A processing method for black tea

Abstract

The present invention relates to the technical field of tea processing, and particularly to a black tea processing method for improving the color, aroma and taste quality of black tea. The method comprises the following steps: S1, withering; S2, vibration: placing the withered leaves in a vibration trough for transmission and vibration to obtain cooled leaves; S3, rolling; S4, fermentation; S5, primary drying; S6, fermentation conversion: placing the tea leaves after primary drying in step S5 in a fermentation room for fermentation conversion to obtain fermented-converted leaves; S7, final drying. On the basis of the existing processes of withering, rolling, fermentation, primary drying, re-drying, etc. for making black tea, on the one hand, the present invention introduces a flow trough vibration process, which accelerates the conversion of aroma precursor substances and at the same time reduces the excessive mechanical damage to leaves caused by the traditional shaking process. On the other hand, this method adopts a fermentation conversion process after the primary drying of black tea to synthesize polyesters of catechins, theaflavins and thearubigins, further improving the taste and soup color quality of black tea.

Description

Technical Field

[0001] The present invention relates to the technical field of tea processing, and in particular to a black tea processing method for improving the color, aroma and taste quality of black tea. Background Art

[0002] Most black teas are processed from fresh leaves in summer or autumn. Due to the relatively high content of tea polyphenols and low content of amino acids in the fresh leaf raw materials of summer and autumn teas, and the limitations of traditional black tea processing techniques, the processed black teas generally have quality defects such as strong bitter taste, greenish color, cloudy soup color, and lack of characteristic aroma, which seriously affect the market expansion of tea. Innovating traditional black tea processing techniques and improving the color, taste and aroma quality of black tea are the keys to the development of black tea. Currently, the main measures to improve the color, aroma and taste quality of black tea are as follows: [[ID=!0]]

[0003] (1) Improve the traditional black tea processing technology. Improving the traditional black tea processing technology involves optimizing key steps such as withering, rolling, fermentation, and drying. Research by Zhang Xianglin et al. shows that the use of hot air withering technology can significantly increase the content of volatile compounds and catechins in black tea. Wu Zhuanrong et al. effectively reduced the green smell of tea leaves and enhanced the sweet and fruity aroma by extending the sunlight withering time. Zhu Hongkai et al. used low-temperature rolling (20°C ± 2°C), which increased the amino acid content, reduced the loss of tea polyphenols and caffeine, increased the theaflavin content, and enhanced the freshness and aroma quality of the tea soup. During the fermentation process, time, temperature, humidity, and oxygen ventilation are key quality influencing factors. Xie Nianci et al. found that fermenting Baojing Huangjincha No. 1 at 28°C for 2 hours first and then reducing the temperature to 22°C and continuing fermentation for 1 hour can significantly improve the floral aroma of black tea. Research by Pan Ke et al. pointed out that oxygen ventilation fermentation can better improve the aroma, taste, soup color and brightness of the leaf bottom of black tea than natural fermentation.

[0004] (2) Introduce the processing techniques of other tea categories. Qing-making is the core process of oolong tea processing, including processes such as sunning, shaking, and static spreading, which are carried out alternately. Its essence is to damage the edges of the leaves through physical means, thereby promoting the transformation of internal chemical substances in the tea leaves, especially the oxidation of phenolic compounds, which helps the formation and transformation of aroma components. For example, Liu Shujuan et al. applied the Qing-making process of oolong tea to black tea processing and found that this method can effectively improve the aroma quality of black tea.

[0005] The prior art CN 112741167 A discloses a processing method for large-leaf fruity black tea, which comprises the following steps: S1, fresh leaves: picking one bud with one leaf or one bud with two leaves from large-leaf tea trees in Yunnan; S2, sun withering; S3, indoor natural withering and shaking; S4, rolling; S5, fermentation; and S6, drying. The processing method for large-leaf fruity black tea provided by the invention adds the shaking process of oolong tea to the traditional black tea processing technology. Through multiple shaking processes, the tea leaves are continuously subjected to vibration, friction and collision, thereby accelerating the enzyme-catalyzed oxidation reaction induced thereby. The oxidation products and the conversion products of other internal substances accumulate continuously during the making process, emitting a unique flower and fruit fragrance, forming a fruity black tea with a refreshing flower and fruit fragrance added to the sweet fragrance of traditional Gongfu black tea, which is beneficial to improving the problem of single tea products and enhancing the ability to respond to the market.

[0006] The prior art CN 106343051 A relates to a method for making black tea. It includes five major steps: withering, shaking, rolling, and sun drying, among which the sun drying is divided into three stages. In the black tea made by this invention, the contents of tea polyphenols and caffeine are significantly reduced compared with those in traditional black tea. The oxidation and polymerization of tea polyphenols are more sufficient, and the production amounts of theaflavins, thearubigins, etc. increase, enhancing the pharmacological and health care functions of black tea, while the harm of caffeine to the human body is reduced; during the process of making black tea by this invention, no high temperature is added, and it can be stored for a long time without the components in the black tea changing; the new shaking process is added in the process of making black tea by this invention, which fully enhances the fragrance of the tea leaves, and the fragrance is fresh, mellow, and similar to flower and fruit fragrance.

[0007] However, the above three prior art making processes have obvious defects. In particular, continuous shaking is likely to cause excessive mechanical damage to the tea leaves, which in turn leads to uneven fermentation and affects the leaf color of the final finished tea. During multiple shaking processes, the tea leaves are prone to excessive hydrolysis and oxidation-reduction reactions, resulting in the loss of key aroma components such as linalool, methyl salicylate, and α-ionone, thus directly affecting the quality of the finished tea. In addition, the repeated mechanical action not only increases the labor intensity but also makes it difficult to automate and scale the production process.

[0008] In addition, research shows that after the initial drying by rough firing, polyphenol oxidase and peroxidase in black tea are not completely inactivated, and their activities are reduced to about 8% and 7.5% of that during withering respectively. At the same time, there are also certain residues of internal components such as tea polyphenols and catechins, providing a biochemical basis for further fermentation and transformation. Xia Yimin et al. referred to the "pile fermentation" process of dark tea and carried out post-fermentation treatment on the finished rough tea, and found that this method can significantly reduce the ratio of ester catechins to simple catechins, reduce the bitter and astringent taste, and increase the content of quality components such as theaflavins and thearubigins. In addition, Zhou Qinyu et al. found through research that after the initial drying by rough firing, a 3-hour piling treatment significantly increased the content of theaflavins, fruity alcohols and ketone aroma substances in black tea, improving the soup color, taste and aroma quality of black tea.

[0009] Although the previous measures have improved the internal quality of black tea to a certain extent, they have not fundamentally solved the problems faced by black tea, such as a strong bitter and astringent taste, insufficient aroma, low internal quality, and difficulty in expanding the consumer market. Summary of the Invention

[0010] The present invention provides a new processing method for black tea, enabling black tea to form excellent quality characteristics of bright orange-red soup color, strong fruity and floral aroma, and strong, mellow, fresh and brisk taste during processing, breaking through the problems of color, aroma and taste quality defects of traditional black tea, and effectively alleviating the industrial problem of waste of fresh leaf resources of summer and autumn tea.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] A processing method for black tea, comprising the following steps:

[0013] S1. Withering: Placing the fresh tea leaves in a withering trough for withering to obtain withered leaves;

[0014] S2. Vibration: Placing the withered leaves in a vibration trough for transmission and vibration to obtain cooled leaves;

[0015] S3. Rolling: Rolling the cooled leaves and then loosening the lumps to obtain loosened leaves;

[0016] S4. Fermentation: Placing the loosened leaves in a fermentation chamber at a temperature of 25°C - 28°C and a humidity of 90% - 95% for fermentation until the leaf color of more than 85% of the leaves turns red-yellow;

[0017] S5. Initial drying: Drying the tea leaves after fermentation in step S4 at 115 - 125°C and then allowing them to stand and cool;

[0018] S6. Fermentation conversion: Placing the tea leaves after initial drying in step S5 in a fermentation room for fermentation conversion to obtain fermented-converted leaves;

[0019] S7. Final drying: Finally drying the fermented-converted leaves at 85 - 95°C until the water content is lower than 7%.

