CN112106844B - Processing method of high-quality summer and autumn black tea - Google Patents

Abstract

A processing method of high-quality summer and autumn black tea is characterized in that on the basis of the existing processes of withering, rolling, fermentation, primary drying, redrying and the like for preparing black tea, fresh tea leaves in summer or autumn are used as raw materials, and according to a biochemical mechanism formed by the quality of the black tea with relatively high nectarine fragrance and theaflavin content, a process technology for promoting the black tea to form nectarine fragrance and high theaflavin quality characteristics to the maximum extent in processing is innovated through green-making withering (including sunlight sunning, indoor spreading cooling, green rocking and standing), raw material blending, low-temperature rolling, regulation and control fermentation, microwave primary drying, variable-temperature redrying and the like. The method aims at the quality defects of thin aroma, bitter taste and the like of the traditional summer and autumn black tea and the industrial development bottleneck problems of serious abandonment and low utilization rate of fresh leaves of the summer and autumn tea and the like caused by the quality defects, and the prepared summer and autumn black tea has the quality characteristics of rich flower and honey aroma, red and orange bright liquor color, mellow taste, relatively high theaflavin content and the like, so that the problem of quality defect of the summer and autumn black tea is broken through, and the problem of waste of fresh leaf resources of the summer and autumn tea is effectively alleviated.

Description

Processing method of high-quality summer and autumn black tea

Technical Field

The invention relates to a method for processing high-quality black tea by using fresh summer and autumn tea leaves, in particular to a method for processing high-quality summer and autumn black tea with floral honey fragrance and relatively high theaflavin content.

Background

The black tea is the tea with the largest yield, the widest consumption area and the largest trade quantity in the world, but is not the tea export of China, and the main reason is that the black tea of China has the quality defects of light fragrance, bitter taste and the like compared with the black tea of countries such as India, Srilanka, Kenya and the like. The research proves that the quality of the black tea is closely related to the water-soluble oxidation products of the polyphenols on the one hand, and particularly has the highest degree of relation with the theaflavins, and the content of the black tea not only influences the color and luster of the dry black tea, the color and taste of the tea soup, but also influences the physiological function of the drinking black tea. Researches find that the factors influencing the theaflavin content of black tea mainly comprise tea plant varieties, processing machinery, processing technology and the like, and the theaflavin content of Chinese black tea is generally 0.3-0.7 percent and is far lower than the theaflavin content (mostly higher than 1.2 percent) of black tea in China such as Kenya, Srilanca, India and the like. On the other hand, the aroma is also an important quality characteristic of the black tea, and can directly influence the visual judgment of tea grade division by a drinker. During the processing of black tea, new fragrant substances are generated by oxidation of alcohols, degradation of carotenoid and fatty acid, Maillard reaction, caramelization reaction and the like, so that the black tea shows rich fragrance. The factors influencing the formation of the aroma of the black tea mainly comprise tea tree varieties, regional differences, processing technologies and the like, wherein the improvement and innovation of the processing technologies can excite and retain aroma substances in the tea leaves to a certain extent.

In recent years, with the intensive research on the mechanism of formation of theaflavin and aroma, the processing technology of black tea mainly obtains the following development and improvement:

(1) withering: during sunning, along with the loss of water of leaf parts and the change of acidity of cell juice, a part of bound enzyme in fresh leaves can be changed into a free state, so that the quantity of the enzyme is increased, preparation can be made for biochemical change in the next processing process of black tea, meanwhile, the research of Wangdongliang and other people finds that proper sunning can reduce the phenol-ammonia ratio of tea, reduce the bitter taste of the tea, and is beneficial to improving the quality of summer and autumn tea.

(2) Shaking green: the fresh tea leaves are subjected to green rocking, the marginal cells of the tea leaves are damaged to a certain degree, the contact area of a matrix and enzyme in the tea leaves is increased, and the activity of main oxidase is improved to a certain degree. Maya Ping et al introduce the processes of sunning and green-making in the withering stage of black tea processing, and the prepared black tea has more prominent fragrance and quality. The study also finds that the green tea leaves are beneficial to the degradation of ester catechin in the tea leaves and the increase of the content of soluble sugar, thereby indirectly reducing the bitter taste in the tea leaves.

