at 13-15%, the temperature of the aging warehouse is 20-30°C, the relative humidity is 70-75%, and the aging time is 90-180 days; in the third stage, the moisture content of the semi-finished tea is controlled at 10-12%, the temperature of the aging warehouse is 20-30°C, the relative humidity is 65-80%, and the aging is carried out for 150-180 days to obtain the aged fragrant Liubao tea.

3. The production method according to claim 1, characterized in that The aging method of the semi-finished tea of ​​B2 grade is as follows: in the first stage of aging, the moisture content of the semi-finished tea is controlled at 18-20%, the temperature of the aging warehouse is 22-26°C, the relative humidity is 75-85%, and the aging time is 10-20 days; in the second stage of aging, the moisture content is controlled at 15-18%, the temperature of the aging warehouse is 22-28°C, the relative humidity is 80-85%, and the aging time is 90-120 days; in the third stage of aging, the moisture content is controlled at 10-12%, the temperature of the aging warehouse is 20-30°C, the relative humidity is 70-75%, and the aging is carried out for 90-180 days to obtain the mushroom-aroma Liubao tea.

4. The production method according to claim 1, characterized in that The aging method for the semi-finished tea with a fermentation degree of B3 gear is as follows: in the first stage, the water content of the semi-finished tea during aging is controlled at 15-18%, the temperature of the aging warehouse is 22-28°C, the relative humidity is 80-85%, and the aging time is 150-180 days; In the second stage, the water content of the semi-finished tea during aging is controlled at 13-15%, the temperature of the aging warehouse is 20-30°C, the relative humidity is 70-75%, and the aging time is 90-180 days; in the third stage, the water content during aging is controlled at 10-12%, the temperature of the aging warehouse is 20-30°C, the relative humidity is 65-80%, and the aging is carried out for 150-180 days to obtain the Liubao tea with betel nut flavor.

5. The production method according to claim 1, characterized in that: The environmental temperature for the pile fermentation is 25-35°C, the humidity is 80-95%, and the temperature inside the pile is controlled at 45-55°C.

6. The production method according to claim 5, characterized in that During pile fermentation, the wet billets are piled into blocks or strips, and the height of the pile body is 80-100 cm.

7. The production method according to claim 6, characterized in that: The height of the pile during piling is 60-120 cm.

8. The production method according to claim 7, characterized in that: During aging, the semi-finished tea is packed in bamboo baskets according to the specification of 15-45 kg, and the bamboo baskets are stacked in a "pin" shape, and the positions are changed up and down and left and right every 20-30 days.

9. Liubao tea prepared by the production method according to any one of claims 1-8.

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