[0020] In one preferred embodiment, the fresh tea leaves are fresh leaves in summer or autumn.

[0021] In one preferred embodiment, the fresh tea leaves are one bud with two leaves of Zhuyeqi.

[0022] In one preferred embodiment, the surface of the withered leaves in step S1 loses luster, the leaf color turns dark green, the leaf texture becomes soft and has a slight fragrance.

[0023] In one preferred embodiment, the temperature of withering in step S1 is 25-27°C and the humidity is 60%-70%.

[0024] In one preferred embodiment, the withering in step S1 is first carried out in a ventilated environment for 30-60 min, and then naturally withered for 8-9 h to obtain withered leaves.

[0025] In one preferred embodiment, the vibrating trough in step S2 is a ZDC-40 type vibrating trough.

[0026] In one preferred embodiment, the process of transmission vibration in step S2 is as follows: the power of vibration is 0.50-0.60 kW, the transmission speed is 0.080-0.090 m / s, after transmission vibration for 65-75 s, it is left standing; repeated several times.

[0027] The transmission vibration is achieved by controlling the acceleration of forward vibration and backward vibration to be different, so that the material on it advances more in the feeding direction and retreats less in the reverse direction, thereby realizing the material transportation.

[0028] The power of vibration determines the amplitude of vibration of the fresh tea leaves. If the power is too large, the degree of damage to the edges of the fresh tea leaves will be too heavy, which is not conducive to retaining the integrity of the finished tea leaves; if the power is too small, the effect of accelerating the conversion of aroma precursor substances cannot be achieved.

[0029] If the transmission time is too long or the transmission speed is too slow, it will cause excessive fermentation of the leaf edges, and the color (darker), aroma (loss of fruity aroma), and taste (more astringent) of black tea will all be affected; if the time is too short or the transmission speed is too fast, the effect of accelerating the conversion of aroma precursor substances cannot be achieved.

[0030] In one preferred embodiment, the process of transmission vibration in step S2 is as follows: the power of vibration is 0.50-0.60 kW, the transmission speed is 0.080-0.090 m / s, after transmission vibration for 65-75 s, it is left standing; repeated 3-6 times.

[0031] In one preferred embodiment, the transmission vibration in step S2 is repeated 4 times.

[0032] In one preferred embodiment, the transmission vibration in step S2 is repeated 5 times.

[0033] If the number of times is too large, that is, the time of transmission vibration is too long, first of all, the leaf edges will be excessively damaged, which is not conducive to retaining the integrity of the leaves. The leaves of the finished tea lose too much water, which is not conducive to the key step of subsequent fermentation. The color (darker), aroma (loss of floral and fruity aroma), and taste (more astringent) of black tea will all be affected.

[0034] In one preferred embodiment, the standing time after the subsequent transmission vibration in step S2 is longer than the standing time after the previous transmission vibration.

[0035] In one preferred embodiment, the process of transmission vibration in step S2 is as follows: stand for 3 - 7 minutes after the first transmission vibration, stand for 8 - 12 minutes after the second transmission vibration, and stand for 13 - 18 minutes after the third transmission vibration.

[0036] The standing time increases successively. During the previous vibration process, the edges of the leaves lose water. When standing, the water in the leaf stalks transfers into the leaves. As the number of vibrations increases, the degree of water loss at the leaf edges becomes more serious, and the standing time increases accordingly, which is conducive to the full transfer of water in the leaf stalks into the leaves.

[0037] In one preferred embodiment, the process of rolling in step S3 is as follows: first roll in a rolling machine at a certain frequency for 40 - 60 minutes, and then perform empty rolling for 3 - 5 minutes; the rolling speed is 40 - 55 r / min.

[0038] In one preferred embodiment, in step S3, first roll at a certain frequency until the cell breakage rate reaches more than 85% and the strip formation rate reaches more than 70%; then perform empty rolling for 3 - 4 minutes.

[0039] In one preferred embodiment, in step S4, the stacking thickness of the fermented tea is 3.5 - 4.5 cm.

[0040] In one preferred embodiment, the fermentation time in step S4 is 1.5 - 2 h.

[0041] In one preferred embodiment, the tea leaves fermented in step S5 are dried at 115 - 125 °C for 10 - 15 s.

[0042] In one preferred embodiment, the temperature of the fermentation conversion in step S6 is 27 - 30 °C, and the humidity is 65% - 70%.

[0043] In one preferred embodiment, the fermentation time in step S6 is 3.5 - 4h.

[0044] In one preferred embodiment, the stacking thickness of the tea leaves during fermentation in step S6 is 5 - 6 cm.

[0045] In one preferred embodiment, when the tea leaves are fully dried in step S7, the spreading thickness of the tea leaves is 1 - 2 cm.

[0046] In one preferred embodiment, the full drying time in step S7 is 50 - 80 min.

[0047] Aiming at the quality defects of black tea processed by traditional processes, such as generally heavy bitter taste, partial greenness, turbid soup color, insufficient aroma, etc., and the industrial development bottleneck problems caused by this, such as limited market expansion of black tea, serious abandonment of fresh summer and autumn tea leaves, and low utilization rate, the present invention innovatively introduces a chute vibration and fermentation process at specific time nodes to provide a processing method for improving the color, aroma and taste quality of black tea.

[0048] Based on the existing processes of withering, rolling, fermenting, primary drying, re-drying, etc. for making black tea, on the one hand, the chute vibration process is introduced. By precisely adjusting the frequency and amplitude of the chute vibration, uniform and gentle vibration of the fresh tea leaves is achieved, accelerating the conversion of aroma precursor substances, stimulating floral and fruity aroma substances such as geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethyl alcohol, etc., and at the same time reducing the excessive mechanical damage to the leaves caused by the traditional shaking process. On the other hand, in this method, a fermentation process is adopted after the primary drying of black tea. The black tea after primary drying is stacked in an oxygen-permeable environment, and the activity of polyphenol oxidase that has not been completely inactivated is used to continue enzymatic fermentation to synthesize polyesters of catechins, theaflavins and thearubigins, further improving the taste and soup color quality of black tea. Through processes such as withering, chute vibration, rolling, fermenting, primary drying, fermentation, full drying, etc., the present invention improves the color, aroma and taste quality of black tea, and the prepared black tea has an orange-red and bright color, a strong floral and fruity aroma, and a strong, mellow, fresh and refreshing taste.

[0049] Compared with the prior art, the advantages of the present invention are as follows:

[0050] 1. The innovation of the present invention is to introduce the chute vibration process before rolling. Compared with the traditional green-making process, this process has the following advantages: (1) Precisely adjust the vibration frequency and amplitude to achieve uniform and gentle vibration, reducing excessive damage to the leaves. (2) Low-frequency vibration accelerates the collision between enzymes and substrates, promotes the dynamic change of enzyme conformation, and improves the catalytic efficiency. (3) Compared with the green-making method with intense friction, the chute vibration generates a small amount of local heat, avoiding overheating problems and maintaining a temperature suitable for enzyme activity. (4) The chute vibration evenly distributes the tea leaves, increases the oxygen contact area and gas exchange efficiency, and accelerates the oxidation-reduction reaction. This process stimulates the precursor substances conducive to the production of floral and fruity aromas, while maintaining the integrity of the leaves, improving the processing efficiency and quality consistency. Introducing the chute vibration process before rolling will cause faster water loss, increase the strip-forming rate of rolling, reduce the rolling time, improve the uniformity of fermentation, and shorten the fermentation time.

