Method for preparing black tea based on ultrahigh pressure technology

Abstract

The invention discloses a method for preparing black tea based on an ultrahigh pressure technology, and relates to the technical field of tea production. The method at least comprises the following steps: S1, harvesting and withering tea leaves; s2, ultrahigh pressure processing; s3, rolling and shaping by using a rolling machine or manual work; s4, performing fermentation: uniformly spreading the rolled tea leaves in a fermentation machine, and performing fermentation treatment; and S5, drying: drying the tea leaves treated in the S4 twice by using a drying machine. Through the corresponding preparation method design, cell content exudation is promoted, the tea taste is improved, meanwhile, the oxidation reaction in the black tea fermentation process is accelerated, the bitterness of tea is reduced, the flower and fruit fragrance is increased, tea tissue is softened, and the subsequent rolling, fermentation and other processes are facilitated.

Description

Technical Field

[0001] This invention relates to the field of tea production technology, specifically a method for preparing black tea based on ultra-high pressure technology. Background Technology

[0002] The tea industry is a distinctive and advantageous industry in my country, undertaking the important tasks of supporting the economy of tea-producing areas, meeting health-conscious consumption needs, and expanding employment. However, the tea industry in my country currently faces the problem of low resource utilization. Many tea-producing areas only produce spring tea, while summer and autumn tea, which account for 60% of the total annual tea production, suffer from a lack of high-value utilization models and technologies, resulting in a large waste of resources.

[0003] However, summer and autumn teas have the following main drawbacks:

[0004] It is rich in caffeine and tea polyphenols, and has a strong bitter taste.

[0005] Due to the increased number of harvesting rounds, summer and autumn tea leaves contain fewer amino acids and other internal components, resulting in lower freshness and a weaker flavor.

[0006] The leaves are coarse and tough, making them unsuitable for processing;

[0007] With the widespread use of mechanized harvesting, the fresh leaves of summer and autumn tea still have problems with uneven tenderness and size, which further increases the difficulty of setting up processing techniques.

[0008] Ultra-high pressure technology can use high hydrostatic pressure to cause irreversible tearing and damage to cell membranes, resulting in the leakage of cell contents. This can effectively solve the problems of weak flavor, strong bitterness, and difficulty in processing summer and autumn teas. Summary of the Invention

[0009] The purpose of this invention is to provide a method for preparing black tea based on ultra-high pressure technology, so as to solve the technical problems mentioned in the background art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing black tea based on ultra-high pressure technology, comprising at least the following steps:

[0011] S1: Tea harvesting and withering. After processing, the tea leaves are soft, the stems do not break when broken, and the grassy smell is transformed into a fresh fragrance.

[0012] S2: Ultra-high pressure machining;

[0013] S3: Kneading and shaping, done using a kneading machine or by hand. The leaves after kneading and shaping are light yellowish-green with some reddish tinges.

[0014] S4: Fermentation. The kneaded tea leaves are evenly spread in a fermentation machine for fermentation.

[0015] S5: Drying. The tea leaves treated in S4 are dried twice using a dryer.

[0016] Furthermore, the tea harvesting and withering process includes at least the following steps:

[0017] Spread the fresh tea leaves on the tea withering machine to a thickness of about 15 centimeters.

[0018] The leaves are turned over every one or two hours by controlled hot air blowing to facilitate the even evaporation of surface moisture from the fresh leaves.

[0019] The temperature of the hot air is 35℃-38℃;

[0020] Finally, the withering process was completed.

[0021] When the leaves are properly wilted, they are soft, can be clenched into a ball when squeezed, and do not easily fall apart when released. The leaf surface loses its luster, and the leaf stalks can be broken but not broken. The water loss rate of fresh leaves is usually around 40%-50%.

[0022] Furthermore, S2 includes at least the following steps:

[0023] The tea obtained from the S1 treatment was placed in a vacuum-sealed bag and vacuum-sealed to prevent contact with moisture.

[0024] The packaged tea leaves are placed in an ultra-high pressure processing chamber and treated with ultra-high pressure of 100MPa-300MPa for 3-10 minutes.

[0025] Furthermore, the kneading and shaping includes at least the following steps:

[0026] Take out the tea leaves after S2 treatment and put them into a rolling machine or roll them by hand;

[0027] Follow the principles of light-heavy-light and slow-fast-slow, gradually increasing pressure;

[0028] When the rolling is finished, more than 80% of the leaves are in strips, the leaf color is light yellowish-green with some reddish parts, and the tea juice overflows when squeezed by hand without dripping.

