CN115590082A - Composite withering method, flower-fragrance diced osmanthus black tea and processing method thereof - Google Patents

Abstract

The invention belongs to the technical field of tea processing, and particularly relates to a composite withering method, a flower-fragrance diced osmanthus black tea and a processing method thereof. According to the invention, natural withering, sunlight withering and withering in the withering trough are combined, so that partial water is slowly and uniformly evaporated from the leaves, the swelling pressure of cells is reduced, the leaves are soft, the toughness is enhanced, and the leaves are convenient to roll and shape; the protein is hydrolyzed along with the reduction of water content, the enzyme is changed from a binding state to a free state, the activity is enhanced, and the conversion of chemical components in the leaves is promoted; the green grass flavor disappears, the faint scent appears, the tea aroma is formed, the three withering modes have a synergistic effect, and the tea aroma and quality can be improved to the maximum extent.

Description

Composite withering method, flower-fragrance diced osmanthus black tea and processing method thereof

Technical Field

The invention belongs to the technical field of tea processing, and particularly relates to a composite withering method, a flower fragrance type diced osmanthus black tea and a processing method thereof.

Background

China is the hometown of tea, is the core of the tea tree origin in the world, has good ecological environment and creates the advantage of abundant and diverse wild tea resources in China. In recent years, various tea-producing areas in China actively explore the development and utilization values of wild tea tree resources while devotionally protecting the wild tea tree resources, devotively establish a sound wild tea tree resource protection system, further promote reasonable development and utilization of resources, create wild tea brands, improve brand influence and realize win-win of ecological benefits and economic benefits.

The Guiding tea is a unique rare tea tree fine variety in Hunan province, is produced from the national 4A scenic spot, namely the mountain deep with the altitude near dolomite of about 800 meters, has excellent quality, is fresh and mellow in taste after being made into green tea, is obvious in aftertaste, and is rich in contained components, wherein the content of epigallocatechin gallate (EGCG) reaches about 10 percent. Because of its excellent quality, gui Ding tea was chosen as the imperial tea and is recorded in detail in Hu nan Tong Zhi and Bao Qing Fu Zhi.

The black tea is one of six Chinese teas, belongs to the whole fermentation tea, and has the health-care functions of resisting oxidation, softening blood vessels, nourishing stomach and the like. Generally, tea tree varieties with large bud leaves, rich internal components, high ester catechin content and moderate caffeine content are suitable for making black tea. The tea of the cinnamon leaves meets the requirement, so the tea of the cinnamon leaves is also suitable for producing high-quality black tea. However, most of the traditional processing methods of the black tea containing the sweet-scented osmanthus dices are withered in a withering tank, fermented at normal temperature and dried at one time, the aroma is unstable, the taste is not sweet and mellow enough, and the problems of how to ensure the blending of the aroma and the sweet aroma of the black tea containing the sweet-scented osmanthus dices, and how to ensure the high sharpness and the lasting taste and the sweet and mellow taste are urgent.

Disclosure of Invention

The invention aims to provide a composite withering method, a flower fragrance type diced osmanthus black tea and a processing method thereof, the aroma and the quality of the black tea of the broadleaf holly leaf are improved, so that the obtained black tea of the broadleaf holly leaf has mixed aroma and sweet aroma and is high, sharp and lasting.

The invention provides a composite withering method, which comprises natural withering, sunlight withering and withering in a withering trough in sequence.

Preferably, the natural withering time is 8-18 h, the temperature is 20-24 ℃, and the relative humidity is 60% -70%;

the sunlight withering time is 1-2 h;

the withering time of the withering trough is 2-4 h, the air volume is 16000-20000 cubic meters per hour, the temperature is 35-38 ℃, and the thickness of the spread leaves is 18-20 cm; and stopping ventilation and shaking for 1 time every 1h in the withering process of the withering trough.

The invention also provides a processing method of the diced cinnamon black tea, which comprises the following steps:

carrying out withering treatment on the fresh tea leaves of the cinnamomum cassia presl by using the composite withering method in the technical scheme to obtain withered tea leaves;

and sequentially carrying out rolling treatment, fermentation treatment, drying treatment and aroma improvement treatment on the withered leaves to obtain the diced black tea.

Preferably, the tender degree of the fresh tea leaves of the cinnamomum cassia presl is one bud and one leaf or one bud and two leaves; the water content of the withered tea is 60-64%, and the weight loss rate of the fresh tea leaves of the sweet-scented osmanthus tea is 31-38%.

