Method for increasing the content of ergothioneine in white tea of golden leaf

Abstract

The present application relates to the technical field of tea processing, and particularly relates to a method for increasing ergothioneine content in golden leaf white tea. The present application provides a method for increasing ergothioneine content in golden leaf white tea, comprising the following steps: wilting the golden leaf white tea for 24-60 hours to obtain wilted leaves; drying the wilted leaves at 60-70 DEG C to obtain rough tea; picking, blending, uniform stacking and packaging the rough tea to obtain the golden leaf white tea. The present application first discovers the existence of ergothioneine in tea, and maximally retains the ergothioneine in tea by regulating the wilting time and drying temperature; and the golden leaf prepared by the present application is rich in the important functional component ergothioneine, has good antioxidant health care function, and provides a new way for the development of high value-added functional tea products.

Description

Technical Field

[0001] This invention relates to the field of tea processing technology, and in particular to a method for increasing the ergothioneine content in Golden Leaf White Tea. Background Technology

[0002] White tea is one of the six major traditional tea categories in China, named for its finished product consisting mostly of buds covered in white down, resembling silver and snow. Not only does white tea possess a unique flavor and quality, but it also boasts excellent health benefits, making it widely popular among consumers. Withering is the most crucial process in the formation of white tea's quality. During withering, the tea leaves undergo a series of complex physical and chemical changes that directly affect the color, aroma, taste, and nutritional value of the finished tea. Withering too quickly or too slowly will negatively impact the quality of white tea to varying degrees; too short a time results in insufficient oxidation, high polyphenol content, and a strong bitter taste; too long a time leads to the consumption of major biochemical components, resulting in a weak flavor and hindering the formation of quality.

[0003] Golden Leaf is a new photosensitive, yellow-toned mutant green tea variety, first successfully cultivated in Anji, Zhejiang Province. Golden Leaf buds have an amino acid content as high as 9%, while ordinary tea buds contain only 3% to 4%. Golden Leaf exhibits stable characteristics, with its leaves remaining consistently golden yellow. In early spring, Golden Leaf has a fresh and invigorating flavor, with both the leaf base and the tea liquor displaying a certain yellow hue, resulting in a unique quality and flavor. As a high-quality tea variety, Golden Leaf has enormous potential for developing high-value-added white tea products.

[0004] Ergothioneine (EGT) is a natural, non-toxic, rare amino acid derivative widely found in edible fungi and has been proven to possess excellent antioxidant activity. Studies have shown that ergothioneine exhibits various biological activities, including antioxidant, anti-inflammatory, and anti-tumor effects. In terms of antioxidant activity, ergothioneine can effectively scavenge free radicals in the body, protecting cells from oxidative damage. The human body cannot synthesize ergothioneine and must obtain it through diet. Currently, ergothioneine is mainly extracted from edible fungi, which limits its availability and costs, restricting its widespread application.

[0005] Tea, as a natural plant resource rich in various functional components, has been the subject of numerous studies focusing on the health benefits of its polyphenols, amino acids, alkaloids, and other components. However, there are currently no research reports, either domestically or internationally, on the ergothioneine content in tea and its processing regulation. Whether tea contains ergothioneine and whether the processing method affects ergothioneine accumulation are both areas of technological gaps in this field.

[0006] Therefore, it is necessary to provide a withering process for Golden Leaf White Tea rich in ergothioneine to address the current research gap on ergothioneine in tea and the technical problem of how to effectively enrich the ergothioneine content in Golden Leaf through withering. Summary of the Invention

[0007] The purpose of this invention is to provide a method for increasing the ergothioneine content in Golden Leaf White Tea while maintaining its excellent sensory quality.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for increasing the ergothioneine content in Golden Leaf White Tea, comprising the following steps: (1) Wither the golden leaf white tea leaves for 24-60 hours to obtain withered leaves; (2) Dry the withered leaves at 60~70℃ to obtain raw tea; (3) The raw tea leaves are sorted, blended, mixed and packaged to obtain Golden Leaf White Tea.

[0009] Preferably, in step (1), the Golden Leaf White Tea is made from one bud and two leaves of fresh tea leaves.

[0010] Preferably, in step (1), the withering method is natural withering.

[0011] Preferably, the withering temperature is 15~25℃.

[0012] Preferably, in step (1), the withering time is 42-54 hours.

[0013] Preferably, in step (2), the withering temperature is 60°C.

[0014] Preferably, in step (2), the moisture content of the raw tea is 5-7%.

[0015] The present invention also provides a method for preparing golden leaf white tea rich in ergothioneine.

[0016] The present invention also provides the application of the golden leaf white tea prepared by the method or the golden leaf white tea in the preparation of antioxidant products.