[0029] Furthermore, S4 includes at least the following steps:

[0030] Place the tea leaves prepared by S3 into a black tea fermentation machine, control the temperature at 25-28℃, and maintain the humidity above 95%;

[0031] Maintain a moderate oxygen supply and allow fermentation time of 2-4 hours.

[0032] Furthermore, S5 includes at least the following steps:

[0033] The first high-temperature rapid drying process, at a temperature of 110℃-120℃, causes the tea leaves to lose moisture quickly, stops fermentation, and reduces the moisture content of the tea leaves to about 15%. During this process, there is a large airflow inside the dryer.

[0034] After the first drying, let it cool for about 40 minutes;

[0035] The second drying process involves slow, low-temperature drying at 70-90℃ for 15-20 minutes, until the tea leaves have a moisture content of approximately 5%-6%.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] 1. The present invention, through a corresponding preparation method, promotes the exudation of cell contents and enhances the flavor of tea.

[0038] 2. The invention, through the design of a corresponding preparation method, accelerates the oxidation reaction during the fermentation process of black tea, reduces the bitterness of the tea, and increases the floral and fruity aroma.

[0039] 3. The invention designs a corresponding preparation method that softens the tea tissue, which is beneficial for subsequent processes such as rolling and fermentation. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A comparison diagram of the black tea prepared according to the present invention and that made using traditional methods;

[0042] Figure 2 This is a schematic diagram showing the content of water extracts in this invention;

[0043] Figure 3 This is a schematic diagram illustrating the thearubigin and theabrownin content of black tea processed in different ways according to the present invention;

[0044] Figure 4 This is a schematic diagram illustrating the sensory evaluation of different treatments in this invention. Detailed Implementation

[0045] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0046] A method for preparing black tea based on ultra-high pressure technology includes at least the following steps:

[0047] S1: Tea harvesting and withering. After processing, the tea leaves are soft, the stems do not break when broken, and the grassy smell is transformed into a fresh fragrance.

[0048] S2: Ultra-high pressure machining;

[0049] S3: Kneading and shaping, done using a kneading machine or by hand. The leaves after kneading and shaping are light yellowish-green with some reddish tinges.

[0050] S4: Fermentation. The kneaded tea leaves are evenly spread in a fermentation machine for fermentation.

[0051] S5: Drying. The tea leaves treated in S4 are dried twice using a dryer.

[0052] Tea harvesting and withering include at least the following steps:

[0053] Spread the fresh tea leaves on the tea withering machine to a thickness of about 15 centimeters.

[0054] The leaves are turned over every one or two hours by controlled hot air blowing to facilitate the even evaporation of surface moisture from the fresh leaves.

[0055] The temperature of the hot air is 35℃-38℃;

[0056] Finally, the withering process was completed.

[0057] When the leaves are properly wilted, they are soft, can be clenched into a ball when squeezed, and do not easily fall apart when released. The leaf surface loses its luster, and the leaf stalks can be broken but not broken. The water loss rate of fresh leaves is usually around 40%-50%.

[0058] S2 includes at least the following steps:

[0059] The tea obtained from the S1 treatment was placed in a vacuum-sealed bag and vacuum-sealed to prevent contact with moisture.

[0060] The packaged tea leaves are placed in an ultra-high pressure processing chamber and treated with ultra-high pressure of 100MPa-300MPa for 3-10 minutes.

[0061] Kneading and shaping includes at least the following steps:

[0062] Take out the tea leaves after S2 treatment and put them into a rolling machine or roll them by hand;

[0063] Follow the principles of light-heavy-light and slow-fast-slow, gradually increasing pressure;

[0064] When the rolling is finished, more than 80% of the leaves are in strips, the leaf color is light yellowish-green with some reddish parts, and the tea juice overflows when squeezed by hand without dripping.

[0065] S4 includes at least the following steps:

[0066] Place the tea leaves prepared by S3 into a black tea fermentation machine, control the temperature at 25-28℃, and maintain the humidity above 95%;

[0067] Maintain a moderate oxygen supply and allow fermentation time of 2-4 hours.

[0068] S5 includes at least the following steps:

[0069] The first high-temperature rapid drying process, at a temperature of 110℃-120℃, causes the tea leaves to lose moisture quickly, stops fermentation, and reduces the moisture content of the tea leaves to about 15%. During this process, there is a large airflow inside the dryer.