[0051] 2. Based on the traditional black tea processing technology, the present invention innovatively introduces the fermentation conversion process before the full-drying step. By making full use of the polyphenol oxidase activity that has not been completely inactivated in the tea leaves after the first drying, under the conditions of the heat and humidity generated by the tea leaves themselves, it promotes the further transformation of the substances contained in the tea leaves. This not only increases the content of key taste substances such as water extract, tea polyphenols, amino acids, caffeine, and soluble sugars in the tea leaves, but also reduces the ratio of ester-type catechins to total catechins, alleviating the bitterness and astringency of black tea. In addition, the fermentation conversion process promotes the formation of key quality components such as polyesters and theaflavins in black tea, improving the color quality of the tea soup.

[0052] 3. Aiming at the limitations of the current black tea processing technology level, this method introduces two innovative processes of chute vibration and fermentation conversion. The black tea produced has an orange-red and bright color, a rich floral and fruity aroma, and a strong, mellow, fresh, and refreshing taste, comprehensively improving the color, aroma, and taste quality of black tea. It not only has good social and economic benefits, but also is convenient to operate, suitable for large-scale production, and has a low processing cost. Description of the Drawings

[0053] Figure 1 It is a comparison chart of the relative contents of the main aroma substances of the product of the present invention and the product of the traditional process; different lowercase letters represent the results of multiple comparisons of each group. The same letter indicates no significant difference, and different letters indicate a significant difference (P < 0.05). Detailed Embodiments

[0054] The present invention is not limited to the following specific embodiments. Those of ordinary skill in the art can implement the present invention in many other specific embodiments according to the content disclosed in the present invention. Or, any simple changes or modifications made by adopting the design structure and concept of the present invention fall within the protection scope of the present invention. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The vibration trough used in the experiment is the ZDC-40 type vibration trough of Zhejiang Zhufeng Machinery Co., Ltd.

[0055] Example 1

[0056] Place the fresh leaves of one bud and two leaves of Zhuyeqi in summer on an LCWD-5 type withering trough, blow and wither at a relative humidity of 60% and a room temperature of 26°C for 40 minutes, and then naturally wither at room temperature for 8.5 hours until the leaf color changes from bright green to dark green, the leaf texture is soft and there is a slight fragrance; spread the above withered leaves thinly in a ZDC-40 type vibration trough, set the vibration intensity to 0.55 kW, the vibration time to 70 seconds, and the tea leaves pass through the vibration trough at a speed of 0.085 m / s. After completion, let it stand for 5 minutes. The vibration conditions for the second and third times are the same. The tea leaves are left standing at room temperature for 10 minutes and 15 minutes respectively and then spread out to cool; use a 6CR-Z55 type rolling machine at 48 r / min to roll for 50 minutes at 20-22°C. After that, the tea leaf strip formation rate is over 70%, and the cell breakage rate reaches over 85%. After empty rolling for 3 minutes, use a 6CJW-50 type lump breaker to break the lumps; stack the broken leaves at a thickness of 4 cm in an intelligent fermentation room and ferment for 1.5 hours at a fermentation temperature of 25-26°C and a relative humidity of 90-95% until the grassy smell of the fermented leaves disappears and a fresh and strong fruity and floral fragrance appears. Dry the above fermented leaves in a 4-72A centrifugal ventilator at an inlet air temperature of 120°C for 10 s; stack the above preliminarily dried leaves in an intelligent fermentation room for fermentation conversion, with the leaf stack thickness of 5 cm, the temperature of 27°C - 30°C, and the humidity of 65% - 70%; bake the above fermented leaves in a 6CHZ-9B type tea baking machine at 88-89°C until the tea leaves can be ground into powder by hand, with a water content of about 6%, take them out, spread them out to cool to room temperature, and then store them sealed.

[0057] After sensory evaluation, the obtained black tea has tightly wound and knotted tea leaves, a relatively moist black color, bright orange-red soup, a strong fruity and floral aroma, a mellow taste, and bright and even red tea leaves at the bottom. Through the determination of the color of the tea soup, the lightness (L* value) and red-green degree (a* value) of the black tea soup (100 °C) have increased significantly (P < 0.05); through the analysis of the taste quality components, the contents of water extract, tea polyphenols, amino acids, caffeine, and soluble sugars in the obtained black tea soup have increased significantly by 14.17%, 43.19%, 7.84%, 30.18%, and 32.76% respectively (P < 0.05); through HPLC detection and analysis, the ratio of ester catechins to total catechins in the obtained black tea has decreased significantly (P < 0.05), and the contents of theaflavins and polyesters of catechins have increased significantly by 83.33% and 67.56% respectively (P < 0.05); through GC-MS detection, a total of 228 aroma substances have been detected in the finished tea sample, including 17 alcohols, 24 aromatic hydrocarbons, 16 phenols, 26 aldehydes, 8 acids, 23 terpenes, 18 ketones, 35 alkanes, 5 alkenes, 14 heterocyclic compounds, and 42 esters. Among the aroma quality components of the obtained black tea, the contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethyl alcohol, benzaldehyde, trans-β-ionone, nonanal, and cis-3-hexenyl-α-methylbutyrate with fruity and floral aromas are 13.12%, 12.69%, 12.61%, 6.29%, 3.25%, 2.23%, 3.09%, 1.51%, and 1.16% respectively, and new fruity and floral aroma components such as 2,4-di-tert-butylphenol, epoxy linalool (furan type), decanal, and nonanol have been generated.

[0058] Example 2

[0059] Fresh leaves of one bud and two leaves of Zhuyeqi in autumn were selected as raw materials.

[0060] Place the fresh leaves of one bud and two leaves of Zhuyeqi in autumn in an LCWD-5 type withering trough, with a relative humidity of 60%, a room temperature of 27°C, and blow withering for 40 minutes. Then, let it wither naturally at room temperature for 8 hours until the leaf color changes from bright green to dark green, the leaf texture becomes soft and has a slight fragrance. Spread the above withered leaves thinly on a ZDC-40 type vibrating trough, set the vibration intensity to 0.50 kW, the vibration time to 75 seconds, and let the tea leaves pass through the vibrating trough at a speed of 0.085 m / s. After completion, let it stand for 5 minutes. The second and third vibration conditions are the same, and the tea leaves are left to stand at room temperature for 10 minutes and 15 minutes respectively and then spread out to cool. Use a 6CR-Z55 type rolling machine at 48 r / min to roll for 50 minutes at 20-22°C. After that, the strip formation rate of the tea leaves is over 70%, and the cell breakage rate reaches over 85%. After empty rolling for 3 minutes, use a 6CJW-50 type lump breaker to break the lumps. Stack the lump-broken leaves with a thickness of 4 cm in an intelligent fermentation room and ferment for 1.5 hours at a fermentation temperature of 25-26°C and a relative humidity of 90-95% until the grassy smell of the fermented leaves disappears and a fresh, strong floral and fruity fragrance appears. Dry the above fermented leaves in a 4-72A type centrifugal ventilator at an inlet temperature of 120°C for 10 s. Stack the above preliminarily dried leaves in an intelligent fermentation room for fermentation conversion, with a stack leaf thickness of 5 cm, a temperature of 26°C-30°C, and a humidity of 65%-70%. Bake the above fermented leaves in a 6CHZ-9B type tea roasting machine at 89-90°C until the tea leaves can be ground into powder by hand, with a water content of about 6%. Take them out, spread them out to cool to room temperature, and then store them sealed.

