Processing method for simultaneously improving flower fragrance concentration and red soup color brightness of congou black tea

Abstract

The invention belongs to the technical field of tea processing, and particularly relates to a processing method for simultaneously improving the flower fragrance concentration and red liquor color brightness of congou black tea. The method comprises the following steps: selecting fresh tea leaf raw materials; performing low-temperature and low-humidity ultraviolet irradiation withering; rolling for a long time for the first time; performing primary long-time fermentation; performing secondary short-time re-rolling; performing short-time low-temperature high-oxygen fermentation for the second time; and drying the tea leaves subjected to the secondary short-time low-temperature high-oxygen fermentation with gross fire and full fire to obtain a medium-and-small-leaf congou black tea product with flower fragrance and high tea pigment. According to the method provided by the invention, a low-temperature low-humidity ultraviolet irradiation withering technology, a re-kneading fermentation technology and a short-time low-temperature high-oxygen fermentation technology are created on the basis of a traditional processing technology of the congou black tea, new technologies are fused into a traditional processing flow of the congou black tea, and the congou black tea is obtained by organically combining the traditional processing technology and the new technologies. Aiming at middle and small leaf tea trees, the invention provides a processing method for simultaneously improving flower fragrance concentration and red liquor color brightness of congou black tea.

Description

Technical Field

[0001] The invention belongs to the technical field of tea processing, and in particular relates to a processing method for simultaneously improving the concentration of floral aroma of Gongfu black tea and the red brightness of tea soup. Background Art

[0002] Black tea is one of the six major types of tea in my country. It has the characteristics of bright red soup color, obvious sweet fragrance, sweet and mellow taste, and is rich in functional ingredients such as theaflavins, thearubigins, amino acids, etc., and is widely loved by consumers. Black tea is divided into Gongfu black tea, Xiaozhong black tea and broken black tea, among which Gongfu black tea is the main type of black tea produced in my country. According to the size of the leaves of the tea tree varieties, Gongfu black tea can be divided into large-leaf Gongfu black tea and medium-small-leaf Gongfu black tea; among them, large-leaf Gongfu black tea refers to Gongfu black tea made from large-leaf tea trees with mature leaves of more than 10cm in length and more than 4cm in width, and medium-small-leaf Gongfu black tea refers to Gongfu black tea made from medium-small-leaf tea trees with mature leaves of less than 10cm in length and 3cm to 4cm in width.

[0003] The traditional processing technology of Gongfu black tea includes withering, rolling, fermentation, rough fire drying and full fire drying. Among them, withering and fermentation have a greater impact on the aroma and soup color of Gongfu black tea. The conventional withering method of Gongfu black tea is natural withering indoors, which cannot induce the tea leaves to produce floral fragrance. The conventional fermentation method of Gongfu black tea is to put the tea leaves in a fermentation machine, set the temperature and humidity, and ferment continuously until suitable; in this process: the aroma first changes from green to floral, and finally to sweet, and the concentration of floral fragrance shows a change pattern of first increasing and then decreasing; the content of theaflavins and thearubigins also increases first and then decreases; ultimately resulting in the lack of floral fragrance of Gongfu black tea and insufficient red soup color brightness.

[0004] When using traditional technology to produce large-leafed Gongfu black tea, because the fresh leaves of large-leafed tea trees have a high content of polyphenols, high oxidase activity, and rich aroma precursors, it is easier to produce floral fragrance, and the soup color is bright red, and the quality is good; while when using traditional technology to produce small- and medium-leafed Gongfu black tea, because the fresh leaves of small- and medium-leafed tea trees have a low content of polyphenols, low oxidase activity, and fewer aroma precursors, the aroma is often mainly sweet, with less floral fragrance, and the content of theaflavins and thearubigins is low, and the soup color is not bright red. With the continuous upgrading of the black tea consumption market, consumers have higher and higher requirements for the aroma, soup color and other qualities of black tea. More and more people prefer to drink Gongfu black tea with floral fragrance and bright red soup color, but the floral fragrance concentration and red brightness of the small- and medium-leafed Gongfu black tea produced by traditional technology at this stage cannot meet the needs of the majority of consumers. Therefore, if a processing method can be developed for small and medium-leaf tea trees that can simultaneously increase the floral aroma concentration and the content of theaflavins and thearubigins in small and medium-leaf Gongfu black tea, it will greatly increase the floral aroma concentration and red brightness of the small and medium-leaf Gongfu black tea, improve its market competitiveness, and increase economic benefits. Summary of the invention

