This paper reviews the recent progress of tea extracts in cosmetics. At present, tea polyphenols are most widely used in cosmetics, especially epigallocatechin gallate, which has been applied in antioxidant and anti-aging products with excellent antioxidant activity. However, there are some problems related to the application of epigallocatechin gallate such as poor stability, low bioavailability, and high requirements for formula compatibility. In recent years, the application of tea alkaloids has gradually increased, because it has multiple effects including anti-oxidant, anti-aging and soothing. Theanine has the potential to be used in products for relieving, soothing and repair sensitive skin. Tea extract is one of the most popular raw materials of cosmetics, which has won the attention of consumers and manufacturers at home and abroad. In the future, combined with the new extraction and purification technology and marketing requirements, further research on the active ingredients and effects of tea will promote the full use of tea extract in cosmetics.

To study the quality changes of Jinggu Big White Tea during storage over different years,samples aged from 1 to 7 years were collected. Sensory evaluation, biochemical component analysis, and taste activity value (TAV) calculation were conducted to assess quality variations. The sensory evaluation revealed that with prolonged storage, the aroma of the tea shifted from floral and sweet to a stale aroma, with samples aged over five year being dominated by stale aromas. The taste also transformed from fresh and sweet to mellow. With increasing aging years, the content of certain compounds such as gallic acid, ellagic acid, rutin, myricetin, quercetin, and luteolin increased significantly; while most amino acids and catechin decreased, and the level of caffeine and certain amino acids such as phenylalanine fluctuated. Additionally, seven characteristic components with TAV＞1 were identified, including caffeine, epicatechin gallate, and epigallocatechin gallate responsible for bitterness, and epigallocatechin, epigallocatechin gallate, epicatechin gallate, and gallic acid responsbile for astringency. This study clarified the variations in sensory quality and characteristic taste compounds of Jinggu Big White Tea at different storage years, providing a foundation for systematic analysis of its aging mechanism.

Ten representative sun-dried green tea were collected from the tea area in Lincang. Sensory evaluation showed that the overall appearance was dark green and straight, the infusion color was light yellow and bright, the taste was strong, mellow and sweet aftertaste, the aroma was fresh and rich, and the infused leaves were yellow-green. The characteristic components in tea leaves were measured with contents as follows: water extract (45.19%～49.01%), free amino acids (1.62%～2.85%), soluble sugar (5.6%～9.76%), gallocatechin (11.65～33.34 mg/g), epicatechin gallate (14.49～23.39 mg/g), epigallocatechin gallate (10.75～22.40 mg/g), caffeine (9.29～15.78 mg/g), theophylline (0.02～0.13 mg/g), theanine (8.06～20.16 mg/g), glutamic acid (2.23～4.23 mg/g), aspartic acid (2.01～3.29 mg/g), etc. The preliminary results showed that the contents of catechins, caffeine, amino acids in Lincang tea were relatively low, while water extract, soluble sugars, and gallic acid (GA) were relatively high.. Taste activity value (TAV) analysis revealed six characteristic components with TAV＞1 including: epigallocatechin, epicatechin gallate, gallocatechin, gallic acid contributing to astringency; epicatechin gallate, caffeine, epigallocatechin gallate contributing to bitterness. This study clarified the taste characteristics and material basis of sun-dried green tea in the Lincang tea area which provided a reference for further systematic analysis of its taste component.

In this study, Debaryomyces hansenii PETY002, isolated from Pu-erh tea, was used for enhanced fermentation (EF) of Pu-erh tea. The total number of yeast colonies was significantly higher in the EF group than in the natural fermentation (NF) group. Sensory evaluation revealed that the tea infusion from the EF group was darker in color, mellower in taste, and had a mushroom-like aroma. Compared with NF, EF showed an increase in the contents of theabrownins and water extracts and a decrease in the contents of tea polyphenols, catechins including catechin (C), epigallocatechin (EGC), gallocatechin (GC) and epigallocahechin-3-gallate (EGCG), and caffeine. On the other hand, there was little difference in the contents of flavonoids or amino acids. Microbial community analysis revealed that Debaryomyces was the dominant fungus in EF. Furthermore, there was a competitive interaction between Debaryomyces and Thermomyces. Correlation analysis revealed that Debaryomyces were positively correlated with theabrownins, but negatively correlated with soluble sugars and theaflavins. In conclusion, inoculation with D. hansenii PETY002 changed the diversity and composition of the microbial community during Pu-erh tea fermentation, which improved the quality of Pu-erh tea through interactions with other dominant microorganisms.