[0061] After sensory evaluation, the obtained black tea has tightly rolled leaves, a relatively moist black color, an orange-red and bright soup color, a strong floral and fruity aroma, a mellow taste, and a uniformly red and bright leaf bottom. Through the determination of the soup color of the tea, the lightness (L* value) and red-green degree (a* value) of the black tea soup (100 °C) were significantly increased (P<0.05); through the analysis of the taste quality components, the contents of water extract, tea polyphenols, amino acids, caffeine, and soluble sugars in the obtained black tea soup were significantly increased by 20.63%, 13.16%, 7.56%, 31.64%, and 32.76% respectively (P<0.05); through HPLC detection and analysis, the ratio of ester catechins to total catechins in the obtained black tea was significantly decreased (P<0.05), and the contents of theaflavins and polyesters of catechins were significantly increased by 83.33% and 51.35% respectively (P<0.05); through GC-MS detection, a total of 225 aroma substances were detected in the finished tea sample, including 17 alcohols, 24 aromatic hydrocarbons, 16 phenols, 26 aldehydes, 7 acids, 22 terpenes, 18 ketones, 34 alkanes, 5 alkenes, 14 heterocyclic compounds, and 42 esters. The contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenethyl alcohol, benzaldehyde, trans-β-ionone, nonanal, and cis-3-hexenyl-α-methylbutyrate with floral and fruity aromas in the aroma quality components of the obtained black tea were 13.07%, 13.10%, 12.34%, 6.35%, 3.26%, 2.61%, 2.43%, 1.53%, and 1.06% respectively, and new floral and fruity aroma components such as 2,4-di-tert-butylphenol, epoxy linalool (furan type), decanal, and nonanol were generated.

[0062] Example 3

[0063] Choose the fresh leaves of one bud and two leaves of Zhuyeqi in summer as the raw material.

[0064] Place the fresh leaves of one bud and two leaves of Zhuyeqi in summer in an LCWD-5 type withering trough, with a relative humidity of 60%, a room temperature of 26°C, and blow withering for 50 minutes. Then, let it wither naturally at room temperature for 8 hours. The thickness of the withered leaves is 1 - 1.5 cm, until the leaf color changes from bright green to dark green, the leaf texture is soft and there is a slight fragrance; spread the above withered leaves thinly on a ZDC-40 type vibrating trough. Set the vibration intensity to 0.60 kW and the vibration time to 65 seconds. The tea leaves pass through the vibrating trough at a speed of 0.085 m / s. After completion, let it stand for 5 minutes. The vibration conditions for the second and third times are the same. After the tea leaves stand at room temperature for 10 minutes and 15 minutes respectively, they are spread out to cool; use a 6CR-Z55 type rolling machine at 48 r / min to roll for 50 minutes at 20 - 22°C. The strip formation rate of the tea leaves is over 70%, and the cell breakage rate reaches over 85%. After empty rolling for 3 minutes, use a 6CJW-50 type lump breaker to break the lumps; stack the broken leaves at a thickness of 4 cm in an intelligent fermentation room for fermentation for 1.5 hours, with a fermentation temperature of 25 - 26°C and a relative humidity of 90 - 95%, until the grassy smell of the fermented leaves disappears and a fresh, strong fruity and floral fragrance appears. Dry the above fermented leaves in a 4 - 72A type centrifugal ventilator at an inlet temperature of 120°C for 10 s; stack the above preliminarily dried leaves in an intelligent fermentation room for fermentation conversion, with a stack leaf thickness of 5 cm, a temperature of 26°C - 30°C, and a humidity of 65% - 70%; bake the above fermented leaves in a 6CHZ-9B type tea roasting machine at 88 - 89°C until the tea leaves can be ground into powder by hand, with a water content of about 6%. Take it out, spread it out to cool to room temperature, and then store it sealed.

[0065] After sensory evaluation, the obtained black tea has tightly rolled strips, a relatively moist black color, an orange-red and bright soup color, a strong fruity and floral aroma, a mellow taste, and a uniformly red and bright leaf bottom. Through the determination of the soup color of the black tea, the lightness (L* value) and red-green degree (a* value) of the black tea soup (100 °C) are significantly increased (P<0.05); through the analysis of the taste quality components, the contents of water extract, tea polyphenols, amino acids, caffeine, and soluble sugars in the obtained black tea soup are significantly increased by 29.24%, 11.93%, 7.28%, 33.82%, and 22.87% respectively (P<0.05); through HPLC detection and analysis, the ratio of ester catechins to total catechins in the obtained black tea is significantly decreased (P<0.05), and the contents of theaflavins and polyesters of catechins are significantly increased by 61.11% and 59.46% respectively (P<0.05); through GC-MS detection, a total of 226 aroma substances are detected in the finished tea sample, including 17 alcohols, 24 aromatic hydrocarbons, 16 phenols, 26 aldehydes, 7 acids, 23 terpenes, 18 ketones, 34 alkanes, 5 alkenes, 14 heterocyclic compounds, and 42 esters. The contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenethyl alcohol, benzaldehyde, trans-β-ionone, nonanal, and cis-3-hexenyl-α-methylbutyrate with fruity and floral aromas in the aroma quality components of the obtained black tea are 12.66%, 11.68%, 12.71%, 6.42%, 3.31%, 2.67%, 2.69%, 1.68%, and 1.18% respectively, and fruity and floral aroma components such as 2,4-di-tert-butylphenol, epoxy linalool (furan type), decanal, and nonanol are newly generated.

[0066] Comparative Example 1

[0067] Traditional process

[0068] Place the fresh leaves of Zhuyeqi with one bud and two leaves in summer on an LCWD-5 type withering trough, and wither for 8 hours under the conditions of relative humidity of 60%, room temperature of 26°C and good ventilation. The thickness of the withered leaves is 1 - 1.5 cm, until the leaf color changes from bright green to dark green, the leaf texture is soft and has a slight fragrance; roll the above withered leaves at 20 - 22°C with a 6CR-Z55 type rolling machine at 48 r / min for 50 minutes to make the tea into strips, and then empty roll for 3 minutes and use a 6C JW-50 type lump breaker to break the lumps; stack the broken leaves at a thickness of 4 cm in an intelligent fermentation room and ferment for 1.5 hours, with the fermentation temperature of 25 - 26°C and relative humidity of 90 - 95%. Dry the above fermented leaves in a 6CCP-60 type bottle dryer with an inlet air temperature of 100°C for 20 minutes, then take them out and cool to room temperature. Dry the above cooled leaves in a 6CHZ-9B type tea baking machine at 88 - 89°C until the tea can be ground into powder by hand, and the water content is about 6%; cool immediately after drying, seal and store after cooling, take out and cool to room temperature, seal and store after cooling.

[0069] Through sensory evaluation, the obtained black tea has relatively tight and knotted strips, the color is black and still moist, the soup color is red and still bright, the aroma is pure, the taste is still mellow and slightly green, and the leaf bottom is still even, less red and mostly green leaves. Through the determination of the color of the tea soup, the L*, a*, b* values of the black tea soup (100°C) are 83.64, 0.84, 55.28 respectively; through the analysis of the taste quality components, the contents of water extract, tea polyphenols, amino acids, caffeine, and soluble sugar in the obtained black tea soup are 33.35%, 10.14%, 3.57%, 2.75%, 2.93% respectively; through HPLC detection and analysis, the contents of theaflavins and polyesters of catechins in the obtained black tea are 0.18% and 0.37% respectively; through GC-MS detection, a total of 191 aroma substances are detected in the finished tea sample, including 14 alcohols, 19 aromatic hydrocarbons, 14 phenols, 24 aldehydes, 3 acids, 22 terpenes, 14 ketones, 28 alkanes, 5 alkenes, 12 heterocyclic compounds, and 36 esters.

