Changes and dynamics of the main quality components in tea leaves of 4 tea cultivars during the shading process

Abstract

The purpose of this study was to analyze the relationship between different shading conditions, picking time for main quality components of tea. The main quality components of 4 tea cultivars [Camellia sinensis (L.) O. Kuntze], including the separated tea shoot tissues (leaves, buds, stems), under 4 shading rates during the traditional 20-day shading period were examined. Results showed the Chlorophyll contents after 12 days of shading treatment were significantly higher than control, but after that it ceased increasing significantly Initially, the theanine, total free amino acid, caffeine, and tea polyphenol contents showed decreased trend but then leveled off after 12 days. The increase of free amino acids, caffeine, chlorophyll and the decrease of tea polyphenols induced by shading were mainly determined by shading level and tenderness. Meanwhile, shading changed the proportion of main quality components in tea leaves and stems, long-term shading does not promote high quality matcha. All of the results indicated the quality of matcha with grade 1 could be produced by shading rate of 80 % and shading for 12 days. Appropriate shading time and shading rate are beneficial to improve the quality of Matcha.