(3) Fermentation: fermentation is one of the key processes for forming the quality characteristics of black tea. The formation of the taste and aroma quality of black tea is closely related to the temperature, humidity, time and oxygen content of the black tea during fermentation. Guoguiyi, Fangshihui and the like consider that the black tea has good quality and high theaflavin and thearubigin contents at the fermentation temperature of 22-24 ℃ and the fermentation time of 100-140 min; owuor and other researches find that the short fermentation time produces less theaflavin and thearubigins, but the liquor color is brighter and the aroma index is higher; researches such as summer waves and the like believe that the content of each component of theaflavin is obviously increased along with the reduction of the pH value of a fermentation system; the research on the increasing state of main aromatic substances in the fermentation of the Keemun black tea, such as Zhao and Tao, discovers that the aromatic substances, such as alcohols, aldehydes and the like in the tea are increased, the aromatic substances, such as acids, esters and the like are reduced, and the green grass smell of the tea is converted into sweet fragrance.

(4) And (3) drying: enemy formula and the like analyze the influence of different aroma raising temperatures on the sensory quality and main biochemical components of congou black tea, and under the experimental conditions, the sensory quality of each processed tea sample is found to increase firstly and then decrease along with the increase of the aroma raising temperature; according to the Lushiunderstandable and the like, the comparative analysis of the aroma components of the Yunnan sun-dried black tea and the roasted black tea is researched, and the combined analysis result shows that different drying modes have certain influence on the aroma components of the black tea; the research of Zobia Naheed and the like finds that under the same experimental conditions, black tea is dried at three temperatures of 100 ℃, 110 ℃ and 120 ℃, and the result shows that the quality factors such as aroma, taste and the like of the black tea dried at the temperature of 110 ℃ are the best.

Therefore, the aroma quality components and the taste quality components (theaflavin and the like) in the black tea are gradually formed in the processing processes of sunning, shaking, rolling, fermenting, drying and the like. Therefore, according to the biochemical mechanism formed by the quality of the black tea with relatively high floral honey aroma and theaflavin content, on the basis of the prior processes of withering, rolling, fermenting, primary drying, secondary drying and the like for making the black tea, the fresh tea leaves in summer or autumn are taken as the raw material, and through the processing technology and process innovation of the black tea, the necessity and feasibility for processing the black tea with the floral honey aroma and high theaflavin quality characteristics are realized in theory and practice, the problem of the quality defect of the black tea in summer and autumn is expected to be broken through, the problem of low utilization of the fresh tea leaves in summer and autumn at present is scientifically solved, and the quality improvement and synergy and the benign development of the tea industry are further promoted.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at the quality defects of light aroma, bitter taste and the like of the traditional summer and autumn black tea in the prior art and the industrial development bottleneck problems of serious abandonment and collection, low utilization rate and the like of fresh leaves of the summer and autumn tea caused by the quality defects, the method for processing the high-quality summer and autumn black tea is provided, and the method innovatively performs green-making withering (containing sunlight-sunning, indoor spreading and cooling, green-rocking and standing), raw material blending, low-temperature rolling, regulation and control fermentation, microwave primary drying, temperature-changing redrying and other technical processes according to the flower honey aroma and the biochemical mechanism of formation of key taste quality component theaflavin, and excites precursor substances and glycosidase activity beneficial to the generation of the flower honey aroma and promotes the degradation of ester type catechin, anthocyanin and other bitter taste substances through the green-making withering; substrates and enzyme activities of floral honey aroma and theaflavin formed in the raw materials are optimized to the maximum extent through raw material blending; reducing the activity of enzyme and inhibiting enzymatic oxidative fermentation by 'low temperature rolling'; the activity of enzymes in the fermented leaves is rapidly passivated through microwave primary drying, and the excessive enzymatic oxidation of theaflavin is prevented to the maximum extent; through temperature change drying, the floral honey aroma substances with different boiling points of high, medium and low are excited; therefore, the prepared summer and autumn black tea has the high-quality characteristics of strong flower and honey aroma, bright red orange liquor color, mellow taste, relatively high theaflavin content and the like, thereby breaking through the problem of quality defect of the summer and autumn black tea and effectively relieving the problem of waste of fresh leaf resources of the summer and autumn tea.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a processing method of high-quality summer and autumn black tea comprises the following steps:

(1) performing green-making withering: spreading fresh tea leaves in summer or autumn thinly, and withering the fresh tea leaves in the sun in an outdoor environment with the temperature of 28-35 ℃, the relative humidity of 80-90%, good ventilation and the sunlight intensity of 2000-4000lx until the leaves lose luster, the leaves are soft and have faint scent; then spreading and airing the sunned leaves in a ventilated and cool indoor environment for 30-40min, controlling the room temperature at 20-30 ℃ and the relative humidity at 80-90%; rocking the obtained aired green leaves, and taking the condition that the edge parts of the leaves are red, green grass smell disappears and the flower fragrance begins to be diffused as appropriate; standing after shaking; wherein the fresh tea leaves are selected from the three tea varieties of the castanopsis sclerophylla leaf, the Bixiangzao tea and the Xiangfei tea in summer or autumn with one bud and two leaves;

preferably, the spreading thickness during the sun drying is 1-1.5cm, and the spreading is turned over for 1-2 times; the green rocking speed is 8-12 rpm; standing for 45-75 min.

(2) Raw material blending: uniformly mixing the castanopsis sclerophylla leaves after the green-making, the fragrant early-maturing and the Hunan Fei jade-green withered leaves according to the mass ratio of (5-6) to (2-3) to (3-1);

(3) low-temperature rolling: rolling the assembled withered leaves at 16-20 ℃ according to a principle of light-heavy-light until the cell breakage rate reaches more than 85 percent and the strip forming rate reaches more than 90 percent; preferably, the block is removed once in the rolling process.

(4) Regulating and controlling fermentation: deblocking the rolled leaves, putting the leaves into a fermentation chamber or a fermentation machine with controlled temperature, controlled humidity and oxygen, setting the working parameters of temperature of 28-32 ℃, humidity of 90-99% and one-time ventilation for 10s, fermenting until the leaves and veins and juice of the fermented leaves turn reddish, the leaves become reddish yellow after more than 85% of color, no grass smell exists, and orchid fragrance is given out, wherein the fragrance becomes rich; preferably, the thickness of the spread leaves during fermentation is regulated to be 4-6 cm.

(5) Microwave primary drying: drying the fermented leaves in microwave with the intensity of 400-600W until the tea leaves are slightly harsh when being pinched by hands, but the leaves are soft and the tender stems are broken to be moderate continuously, and then spreading for cooling;

preferably, the thickness of the spread leaves during the microwave initial drying is 2-3 cm; spreading for cooling for 20-30 min.

(6) Temperature changing and drying again: drying the primarily dried leaves subjected to microwave primary drying at 90 ℃ for 10min, then heating to 100 ℃ and 120 ℃, drying for 2-4min, then cooling to 90 ℃, and drying until the moisture content is less than 7%; and then immediately spreading for cooling.

Preferably, the thickness of the spread leaves during the temperature-changing redrying is 1-2 cm; spreading for cooling for 30-40 min.

The method starts from raw material selection, according to a formation mechanism of floral honey aroma quality components (the glycoside aroma precursor substance content and the glycosidase activity are superior) in black tea processing and a formation mechanism of key taste quality components theaflavin (the catechin EGCG, the EGC content and the polyphenol oxidase activity are superior) in black tea processing, and combines the popularization and planting situation of main tea plant varieties in China, and selects the summer and autumn fresh tea leaves of three tea plant varieties of chinquapin leaf, Bixiangzao and Xiangfei jade-jade (please refer to the following table 1 in combination) from 20 tea varieties; through the combination of the green making and withering, sunlight green drying, indoor green drying, green rocking and standing, precursor substances and glycosidase activity generated by floral honey fragrance are stimulated, and bitter substances such as ester catechin, anthocyanin and the like are promoted to be degraded; through the blending of the raw materials, the substrates and enzyme activities for forming floral honey aroma and theaflavin in the raw materials are optimized to the maximum extent (please refer to the following table 2 in combination); through low-temperature rolling, the activity of enzyme can be reduced, and the problem that enzymatic oxidative fermentation in different leaf cells is not synchronous due to different damage degrees of the leaf cells can be solved; the activity of enzymes in the fermented leaves can be further and rapidly passivated by microwave primary drying, and the excessive enzymatic oxidation of theaflavin is prevented to the maximum extent (different microwave primary drying treatment effects are shown in the following table 3); finally, the nectar substances with different boiling points of high, medium and low can be stimulated to release by changing the temperature and drying again (the treatment effect of different temperature and drying again is shown in the table 4). Meanwhile, on the basis of respectively carrying out single-factor experiments and orthogonal experiments on the technical processes of green making and withering (including sunlight green drying, indoor spreading and cooling, green rocking and standing), raw material blending, low-temperature rolling, regulation and control fermentation, microwave primary drying, variable-temperature redrying and the like one by one and obtaining the optimal technical parameters of each process, the invention innovatively integrates each optimized process and the technical parameters thereof to carry out black tea processing, so that the black tea can maximally form the quality characteristics of floral honey fragrance and high theaflavin in the processing process.