Preferably, the total time of the rolling treatment is 60-90 mim, the temperature is 20-24 ℃, and the relative humidity is 80-90%;

the kneading treatment is sequentially carried out according to the sequence of empty kneading, first light kneading, heavy kneading and second light kneading; the time for the air kneading, the first light kneading, the heavy kneading and the second light kneading is 30-45 min, 10-15 min and 10-15 min in sequence.

Preferably, the fermentation treatment is variable-temperature fermentation, and comprises first fermentation and second fermentation;

the temperature of the first fermentation is 35 ℃, the fermentation time is 1h, and the humidity is more than 95 percent; the temperature of the second fermentation is 28 ℃, the time is 2-3 h, and the humidity is more than 95%.

Preferably, the drying treatment comprises gross fire drying and full fire drying;

the temperature for drying by gross fire is 200-225 ℃, and the temperature for drying by full fire is 95-105 ℃.

Preferably, the method further comprises the following steps after the drying by the gross fire: spreading for cooling for 50-60 min, drying with full fire, spreading for cooling and moisture regaining for 30-40min, and flavoring.

Preferably, the temperature of the aroma raising treatment is 80-90 ℃, and the aroma raising time is 60-90 min.

The invention also provides the diced black tea obtained by the processing method in the technical scheme, and the diced black tea contains nerol, linalool and linalool oxide, wherein the nerol accounts for 33.65-35.45% of the total aroma substances, and the linalool oxide account for 18.67-20.30% of the total aroma substances.

According to the invention, natural withering, sunlight withering and withering in the withering trough are combined, so that partial water is slowly and uniformly evaporated from the leaves, the cell expansion pressure is reduced, the leaves are soft, the toughness is enhanced, and the rolling and shaping are convenient; the protein is hydrolyzed along with the reduction of water content, the enzyme is changed from a binding state to a free state, the activity is enhanced, and the conversion of chemical components in the leaves is promoted; the green grass flavor disappears, the faint scent appears, the tea aroma is formed, the three withering modes have a synergistic effect, and the tea aroma and quality can be improved to the maximum extent.

According to the invention, the black tea is processed from the broadleaf holly leaves, the processing conditions are strictly controlled, the good quality of the tea is favorably maintained and formed, the prepared broadleaf holly leaves have elegant natural flower fragrance, the flower fragrance and the sweet fragrance are mixed, and the main fragrance substances are as high as 105. Wherein the content of the most sweet substances is nerol which accounts for 33.65 to 35.45 percent of the total fragrant substances, and the substances have rose sweet fragrance; secondly, linalool and linalool oxide account for 18.67 to 20.30 percent of the total aroma substances, and have the flower fragrance of lilac, lily of the valley and rose, and the aroma of costustoot and fruit; in addition, the aroma substances with the content of more than 2 percent also comprise trans-2-hexenal (with grass smell), phenylacetaldehyde (with the sweet smell of fruits), methyl salicylate (with the fragrance of Chinese holly oil herbs) and hexanal (with the fragrance of grass smell and apple smell), the aroma lasts fresh and the quality is high.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below.

FIG. 1 is a mass spectrum total ion flow diagram of the first-grade Guiding black tea obtained in example 1;

FIG. 2 is a mass spectrum total ion flow diagram of the secondary Guiding black tea obtained in example 2.

Detailed Description

The invention provides a composite withering method, which comprises natural withering, sunlight withering and withering in a withering trough in sequence.

In the invention, the time for naturally withering is preferably 8-18 h, more preferably 8-12 h, and even more preferably 10h; the temperature for naturally withering is preferably 20-24 ℃, and more preferably 22 ℃; the relative humidity of the natural withering is preferably 60% to 70%, and more preferably 65%. In the natural withering process, the spreading amount of the material to be withered is preferably 0.5-0.75 kg/m ² . The invention preferably includes a slight withering during said natural withering process to avoid red discoloration of the leaves as a result of damage thereto. The invention has no strict requirements on the natural withering mode, and the natural withering can be carried out indoors. The natural withering disclosed by the invention can ensure the withering quality.