[0005] In order to solve the technical problem that the flower aroma concentration and red soup brightness of small-leaf Gongfu black tea produced by traditional technology at the current stage in the prior art are difficult to meet the needs of consumers, the present invention provides a processing method for simultaneously improving the flower aroma concentration and red soup brightness of Gongfu black tea.

[0006] To achieve the above purpose, the present invention adopts the following technical solution.

[0007] The present invention provides a processing method for simultaneously improving the concentration of the floral aroma of Gongfu black tea and the brightness of the red tea soup color, comprising the following steps:

[0008] Selection of fresh tea leaf raw materials: Fresh leaves of small and medium-leaf tea trees are used as fresh tea leaf raw materials.

[0009] Low-temperature, low-humidity, ultraviolet irradiation withering: The fresh tea leaf raw materials are withered at a temperature of 12°C to 19°C and an air humidity of 28% to 52%. During the withering period, ultraviolet irradiation treatment is performed, and the fresh tea leaf raw materials are finally withered until the water content of the fresh tea leaf raw materials is between 58% and 62%, thereby obtaining withered tea leaves.

[0010] The first long-time rolling: the withered tea leaves are subjected to the first long-time rolling, the first long-time rolling time is 55min-65min; after the first long-time rolling is completed, the tea leaves subjected to the first long-time rolling are obtained.

[0011] First long fermentation: After the tea leaves are fermented for 2 hours to 2.5 hours, the tea leaves are obtained. The process conditions of the first long fermentation can ensure that the compounds in the tea leaves are basically oxidized to form the basic quality characteristics of Gongfu black tea.

[0012] Second short-term re-kneading: The tea leaves after the first long-term fermentation are subjected to a second short-term re-kneading, and the time of the second short-term re-kneading is 25min to 35min; after the second short-term re-kneading is completed, the tea leaves after the second short-term re-kneading are obtained. The structure of the tea leaves cells is once again fully broken without being over-broken, and the enzyme and substrate are once again fully integrated, laying a good foundation for the next step of short-term low-temperature and high-oxygen fermentation. Short-term re-kneading can also promote protein hydrolysis to form free amino acids and increase the free amino acid content.

[0013] Second short-time low-temperature high-oxygen fermentation: The tea leaves after the second short-time re-rolling are fermented at low temperature and high oxygen for 1 hour to 1.5 hours at a temperature of 21°C to 27°C, a humidity of 89% to 96%, and an oxygen concentration of 29% to 36%, to obtain tea leaves after the second short-time fermentation. Appropriate short-time fermentation is conducive to the retention of floral fragrance, and does not allow theaflavins and thearubigins to be excessively oxidized to form theabrownins, making the tea soup redder and brighter.

[0014] After the tea leaves have been fermented for a second time for a short period of time, they are then dried by rough fire and fully dried to obtain a medium- and small-leaf Gongfu black tea product with a floral aroma and high theaflavins content.

[0015] The present invention provides a processing method for simultaneously improving the floral aroma concentration and the red brightness of Gongfu black tea soup. On the basis of the traditional processing technology of Gongfu black tea, the present invention creates a low-temperature and low-humidity ultraviolet irradiation withering technology, a double kneading fermentation technology and a short-time low-temperature and high-oxygen fermentation technology, and integrates the new technology into the traditional Gongfu black tea processing flow. Through the organic combination of traditional processing technology and new technology, a processing method for simultaneously improving the floral aroma concentration and the red brightness of small and medium-leaf Gongfu black tea soup is provided. The product processed by the method provided by the present invention has the advantages of obvious floral aroma and brighter soup color, which solves the technical problem that the floral aroma concentration and red brightness of small and medium-leaf Gongfu black tea produced by traditional technology at this stage in the prior art are difficult to meet the needs of consumers.

[0016] Preferably, the fresh leaves of the small and medium-leaf tea trees are tender fresh leaves with one bud and two or three leaves.