[0070] Compare the performance of the finished products prepared in the examples and comparative examples, and the data are shown as follows. Tables 1 - 5 of the present invention and Figure 1 In it, this product is a black tea product produced according to the method of the present invention. This product 1, this product 2, and this product 3 respectively correspond to the black tea products processed in Example 1, Example 2, and Example 3 in the following specific embodiments, and the traditional product corresponds to the black tea product processed in the traditional process example in the following specific embodiments.

[0071] The sensory quality comparison of black tea (traditional product) processed by traditional technology is shown in Table 1 below. It can be seen from Table 1 that the products of the present invention are significantly superior to traditional black tea products in terms of sensory color, aroma, and taste quality.

[0072] Table 1 Sensory Evaluation Comparison Table

[0073]

[0074] The comparison of the color difference of the tea soup between the finished black tea processed by the method of the present invention (this product) and the black tea processed by the traditional process (traditional product) is shown in Table 2 below. It can be seen from Table 2 that for the three products processed by the method of the present invention, the L* values of the tea soup have increased significantly by 6.27%, 6.75%, and 4.59% respectively (P<0.05), and the a* value has increased from 0.84 to 3.35, 3.27, and 3.98, with significant differences (P<0.05), indicating that the brightness and redness of its tea soup have been significantly enhanced (P<0.05), which is consistent with the sensory evaluation showing that it has an orange-red and bright color, indicating that this method can effectively improve the color quality of the black tea soup.

[0075] Table 2 Comparison of Tea Soup Color Differences

[0076] Processing L* a* b* Traditional product 83.64±0.22 0.84±0.02 55.28±0.23 This product 1 <![CDATA[88.89±0.20 * > <![CDATA[3.35±0.01 * > 53.33±0.38 This product 2 <![CDATA[89.29±0.30 * > <![CDATA[3.27±0.02 * > 55.17±0.20 This product 3 <![CDATA[87.48±0.11 * > <![CDATA[3.98±0.03 * > 53.29±0.23

[0077] Note: The L* value represents brightness. A higher L* value means higher tea soup brightness and stronger light transmittance; the a* value represents red-green degree. The higher the a* value, the redder the tea soup color. The b* value represents yellow-blue degree. The higher the b* value, the yellower the tea soup color. * indicates significant difference compared with the traditional product (P<0.05), the same below.

[0078] For the three finished black teas (this product) processed by the method of the present invention and the black teas (traditional products) processed by the traditional process, the water extracts of the tea samples have increased significantly by 14.17%, 20.63%, and 29.24% respectively (P<0.05); the tea polyphenol contents have increased significantly by 14.03%, 13.16%, and 11.93% respectively (P<0.05); the amino acid contents have increased significantly by 7.84%, 7.56%, and 7.28% respectively (P<0.05); the caffeine contents have increased significantly by 30.18%, 31.64%, and 33.82% respectively (P<0.05); the soluble sugars have also increased significantly by 32.76%, 32.76%, and 22.87% respectively (P<0.05). The above results indicate that this method can significantly improve the taste quality of black tea.

[0079] Table 3 Comparison of Water Extract, Tea Polyphenol, Amino Acid, Caffeine, and Soluble Sugar Contents

[0080] Grouping Water extract (%) Tea polyphenols (%) Amino acids (%) Caffeine (%) Soluble sugar (%) Traditional product 33.35±0.40 16.25±0.06 3.57±0.04 2.75±0.08 2.93±0.06 This product 1 <![CDATA[38.08±0.08 * > <![CDATA[18.53±0.04 * > <![CDATA[3.85±0.02 * > <![CDATA[3.58±0.03 * > <![CDATA[3.89±0.07 * > This product 2 <![CDATA[40.23±0.69 * > <![CDATA[18.39±0.30 * > <![CDATA[3.84±0.03 * > <![CDATA[3.62±0.04 * > <![CDATA[3.89±0.13 * > This product 3 <![CDATA[43.10±0.66 * > <![CDATA[18.19±0.09 * > <![CDATA[3.83±0.03 * > <![CDATA[3.68±0.10 * > <![CDATA[3.60±0.07 * >

[0081] The comparison of the catechin component contents between the finished black tea (this product) processed by the method of the present invention and the black tea (traditional product) processed by the traditional process is shown in Table 4 below. It can be seen from Table 4 that compared with the traditional product, the ratios of ester-type catechins to total catechins in the tea samples of the three products of the method of the present invention are all significantly reduced (P<0.05).

[0082] Comparison of Catechin Component Contents in Table 4

[0083]

[0084] Note: Ester catechins: EGCG, GCG, ECG; simple catechins: EGC, C, EC.

[0085] The comparison of the contents of theaflavins and polyesters of catechins in the finished black tea processed by the method of the present invention (this product) and the black tea processed by the traditional process (traditional product) is shown in Table 5 below. As can be seen from Table 4, the theaflavin contents in the three tea samples of the method of the present invention increased significantly by 83.33%, 83.33%, and 61.11% respectively (P<0.05), and the total amounts of polyester catechins increased significantly by 67.56%, 51.35%, and 59.46% respectively (P<0.05).

[0086] Comparison of the Contents of Theaflavins and Polyester Catechins in Table 5

[0087]

[0088] Note: TFs represents the total amount of theaflavins, which is the sum of the contents of TF1, TF2A, TF2B, and TFDG; TSs represents the total amount of polyester catechins, which is the sum of the contents of TSA, TSB, and TSC.

[0089] The comparison of the relative contents of the main aroma substances in the finished black tea processed by the method of the present invention and the black tea processed by the traditional process is as Figure 1 shown. As can be seen from Figure 1 it, the contents of ketone substances, esters, heterocyclic substances, and phenolic substances in the black tea produced by the method of the present invention are significantly higher than those of the traditional process products (P<0.05).

[0090] Comparison of the Contents of the Main Flower and Fruit Aroma Compounds in Table 6

[0091]

[0092]

[0093] The comparison of the contents of the main floral and fruity aroma compounds in the finished black tea processed by the method of the present invention and the black tea processed by the traditional process is shown in Table 6. It can be seen from Table 6 that the contents of geraniol in the three tea samples processed by the method of the present invention increased significantly by 55.82%, 55.23%, and 50.36% respectively (P<0.05); the contents of methyl salicylate increased significantly by 24.41%, 28.43%, and 14.51% respectively (P<0.05); the contents of phenylacetaldehyde increased significantly by 13.30%, 10.88%, and 14.19% respectively (P<0.05); the contents of linalool increased significantly by 16.70%, 17.81%, and 19.11% respectively (P<0.05); the contents of phenylacetaldehyde increased significantly by 12.85%, 13.19%, and 14.93% respectively (P<0.05); the contents of benzaldehyde increased significantly by 12.06%, 31.16%, and 34.17% respectively (P<0.05); the contents of trans-β-ionone increased significantly by 47.14%, 15.71%, and 28.10% respectively (P<0.05); the contents of nonanal increased significantly by 8.63%, 10.07%, and 20.86% respectively (P<0.05); the contents of cis-3-hexenyl-α-methylbutyrate increased significantly by 36.47%, 24.71%, and 38.82% respectively (P<0.05). In addition, floral and fruity aroma components such as 2,4-di-tert-butylphenol, epoxy linalool (furan type), decanal, and nonanol were newly added to the finished black tea processed by the method of the present invention. The above results indicate that the method of the present invention can effectively improve the aroma quality of black tea and process floral and fruity black tea products.

[0094] Comparative Example 2

[0095] Only the flume vibrates without enzymatic conversion (compared with Example 3)

[0096] Choose fresh leaves of one bud and two leaves of Zhuyeqi in summer as raw materials.