TABLE 1 comparison table of suitability of fresh tea leaves of different tea varieties for processing high-quality black tea

TABLE 2 comparison table of influence of different proportions of three tea tree variety raw materials on black tea quality

Note: no. 1, the castanopsis sclerophylla leaf is uniform, and the ratio of Bixiangzao to Bixiangzao is 7: 3; no. 2, the castanopsis sclerophylla leaf is uniform, and the green fragrance is 5: 5; 3, the number of the chinquapin leaves is 5: 5; no. 4, the castanopsis sclerophylla leaves are even, and the Hunan Fei Cui is 6: 4; no. 5, Bixiangzao, Xiangfei cui is 4: 6; no. 6, Bixiangzao, Xiangfei cui is 6: 4; no. 7, the castanopsis sclerophylla leaves are even, the fragrant is early, and the fragrant is 6:2: 3; 8, the castanopsis sclerophylla leaves are even, the green fragrance is early, and the ratio of Xiangfei cui is 4.5:2.5: 3; no. 9, the castanopsis sclerophylla leaves are even, the fragrant is early, and the ratio of Xiangfei cui is 6:2.5: 2; no. 10, the castanopsis sclerophylla leaves are even, the fragrant is early, and the ratio of Xiangfei cui is 5.5:2.5: 2; no. 11, the castanopsis sclerophylla leaves are even, the Bixiangzao is 5:3: 1.5; no. 12, the castanopsis sclerophylla leaf is aligned, the Bixiangzao is equal to Xiangfei cui in the ratio of 5:3:1, and the ratios of No. 1 to No. 12 are mass ratios.

TABLE 3 comparison of the effect of different microwave primary drying treatments on the content of the components and the total amount of the theaflavin in black tea

Note: WB1-WB5 with microwave intensity of 300W and microwave time of 1-5 min; WB6-WB10 with microwave intensity of 400W and microwave time of 1-5 min; WB11-WB15 with microwave intensity of 500W and microwave time of 1-5 min; WB16-WB20 is microwave intensity of 600W, and the microwave time is 1-5min respectively; the WB21-WB25 is microwave intensity of 700W, and the microwave time is 1-5min respectively.

TABLE 4 comparison table of the influence of different temperature change drying treatments on the relative contents of main aroma quality components of black tea

Note: CK is control group, BW1 is 100 ℃ +10min → 120 ℃ +2min → 100 ℃ +10min, BW2 is 90 ℃ +10min → 110 ℃ +2min → 90 ℃ +10min, BW3 is 90 ℃ +10min → 110 ℃ +5min → 90 ℃ +10min, BW4 is 110 ℃ +10min → 130 ℃ +2min → 110 ℃ +10 min.

The black tea product processed by the method of the invention is obviously superior to the black tea product processed by the traditional process in sensory quality (please refer to table 5 in combination), theaflavin content (see figure 1) and key aroma quality component relative content (see figure 2).