[0017] Preferably, the low temperature and low humidity withering conditions are: temperature: 13°C to 18°C, air humidity 30% to 50%. Low temperature withering is conducive to the production of floral aroma components in tea leaves, while low air humidity is conducive to accelerated dehydration of tea leaves at low temperatures, so that the withering time is not too long.

[0018] Preferably, the method of ultraviolet irradiation treatment is as follows:

[0019] The fresh tea leaves are first withered for 4 to 6 hours, and then heated with a concentration of 3 μmol / m 2 / s~4μmol / m 2 / s UV-B irradiation for 2h~3h. After the first UV irradiation, turn off the UV lamp, turn over the tea leaves and use it again with an intensity between 3μmol / m 2 / s~4μmol / m 2 / s UV-B irradiation for 2h to 3h. Moderate ultraviolet light is conducive to inducing the formation of aroma components, especially promoting the degradation of carotenoids to form β-ionone, α-ionone, β-damascenone and other floral and fruity aroma components.

[0020] Preferably, the first long-time kneading has a rotation speed of 43 r / min to 48 r / min. ， The kneading is carried out in three stages according to the kneading method with increasing kneading pressure.

[0021] The first stage of rolling is 10-15 minutes; the second stage of rolling is 10-15 minutes; the third stage of rolling is 20-30 minutes; the total rolling time is 55-65 minutes. The above method can ensure that the tea leaves are basically broken, laying a good foundation for long-term fermentation.

[0022] Preferably, the conditions for the first long fermentation are a temperature of 30° C. to 35° C. and a humidity of ≥90%.

[0023] Preferably, the rotation speed of the second short-time repeated kneading is 43 r / min to 48 r / min.

[0024] Preferably, the conditions of low-temperature high-oxygen fermentation are a temperature of 22°C to 26°C, a humidity of 90% to 95%, and an oxygen concentration of 30% to 35%. A higher oxygen concentration can promote the oxidation of polyphenols to form theaflavins and thearubigins, while low-temperature fermentation is conducive to the accumulation of theaflavins and thearubigins; high-oxygen conditions are also conducive to the degradation of carotenoids and amino acids, forming floral aroma components and increasing the floral aroma concentration of tea leaves.

[0025] Preferably, the conditions for the rough fire drying are a temperature of 110° C. to 120° C. and a duration of 25 min to 35 min.

[0026] Preferably, the conditions for the full-fire drying are a temperature of 85°C to 95°C and a duration of 25min to 35min.

[0027] Preferably, the improvement of the red brightness of the Gongfu black tea soup color is achieved by increasing the content of theaflavins and thearubigins by ≥8%.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention provides a processing method for simultaneously improving the concentration of floral aroma and the red brightness of the soup color of Gongfu black tea. Based on the traditional processing technology of Gongfu black tea, the present invention creates low-temperature and low-humidity ultraviolet irradiation withering technology, multiple kneading and fermentation technology, and short-time low-temperature and high-oxygen fermentation technology, and integrates the new technology into the traditional processing flow of Gongfu black tea. Through the organic combination of traditional processing technology and new technology, a processing method for simultaneously improving the concentration of floral aroma and the red brightness of the soup color of small and medium-leaf Gongfu black tea is provided. The method provided by the present invention increases the content of floral and fruity aroma components in tea leaves through low temperature conditions and ultraviolet irradiation, and through two long and short kneading and fermentation, the content of theaflavins and thearubigins is increased, making the soup color redder and brighter, and finally making the processed product have the advantages of obvious floral aroma and brighter soup color, solving the technical problem that the floral aroma concentration and red brightness of the small and medium-leaf Gongfu black tea produced by traditional technology at this stage in the prior art are difficult to meet the needs of consumers.

[0030] 2. The present invention innovatively invented the "low-temperature and low-humidity ultraviolet irradiation withering technology for tea leaves". Both low temperature conditions and ultraviolet irradiation can form abiotic stress on fresh tea leaves, promote the production of tea aroma components, especially increase the content of floral and fruity aroma components in tea leaves, such as linalool, β-ionone, α-ionone, phenylethyl alcohol, β-damascenone, indole, nerolidol, etc., thereby improving the aroma quality of black tea.