In the invention, the time for the solar withering is preferably 1-2 h; the time of solar withering is preferably 10 am or 2 pm. The invention preferably turns gently 1-2 times during the solar withering process. The invention has no strict requirement on the sunlight withering mode, and the material to be withered is spread in sunlight for withering. The material to be withered according to the present invention preferably comprises spring tea or summer tea. The sunlight withering machine has the advantages of less equipment, simplicity and convenience, and quick withering.

In the invention, the withering time of the withering trough is preferably 2-4 h; the air volume for withering the withering trough is preferably 16000-20000 cubic meters per hour, and is further preferably 18000 cubic meters per hour; the withering temperature of the withering trough is preferably 35-38 ℃, and is further preferably 36 ℃; the thickness of the withered spreading leaves in the withering trough is preferably 18-20 cm; preferably, ventilation is stopped every 1h in the withering process of the withering trough, and the withering trough is turned and shaken for 1 time. In the specific implementation process of the invention, the withered leaves are different according to the old and tender quality of the leaves and the different sizes of the leaves, and according to the principles of 'tender leaf spreading, old leaf spreading, small leaf spreading and large leaf spreading', the thickness of the spread leaves is preferably 20cm if the leaves are small leaf seeds, and is preferably 18cm if the leaves are large leaf seeds. The invention has no strict requirement on the shaking mode, and the blade is prevented from being damaged by conventional operation. The source of the withering trough is not strictly required, and the withering trough can be purchased conventionally. The withering trough comprises a heating stove, a blower, a trough body and a leaf containing frame curtain, the length of the trough is 10m, the width of the trough is 1.5m, the height of the trough is 20cm, and the effective leaf spreading area is 15m ² . In the practice of the present invention, the withering trough is purchased from Zhejiang Shanghai mechanical parts, inc. The withering trough is used for withering, hot air is forced to penetrate through the leaf layer by the air blower, and the leaf layer is enabled to disperse water under the action of hot air flow, so that the withering trough is a better withering mode. In the withering process, a No. 7 axial flow fan is preferably used. In the invention, the temperature is preferably reduced within 10-15 min before the withering of the withering trough is finished, and further preferably, the temperature is cooled by blowing cold air. The invention strictly controls the withering temperature, air quantity, leaf spreading thickness and stirring and withering time of the withering trough, and can improve withering rateAnd (5) withering the tea quality.

The invention adopts a 'composite withering' mode of combining natural withering, sunlight withering and withering in a withering trough, and can reduce the cell expansion pressure by prolonging the withering time, so that the leaves are soft, the toughness is enhanced, and the rolling and shaping are convenient; the protein is hydrolyzed along with the reduction of water content, the enzyme is changed from a binding state to a free state, the activity is enhanced, and the conversion of chemical components in the leaves is promoted; the green grass flavor disappears, the faint scent appears, the tea aroma is formed, the three withering modes have a synergistic effect, and the tea aroma and quality can be improved to the maximum extent.

The invention also provides a processing method of the diced black tea, which comprises the following steps:

carrying out withering treatment on the fresh tea leaves of the diced cinnamon by using the composite withering method in the technical scheme to obtain withered tea leaves;

and sequentially carrying out rolling treatment, fermentation treatment, drying treatment and aroma raising treatment on the withered leaves to obtain the diced black tea.

According to the invention, the picked fresh cinnamon leaves are subjected to withering treatment by using a composite withering method to obtain withered leaves. The tenderness of the fresh tea leaves of the cinnamomum cassia presl is preferably one bud and one leaf or one bud and two leaves, and more preferably one bud and one leaf; the raw materials of the wild tea of the cinnamomum cassia presl tea in wild tea gardens of alpine and semi-alpine in the famous regions of dolomite landscape are preferably selected as the fresh leaves of the cinnamomum cassia presl tea, compared with the original tea, the external pollution is basically zero, the buds are plump, the color and luster are green, the leaf quality is soft, the nutrition accumulation is thick, the nutritional ingredients are rich, the soaking resistance is high, the fragrance is strong, the lasting aroma is long, the taste is fresh and cool, and the quality of the cinnamomum cassia presl black tea can be improved by taking the raw materials as the raw materials to prepare the cinnamomum cassia presl black tea. The specific method of the composite withering of the present invention is described in the foregoing, and is not repeated herein. The composite withering ending mark preferably comprises the steps that picked fresh cinnamomum cassia leaves lose original luster, the leaf color is changed from fresh green to dark green, no withered buds, burnt edges and reddish, the leaves are softened, the leaves of the picked fresh cinnamomum cassia leaves droop, the leaves are not easy to break, the leaves are kneaded into soft lumps like cotton by hands, the soft lumps are tightly held into lumps, the hands are loose and are not easy to scatter, the green odor disappears, slight fresh flower fragrance is given out, the water content of the obtained withered leaves is 60% -64%, and the weight loss rate of the fresh cinnamomum cassia leaves is 31% -38%.