[0097] Place the fresh leaves of one bud with two leaves of Zhuyeqi in summer in an LCWD-5 type withering trough, with a relative humidity of 60%, a room temperature of 26°C, and blow withering for 50 minutes. Then, let it wither naturally at room temperature for 8 hours. The thickness of the withered leaves is 1 - 1.5 cm until the leaf color changes from bright green to dark green, the leaf texture becomes soft and has a slight fragrance; spread the above withered leaves thinly on a ZDC-40 type vibrating trough. Set the vibration intensity to 0.60 kW and the vibration time to 65 seconds. The tea leaves pass through the vibrating trough at a speed of 0.085 m / s. After completion, let it stand for 5 minutes. The second and third vibration conditions are the same. After the tea leaves stand at room temperature for 10 minutes and 15 minutes respectively, they are spread out to cool; use a 6CR-Z55 type rolling machine at 48 r / min to roll for 50 minutes at 20 - 22°C. The strip-forming rate of the tea leaves is over 70%, and the cell breakage rate reaches over 85%. After empty rolling for 3 minutes, use a 6CJW-50 type lump-breaking machine to break the lumps; stack the lump-broken leaves with a thickness of 4 cm in an intelligent fermentation room and ferment for 1.5 hours at a fermentation temperature of 25 - 26°C and a relative humidity of 90 - 95% until the grassy smell of the fermented leaves disappears and a fresh, strong floral and fruity fragrance appears. Dry the above fermented leaves in a 4 - 72A type centrifugal ventilator at an inlet air temperature of 120°C for 10 s; then take it out and spread it out to cool to room temperature. Put the above cooled leaves in a 6CHZ-9B type tea roasting machine and dry at 88 - 89°C until the tea leaves can be ground into powder by hand, with a water content of about 6%; immediately spread it out to cool after drying, seal it for storage after spreading out to cool to room temperature, take it out and spread it out to cool to room temperature, and seal it for storage after spreading out to cool.

[0098] After sensory evaluation, the obtained black tea has relatively tight and knotted strips, a dull blackish color, an orange-red soup color, a pure aroma with a floral fragrance, a mellow and slightly greenish taste, and a relatively uniform, reddish leaf bottom with some green leaves. Compared with the product of the present invention, the tightness of the strips, the moisture of the dry tea color, the richness of the floral and fruity aroma, the mellow degree of the taste, and the evenness of the leaf bottom of this product are all poor. Through the determination of the soup color of the tea, the L*, a*, and b* values of the black tea soup (100 °C) are 85.33, 0.91, and 55.08 respectively. The brightness and red-green degree of its soup color are inferior to those of the finished black tea processed by the methods of Examples 1-3. Through the analysis of the taste quality components, the contents of water extract, tea polyphenols, amino acids, caffeine, and soluble sugars in the obtained black tea soup are 35.83%, 14.14%, 3.77%, 3.02%, and 3.22% respectively; through HPLC detection and analysis, the contents of theaflavins and polyesters of catechins in the obtained black tea are 0.20% and 0.38% respectively; compared with the finished black tea processed by the methods of Examples 1-3, the contents of taste substances such as water extract, tea polyphenols, amino acids, caffeine, soluble sugars, theaflavins, and polyesters of catechins are all significantly reduced (P<0.05), resulting in a poor taste. Through GC-MS detection, a total of 196 aroma substances are detected in the finished tea sample, including 15 alcohols, 20 aromatic hydrocarbons, 15 phenols, 24 aldehydes, 3 acids, 22 terpenes, 14 ketones, 28 alkanes, 7 alkenes, 12 heterocyclic compounds, and 36 esters. The contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenethyl alcohol, benzaldehyde, and trans-β-ionone with floral and fruity aromas in the aroma quality components of the obtained black tea are 10.10%, 10.01%, 7.12%, 3.98%, 3.01%, 2.21%, and 2.48% respectively. Compared with the finished black tea processed by the methods of Examples 1-3, this black tea is slightly lacking in the types of aroma substances, and the contents of each floral and fruity aroma component are significantly reduced (P<0.05), and the overall aroma is inferior to that of the finished black tea processed by the methods of Examples 1-3.

[0099] Comparative Example 3

[0100] No chute vibration, only fermentation rotation (compared with Example 3)

[0101] Choose the fresh leaves of one bud and two leaves of Zhuyeqi in summer as raw materials.

[0102] Place the fresh leaves of one bud with two leaves of Zhuyeqi in summer in an LCWD-5 type withering trough, and conduct blowing withering at a relative humidity of 60% and a room temperature of 26°C for 50 minutes. Then, conduct natural withering at room temperature for 8 hours. The thickness of the withered leaves is 1-1.5 cm until the leaf color changes from bright green to dark green, the leaf texture is soft and has a slight fragrance. After kneading at 48 r / min for 50 minutes with a 6CR-Z55 type rolling machine at 20-22°C, the strip-forming rate of the tea leaves is over 70%, and the cell breakage rate reaches over 85%. After empty kneading for 3 minutes, use a 6CJW-50 type lump-breaking machine to break the lumps. Stack the lump-broken leaves at a thickness of 4 cm in an intelligent fermentation room for 1.5 hours. The fermentation temperature is 25-26°C, and the relative humidity is 90-95% until the grassy smell of the fermented leaves disappears and a fresh, strong floral and fruity fragrance appears. Dry the above fermented leaves in a 4-72A type centrifugal ventilator at an inlet temperature of 120°C for 10 seconds. Stack the above preliminarily dried leaves in an intelligent fermentation room for fermentation conversion. The thickness of the stacked leaves is 4 cm, the temperature is 26°C-30°C, and the humidity is 65%-70%. Bake the above fermented leaves in a 6CHZ-9B type tea roasting machine at 88-89°C until the tea leaves can be ground into powder by hand, with a water content of about 6%. Take them out, cool them to room temperature, and then store them sealed.

[0103] After sensory evaluation, the obtained black tea has relatively tight and knotted strips, a dull blackish color, a slightly dark red soup color, a low and stuffy aroma, a flat taste, and a slightly dark and uniform red leaf bottom. Compared with the products of Examples 1-3, the tightness of the tea strips, the luster of the dry tea color, the richness of the floral and fruity aroma, the alcohol content of the taste, and the brightness of the leaf bottom of this product are all poor. Through the determination of the color of the tea soup, the L*, a*, and b* values of the black tea soup (100 °C) are 80.33, 2.11, and 56.38 respectively. The brightness and red-green degree of its tea soup color are inferior to those of the finished black tea processed by the methods of Examples 1-3. Through the analysis of the taste quality components, the contents of water extract, tea polyphenols, amino acids, caffeine, and soluble sugar in the obtained black tea soup are 38.12%, 16.14%, 3.42%, 2.80%, and 3.41% respectively; through HPLC detection and analysis, the contents of theaflavins and polyesters of catechins in the obtained black tea are 0.31% and 0.52% respectively, and the contents of each taste substance are significantly lower than those of the finished black tea processed by the methods of Examples 1-3 (P<0.05); through GC-MS detection, a total of 190 aroma substances are detected in the finished tea sample, including 14 alcohols, 19 aromatic hydrocarbons, 14 phenols, 24 aldehydes, 3 acids, 22 terpenes, 14 ketones, 27 alkanes, 5 alkenes, 12 heterocyclic compounds, and 36 esters. The contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenethyl alcohol, benzaldehyde, and trans-β-ionone with floral and fruity aromas in the aroma quality components of the obtained black tea are 9.29%, 8.03%, 5.02%, 3.37%, 3.43%, 1.91%, and 2.44% respectively. Compared with the finished black tea processed by the methods of Examples 1-3, this black tea is slightly lacking in the variety of aroma substances, the contents of each floral and fruity aroma component are significantly reduced (P<0.05), and the overall aroma is inferior to that of the finished black tea processed by the methods of Examples 1-3.