[0031] 3. The present invention innovatively invented the "re-kneading fermentation technology", which splits the traditional single kneading fermentation technology into two kneading fermentations, one long and one short. In the traditional single fermentation process, in the late fermentation period, because the substrate around the enzyme is consumed in large quantities, the catalytic efficiency of the enzyme will be significantly reduced, which is not conducive to the accumulation of theaflavins and thearubigins. Compared with the traditional single kneading fermentation, the second short-term kneading of the "re-kneading fermentation technology" in the present invention can more effectively promote the breakage of tea cells and make the breakage effect more uniform; it can promote the recombination of enzymes and substrates, improve the reaction efficiency of polyphenol oxidase and peroxidase, thereby increasing the content of theaflavins and thearubigins, and making the soup color brighter and redder. In the traditional single fermentation process, the aroma first changes from green to floral, and finally to sweet. The concentration of floral aroma shows a change pattern of first increasing and then decreasing. When the fermentation is suitable, the floral aroma basically disappears. The second short-term re-kneading of the "re-kneading fermentation technology" in this patent can make the fermented leaves produce floral aroma again. Combined with the subsequent short-term fermentation, the floral aroma can be retained, and ultimately the black tea product has a distinct floral aroma.

[0032] 4. The present invention innovatively invented the "short-time low-temperature high-oxygen fermentation technology", which is applied to the second fermentation. Low temperature conditions can effectively avoid the rapid transformation of theaflavins and thearubigins to theabrownins under high temperature and high humidity conditions in the late stage of traditional fermentation, and increase the content of theaflavins and thearubigins. Combined with high oxygen conditions, it accelerates the oxidation of polyphenols by polyphenol oxidase and peroxidase to form theaflavins and thearubigins, while promoting the oxidative degradation of carotenoids, amino acids, etc. to form aroma components with floral fragrance, thereby increasing the concentration of floral fragrance and improving the aroma quality of black tea. Combined with short-time fermentation, the floral fragrance of the fermented leaves is retained, and the transformation of theaflavins and thearubigins to theabrownins in the late stage of long-term fermentation is avoided. Ultimately, the floral fragrance concentration of black tea can be effectively increased, the content of theaflavins and thearubigins can be increased, and the quality of the soup color can be improved.

[0033] 5. The "re-kneading fermentation technology" and "short-time low-temperature high-oxygen fermentation technology" adopted in the present invention can effectively promote the conversion of polyphenols and increase the content of free amino acids; polyphenols are an important source of the bitter taste of tea, while amino acids are an important source of the fresh taste of tea; therefore, promoting the oxidation of polyphenols to form theaflavins and thearubigins and increasing the content of free amino acids can also effectively reduce the bitter taste of black tea and improve the taste quality of black tea. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The soup color comparison of the products of Comparative Example 1 and Example 1 of the present invention; wherein, Figure 1 A in the figure is the tea soup of the product of Comparative Example 1; Figure 1 B in the embodiment 1 is the tea soup of the product. DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with the accompanying drawings and specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the following examples are conventional means well known to those skilled in the art, and the materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources.

[0036] The small and medium-leaf tea materials used in the following embodiments include fresh leaves of Ningzhou No. 2, Ningzhou group species and Huang Guanyin, and the grade of the fresh leaves is one bud and two or three leaves.

[0037] Among them, the fresh leaves of Ningzhou No. 2 were picked in the tea garden of Tonggu County Tea Co., Ltd. in Jiangxi Province, and the picking period was April 8, 2022.

[0038] The fresh leaves of the Ningzhou group variety were picked in the tea garden of Tonggu County Tea Co., Ltd. in Jiangxi Province. The picking period was April 8, 2022.

[0039] The fresh leaves of Huang Guanyin were picked in the tea garden of Tonggu County Xianguquan Tea Co., Ltd. on April 10, 2023.

[0040] The embodiments of the present invention use the fresh leaves of the above three varieties as fresh tea leaf raw materials.