After the withered leaves are obtained, the invention preferably carries out rolling treatment on the withered leaves to obtain rolled leaves. The total time of the rolling treatment is preferably 60 to 90 mm, more preferably 65 to 85min, even more preferably 70 to 80min, and most preferably 75min; the temperature of the rolling treatment is preferably 20-24 ℃, and more preferably 22 ℃; the relative humidity of the rolling treatment is preferably 80% to 90%, and more preferably 85%. The rolling treatment of the invention is preferably carried out in the sequence of empty rolling, first light rolling, heavy rolling and second light rolling; the air kneading time is preferably 30-45 min, and more preferably 35-40 min; the first gentle kneading time is preferably 10 to 15min, and more preferably 12min; the time for re-kneading is preferably 10 to 15min, and more preferably 12min; the time for the second gently kneading is preferably 10 to 15min, and more preferably 12min. In the rolling treatment of the present invention, a small-sized rolling machine is preferably used, and a 6CR-40 rolling machine is more preferably used. The invention adopts a low-temperature high-humidity mode to knead, and no pressurization is carried out at the beginning of kneading, so that withered tea leaves are preliminarily formed into strips, then the strips are gradually pressed and rolled into strips (the strip forming rate reaches 95 percent), and the pressure is reduced for a period of time (namely a second light kneading stage) before the kneading is finished, so that the tea leaves are formed and the color, the aroma and the concentration are improved; the damaged cell tissue (the cell damage rate is 78-85 percent), the tea juice is fully kneaded out and attached to the surface of the leaf without loss, the necessary polyphenol oxidation is conveniently carried out under the action of enzyme, the smooth fermentation is facilitated, and the foundation is laid for forming the quality of the black tea.

After the twisted leaves are obtained, the twisted leaves are preferably subjected to fermentation treatment to obtain fermented leaves. The fermentation treatment is preferably variable-temperature fermentation, and comprises first fermentation and second fermentation. The temperature of the first fermentation is preferably 35 ℃, the time is preferably 1h, and the humidity is preferably more than 95%; the temperature of the second fermentation is preferably 28 ℃, the time is preferably 2-3 h, and the humidity is preferably more than 95%. In the fermentation process, the water content of the twisted leaves is preferably controlled to 60-64% to ensure the normal fermentation, and in the fermentation treatment process, the thickness of the spread leaves is preferably 5-10 cm, and more preferably 6-8 cm. In the specific implementation process of the invention, the time of fermentation treatment is preferably determined according to seasons, when the fermentation treatment is spring, the time of the first fermentation is preferably 1h, and the time of the second fermentation is preferably 3-4 h, namely the total fermentation time is 4-5 h; when the fermentation treatment is summer, the time of the first fermentation is preferably 1h, and the time of the second fermentation is preferably 2-3 h, namely the total fermentation time is 3-4 h. The invention adopts a variable temperature fermentation technology, is beneficial to the formation and accumulation of theaflavin and improves the quality of black tea.

After the fermented leaves are obtained, the invention preferably carries out drying treatment on the fermented leaves to obtain the dried leaves. The drying treatment according to the present invention preferably includes gross fire drying and full fire drying. The invention carries out the gross fire drying treatment on the fermented leaves to obtain the gross fire leaves; the temperature for drying by the flame is preferably 200 to 225 ℃, more preferably 205 to 220 ℃, and still more preferably 210 to 215 ℃. When the gross fire drying is carried out, the leaf temperature of the fermented leaves is preferably 80-90 ℃; the type 50 electric heating roller water removing machine is preferably used for drying by gross fire, rolling instead of drying is adopted, and the machine has the advantages of short time, high dehydration speed, tight strip shape and high fragrance. The raw fire leaf obtained by the invention is dried by 7 to 8 percent, the leaf strips are basically dry and hard, the tender stems are slightly soft, the hand can feel stabbing and slightly soft, and the water content is 20 to 25 percent.