[0070] After the first drying, let it cool for about 40 minutes;

[0071] The second drying process involves slow, low-temperature drying at 70-90℃ for 15-20 minutes, until the tea leaves have a moisture content of approximately 5%-6%.

[0072] from Figure 1 It can be seen that, compared with the traditional processing method (CK group), ultra-high pressure treatment can significantly improve the color of black tea, with the tea soup being significantly redder, brighter, and more lustrous.

[0073] The content of water extract in black tea with different treatments, such as Figure 2 As shown.

[0074] Depend on Figure 2 It can be seen that the content of water extract in black tea increased significantly after ultra-high pressure treatment, indicating that the number of compounds in the tea soup increased significantly and the flavor was richer.

[0075] The thearubigin and theabrownin content of black tea processed in different ways, such as Figure 3 As shown.

[0076] Depend on Figure 3 It can be seen that the content of thearubigin and theabrownin in black tea increased significantly after ultra-high pressure treatment, indicating that ultra-high pressure treatment can promote the conversion of catechins, reduce the bitterness of tea, and enhance the mellowness of tea.

[0077] Depend on Figure 4 It can be seen that the black tea treated with ultra-high pressure at 100MPa-300MPa has a higher sweetness, floral and fruity aroma, mellowness and freshness than the traditionally treated (CK group), indicating that the taste and aroma of black tea are significantly improved after ultra-high pressure treatment.

[0078] In summary:

[0079] This invention utilizes ultra-high pressure to process fresh tea leaves, which can effectively promote the exudation of tea cell contents, enhance the color of black tea soup, and increase the content of flavor substances. At the same time, it can also promote the conversion of catechins into thearubigins, theabrownins, and other substances, reduce the bitterness of black tea, and enhance its aroma.

[0080] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing black tea based on ultra-high pressure technology, characterized in that: At least the following steps are included: S1: Tea harvesting and withering; S2: Ultra-high pressure machining; S3: Kneading and shaping, done using a kneading machine or by hand; S4: Fermentation. The kneaded tea leaves are evenly spread in a fermentation machine for fermentation. S5: Drying. The tea leaves treated in S4 are dried twice using a dryer.

2. The method for preparing black tea based on ultra-high pressure technology according to claim 1, characterized in that: The tea harvesting and withering process includes at least the following steps: Spread the fresh tea leaves on the tea withering machine to a thickness of about 15 centimeters. The leaves are turned over every one or two hours by controlled hot air blowing to facilitate the even evaporation of surface moisture from the fresh leaves. The temperature of the hot air is 35℃-38℃; Finally, withering was completed.

3. The method for preparing black tea based on ultra-high pressure technology according to claim 2, characterized in that: S2 includes at least the following steps: The tea obtained from the S1 treatment was placed in a vacuum-sealed bag and vacuum-sealed to prevent contact with moisture. The packaged tea leaves are placed in an ultra-high pressure processing chamber and treated with ultra-high pressure of 100MPa-300MPa for 3-10 minutes.

4. The method for preparing black tea based on ultra-high pressure technology according to claim 3, characterized in that: The kneading and shaping process includes at least the following steps: Take out the tea leaves after S2 treatment and put them into a rolling machine or roll them by hand; Follow the principles of light-heavy-light and slow-fast-slow, gradually increasing pressure; When the rolling is finished, more than 80% of the leaves are in strips, the leaf color is light yellowish-green with some reddish parts, and the tea juice overflows when squeezed by hand without dripping.

5. The method for preparing black tea based on ultra-high pressure technology according to claim 1, characterized in that: The S4 includes at least the following steps: Place the tea leaves prepared by S3 into a black tea fermentation machine, control the temperature at 25-28℃, and maintain the humidity above 95%; Maintain a moderate oxygen supply and allow fermentation time of 2-4 hours.

6. The method for preparing black tea based on ultra-high pressure technology according to claim 1, characterized in that: The S5 includes at least the following steps: The first high-temperature rapid drying process, at 110℃-120℃, causes the tea leaves to lose moisture quickly, stops fermentation, and reduces the moisture content of the tea leaves to 15%. During this process, there is a large airflow inside the dryer. After the first drying, let it cool for 40 minutes. The second drying process involves slow, low-temperature drying at 70-90℃ for 15-20 minutes, until the tea leaves have a moisture content of 5%-6%.

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