A processing method for increasing the content of non-esterified EPSF compounds in white tea

Abstract

A processing method for increasing the content of non-esterified EPSF compounds in white tea, belonging to the technical field of tea processing. The method comprises the following steps: taking white tea for high-temperature and high-pressure steam treatment, cooling treatment, drying treatment, and successively subjecting the dried white tea to normal-pressure steam treatment, brick pressing treatment, flower-forming treatment, and drying and fragrance-enhancing treatment. In this tea processing method, the high-temperature and high-pressure steam treatment can promote the reaction between theanine and catechins to form EPSF compounds, and the flower-forming treatment can promote the degradation and conversion of esterified EPSF into non-esterified EPSF, which has a significant effect on increasing the content of non-esterified EPSF compounds in white tea, and the increase multiple can reach more than 10 times.

Description

Technical Field

[0001] The present invention belongs to the technical field of tea processing, and particularly relates to a processing method for increasing the content of non-esterified EPSF compounds in white tea. Background Art

[0002] White tea is one of the six traditional tea categories in China. It belongs to slightly fermented tea and has the effects of reducing internal heat and inflammation, antioxidant, anti-radiation, anti-mutation, regulating blood lipid, regulating immune function, and preventing cardiovascular and cerebrovascular diseases. White tea stored for a long time (aged white tea) is considered to have stronger pharmacological effects and is often used as a good medicine for reducing internal heat and inflammation and treating colds in folk. Through research, it is found that aged white tea contains a relatively high content of N-ethyl-2-pyrrolidone-substituted catechins (EPSF) characteristic components. EPSF is a class of catechin derivatives. In recent years, studies have shown that EPSF compounds have a wide range of biological activities. For example, they have a good protective effect on hydrogen peroxide-induced damage of human microvascular endothelial cells, suggesting that EPSF components may have the effect of preventing cardiovascular diseases; they can inhibit the formation of advanced glycation end products, suggesting that EPSF components may have the effect of preventing the occurrence and development of diabetes; in addition, it is also found that EPSF compounds have antioxidant, anti-inflammatory, inhibiting acetylcholinesterase activity, inhibiting α-glucosidase activity and other effects. According to whether they contain a galloyl group, EPSF compounds can be divided into esterified EPSF (R-EGCG-cThea, S-EGCG-cThea, R-ECG-cThea, S-ECG-cThea, etc.) and non-esterified EPSF (R-EGC-cThea, S-EGC-cThea, R-EC-cThea, S-EC-cThea, etc.).

[0003] The applicant applied for a Chinese invention patent for a processing method for increasing the content of R-EGCG-cThea in white tea on January 29, 2019, with the publication number of 109757569 A. This invention specifically discloses taking white tea for high-temperature and high-pressure steam treatment; spreading and cooling treatment; drying treatment; storing treatment under room-temperature oxygen-rich conditions; and flavor-enhancing treatment. The present invention is a tea processing method that can significantly increase the content of R-EGCG-cThea in white tea and has the following advantages: The 8-CN-ethyl-2-pyrrolidone-substituted catechin components have good biological activities and health care effects. Increasing the content of this type of component represented by R-EGCG-cThea in white tea has originality and great market potential; this tea processing method has a significant effect on increasing the content of R-EGCG-cThea in white tea, and the increase multiple can reach 5-50 times; this processing method has the advantages of simple operation and low cost, and has broad application prospects in the field of white tea processing.

[0004] However, through research, it is found that non-ester catechins have a lower bitter and astringent taste and a sweet aftertaste compared to ester catechins. Therefore, the applicant speculates that non-ester EPSF may have a better flavor contribution to the flavor quality of tea leaves compared to ester EPSF. Based on this, developing a tea processing method that can significantly increase the content of non-ester EPSF in white tea is expected to further improve the health benefits and flavor quality of white tea. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the purpose of the present invention is to design and provide a technical solution for a processing method to increase the content of non-ester EPSF compounds in white tea, which has the advantages of simple operation, low cost, and remarkable effect.