TABLE 5 comparison of sensory quality of the black tea products of the present invention with the conventional art black tea products

The results show that compared with the traditional process, the invention has the advantages that the technical processes of green withering, raw material blending, low-temperature rolling, fermentation regulation and control, microwave primary drying, temperature-changing secondary drying and the like are innovated, so that the enzymatic fermentation is facilitated to directionally form theaflavin and the further conversion of theaflavin and theabrownin is prevented, the theaflavin content in the finished black tea is obviously improved, and the theaflavin content is increased from 0.38% to 0.56% of the black tea product in the traditional process and increased by 47.37%; meanwhile, the aroma quality component analysis of the black tea product shows that the aroma quality component of the black tea product is mainly dominated by nectar-flavor linalool and oxidation products thereof, the contents of phenethyl alcohol, methyl salicylate and the like are higher, and the relative contents of alcohols and esters are respectively 19.75% and 50.11% higher than that of the black tea product prepared by the traditional process. The prepared summer and autumn black tea has the high-quality characteristics of rich floral honey aroma, bright red orange liquor color, mellow taste, relatively high theaflavin content and the like.

Drawings

Figure 1 is a graph comparing the theaflavin content of a black tea product of the present invention with a prior art black tea product.

Wherein: TF is theaflavin, TF-3G is theaflavin-3-gallate, TF-3 'G is theaflavin-3' -gallate, and TFDG is theaflavin digallic acid.

Figure 2 is a graph comparing the relative content of key aroma quality components of the black tea product of the present invention and the traditional process black tea product.

Detailed Description

Example 1

Respectively spreading the fresh tea leaves of the tea plant variety, namely the castanopsis sclerophylla leaves, the Bixiangzao tea leaves and the Xiangfei tea leaves in summer or autumn with one bud and two leaves at the thickness of 1cm on bamboo skin, withering for 35min in an outdoor environment with the temperature of 28 ℃, the relative humidity of 80%, good ventilation and the sunlight intensity of 2000lx, and turning for 1 time in the period until the leaf surfaces lose luster, and the leaves are soft and fragrant; then placing the dried green leaves in a ventilated and cool indoor environment for spreading and airing for 30min, controlling the room temperature at 20 ℃ and the relative humidity at 80%; then placing the dried green leaves into a green rocking machine and rocking green at the rotating speed of 8rpm until the edge parts of the leaves turn red, green grass smell disappears and the fragrance of the emitted flowers is moderate; standing for 45min after shaking; then uniformly mixing the castanopsis sclerophylla leaves, the fragrant early-maturing castanopsis sclerophylla leaves and the Hunan Fei jade-green withered leaves according to the mass ratio of 6:2: 3; placing the well-spliced withered leaves in an air-conditioned room at the temperature of 16 ℃, and rolling and deblocking once in the midway according to the principle of light-weight-light weight until the cell damage rate reaches more than 85 percent and the strip forming rate reaches more than 90 percent; deblocking the twisted leaves, putting the leaves into a fermentation chamber with controlled temperature, controlled humidity and oxygen, spreading the leaves to a thickness of 4cm, fermenting at 28 deg.C and humidity of 90% for 10s until the fermented leaf veins and juice become reddish, the color of the leaves is more than 85% red yellow, no grass smell exists and pleasant flower fragrance is generated; placing the fermented leaves in microwave with intensity of 400W, spreading the leaves with thickness of 2cm, drying for 75s by microwave until the tea leaves are slightly sharp when being pinched by hands, but the leaves are soft and tender, and spreading for cooling for 20min with a thin bamboo plate; placing the primarily dried leaves subjected to microwave primary drying in a tea leaf drying box type dryer, drying for 10min at the temperature of 90 ℃, then heating to 100 ℃, continuing to dry for 4min, then cooling to 90 ℃, drying until the moisture content is below 7%, and finally immediately spreading for cooling for 30 min.

Through sensory evaluation, the obtained black tea product has compact strip, nectar fragrance and black, smooth and uniform; the tea soup is orange red, bright, thick and long in nectar fragrance, mellow and sweet in taste, and even and bright in red leaf bottom; the composite score was 94.3. By analyzing the quality components of theaflavin and aroma, the theaflavin content in the obtained black tea product is 0.57%; the fragrance component mainly comprises linalool and oxidation products thereof, wherein the relative content of the linalool is 27.64%, the relative content of the phenethyl alcohol is 8.36%, the relative content of the geraniol is 15.20%, the relative content of the methyl salicylate is 11.56%, the relative content of the alcohols in the fragrance component is 62.99%, and the relative content of the esters in the fragrance component is 21.42%.