After the leaf of the hairy fire is obtained, the leaf of the hairy fire is preferably spread for cooling for 50-60 min and then is dried with full fire to obtain the leaf of the full fire. The thickness of the spread leaves in spreading and cooling is preferably 3-5 cm. The method has no strict requirement on the spreading and cooling mode, and can be carried out by conventional operation. The temperature of the full fire drying is preferably 95-105 ℃, and more preferably 100 ℃; the full fire drying preferably uses a five-bucket dryer.

After the leaf of the Chinese podagra is obtained, the invention preferably spreads the full-fleshed leaf for cooling for 30-40min, obtaining the dry leaves. The thickness of the spread leaves in the spreading and cooling process is preferably 4-6 cm. The method has no strict requirement on the spreading and cooling mode, and can be carried out by conventional operation.

After the dry leaves are obtained, the invention carries out aroma-improving treatment on the dry leaves to obtain the diced bay black tea. The temperature of the aroma raising treatment is preferably 80-90 ℃, and more preferably 85 ℃; the time for the aroma raising treatment is preferably 60 to 90min, more preferably 65 to 85min, even more preferably 70 to 80min, and most preferably 75min. The thickness of the spreading leaves is preferably 2-3 cm when the aroma raising treatment is carried out. The water content of the dried leaves obtained by the method is 4-5%. The invention adopts a drying technology of high-temperature drying, firstly high and then low, rolling instead of drying and drying for multiple times, and the drying process is added with spreading cooling and moisture regaining treatment, thereby being beneficial to maintaining and forming good quality of tea.

The invention also provides the diced black tea obtained by the processing method of the technical scheme, and the diced black tea contains nerol, linalool and linalool oxide, wherein the mass percentage of the nerol in the total aroma substances is 33.65-35.45%, and the mass percentage of the linalool and the linalool oxide in the total aroma substances is 18.67-20.30%.

For further illustration of the present invention, the composite withering method, floral black tea and processing method thereof according to the present invention will be described in detail with reference to the accompanying drawings and examples, which should not be construed as limiting the scope of the present invention.

Example 1

1. Picking fresh leaves

The wild tea raw material of the 4-month osmanthus fragrans tea in 2017 is from alpine and semi-alpine wild tea gardens in a core production area Baiyun rock scenic spot, and fresh leaves are required to be tender, neat and fresh. Picking one bud and one leaf as main materials (one bud and one leaf account for more than 90%), not picking old leaves, old stems, purple bud leaves, disease and pest leaves and other impurities, picking fresh leaves and storing bamboo products such as bamboo baskets, bamboo baskets and the like; the fresh leaves are required to be classified, checked, managed and paid.

2. Withering

2.1 indoor withering

The picked fresh tea leaves of the cinnamomum japonicum thunb are spread on a withering curtain, and the curtain is arranged on a withering frame indoors. The indoor air inlet has good air permeability and no direct sunlight. Indoor temperatureThe degree is required to be kept at 22 ℃, the relative humidity is 65 percent, and the fresh leaves are spread and put at about 0.5 to 0.75kg/m ² The withering time is generally controlled within 18 h. During withering, the leaves are turned over appropriately, but care is taken to avoid the leaves from being damaged and becoming red.

2.2 solar withering

The method is a mode for directly spreading the fresh leaves naturally withered indoors under the sunlight, wherein the withering time is before 10 am, and the fresh leaves cannot be withered by the sunlight when the sunlight is too strong. The leaves were spread on a sun-drying mat so thinly that the leaves did not substantially overlap. The withering time of the spring tea is 1h, and the middle is slightly turned for 1 to 2 times. The leaves are soft after being dried and the leaf surfaces are moderately curled. If the sunlight is weak, the withering time can be prolonged properly.