[0017] Beneficial effects: This invention is the first to discover the presence of ergothionein in tea and systematically studies the dynamic changes of ergothionein during the natural withering process of golden leaves (0~60h), filling the gap in the research on ergothionein in tea and opening up a new direction for the research on functional components of tea.

[0018] This invention provides a method for increasing the ergothioneine content in Golden Leaf White Tea. This method maximizes the retention of ergothioneine in tea leaves by controlling the withering time and drying temperature. The golden tea leaves prepared by this invention are rich in ergothioneine, an important functional component, and have good antioxidant and health-promoting functions, providing a new approach for the development of high-value-added functional tea products. Attached Figure Description

[0019] Figure 1 A diagram illustrating the morphological changes of Golden Leaf White Tea during its natural withering process. Figure 2 Ergothionein content in wilted leaves at different wilting times; Figure 3 The content of ergothioneine in Golden Leaf White Tea at different drying temperatures. Detailed Implementation

[0020] This invention provides a method for increasing the ergothioneine content in Golden Leaf White Tea, comprising the following steps: (1) Wither the golden leaf white tea leaves for 24-60 hours to obtain withered leaves; (2) Dry the withered leaves at 60~70℃ to obtain raw tea; (3) The raw tea leaves are sorted, blended, mixed and packaged to obtain Golden Leaf White Tea.

[0021] In this invention, in step (1), the Golden Leaf White Tea is made from one bud and two leaves of tea leaves.

[0022] In this invention, in step (1), the withering method is natural withering; the withering temperature is 15~25℃, preferably 18~22℃, and more preferably 20℃; the natural withering of spring tea is carried out under this temperature condition, which is conducive to the orderly transformation of various biochemical components inside the tea leaves; during the withering process, as the moisture gradually dissipates under certain temperature and humidity conditions, the concentration of contents in the leaf cells changes, which stimulates the activity of various enzymes, causes the decomposition of organic matter, and promotes the change of various components.

[0023] In this invention, the natural withering is carried out in a well-ventilated environment that avoids direct sunlight; the leaf spreading rate is 2~4 kg / m². 2 The preferred value is 3kg / m 2 This is to ensure air circulation and even moisture loss during the withering process.

[0024] In this invention, the withering time is preferably 42-54 hours, and more preferably 48 hours.

[0025] In this invention, in step (2), the drying temperature is preferably 60°C; withering until the moisture content of the withered leaves reaches below 20% is considered appropriate; the drying temperature is stable to prevent sudden changes in temperature, so as to ensure the uniformity of tea quality; In this invention, in step (2), the moisture content of the raw tea is 5-7%, preferably 6%.

[0026] In this invention, in step (3), sorting: the dried tea leaves are sorted to remove impurities and leaves that do not meet the requirements; blending: the sorted tea leaves are blended according to the quality requirements; uniform piling: the blended tea leaves are uniformly piled; packaging: the uniformly piled finished tea is packaged to obtain golden leaf white tea rich in ergothioneine.

[0027] The present invention also provides a method for preparing golden leaf white tea rich in ergothioneine.

[0028] The present invention also provides the application of the golden leaf white tea prepared by the method or the golden leaf white tea in the preparation of antioxidant products.