[0041] Example 1

[0042] A processing method for simultaneously improving the concentration of Gongfu black tea flower aroma and the brightness of tea soup red, comprising the following steps:

[0043] 1. Selection of fresh tea leaves:

[0044] One bud and two or three leaves of Ningzhou No. 2 variety, totaling 20 kg, were used as the fresh tea leaf raw material of this embodiment.

[0045] 2. Low temperature, low humidity and ultraviolet irradiation withering:

[0046] The thickness of fresh tea leaves is 5cm, the temperature is 15.5±2.5℃, and the air humidity is 40±5%; wither for 5h before using at a strength of 3.4μmol / m 2 / s UV-B irradiation for 2h. After the first UV irradiation, turn off the UV lamp, turn over the tea leaves and use it again with an intensity of 3.4μmol / m 2 / s UV-B irradiation for 2 hours, and finally withering to the moisture content of the tea leaves of 61.4%, which took a total of 18 hours to obtain the withered tea leaves.

[0047] 3. The first long kneading:

[0048] The withered tea leaves are placed in a rolling machine for the first long rolling, according to the traditional "light-heavy-light" rolling method, with a rolling time of 60 minutes to obtain the tea leaves after the first long rolling.

[0049] Among them, the specific operation of the rolling machine for the first long rolling is as follows:

[0050] A 45-type kneading machine is used, and the speed of the kneading machine is set to 45r / min. The kneading is carried out in three stages according to the kneading method with increasing kneading pressure. The first stage of kneading is light pressure kneading, the second stage of kneading is medium pressure kneading, and the third stage of kneading is heavy pressure kneading. First, light pressure kneading for 10 minutes, medium pressure kneading for 15 minutes, heavy pressure kneading for 20 minutes, and finally light pressure kneading for 15 minutes.

[0051] Among them, light pressure kneading refers to the top surface of the tea leaves in the cover of the kneading barrel dropping to five-sixths of the height of the kneading barrel; medium pressure kneading refers to the top surface of the tea leaves in the cover of the kneading barrel dropping to three-fifths of the height of the kneading barrel; heavy pressure kneading refers to the top surface of the tea leaves in the cover of the kneading barrel dropping to two-fifths of the height of the kneading barrel.

[0052] 4. The first long fermentation:

[0053] The tea leaves after the first long rolling are placed in a fermentation machine and fermented under traditional fermentation conditions for 2 hours to obtain the tea leaves after the first long fermentation.

[0054] Among them, the tea leaves after the first long rolling are spread out to a thickness of 10cm and are turned over once during this fermentation.

[0055] Traditional fermentation conditions are as follows:

[0056] The fermentation temperature was 32°C, the humidity was 95%, and the fermentation time was 2.2 h.

[0057] 5. Second short kneading:

[0058] The tea leaves after the first long fermentation are placed in a rolling machine for a second short-time re-rolling, with the rolling time being about 30 minutes, to obtain the tea leaves after the second short-time re-rolling.

[0059] Among them, the specific operation of the second short-time re-kneading of the rolling machine is as follows:

[0060] A 45-type rolling machine is used, the speed of the rolling machine is set to 48r / min, medium pressure rolling, and the rolling time is 30 minutes. Among them, medium pressure rolling is the same as step 3, which means that the top surface of the tea leaves in the rolling barrel cover drops to three-fifths of the height of the rolling barrel.

[0061] It should be noted that the kneading pressure during the second short-term kneading in the kneading machine should not be too heavy, because too heavy a pressure will cause the tea leaves to break easily after drying.

[0062] 6. Second short-term low-temperature and high-oxygen fermentation:

[0063] The tea leaves after the second short-time re-kneading are placed in a fermentation machine for low-temperature high-oxygen fermentation for 1.2 hours to obtain tea leaves after the second short-time low-temperature high-oxygen fermentation.

[0064] Among them, the thickness of the tea leaves after the second short-term re-kneading is 1.5cm, and they are turned over once in the middle.

[0065] The conditions for low temperature and high oxygen fermentation are as follows:

[0066] The temperature was 25°C, the humidity was 95%, the oxygen concentration was 32%, and the fermentation time was 1.2h.