Example 2

Respectively spreading the fresh leaves of the tea plant variety of the castanopsis sclerophylla leaves with the thickness of 1.25cm on the bamboo skin in summer or autumn, wherein the castanopsis sclerophylla leaves with the fragrance of early and Hunan Fei Cui are thin, withering for 30min in an outdoor environment with the temperature of 32 ℃, the relative humidity of 85%, good ventilation and the sunlight intensity of 3000lx, and turning for 1 time in the period until the leaves lose luster, and the leaves are soft and have faint scent; then spreading and airing the sun-dried green leaves for 35min in a ventilated and cool indoor environment, controlling the room temperature at 25 ℃ and the relative humidity at 85%; then placing the dried green leaves into a green rocking machine, rocking at the rotating speed of 10rpm until the edge parts of the leaves turn red, green grass gas disappears and the fragrance of the emitted flowers is moderate, and then standing for 60 min; uniformly mixing the castanopsis sclerophylla leaves after the green-making, the fragrant early-maturing and the Hunan Fei jade-green withered leaves according to the mass ratio of 5.5:2.5: 2; putting the well-spliced withered leaves into an air-conditioned room at the temperature of 18 ℃, rolling according to the principle of 'light-heavy-light', deblocking once midway until the cell damage rate reaches more than 85 percent and the strip forming rate reaches more than 90 percent; deblocking the twisted leaves, putting the leaves into a fermentation machine with controlled temperature, controlled humidity and oxygen, spreading the leaves to a thickness of 5cm, fermenting at 30 ℃ and a humidity of 95% for 10s for one time until the fermented leaf veins and juice become reddish, the leaf color is more than 85% red yellow, no grass smell exists, and the pleasant flower fragrance is moderate; placing the fermented leaves in microwave with intensity of 500W, spreading the leaves with thickness of 2.5cm, drying for 60s by microwave until the tea leaves are slightly sharp when pinched by hand, but the leaves are soft and tender, and spreading for cooling for 25min with a bamboo strip disc; placing the primarily dried leaves subjected to microwave primary drying in a tea leaf drying box type dryer, drying for 10min at 90 ℃, then heating to 110 ℃, continuing to dry for 3min, then reducing to 90 ℃, drying until the moisture content is below 7%, and finally immediately spreading for cooling for 35 min.

According to sensory evaluation, the obtained black tea product is compact in cord, has nectar fragrance, and is black, smooth and uniform; the tea soup is orange red, bright, thick and long in nectar fragrance, mellow and sweet in taste, and even and bright in red leaf bottom; the composite score was 95.4. By analyzing the quality components of theaflavin and aroma, the theaflavin content in the obtained black tea product is 0.56%; the fragrance components mainly comprise linalool and oxidation products thereof, wherein the relative content of linalool is 18.92%, the relative content of phenethyl alcohol is 7.95%, the relative content of geraniol is 12.60%, the relative content of methyl salicylate is 12.11%, the contents of phenethyl alcohol, methyl salicylate and the like are high, the relative content of alcohols in the fragrance components is 58.46%, and the relative content of esters in the fragrance components is 19.86%.