[0006] The present invention is specifically implemented by the following technical solutions:

[0007] The present invention provides a processing method for increasing the content of non-ester EPSF compounds in white tea, comprising the following steps: taking white tea for high-temperature and high-pressure steam treatment, cooling treatment, drying treatment, atmospheric-pressure steam treatment, brick pressing treatment, flower development treatment, and drying and fragrance enhancement treatment.

[0008] Further, the high-temperature and high-pressure steam treatment is specifically as follows: carried out in a temperature-controlled high-pressure closed device, with a high temperature of 100°C - 150°C, a high pressure of 0.15 - 0.5 MPa, and a steam treatment time of 5 - 120 min.

[0009] Further, the cooling treatment is specifically as follows: spreading out at room temperature of 20 - 30°C, with a leaf thickness of 3 - 10 cm and a spreading time of 0.5 - 24 h.

[0010] Further, the drying treatment is specifically as follows: carried out in an oven, with a temperature of 60 - 110°C and a time of 10 - 120 min.

[0011] Further, the atmospheric-pressure steam treatment is specifically as follows: at atmospheric pressure, with a steam temperature of 100°C and a time of 30 - 60 seconds.

[0012] Further, the brick pressing treatment is specifically as follows: pressing the white tea after atmospheric-pressure steam treatment into bricks, with each white tea brick weighing 300 - 1000 grams.

[0013] Further, the "flower development" treatment is specifically as follows: placing the white tea bricks in a flower development room inoculated with Eurotium cristatum for 12 - 24 days.

[0014] Further, the process of flower formation is specifically as follows: ① Control the temperature in the flower formation room at 31 - 33°C and the humidity at 70% - 80% for 3 - 7 days; ② Control the temperature in the flower formation room at 28 - 31°C and the humidity at 80% - 85% for 2 - 4 days; ③ Control the temperature in the flower formation room at 25 - 28°C and the humidity at 80% - 85% for 2 - 4 days; ④ Control the temperature in the flower formation room at 25 - 28°C and the humidity at 76% - 83% for 5 - 9 days.

[0015] Further, the process of drying and fragrance enhancement is specifically as follows: Use a tea fragrance enhancement machine for drying and fragrance enhancement, with the temperature at 70 - 100°C and the time at 20 - 60 min.

[0016] The beneficial effects of the present invention are as follows:

[0017] 1) Non - ester - type EPSF compounds have good biological activities and health - care effects. Increasing the content of non - ester - type EPSF compounds in white tea is original and has great market potential.

[0018] 2) In this tea - processing method, the high - temperature and high - pressure steam treatment can promote the reaction between theanine and catechins to form EPSF compounds, and the flower - formation treatment can promote the degradation and transformation of ester - type EPSF into non - ester - type EPSF, which has a significant effect on increasing the content of non - ester - type EPSF compounds in white tea, and the increase multiple can reach more than 10 times.

[0019] 3) This processing method has the advantages of simple operation and low cost, and has broad application prospects in the field of white - tea processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 They are the chemical structural formulas of 4 main non - ester - type EPSF compounds in white tea.

[0021] Figure 2 They are the photos of the dry white tea and the tea soup before and after the technical treatment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following is a detailed description with reference to the embodiments: These embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0023] Example 1

[0024] 1) Collect 10 kg of Shoumei white tea.

[0025] 2) Subject the Shoumei white tea to steam treatment at a temperature of 125°C and a pressure of 0.18 MPa for 10 min.

[0026] 3) Cool it at room temperature of 25°C, with the thickness of the spread leaves being 5 cm and the spreading time being 3 h.

[0027] 4) Dry the cooled Shoumei white tea in an oven at a drying temperature of 90 °C for 40 min;

[0028] 5) Subject the dried Shoumei white tea to atmospheric steam treatment at normal pressure, with a steam temperature of 100 °C for 45 seconds.

[0029] 6) Press the white tea into bricks, with each white tea brick weighing 500 grams.

[0030] 7) Place the white tea bricks in a flowering room inoculated with Eurotium cristatum for flowering. Control the temperature in the flowering room at 32 °C and the humidity at 75% for 4 days; adjust the temperature in the flowering room to 30 °C and the humidity to 84% for 3 days; adjust the temperature in the flowering room to 28 °C and the humidity to 85% for 3 days; adjust the temperature in the "flowering" room to 28 °C and the humidity to 80% for 6 days; a total of 16 days.