[0067] 7. Drying:

[0068] The tea leaves after the second short-term low-temperature high-oxygen fermentation are placed in an aroma machine for rough fire drying, and dried until the moisture content of the tea leaves is 20.3%. After discharging, the tea leaves are cooled and spread out for 50 minutes to obtain rough fire dried tea leaves.

[0069] Among them, the thickness of the tea leaves after the second short-term low-temperature and high-oxygen fermentation is 1 cm, the temperature of the raw fire drying is 115°C, and the duration of the raw fire drying is 30 minutes.

[0070] 8. Dryness due to fire:

[0071] The tea leaves after rough fire drying are scented by an aroma machine, and then roasted to a water content of 5.4%. The material is cooled to room temperature to obtain a patented small and medium leaf Gongfu black tea product with floral fragrance and high tea pigment. The patented small and medium leaf Gongfu black tea product with floral fragrance and high tea pigment is a small and medium leaf Gongfu black tea product with floral fragrance and high theaflavins, also referred to as Gongfu black tea product.

[0072] Among them, the thickness of the tea leaves after rough fire drying is 2.5cm, the temperature of full fire drying is 85℃, and the time of full fire drying is 30min.

[0073] Example 2

[0074] A processing method for simultaneously improving the concentration of Gongfu black tea flower aroma and the brightness of tea soup red, comprising the following steps:

[0075] The same as Example 1, the difference is that the fresh tea leaf raw material variety selected in this embodiment is the Ningzhou group variety.

[0076] Example 3

[0077] A processing method for simultaneously improving the concentration of Gongfu black tea flower aroma and the brightness of tea soup red, comprising the following steps:

[0078] The same as Example 1, the difference is that the variety of fresh tea leaves selected as raw material in this embodiment is Huang Guanyin.

[0079] Comparative Example 1

[0080] A traditional black tea processing method comprises the following steps:

[0081] 1. Selection of fresh tea leaves:

[0082] The same batch of fresh leaves as in Example 1 was used, totaling 20 kg.

[0083] 2. Withering:

[0084] Indoor natural withering was used, the fresh tea leaves were spread to a thickness of 5 cm, the withering temperature was 24-30°C, and the final withering time was 20 hours to a moisture content of 61.9%, thereby obtaining withered tea leaves.

[0085] 3. Kneading:

[0086] The withered tea leaves are rolled using a 45-type rolling machine. The specific conditions are as follows:

[0087] The kneading machine rotates at a speed of 45 r / min. First, knead with air pressure for 10 min, then knead with light pressure for 15 min, knead with medium pressure for 15 min, knead with heavy pressure for 40 min, and finally knead with light pressure for 10 min.

[0088] Among them, light pressure rolling, medium pressure rolling and heavy pressure rolling are the same as those in Example 1. Specifically, light pressure rolling means that the top surface of the tea leaves in the rolling barrel cover is lowered to five-sixths of the height of the rolling barrel; medium pressure rolling means that the top surface of the tea leaves in the rolling barrel cover is lowered to three-fifths of the height of the rolling barrel; heavy pressure rolling means that the top surface of the tea leaves in the rolling barrel cover is lowered to two-fifths of the height of the rolling barrel.

[0089] 4. Fermentation:

[0090] The rolled tea leaves are fermented to obtain fermented tea leaves. The specific conditions are as follows:

[0091] The fermentation temperature was 32°C, the humidity was 95%, and the fermentation time was 3.5 hours.

[0092] 5. Drying:

[0093] The fermented tea leaves are dried by rough fire, and then cooled for 50 minutes after being discharged to obtain rough fire dried tea leaves. The specific conditions are as follows:

[0094] The temperature of rough fire drying is 115℃, and the time of rough fire drying is 30 minutes.

[0095] 6. Dryness due to fire:

[0096] The tea leaves after rough fire drying are fully dried to obtain the traditional Gongfu black tea products. The specific conditions are as follows:

[0097] The temperature of full fire drying is 85℃, and the time of full fire drying is 30 minutes.

[0098] The patented Gongfu black tea products (small and medium-leaf Gongfu black tea products with floral fragrance and high tea pigment) prepared in Examples 1 to 3 were compared with the Gongfu black tea products prepared by the traditional technology provided in Comparative Example 1 through sensory evaluation, basic biochemical composition and color difference analysis.