Example 3

Respectively spreading the fresh leaves of the tea plant variety of the castanopsis sclerophylla leaves with the thickness of 1.5cm on the bamboo skin in summer or autumn, wherein the castanopsis sclerophylla leaves with the fragrance of early and Hunan Fei Cui are respectively thin, withering for 25min in an outdoor environment with the temperature of 35 ℃, the relative humidity of 90 percent, good ventilation and the sunlight intensity of 4000lx, and turning for 2 times in the period until the leaf surfaces lose luster, the leaf quality is soft and has faint scent; then spreading and airing the sun-dried green leaves for 40min in a ventilated and cool indoor environment, controlling the room temperature at 30 ℃ and the relative humidity at 90%; then placing the dried green leaves into a green rocking machine, rocking at the rotating speed of 12rpm until the edge parts of the leaves turn red, green grass gas disappears and the fragrance of the emitted flowers is moderate, and then standing for 75 min; uniformly mixing the castanopsis sclerophylla leaves after the green-making, the fragrant early-maturing and the Hunan Fei jade-green withered leaves according to the mass ratio of 5:3: 1; putting the well-spliced withered leaves into an air-conditioned room at the temperature of 20 ℃, rolling according to the principle of 'light-heavy-light', deblocking once midway until the cell damage rate reaches more than 85 percent and the strip forming rate reaches more than 90 percent; deblocking the twisted leaves, putting the leaves into a fermentation chamber with controlled temperature, controlled humidity and oxygen, spreading the leaves to a thickness of 6cm, fermenting at 32 ℃ and a humidity of 99% for 10s until the fermented leaf veins and juice become reddish, the leaf color is more than 85% red yellow, no grass smell exists, and pleasant flower fragrance is generated; placing the fermented leaves in microwave with intensity of 600W, spreading the leaves to a thickness of 3cm, drying for 45s by microwave until the tea leaves are slightly sharp when being pinched by hands, but the leaves are soft and tender, and continuously breaking the stems to be moderate, and then spreading the leaves for cooling for 30min by using a bamboo strip disc; placing the primarily dried leaves subjected to microwave primary drying in a tea leaf drying box type dryer, drying for 10min at 90 ℃, then heating to 120 ℃, continuing to dry for 2min, then reducing to 90 ℃, drying until the moisture content is below 7%, and finally immediately spreading for cooling for 40 min.

According to sensory evaluation, the obtained black tea product is compact in cord, has nectar fragrance, and is black, smooth and uniform; the tea soup is orange red, bright, thick and long in nectar fragrance, mellow and sweet in taste, and even and bright in red leaf bottom; the composite score was 94.6. By analyzing the quality components of theaflavin and aroma, the theaflavin content in the obtained black tea product is 0.58%; the fragrance component mainly comprises linalool and oxidation products thereof, wherein the relative content of the linalool is 19.94%, the relative content of the phenethyl alcohol is 5.98%, the relative content of the geraniol is 13.34%, the relative content of the methyl salicylate is 11.67%, the relative content of the alcohols in the fragrance component is 56.95%, and the relative content of the esters in the fragrance component is 18.38%.

Comparative experiment 1 of conventional process:

selecting fresh summer one-bud two-leaf tea leaves of Bixiang early tea tree varieties as raw materials.

Spreading fresh tea leaves on bamboo skin with a thickness of 1.5cm, naturally withering indoors for 10-12 hours at a temperature of 32 ℃ and a relative humidity of 90% under a good ventilation condition, turning for 1-2 times until the leaves lose luster, tender stems are continuously folded, the leaves are soft and have moderate fragrance; rolling the withered leaves for 80min at room temperature according to the principle of light-heavy-light, deblocking once in the midway until the cell breakage rate reaches more than 85 percent and the strip forming rate reaches more than 90 percent; deblocking the properly rolled leaves, putting the leaves into a fermentation chamber or a fermentation machine with controlled temperature, controlled humidity and oxygen supply, spreading the leaves to a thickness of 5cm, fermenting at 30 ℃ and a humidity of 95% for 10s until the veins and juice of the fermented leaves turn reddish, the color of the leaves becomes more than 85% reddish yellow, no grass smell exists, and the pleasant flower fragrance is given out; placing the properly fermented leaves in a tea drier, spreading the leaves to a thickness of 2.5cm, and quickly drying for 10min at 120 deg.C with slow fire until the leaves are slightly sharp when pinched by hand, but the leaves are soft and tender and have proper stem folding; spreading for cooling for 30min with thin bamboo plate after the crude fire is primarily dried; placing the primarily dried leaves which are primarily dried by gross fire and spread for cooling in a tea leaf dryer, and spreading the leaves to be 1.5cm in thickness; drying at 90 deg.C to dry to water content below 7%, and spreading for 30 min.

Through sensory evaluation, the obtained black tea product has compact, black and smooth and even rope; the tea soup has dark red and bright color, pure sweet and fragrant taste, mellow and refreshing taste, dark red and bright leaf bottom; the composite score was 86.3. By analyzing the quality components of theaflavin and aroma, the theaflavin content in the obtained black tea product is 0.38%; the aroma components comprise 15.25% of linalool, 5.01% of phenethyl alcohol, 15.38% of geraniol and 9.86% of methyl salicylate, wherein the relative content of alcohols is 51.60% and the relative content of esters is 14.27%.

