Method for increasing EGCG (epigallocatechin gallate) content of fresh tea leaves

Abstract

The invention provides a preparation method for improving EGCG content of tea tree fresh leaves, which specifically comprises the following steps: spraying a mixed solution of salicylic acid and methyl jasmonate on new shoot leaves of a current year of tea tree, and picking 48 hours after spraying, so as to obtain the tea tree fresh leaves with high EGCG content, increase the volatile substance content of the tea tree, and improve the EGCG content of the tea tree fresh leaves. The growth of the tea trees can be promoted.

Description

Technical Field

[0001] The invention relates to a method for preparing tea leaves, and in particular to a method for increasing the EGCG content of fresh tea leaves. Background Art

[0002] EGCG (epigallocatechin-3-gallate) is the core component of tea's sensory quality and the key active ingredient for its health-promoting qualities. Scientific research has confirmed that EGCG has a variety of health-promoting functions, including three anti-cancer, anti-radiation, and anti-oxidation, three lowering (lowering blood pressure, lowering blood lipids, and lowering blood sugar), and three eliminating (disinfection, swelling, and deodorization).

[0003] EGCG, a natural active ingredient extracted from tea, has been approved as a new resource food raw material in my country, and has been listed as a natural medicine raw material and a functional ingredient for health food by the United States and Japan respectively. Its market size ranks among the top ten natural health products in the world. Therefore, high-EGCG tea and EGCG series of deep-processed products meet the domestic and foreign market demand for high-quality and high-health tea products. However, how to increase the EGCG content in tea by technical means is one of the key bottlenecks that restrict the improvement of tea quality and the economic benefits of the deep processing industry. The core issue behind solving this technical bottleneck is how to promote the biosynthesis of EGCG in tea trees. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method for increasing the EGCG content in fresh tea leaves, which can greatly increase the EGCG content in tea leaves and also increase the volatile content of fresh tea leaves.

[0005] To achieve the above object, the present invention adopts the following technical solution: A method for increasing the EGCG content of fresh tea leaves comprises spraying a mixed solution of salicylic acid and methyl jasmonate on leaves of new shoots of tea trees of the current year, thereby obtaining fresh tea leaves with a high EGCG content.

[0006] Furthermore, the spraying amount of the mixed solution of salicylic acid and methyl jasmonate is 1 L / m 2 (About 666 L / mu).

[0007] Furthermore, the volume concentration of salicylic acid in the mixed solution is 250 μmol / L, and the volume concentration of methyl jasmonate is 1 mL / L.

[0008] Furthermore, the EGCG content extracted from fresh tea leaves picked 48 hours after spraying was the highest.

[0009] The significant advantages of the present invention are: Under biotic or abiotic stress, tea trees will cause consistent changes in endogenous hormones and EGCG content. The present invention changes the endogenous hormones of tea trees by exogenously spraying a mixed solution of salicylic acid and methyl jasmonate on the leaves of the new shoots of the current year's tea trees, thereby greatly increasing the EGCG content of the tea leaves, and can also increase the content of volatile substances in the tea trees, and can promote the growth of tea trees and increase economic yields. Therefore, the present invention has good economic benefits and application prospects. DETAILED DESCRIPTION

[0010] In order to make the contents of the present invention easier to understand, the technical solution of the present invention is further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.

[0011] 1. Materials, instruments and reagents 1.1 Experimental materials: The experiment was conducted in April 2023 at the tea garden base of Quanjia Tea Co., Ltd. in Meizhuang Village, Huqiu Town, Anxi County, Quanzhou City, Fujian Province (24°54′29″N, 117°51′42″E). The tea tree variety used for the experiment was a 10-year-old asexually propagated tea tree 'Huangyan' ( Camellia sinensis The experimental plot design adopted a completely randomized block design, with each plot including 12 tea shrubs and an area of ​​5 m 2 Each treatment contained three biological replicates at the time of sampling.

[0012] 1.2 Instruments: Sample solid equipment: tea roaster (JY-6CHZ7B, Fujian Jiayou Machinery Co., Ltd.); microwave oven (M1-L213B, Midea); ultra-high performance liquid chromatograph (UPLC H-Class, Waters Acquity); chromatographic column (UPLCHSS T3, Waters Acquity); analytical balance (BSA1245-CW, Sartorius); centrifuge (Sigma, USA); horizontal vortex mixer (SCILOGEX, USA); high-throughput tissue mill (Ningbo Xinzhi Biological); digital display constant temperature water bath (Jingda Instrument).