[0099] Among them, the sensory evaluation method is carried out in accordance with the national standard "GBT 23776-2018 Tea Sensory Evaluation Method".

[0100] The basic biochemical components (tea polyphenols, free amino acids, theaflavins, thearubigins and theabrownins) and color difference analysis methods are as follows:

[0101] The determination of tea polyphenols is carried out in accordance with the national standard "GBT 8313-2018 Determination of Tea Polyphenols and Catechins in Tea".

[0102] The determination of free amino acids was carried out in accordance with the national standard "GBT 8314-2013 Determination of the total amount of free amino acids in tea".

[0103] The determination of theaflavins, thearubigins and theabrownins was carried out according to "Experiment 2-11 Determination of the contents of theaflavins, thearubigins and theabrownins in black tea" in "Tea Biochemistry Experimental Course" (ISBN 978-7-109-13781-3).

[0104] The color difference analysis method is as follows: brew tea according to the national standard "GBT 23776-2018 Tea Sensory Evaluation Method", filter the tea residue with a filter while it is hot; after the tea soup (filtrate) cools to room temperature, use a CR-400 portable colorimeter to measure the color difference of the tea soup, using distilled water as a control; repeat the measurement 3 times. Among them, the tea powder here is the powder obtained by crushing the patented Gongfu black tea product (a medium and small leaf Gongfu black tea product with floral fragrance and high tea pigment) prepared in Examples 1 to 3 and the Gongfu black tea product prepared by the traditional technology provided in Comparative Example 1.

[0105] The comparison results are shown in Tables 1 and 2 below.

[0106] Table 1 Comparison of sensory evaluation results

[0107]

[0108]

[0109] As shown in the results of Table 1, the overall quality of the Gongfu black tea products prepared in Examples 1 to 3 of the present invention is superior to that of the black tea products prepared by the traditional technology, mainly in that the Gongfu black tea product prepared in Example 1 has a more obvious floral aroma, a mellower taste, and a brighter red soup color. The Gongfu black tea products prepared in Examples 2 and 3 of the present invention both have a distinct floral aroma, and a bright or relatively bright orange-red soup color and a mellow taste.

[0110] Table 2 Comparison of basic biochemical components and color difference analysis

[0111]

[0112] As shown in the results of Table 2, the content of tea polyphenols in the Gongfu black tea product prepared in Example 1 of the present invention is significantly reduced, while the contents of free amino acids, theaflavins, thearubigins and theabrownins are significantly increased; the color difference analysis shows that the redness and brightness of the Gongfu black tea product prepared in Example 1 of the present invention are improved, which is consistent with the sensory evaluation results in Table 1.

[0113] It can be seen from the above embodiments that the present invention can process fresh leaf raw materials with one bud and two or three leaves into high-quality black tea, providing tea processing companies with a low-cost, high-quality floral black tea, thereby significantly improving the economic benefits of tea companies.

[0114] In summary, the processing method provided by the present invention in a processing method for simultaneously improving the floral aroma concentration and the red brightness of the soup color of Gongfu black tea can simultaneously improve the floral aroma concentration and the red brightness of the soup color of small and medium leaf Gongfu black tea. Compared with the small and medium leaf Gongfu black tea produced by the traditional processing technology in the prior art, the Gongfu black tea product prepared by the present invention has the effects of obvious floral aroma, bright red soup color, and high content of theaflavins and thearubigins, which solves the technical problems of the small and medium leaf black tea produced by the traditional processing technology of Gongfu black tea in the prior art, which has unclear floral aroma, not bright red soup color, and low content of theaflavins and thearubigins.

[0115] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. In order to avoid redundancy, the present invention describes a preferred embodiment.

[0116] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they understand the basic inventive concepts, and all such changes and modifications fall within the scope of the present invention.