Claims (10)

1. A processing method of high-quality summer and autumn black tea is characterized by comprising the following steps: the method comprises the following steps:

(1) performing green-making withering: spreading fresh tea leaves in summer or autumn thinly, and withering the fresh tea leaves in the sun in an outdoor environment with the temperature of 28-35 ℃, the relative humidity of 80-90%, good ventilation and the sunlight intensity of 2000-4000lx until the leaves lose luster, the leaves are soft and have faint scent; then spreading and airing the sunned leaves in a ventilated and cool indoor environment for 30-40min, controlling the room temperature at 20-30 ℃ and the relative humidity at 80-90%; rocking the obtained aired green leaves, and taking the condition that the edge parts of the leaves are red, green grass smell disappears and the flower fragrance begins to be diffused as appropriate; standing after shaking; wherein the fresh tea leaves are selected from the three tea varieties of the castanopsis sclerophylla leaf, the Bixiangzao tea and the Xiangfei tea in summer or autumn with one bud and two leaves;

(2) blending raw materials: uniformly mixing the castanopsis sclerophylla leaves after the green-making, the fragrant early-maturing and the Hunan Fei jade-green withered leaves according to the mass ratio of 5-6:2-3: 3-1;

(3) low-temperature rolling: rolling the well-spliced withered leaves at 16-20 ℃ according to a 'light-heavy-light' principle until the cell damage rate reaches more than 85 percent and the strip forming rate reaches more than 90 percent;

(4) regulating and controlling fermentation: deblocking the rolled leaves, putting the leaves into a fermentation chamber or a fermentation machine with controlled temperature, controlled humidity and oxygen, setting the working parameters of temperature of 28-32 ℃, humidity of 90-99% and ventilation for 10s, fermenting until the leaves and veins of the fermented leaves and juice become reddish, the leaves become reddish yellow when the color is more than 85%, and the leaves have no grass smell and emit orchid fragrance;

(5) microwave primary drying: drying the fermented leaves in microwave with the intensity of 400-600W until the tea leaves are slightly harsh when being pinched by hands, but the leaves are soft and the tender stems are broken to be moderate continuously, and then spreading for cooling;

(6) temperature changing and drying again: drying the primarily dried leaves subjected to microwave primary drying at 90 ℃ for 10min, then heating to 100 ℃ and 120 ℃, drying for 2-4min, then cooling to 90 ℃, and drying until the moisture content is less than 7%; and then immediately spreading for cooling.

2. The processing method of high-quality summer and autumn black tea as claimed in claim 1, characterized in that: the spreading thickness in the step (1) is 1-1.5cm during sunning, and the spreading thickness is turned over for 1-2 times during sunning.

3. The processing method of high-quality summer and autumn black tea as claimed in claim 1, characterized in that: the green rocking speed in the step (1) is 8-12 rpm.

4. The processing method of high-quality summer and autumn black tea as claimed in claim 1, characterized in that: and (2) standing for 45-75min in the step (1).

5. The processing method of high-quality summer and autumn black tea as claimed in claim 1, characterized by comprising the following steps: and (4) deblocking once in the rolling process of the step (3).

6. The processing method of high-quality summer and autumn black tea as claimed in claim 1, characterized by comprising the following steps: and (4) regulating and controlling the thickness of the spread leaves during fermentation to be 4-6 cm.

7. The processing method of high-quality summer and autumn black tea as claimed in claim 1, characterized by comprising the following steps: the thickness of the spread leaves in the step (5) during microwave primary drying is 2-3 cm.

8. The processing method of high-quality summer and autumn black tea as claimed in claim 1, characterized in that: and (5) spreading for cooling for 20-30 min.

9. The processing method of high-quality summer and autumn black tea as claimed in claim 1, characterized by comprising the following steps: and (4) the thickness of the spread leaves in the temperature-changing redrying step (6) is 1-2 cm.

10. The processing method of high-quality summer and autumn black tea as claimed in claim 1, characterized in that: and (4) spreading for cooling for 30-40min in the step (6).

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