2.3 withering in withering trough

Spreading the fresh leaves withered by sunlight in a withering trough, controlling the ambient temperature to be about 36 ℃ during withering, controlling the maximum temperature to be not more than 38 ℃, controlling the air humidity to be 65%, and withering for 3h; the temperature at the two ends of the trough body is required to be as consistent as possible in the process of withering the trough body. Blowing cold air 10-15 min before withering and leaf setting; the thickness of the leaf layer and the softness of the leaf texture are properly adjusted. The withering trough has a length of 10m, a width of 1.5m, a height of 20cm, and an effective leaf spreading area of 15m ² A No. 7 axial flow fan is adopted; the leaves are different in size according to the old and tender leaves and the shape of the leaves. The principle of ' tender leaf thin spreading, old leaf thick spreading ', small leaf seed thick spreading and large leaf seed thin spreading ' is mastered, and the thickness of the small leaf seed is about 20cm and the large leaf seed is 18cm generally. The leaves are shaken out and spread out, and the thickness is consistent; stopping the blower every 1h, and turning for 1 time, wherein the action is light during turning, and damage to the leaves is avoided. After withering is finished, the fresh leaves lose the original luster, the color of the leaves is changed from dark green to dark green, and the leaves are free of withered buds, scorched edges and reddish; the leaves become soft, the stalk leaves of the leaves hold the leaves droop, the leaves are not easy to break, the leaves are pinched into soft lumps like cotton, the lumps are tightly held, the hands are loose and not easy to scatter, the green odor disappears, slight fresh flower fragrance is given out, the weight loss rate of the fresh leaves is about 31 to 38 percent, and the water content of the withered leaves is 60 to 64 percent.

3. Kneading and twisting

And (3) putting the withered leaves processed in the step (2) into a rolling machine for rolling for 60min, wherein in the embodiment, the rolling is carried out by using a small and medium-sized rolling machine, usually a 6CR-40 rolling machine, according to the principle of air rolling, first light rolling, heavy rolling and second light rolling, and the time for air rolling, first light rolling, heavy rolling and second light rolling is 30min, 10min and 10min in sequence. The invention requires low temperature and high humidity, reduces water loss and evaporation of twisted leaves, and has the temperature of 20-24 ℃ and the relative humidity of 80-90 percent. The invention does not apply pressure when rolling, to make the leaves into strips, then gradually apply pressure to roll into strips, and reduce pressure for a while before rolling to disperse the block mass, dissipate heat, tighten the tea strips, and recover the tea juice. Deblocking with a deblocking machine after the rolling is finished; rolling until the withered leaves are tightly rolled, fully rolling out the tea juice without loss, partially turning red leaves, giving out stronger faint scent, and ensuring that the cell destruction rate reaches 78-85% and the strip forming rate reaches more than 95%.

4. Fermentation of

And (3) uniformly spreading the rolled leaves treated in the step (3) (the thickness of the spread leaves is 4-5 cm), and then putting the leaves into a fermentation chamber for fermentation. The fermentation is carried out according to the conditions of high temperature, high humidity and low temperature, the size of the fermentation chamber is moderate, and the fermentation chamber is clean and sanitary and has no peculiar smell. The window faces north and is 1 to 1.5 meters away from the ground, so that ventilation is facilitated and direct sunlight is avoided; when the temperature is high and the humidity is high, the temperature is 35 ℃, the humidity is more than 95%, and the fermentation time is 1h; when the temperature is low and the humidity is high, the temperature is 28 ℃, the humidity is more than 95 percent, and the fermentation time in spring is 3-4 h; the fermentation in spring requires that the color of the leaves is moderate when the leaves are yellowish red. Fermenting until the color of the tender leaves is red and uniform, the flower fragrance or the fruit fragrance is balanced, and when the temperature of the leaves reaches the peak, the fermentation is proper. The three changes are identical and are all based on the oxidation of polyphenols. The fermentation is proper and should be determined by combining the change degrees of the three. Related experiments show that the temperature-variable fermentation is beneficial to the formation and accumulation of theaflavin and improves the quality of black tea.

5. Drying

5.1 gross fire: drying the fermented tea leaves by using a gross fire until the water content of the tea leaves is 20-25%, wherein the gross fire needs to be dried at high temperature and quickly, and the tea leaves are dried by using a 50-type electric heating roller enzyme deactivating machine at 210 ℃ and above 80 ℃ in a rolling way, so that the method has the advantages of short time, quick dehydration, tight strip shape and high fragrance, and the gross fire leaves are dried up to 7 and 8, and the tea leaves are basically dry and hard, have soft stems and feel harsh and soft when being held by hands;