[0031] 8) Dry and enhance the fragrance of the flowered white tea bricks at a temperature of 90 °C for 30 min.

[0032] 9.5 kg of Shoumei white tea is obtained. As shown in Table 1, by absolute quantitative analysis using liquid chromatography-high resolution mass spectrometry UHPLC-Q-Exactive, the content of non-esterified EPSF compounds increased from 0.1221 mg / g to 2.0233 mg / g, with a change multiple of 16.6 times. Among them, the contents of 4 main non-esterified EPSF compounds, 8- CR -EGC-cThea, 8- CS -EGC-cThea, 8- CR -EC-cThea, 8- CS -EC-cThea were 17.9, 20.0, 15.3, and 14.2 times that before treatment, respectively.

[0033] Figure 1 Chemical structural formulas of 4 main non-esterified EPSF compounds in white tea.

[0034] Figure 2 Photos of the dry white tea and the tea soup before and after the technical treatment of the present invention. Compared with before treatment, the surface of the dry white tea after treatment has "golden flowers" formed by Eurotium cristatum, and the color of the tea soup changes from light yellow to orange-yellow to brownish-yellow.

[0035] Table 1. Changes in the content of main non-esterified EPSF compounds before and after the technical treatment of the present invention

[0036]

[0037] Example 2

[0038] 1) Collect 10 kg of Shoumei white tea;

[0039] 2) Steam-treat the Shoumei white tea at a temperature of 150 °C and a pressure of 0.32 MPa for 60 min;

[0040] 3) Cool it at room temperature of 30 °C with a leaf thickness of 10 cm and a spreading time of 15 h;

[0041] 4) Dry the cooled Shoumei white tea in an oven at a drying temperature of 100 °C for 10 min;

[0042] 5) Subject the dried Shoumei white tea to atmospheric-pressure steam treatment at a steam temperature of 100 °C for 60 seconds.

[0043] 6) Press the white tea into bricks, with each white tea brick weighing 1000 grams.

[0044] 7) Place the white tea bricks in a flowering room inoculated with Eurotium cristatum for flowering, control the temperature in the flowering room at 31 °C and the humidity at 70% for 7 days; adjust the temperature in the flowering room to 31 °C and the humidity to 85% for 4 days; adjust the temperature in the flowering room to 25 °C and the humidity to 80% for 3 days; adjust the temperature in the "flowering" room to 25 °C and the humidity to 83% for 5 days; in total, it is 20 days.

[0045] 8) Dry and enhance the fragrance of the flowered white tea bricks at a temperature of 100 °C for 20 min.

[0046] 9.5 kg of Shoumei white tea is obtained. As shown in Table 2, through ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-Q-Exactive) absolute quantitative analysis, the content of non-esterified EPSF compounds increases from 0.1221 mg / g to 1.6593 mg / g, with a change multiple of 13.6 times. Among them, the contents of 4 main non-esterified EPSF compounds, 8- CR -EGC-cThea, 8- CS -EGC-cThea, 8- CR -EC-cThea, 8- CS -EC-cThea are 14.4, 17.4, 12.8, and 10.9 times that before treatment respectively.

[0047] Table 2. Changes in the contents of main non-esterified EPSF compounds before and after the technical treatment of the present invention

[0048]

[0049] Example 3

[0050] 1) Collect 10 kg of White Peony white tea;

[0051] 2) Steam-treat white peony white tea at a temperature of 100 °C and a pressure of 0.5 MPa for 5 min;

[0052] 3) Cool it at room temperature of 20 °C with a leaf thickness of 5 cm for 24 h;

[0053] 4) Dry the cooled white peony white tea in an oven at a drying temperature of 60 °C for 120 min;

[0054] 5) Subject the dried white peony white tea to atmospheric-pressure steam treatment at a steam temperature of 100 °C for 30 seconds.

[0055] 6) Press the white tea into bricks, with each white tea brick weighing 1000 grams.