[0104] Comparative Example 4

[0105] The vibrating frequency of the launder is relatively low (compared with Example 3)

[0106] Choose the fresh leaves of one bud and two leaves of Zhuyeqi in summer as raw materials.

[0107] Place the fresh leaves of one bud and two leaves of Zhuyeqi in summer in an LCWD-5 type withering trough, with a relative humidity of 60%, a room temperature of 26°C, and blow withering for 50 minutes. Then, let it wither naturally at room temperature for 8 hours. The thickness of the withered leaves is 1 - 1.5 cm until the leaf color changes from bright green to dark green, the leaf texture is soft and has a slightly fragrant smell. Spread the above withered leaves thinly on a ZDC-40 type vibrating trough. Set the vibration intensity to 0.30 kW and the vibration time to 65 seconds. The tea leaves pass through the vibrating trough at a speed of 0.085 m / s, and then let it stand for 5 minutes after completion. The vibration conditions for the second and third times are the same. After the tea leaves stand at room temperature for 10 minutes and 15 minutes respectively, they are spread out to cool. Use a 6CR-Z55 type rolling machine at 48 r / min to roll for 50 minutes at 20 - 22°C. After that, the forming rate of the tea leaves is over 70%, and the cell breakage rate reaches over 85%. After empty rolling for 3 minutes, use a 6CJW-50 type lump breaker to break the lumps. Stack the broken leaves with a thickness of 4 cm in an intelligent fermentation room for fermentation for 1.5 hours at a fermentation temperature of 25 - 26°C and a relative humidity of 90 - 95% until the grassy smell of the fermented leaves disappears and a fresh, strong floral and fruity fragrance appears. Dry the above fermented leaves in a 4 - 72A type centrifugal ventilator at an inlet temperature of 120°C for 10 s. Stack the above preliminarily dried leaves in an intelligent fermentation room for fermentation conversion. The thickness of the stacked leaves is 4 cm, the temperature is 26°C - 30°C, and the humidity is 65% - 70%. Bake the above fermented-converted leaves in a 6CHZ-9B type tea roasting machine at 88 - 89°C until the tea leaves can be ground into powder by hand, with a water content of about 6%. Take them out, spread them out to cool to room temperature, and then store them sealed.

[0108] After sensory evaluation, the obtained black tea has relatively tight and knotted tea strips, a darker and moister color, a brighter red soup color, a pure aroma with fruity and floral scents, a mellow taste, and a uniformly red leaf bottom. Compared with the products of Examples 1-3, the tightness of the tea strips, the moistness of the dry tea color, and the richness of the fruity and floral aromas of this product are poor. Through the determination of the color of the tea soup, the L*, a*, and b* values of the black tea soup (100 °C) are 85.12, 2.21, and 55.43 respectively, and the brightness and red-green degree of its tea soup color are inferior to those of the finished black tea processed by the methods of Examples 1-3. Through the analysis of the taste quality components, the contents of water extract, tea polyphenols, amino acids, caffeine, and soluble sugar in the obtained black tea soup are 35.83%, 17.92%, 3.70%, 3.21%, and 3.50% respectively; through HPLC detection and analysis, the contents of theaflavins and polyesters of catechins in the obtained black tea are 0.30% and 0.52% respectively, and the contents of each taste substance are significantly lower than those of the finished black tea processed by the methods of Examples 1-3 (P<0.05). Through GC-MS detection, a total of 222 aroma substances were detected in the finished tea sample, including 17 alcohols, 22 aromatic hydrocarbons, 16 phenols, 26 aldehydes, 8 acids, 23 terpenes, 18 ketones, 31 alkanes, 5 alkenes, 14 heterocyclic compounds, and 42 esters. The contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethyl alcohol, benzaldehyde, trans-β-ionone, nonanal, and cis-3-hexenyl-α-methylbutyrate with fruity and floral scents in the aroma quality components of the obtained black tea are 9.45%, 10.16%, 9.21%, 4.86%, 3.01%, 1.70%, 2.61%, 0.99%, and 0.51% respectively. Compared with the finished black tea processed by the methods of Examples 1-3, this black tea is slightly insufficient in the types of aroma substances, the contents of each fruity and floral aroma component are significantly reduced (P<0.05), and the overall aroma is not as good as that of the finished black tea processed by the methods of Examples 1-3.

[0109] Comparative Example 5

[0110] The launder vibrates only once - short time (compared with Example 3)

[0111] Choose fresh leaves of one bud and two leaves of Zhuyeqi in summer as raw materials.

[0112] Place the fresh leaves of one bud and two leaves of Zhuyeqi in summer in an LCWD-5 type withering trough, with a relative humidity of 60%, a room temperature of 26°C, and blow withering for 50 minutes. Then, let it wither naturally at room temperature for 8 hours. The thickness of the withered leaves is 1-1.5 cm until the leaf color changes from bright green to dark green, the leaf texture is soft and has a slight fragrance; spread the above withered leaves thinly on a ZDC-40 type vibrating trough. Set the vibration intensity to 0.60 kW and the vibration time to 65 seconds. The tea leaves pass through the vibrating trough at a speed of 0.085 m / s, and then let it stand for 5 minutes after completion. Use a 6CR-Z55 type rolling machine at 48 r / min to roll for 50 minutes at 20-22°C. After that, the forming rate of the tea leaves is over 70%, and the cell breakage rate reaches over 85%. After empty rolling for 3 minutes, use a 6CJW-50 type lump breaker to break the lumps; stack the broken leaves at a thickness of 4 cm in an intelligent fermentation room for fermentation for 1.5 hours, with a fermentation temperature of 25-26°C and a relative humidity of 90-95%, until the grassy smell of the fermented leaves disappears and a fresh and strong fruity fragrance appears. Dry the above fermented leaves in a 4-72A type centrifugal ventilator at an inlet temperature of 120°C for 10 seconds; stack the above initially dried leaves in an intelligent fermentation room for fermentation conversion, with a stack leaf thickness of 4 cm, a temperature of 26°C-30°C, and a humidity of 65%-70%; bake the above fermented leaves in a 6CHZ-9B type tea roasting machine at 88-89°C until the tea leaves can be ground into powder by hand, with a water content of about 6%. Take it out, cool it to room temperature, and then store it sealed.

[0113] Sensory evaluation revealed that the resulting black tea had firm, dark, smooth tea leaves, a bright red tea soup, a pure, floral and fruity aroma, a mellow flavor, and a uniform red tea leaf base. However, compared to the products of Examples 1-3, this product lacked the desired firmness of tea leaves, smoothness of dry tea color, and richness of floral and fruity aroma. Tea soup color measurement revealed that the L*, a*, and b* values of the tea soup (100°C) were 80.02, 2.01, and 55.33, respectively. The tea soup's brightness and red-green hue were inferior to those of the finished black teas processed using the methods of Examples 1-3. Analysis of flavor components revealed that the contents of tea extract, tea polyphenols, amino acids, caffeine, and soluble sugars in the black tea were 38.51%, 16.64%, 3.27%, 2.34%, and 3.28%, respectively. HPLC analysis revealed that theaflavins and polyester catechins in the black tea were 0.32% and 0.49%, respectively. These flavor components were significantly lower than those in the finished black tea processed using the methods of Examples 1-3 (P < 0.05). GC-MS analysis revealed the presence of 192 aroma compounds in the finished tea, including 14 alcohols, 20 aromatic hydrocarbons, 14 phenols, 24 aldehydes, 3 acids, 22 terpenes, 14 ketones, 28 alkanes, 5 alkenes, 12 heterocyclic compounds, and 36 esters. The contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethyl alcohol, benzaldehyde and trans-β-ionone with floral and fruity aroma in the obtained black tea are 10.35%, 9.92%, 9.31%, 5.93%, 4.25%, 2.69% and 3.83%, respectively. Compared with the finished black tea processed by the method of Examples 1-3, the black tea is inferior to the product of the present invention in terms of the types of aroma substances, the content of various floral and fruity aroma components is significantly reduced (P<0.05), and the overall aroma is inferior to the finished black tea processed by the method of Examples 1-3.