[0013] 1.3 Reagents: Methyl jasmonate (purity ≥ 95%, liquid), salicylic acid (purity ≥ 99%), standard EGCG (Epigallocatechingallate), and methanol (chromatographic grade) were purchased from Sigma-Aldrich, USA; acetonitrile (chromatographic grade) was purchased from Merck, Germany; and the experimental water was Watsons distilled water.

[0014] 2. Methods and Results 2.1 Reagent preparation: Methyl jasmonate is dissolved in ethanol to prepare a methyl jasmonate solution of a certain concentration.

[0015] Dissolve salicylic acid in water to prepare a salicylic acid solution of a certain concentration.

[0016] The prepared methyl jasmonate solution is mixed with a salicylic acid solution to prepare a mixed solution of salicylic acid and methyl jasmonate with a certain concentration.

[0017] 2.2 EGCG content determination: One bud and two leaves of the new shoots of tea trees grown that year were taken, sterilized by 700 W microwave for 45 seconds, and dried in an oven at 85 ℃ until completely dry. The EGCG content in the new shoots of tea trees was determined by HPLC according to the national standard "Determination of Tea Polyphenols and Catechins in Tea" (GB / T 8313-2018).

[0018] 2.3 Experiments and Results (1) Spraying methyl jasmonate alone: ​​5 different concentrations of methyl jasmonate solution were used for spraying, with a spraying volume of 1L / m 2 , and samples were taken at 8, 24, and 48 hours after spraying to determine the EGCG content. The results are shown in Table 1.

[0019] Table 1 Effects of different concentrations of methyl jasmonate on the EGCG content in tea leaves

[0020] As can be seen from Table 1, spraying 500 μmol / L methyl jasmonate solution for 48 hours had the most significant effect on EGCG enhancement, so subsequent experiments were carried out at this concentration.

[0021] (2) Spraying salicylic acid alone: ​​Five salicylic acid solutions of different concentrations were used for spraying, with a spraying volume of 1 L / m 2 , and samples were taken at 8, 24, and 48 hours after spraying to determine the EGCG content. The results are shown in Table 2.

[0022] Table 2 Effects of different concentrations of SA on EGCG content

[0023] As shown in Table 2, the best effect of EGCG enhancement was achieved by spraying salicylic acid solution with a concentration of 250 μmol / L for 48 hours, so subsequent experiments were conducted with this concentration.

[0024] (3) Clean water spraying: spraying volume is 1 L / m 2 , samples were taken after 48 h of treatment as blank control.

[0025] (4) Spray salicylic acid solution first, and then spray methyl jasmonate solution 8 hours later (the volume concentration of salicylic acid solution is 250 μmol / L, and the volume concentration of methyl jasmonate solution is 1 mL / L). The spraying volume is 1 L / m 2 , samples were taken after 48 h of treatment as comparative example 1.

[0026] (5) Spray the methyl jasmonate solution first, and then spray the salicylic acid solution 8 hours later (the volume concentration of the salicylic acid solution is 250 μmol / L, and the volume concentration of the methyl jasmonate solution is 1 mL / L). The spraying volume is 1 L / m 2 , samples were taken after 48 h of treatment as Comparative Example 2.

[0027] (6) Spraying a mixture of salicylic acid and methyl jasmonate (the volume concentration of salicylic acid in the mixture is 250 μmol / L, and the volume concentration of methyl jasmonate is 1 mL / L), with a spraying volume of 1 L / m 2 , samples were taken after 48 h of treatment as an example.

[0028] The EGCG content of the samples obtained in the comparative example and the example was measured, and the results are shown in Table 3: Table 3 EGCG content in tea leaves obtained by different treatments

[0029] It can be seen from Table 3 that the EGCG content in the tea leaves obtained in the example is significantly higher than that in the control example and the blank control example. It can be seen that the spraying method of the present invention can effectively increase the EGCG content in the tea leaves and improve the utilization value of the tea leaves.

[0030] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for increasing the EGCG content in fresh tea leaves, characterized in that: A mixed solution of salicylic acid and methyl jasmonate is sprayed on the leaves of the new shoots of tea trees of the current year to obtain fresh tea leaves with a high EGCG content.

2. The method for increasing the EGCG content in fresh tea leaves according to claim 1, characterized in that: The volume concentration of salicylic acid in the mixed solution is 250 μmol / L, and the volume concentration of methyl jasmonate is 1 mL / L.

3. The method for increasing the EGCG content in fresh tea leaves according to claim 1, characterized in that: The spraying rate of the mixed solution of salicylic acid and methyl jasmonate is 1 L / m 2 .

4. The method for increasing the EGCG content in fresh tea leaves according to claim 1, characterized in that: The fruits were harvested 48 h after spraying.

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