5.2 foot fire: after the coarse fire drying is finished, quickly cooling the tea leaves in a spreading cooling tank, uniformly spreading the tea leaves with the thickness of 3-5 cm, cooling to room temperature, continuously spreading for cooling and moisture regaining for 50min, and then drying with full fire, wherein when the tea leaves are dried with full fire, a five-bucket dryer is used, the temperature is 95 ℃, the thickness of the spread tea leaves is 2-3 cm, and the tea leaves are dried at low temperature, thickly spread and slowly dried; drying with strong fire until the water content of the tea leaves is 6-7%, specifically, kneading the tea strips into powder by hand, and breaking the tea stalks;

5.3, spreading for cooling: and after the drying with sufficient fire is finished, quickly cooling the tea leaves in a spreading cooling tank, uniformly spreading the tea leaves with the thickness of 4-6 cm, cooling the tea leaves to room temperature, and continuously spreading the tea leaves for moisture regaining for 30min to obtain the dried leaves.

6. And (3) fragrance extraction: and (3) adopting a fragrance extracting machine to extract fragrance from the dried leaves, wherein the fragrance extracting temperature is 85 ℃, the leaf spreading thickness is 2-3 cm, and the time is 60-90 min. Drying until the water content is 4-5%, specifically, breaking the stems, namely crushing, slightly twisting the tea strips into powder to obtain the diced bay black tea, wherein the main raw materials are one bud and one leaf and are marked as first-grade diced bay black tea.

Example 2

The method is the same as the embodiment 1, and is characterized in that one bud and two leaves are mainly picked in the step 1 (the bud and two leaves account for more than 90%), old leaves, old stems, purple bud leaves, disease and pest leaves and other impurities are not picked, and bamboo strip products such as bamboo baskets, bamboo baskets and the like are used for picking fresh leaves for storage; the fresh leaves are subject to graded inspection, acceptance, management and secondary processing, and the finally obtained black tea with sweet osmanthus and cassia leaves is marked as second-grade black tea with one bud and two leaves as main raw materials.

The difference from example 1 is that the kneading was carried out in accordance with the principle of air kneading, first light kneading, heavy kneading and second light kneading, and the kneading time was 45min, 15min and 15min.

Comparative example 1

The same raw materials of the tea of example 1 were processed by a conventional black tea processing method, except that withering, room temperature fermentation and one-time drying were sequentially performed, and the processed black tea was used as a control 1.

Comparative example 2

The same as example 1 except that natural withering was used for the withering, the resultant black tea was prepared as a control 2.

Comparative example 3

As in example 1, except that solar withering was used for the withering, the resulting black cinnamon leaf tea was prepared as a control product 3.

Comparative example 4

The same as example 1 except that withering was carried out using a witherer and withering trough, the resultant black tea was prepared as a control product 4.

Comparative example 5

The difference from example 1 is that the fermentation is carried out at room temperature, the temperature is 30 ℃, the fermentation time is 4h, and the humidity is more than 95%, and the product is used as a control product 5.

Test example 1

1. The products of examples 1 to 2 and comparative examples 1 to 5 were subjected to sensory evaluation, wherein the sensory evaluation criteria are as shown in table 1 below, and the evaluation results are as shown in table 2 below.

TABLE 1 sensory evaluation index of Black tea

TABLE 2 sensory evaluation results

Product(s)	Scoring
		First-grade diced cinnamon black tea	95.6
Second grade black tea with diced cinnamon	90.1
		Control product 1	88.6
Control product 2	91.2
		Control product 3	90.2
Control product 4	90.8
		Control product 5	91.7

According to the table 2, the sensory evaluation scores of the Guiding black tea prepared by the method are obviously higher than those of a control, and the sensory evaluation scores of the Guiding black tea prepared by variable-temperature fermentation are obviously higher than those of the Guiding black tea prepared by normal-temperature fermentation.

The products of examples 1 to 2 and comparative examples 1 to 5 were sent to the key laboratory of the department of tea education of Hunan agricultural university for major quality component examination in 5 months of 2017, and the results are shown in Table 3.

TABLE 3 measurement results of main quality component

As can be seen from Table 3, the total amount of theaflavin in the Guiding black tea prepared by the method is high and is obviously superior to that in the famous black tea in Hunan province (the theaflavin content is about 0.2-0.3%).

The mass spectrum total ion flow chart of the sample is shown in figures 1 and 2 after GC-MS analysis by detecting the examples 1-2 in 5 months in 2017 in an important laboratory of the department of tea education of Hunan agriculture university, wherein figure 1 is first-grade Guiding black tea of example 1; figure 2 is example 2 second grade Guiding black tea.