Claims

1. A processing method for simultaneously improving the concentration of the floral aroma of Gongfu black tea and the brightness of the red tea soup color, characterized in that: The steps include: Selection of fresh tea leaves: fresh leaves of small and medium-leaf tea trees are used as fresh tea leaves; Low-temperature, low-humidity, ultraviolet irradiation withering: the fresh tea leaves are withered at a temperature of 12°C to 19°C and an air humidity of 28% to 52%, and ultraviolet irradiation is performed during the withering process, and the tea leaves are withered until the water content of the fresh tea leaves is between 58% and 62%, thereby obtaining withered tea leaves; The first long-time rolling: the withered tea leaves are subjected to the first long-time rolling, the first long-time rolling time is 55 minutes to 65 minutes, after the rolling is completed, the tea leaves after the first long-time rolling are obtained; First long-term fermentation: fermenting the tea leaves after the first long-term rolling for 2 hours to 2.5 hours to obtain tea leaves after the first long-term fermentation; Second short-time re-kneading: the tea leaves after the first long-time fermentation are subjected to a second short-time re-kneading, the time of the second short-time re-kneading is 25min to 35min, after the rolling is completed, the tea leaves after the second short-time re-kneading are obtained; Second short-time low-temperature high-oxygen fermentation: the tea leaves after the second short-time re-rolling are subjected to low-temperature high-oxygen fermentation for 1 hour to 1.5 hours at a temperature of 21° C. to 27° C., a humidity of 89% to 96%, and an oxygen concentration of 29% to 36%, to obtain tea leaves after the second short-time fermentation; After the tea leaves have been fermented for a second time for a short period of time, they are then dried by rough fire and fully dried to obtain a medium- and small-leaf Gongfu black tea product with a floral aroma and high theaflavins content.

2. The processing method for simultaneously improving the floral aroma concentration and the red brightness of Gongfu black tea according to claim 1, characterized in that: The varieties of the small and medium-leaf tea trees include any one or more of Ningzhou No. 2, Ningzhou group species and Huang Guanyin.

3. The processing method for simultaneously improving the floral aroma concentration and the red brightness of Gongfu black tea according to claim 1, characterized in that: The fresh leaves of the small and medium-leaf tea trees are tender fresh leaves with one bud, two or three leaves.

4. The processing method for simultaneously improving the floral aroma concentration and the red brightness of Gongfu black tea according to claim 1, characterized in that: The low temperature and low humidity withering conditions are: temperature of 13° C. to 18° C., and air humidity of 30% to 50%.

5. The processing method for simultaneously improving the floral aroma concentration and the red brightness of Gongfu black tea according to claim 1, characterized in that: The method of the ultraviolet irradiation treatment is as follows: The fresh tea leaves are first withered for 4 to 6 hours, and then heated with a concentration of 3 μmol / m 2 / s~4μmol / m 2 / s UV-B irradiation for 2h~3h. After the first UV irradiation, turn off the UV lamp, turn over the tea leaves and use it again with an intensity between 3μmol / m 2 / s~4μmol / m 2 / s UV-B irradiation for 2h to 3h.

6. The processing method for simultaneously improving the floral aroma concentration and the red brightness of Gongfu black tea according to claim 1, characterized in that: The first long kneading has a rotation speed of 43r / min-48r / min ， The kneading is performed in three stages according to the kneading method with increasing kneading pressure; The first stage of kneading takes 10 to 15 minutes; the second stage of kneading takes 10 to 15 minutes; the third stage of kneading takes 20 to 30 minutes; and the total kneading time is 55 to 65 minutes.

7. The processing method for simultaneously improving the floral aroma concentration and the red brightness of Gongfu black tea according to claim 1, characterized in that: The conditions for the first long fermentation are: temperature of 30° C. to 35° C. and humidity ≥ 90%.

8. The processing method for simultaneously improving the floral aroma concentration and the red brightness of Gongfu black tea according to claim 1, characterized in that: The rotation speed of the second short-time repeated kneading is 43r / min to 48r / min.

9. The processing method for simultaneously improving the floral aroma concentration and the red brightness of Gongfu black tea according to claim 1, characterized in that: The conditions of the low-temperature high-oxygen fermentation are: temperature of 22° C. to 26° C., humidity of 90% to 95%, and oxygen concentration of 30% to 35%.

10. The processing method for simultaneously improving the floral aroma concentration and the red brightness of Gongfu black tea according to claim 1, characterized in that: The improvement of the red brightness of the Gongfu black tea soup color is achieved by increasing the content of theaflavins and thearubigins by ≥8%.

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