[0114] Comparative Example 6

[0115] The launder vibration process sequence is adjusted after fermentation (compared to Example 3)

[0116] Select fresh leaves of Castanopsis chinensis with one bud and two leaves in summer as raw materials.

[0117] Place the fresh leaves of one bud with two leaves of Zhuyeqi in summer in an LCWD-5 type withering trough, blow and wither for 50 minutes at a relative humidity of 60% and a room temperature of 26°C, then naturally wither at room temperature for 8 hours. The thickness of the withered leaves is 1 - 1.5 cm until the leaf color changes from bright green to dark green, the leaf texture becomes soft and has a slight fragrance; use a 6CR-Z55 type rolling machine at 48 r / min to roll for 50 minutes at 20 - 22°C. After that, the strip-forming rate of the tea leaves is over 70%. After empty rolling for 3 minutes, use a 6CJW-50 type lump-breaking machine to break the lumps; Stack the lump-broken leaves at a thickness of 4 cm in an intelligent fermentation room and ferment for 1.5 hours at a fermentation temperature of 25 - 26°C and a relative humidity of 90 - 95% until the grassy smell of the fermented leaves disappears and a fresh, strong floral and fruity fragrance appears. Spread the above-mentioned fermented leaves thinly on a ZDC-40 type vibrating trough. Set the vibration intensity to 0.60 kW and the vibration time to 65 seconds. The tea leaves pass through the vibrating trough at a speed of 0.085 m / s. After completion, let it stand for 5 minutes. The second and third vibration conditions are the same. The tea leaves are left to stand at room temperature for 10 minutes and 15 minutes respectively and then spread out to cool. Dry the above-mentioned cooled leaves in a 4-72A type centrifugal ventilator at an inlet temperature of 120°C for 10 s; Stack the above-mentioned preliminarily dried leaves in an intelligent fermentation room for fermentation conversion. The thickness of the stacked leaves is 4 cm, the temperature is 26°C - 30°C, and the humidity is 65% - 70%; Bake the above-mentioned fermented leaves in a 6CHZ-9B type tea roasting machine at 88 - 89°C until the tea leaves can be ground into powder by hand rolling, with a water content of about 6%. Take out and spread out to cool to room temperature and then store it sealed.

[0118] Sensory evaluation revealed that the tea leaves were less firm, with a dark but moist color, a slightly darker red soup color, a low, dull aroma, a bland flavor, and a slightly darker, uniform red leaf bottom. Compared to the products of Examples 1-3, this product was inferior in terms of tea leaf firmness, smooth dry tea color, rich floral and fruity aroma, mellow flavor, and leaf brightness. Tea soup color measurement revealed that the L*, a*, and b* values of the tea soup (100°C) were 79.81, 2.92, and 56.28, respectively. The tea soup color brightness and red-green hue were inferior to those of the finished black tea processed using the methods of Examples 1-3. The flavor quality component analysis showed that the contents of tea extract, tea polyphenols, amino acids, caffeine, and soluble sugar in the obtained black tea were 37.47%, 16.89%, 3.33%, 2.76%, and 3.50%, respectively. The HPLC analysis showed that the contents of theaflavins and polyester catechins in the obtained black tea were 0.23% and 0.49%, respectively. The contents of various flavor substances were significantly lower than those of the finished black tea processed by the method of Examples 1-3 (P<0.05). The GC-MS analysis showed that a total of 191 aroma substances were detected in the finished tea samples, including 14 alcohols, Aromatic hydrocarbons (19 species), phenols (14 species), aldehydes (24 species), acids (3 species), terpenes (22 species), ketones (14 species), alkanes (27 species), alkenes (5 species), heterocyclic compounds (12 species), and esters (37 species) were analyzed. The contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethyl alcohol, benzaldehyde, and trans-β-ionone, which have floral and fruity aromas, were 8.29%, 9.23%, 11.01%, 4.72%, 2.99%, 1.04%, and 1.98%, respectively. Compared to the finished black tea processed by the method of Examples 1-3, this black tea was slightly deficient in the variety of aroma compounds, with the contents of various floral and fruity aroma components significantly reduced (P<0.05), and the overall aroma was inferior to that of the finished black tea processed by the method of Examples 1-3.

[0119] It should be noted that the above embodiments are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make other variations or modifications based on the above description. It is not possible to enumerate all embodiments here. Any obvious variations or modifications arising from the technical solution of the present invention remain within the scope of protection of the present invention.

Claims

1. A processing method of black tea, characterized in that, The following steps are involved: S1. Withering: placing fresh tea leaves in a withering tank for withering to obtain withered leaves; S2, vibration: placing the withered leaves in a vibration tank to transmit vibration to obtain cooling leaves; S3, rolling: rolling the cooled leaves to de-agglomerate them, thereby obtaining de-agglomerated leaves; S4, fermentation: placing the deblocked leaves in a fermentation room at a temperature of 25°C-28°C and a humidity of 90%-95% for fermentation until more than 85% of the leaves turn reddish-yellow; S5, primary drying: drying the tea leaves fermented in step S4 at 115-125°C, and then letting them stand to cool; S6, fermentation: placing the tea leaves that have been initially dried in step S5 in a fermentation room for fermentation to obtain fermented leaves; S7, Full Drying: Fully dry the fermented leaves at 85-95℃ until the moisture content is less than 7%; The transmission vibration process in step S2 is as follows: the vibration power is 0.50-0.60kW, the transmission speed is 0.080-0.090 m / s, the transmission vibration is 65-75s and then the vibration is allowed to stand; and this is repeated several times; The rest time after the last transmission vibration is longer than the rest time after the first transmission vibration; Transmission vibration is achieved by controlling the acceleration of forward vibration and the acceleration of backward vibration to be different, so that the material on it moves forward more in the feeding direction and moves back less in the reverse direction, thereby realizing material transportation; In step S6, the fermentation temperature is 27-30° C., the humidity is 65%-70%, and the fermentation time is 3.5-4 hours.

2. The processing method according to claim 1, wherein Fresh tea leaves are fresh leaves from summer or autumn.

3. The processing method according to claim 1, characterized in that: The withering temperature in step S1 is 25-27°C and the humidity is 60%-70%. The leaves are first withered in a ventilated environment for 30-60 minutes and then naturally withered for 8-9 hours to obtain withered leaves.

4. The processing method according to claim 1, characterized in that: The process of the transmission vibration in step S2 is: let it stand for 3-7 minutes after the first transmission vibration, let it stand for 8-12 minutes after the second transmission vibration, and let it stand for 13-18 minutes after the third transmission vibration.

5. The processing method according to claim 1, wherein The kneading process in step S3 is: first kneading for 40-60 minutes at a certain frequency in a kneading machine, and then kneading in the air for 3-5 minutes; the kneading frequency is 40-55 r / min.

6. The processing method according to claim 1, characterized in that: In step S4, the fermented tea leaves are piled to a thickness of 3.5-4.5 cm and the fermentation time is 1.5-2 h.

7. The processing method according to claim 1, wherein The fermented tea leaves in step S6 are stacked to a thickness of 5-6 cm.

8. The processing method according to any one of claims 1-7, characterized in that, When the tea leaves are fully dried in step S7, the thickness of the tea leaves is 1-2 cm.

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