According to the figures 1 and 2, the black tea of the broadleaf holly leaf obtained by the preparation method disclosed by the invention has the fragrance and sweet fragrance of being mixed, the main fragrance substances are as high as 105, the highest content of the main fragrance substances is nerol, and the substances have the rose sweet fragrance, wherein the nerol in the first-level broadleaf holly leaf accounts for 35.45% of the total fragrance substances, and the nerol in the second-level broadleaf holly leaf tea accounts for 33.65% of the total fragrance substances; secondly, linalool and linalool oxide have the fragrance of lilac, lily of the valley and roses and the fragrance of costustoot and fruit, wherein linalool and linalool oxide in the first-level black tea of the cinnamomum japonicum account for 20.30 percent of the total fragrance substances, and linalool oxide in the second-level black tea of the cinnamomum japonicum account for 18.67 percent of the total fragrance substances; in addition, the fragrance substances with content of more than 2% in the first and second grade black tea include trans-2-hexenal (with grass smell), phenylacetaldehyde (with sweet fragrance of fruit), methyl salicylate (with herbal fragrance of wintergreen oil), and hexanal (with grass smell and apple fragrance). All the aroma substances have the highest alcohol content, mainly nerol, linalool and oxides thereof, and have the greatest contribution to the formation of the black tea aroma.

Although the present invention has been described in detail with reference to the above embodiments, it is only a part of the embodiments of the present invention, not all of the embodiments, and other embodiments can be obtained without inventive step according to the embodiments, and the embodiments are within the scope of the present invention.

Claims (10)

1. A composite withering method is characterized by comprising natural withering, sunlight withering and withering in a withering trough in sequence.

2. The composite withering method as claimed in claim 1, wherein the natural withering time is 8-18 h, the temperature is 20-24 ℃, and the relative humidity is 60-70%;

the sunlight withering time is 1-2 h;

the withering time of the withering trough is 2-4 h, the air quantity is 16000-20000 cubic meters per hour, the temperature is 35-38 ℃, and the spread leaf thickness is 18-20 cm; and stopping ventilation and shaking for 1 time every 1h in the withering process of the withering trough.

3. The processing method of the diced black tea is characterized by comprising the following steps of:

withering fresh tea leaves of the Guiding tea by using the composite withering method as claimed in claim 1 or 2 to obtain withered leaves;

and sequentially carrying out rolling treatment, fermentation treatment, drying treatment and aroma raising treatment on the withered leaves to obtain the diced black tea.

4. The processing method as claimed in claim 3, wherein the tender degree of the fresh tea leaves of the cinnamon leaves is one bud and one leaf or two buds and one leaf; the water content of the withered tea is 60-64%, and the weight loss rate of the fresh tea leaves of the sweet-scented osmanthus tea is 31-38%.

5. The process according to claim 3, characterized in that the total time of the rolling treatment is 60 to 90 mm, the temperature is 20 to 24 ℃, and the relative humidity is 80 to 90%;

the twisting treatment is carried out in sequence of empty kneading, first light kneading, heavy kneading and second light kneading; the time for the air kneading, the first light kneading, the heavy kneading and the second light kneading is 30-45 min, 10-15 min and 10-15 min in sequence.

6. The process of claim 3, wherein the fermentation treatment is a temperature swing fermentation comprising a first fermentation and a second fermentation;

the temperature of the first fermentation is 35 ℃, the fermentation time is 1h, and the humidity is more than 95 percent; the temperature of the second fermentation is 28 ℃, the time is 2-3 h, and the humidity is more than 95%.

7. The process of claim 3, wherein the drying treatment comprises a flash drying and a full drying;

the temperature for drying by gross fire is 200-225 ℃, and the temperature for drying by full fire is 95-105 ℃.

8. The process of claim 7, further comprising, after said flash drying: spreading for cooling for 50-60 min, drying with strong fire, spreading for cooling and moisture regaining for 30-40min, and flavoring.

9. The processing method according to claim 3, wherein the temperature of the aroma raising treatment is 80-90 ℃ and the aroma raising time is 60-90 min.

10. The processed black tea of any one of claims 3 to 8, wherein the black tea comprises nerol, linalool and linalool oxide, wherein the nerol accounts for 33.65% to 35.45% of the total aroma, and linalool oxide account for 18.67% to 20.30% of the total aroma.

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