[0056] 7) Place the white tea bricks in a "flowering" room inoculated with Eurotium cristatum for "flowering", control the temperature in the flowering room at 33 °C and the humidity at 80% for 3 days; adjust the temperature in the flowering room to 28 °C and the humidity to 80% for 2 days; adjust the temperature in the flowering room to 25 °C and the humidity to 85% for 2 days; adjust the temperature in the "flowering" room to 25 °C and the humidity to 76% for 5 days; the above totals 12 days.

[0057] 8) Dry and enhance the fragrance of the flowered white tea bricks at a temperature of 80 °C for 60 min.

[0058] 9.5 kg of white peony white tea is obtained. As shown in Table 3, through UHPLC-Q-Exactive absolute quantitative analysis by liquid chromatography-high resolution mass spectrometry, the content of non-esterified EPSF compounds increases from 0.1156 mg / g to 2.1665 mg / g, with a change multiple of 18.7 times. Among them, the contents of 4 main non-esterified EPSF compounds, 8- CR -EGC-cThea, 8- CS -EGC-cThea, 8- CR -EC-cThea, 8- CS -EC-cThea are 21.2, 22.2, 16.5, and 16.2 times that before treatment respectively.

[0059] Table 3. Changes in the contents of main non-esterified EPSF compounds before and after the technical treatment of the present invention

[0060]

[0061] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A processing method for increasing the content of non-esterified EPSF compounds in white tea, comprising the following steps: Take white tea and conduct high-temperature and high-pressure steam treatment, cooling treatment, and drying treatment. It is characterized in that the dried white tea is successively subjected to normal-pressure steam treatment, brick pressing treatment, flower-growing treatment, and drying and fragrance-enhancing treatment; The specific normal-pressure steam treatment is as follows: the pressure is normal pressure, the steam temperature is 100°C, and the time is 30 - 60 seconds; The specific flower-growing treatment is as follows: place the white tea brick in a flower-growing room inoculated with Eurotium cristatum and let it grow for 12 - 24 days; The non-ester type EPSF compound is 8- CR -EGC-cThea, 8- CS -EGC-cThea, 8- CR -EC-cThea and 8- CS -EC-cThea.

2. The processing method for increasing the content of non-esterified EPSF compounds in white tea according to claim 1, wherein, The specific high-temperature and high-pressure steam treatment is as follows: conduct it in a temperature-controlled high-pressure closed device, the high temperature is 100 - 150°C, the high pressure is 0.15 - 0.5 MPa, and the steam treatment time is 5 - 120 min.

3. A processing method for increasing the content of non-esterified EPSF compounds in white tea according to claim 1, characterized in that, The specific cooling treatment is as follows: spread it at room temperature of 20 - 30°C, the thickness of the spread tea leaves is 3 - 10 cm, and the spreading time is 0.5 - 24 h.

4. A processing method for increasing the content of non-esterified EPSF compounds in white tea according to claim 1, characterized in that, The specific drying treatment is as follows: conduct it in an oven, the temperature is 60 - 110°C, and the time is 10 - 120 min.

5. A processing method for increasing the content of non-esterified EPSF compounds in white tea according to claim 1, characterized in that, The specific brick pressing treatment is as follows: press the white tea after normal-pressure steam treatment, and the mass of each white tea brick is 300 - 1000 grams.

6. The processing method for increasing the content of non-esterified EPSF compounds in white tea according to claim 1, wherein, The specific flower-growing treatment is as follows: ① Control the temperature in the flower-growing room to be 31 - 33°C and the humidity to be 70% - 80% for 3 - 7 days; ② Control the temperature in the flower-growing room to be 28 - 31°C and the humidity to be 80% - 85% for 2 - 4 days; ③ Control the temperature in the flower-growing room to be 25 - 28°C and the humidity to be 80% - 85% for 2 - 4 days; ④ Control the temperature in the flower-growing room to be 25 - 28°C and the humidity to be 76% - 83% for 5 - 9 days.

7. A processing method for increasing the content of non-esterified EPSF compounds in white tea according to claim 1, wherein, The specific drying and fragrance-enhancing treatment is as follows: use a tea fragrance-enhancing machine for drying and fragrance-enhancing, the temperature is 70 - 100°C, and the time is 20 - 60 min.

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