[0029] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0030] Example 1

[0031] Select one bud and two leaves from the Golden Leaf White Tea variety, removing diseased, insect-damaged, reddened, and damaged leaves, as well as any impurities; then apply 2-3 kg / m³ of fresh leaves. 2 The leaves were evenly spread on a clean withering screen and allowed to wither naturally for 0h, 6h, 12h, 18h, 24h, 36h, 42h, 48h, 56h, and 60h in an indoor environment at 20℃, avoiding direct sunlight and maintaining slow ventilation, to obtain withered leaves (morphological changes as shown in the image). Figure 1 (as shown) The ergothionein content in wilted leaves was determined by HPLC, and the results are as follows: Figure 2 As shown; The determination method steps are as follows: (1) Instruments and equipment: high performance liquid chromatograph, AQ-C18 column (4.6×250mm, 5μm), ultrasonic cleaner, analytical balance, high speed centrifuge; (2) Reagents: Ergothioneine standard (purity ≥98%), 0.1% phosphoric acid aqueous solution, 0.22μm organic nylon membrane; (3) Preparation of standard curve: Accurately weigh 2.5 mg (accurate to 0.01 mg) of ergothioneine standard and place it in a 5 mL volumetric flask. Dissolve it in 70% methanol solution and dilute to the mark. Shake well to obtain the standard stock solution. Prepare a series of standard solutions with concentrations of 0.5 μg / mL, 1.0 μg / mL, 1.5 μg / mL, 2.0 μg / mL, 3.0 μg / mL, 5 μg / mL, 10 μg / mL and 15 μg / mL using 70% methanol solution. (4) Sample pretreatment: The tea samples were freeze-dried and then ground into powder; (5) Ergothioneine extraction method: Weigh 0.5g of tea powder into a 10mL centrifuge tube, add 10mL of 70% methanol aqueous solution, mix by inversion, extract with ultrasonic assistance for 10min, then make up to 10mL with extraction solvent, centrifuge at 8000rpm for 5min, take the supernatant and filter it through a 0.22μm filter membrane for analysis; (6) HPLC analysis conditions: The chromatographic column was AQ-C18 (4.6×250mm, 5μm), the mobile phase was 0.1% phosphoric acid aqueous solution, the flow rate was 0.7mL / min, the column temperature was 25℃, the detection wavelength was 254nm, and the injection volume was 10μL; the gradient program was 0~50 min, and the mobile phase was 100%; The results showed that within the withering time range of 0–60 h, the ergothionein content generally increased with the extension of withering time. In unwithered fresh leaves, the ergothionein content was extremely low or undetectable. As the withering time increased from 24 h to 48 h, the ergothionein content in the golden leaves showed a gradual increasing trend. Significant accumulation of ergothionein was observed after 24 h of withering; the content further increased after 36 h of withering; and reached a relatively high level of 252.36 μg / g after 48 h of withering. This indicates that appropriately extending the withering time is beneficial for the enrichment of ergothionein in golden leaves.

[0032] Example 2

[0033] (1) Select one bud and two leaves of the Golden Leaf White Tea tree variety, remove diseased and insect-infested leaves, reddened leaves, damaged leaves and impurities; then spread them evenly on a clean withering sieve with a thickness of 2-3 cm, and wither naturally for 48 hours in an indoor environment at 20℃, avoiding direct sunlight and maintaining slow ventilation, to obtain withered leaves (moisture content up to 20%). (2) The withered leaves were dried once under constant temperature hot air conditions at 40℃, 50℃, 60℃ and 70℃ respectively until the moisture content was 6%. They were then taken out and cooled to obtain raw tea. (3) The raw tea leaves are sorted, blended, mixed and packaged to obtain Golden Leaf White Tea.

[0034] The ergothioneine content of Golden Leaf White Tea was determined according to the method described in Example 1, and the results are as follows: Figure 3 As shown; The results showed that drying temperature significantly affected the retention of ergothioneine in tea. Among the four drying temperatures of 40℃, 50℃, 60℃, and 70℃, 60℃ showed the best retention effect and the highest content of ergothioneine, reaching 242.56 μg / g. Drying at 60℃ could reduce the moisture content of tea to a safe storage level in a shorter time, shortening the contact time between ergothioneine and oxidases during the drying process. Simultaneously, treatment at 60℃ helped to inactivate the activity of residual enzymes such as polyphenol oxidase, reducing enzymatic degradation and oxidative loss of ergothioneine during the drying process. In contrast, drying at 40℃ and 50℃ required longer times, and the tea was exposed to a warm and humid environment for an extended period during drying, which could lead to loss of ergothioneine due to enzymatic oxidation or microbial metabolism. Therefore, 60℃ is the optimal drying temperature for ergothioneine retention.

[0035] As can be seen from the above embodiments, the present invention provides a method for increasing the ergothioneine content in Golden Leaf White Tea. This method significantly increases the ergothioneine content in the finished white tea.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for increasing the ergothioneine content in Golden Leaf White Tea, characterized in that, Includes the following steps: (1) Wither the golden leaf white tea leaves for 24-60 hours to obtain withered leaves; (2) Dry the withered leaves at 60~70℃ to obtain raw tea; (3) The raw tea leaves are sorted, blended, mixed and packaged to obtain Golden Leaf White Tea.

2. The method according to claim 1, characterized in that, In step (1), the Golden Leaf White Tea uses one bud and two leaves as raw material.

3. The method according to claim 1, characterized in that, In step (1), the withering method is natural withering.

4. The method according to claim 3, characterized in that, The withering temperature is 15~25℃.

5. The method according to claim 1, characterized in that, In step (1), the withering time is 42-54 hours.

6. The method according to claim 1, characterized in that, In step (2), the drying temperature is 60°C.

7. The method according to claim 1, characterized in that, In step (2), the moisture content of the raw tea is 5-7%.

8. The method according to any one of claims 1 to 7 is used to prepare golden leaf white tea rich in ergothioneine.

9. The use of the Golden Leaf White Tea prepared by the method according to any one of claims 1 to 7 or the Golden Leaf White Tea according to claim 8 in the preparation of antioxidant products.

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