关键词: 红茶, 加工, LC-Q-LIT-OT-MS, 代谢组学

Abstract:

To explore the dynamic changes of secondary metabolites in five processing stages (fresh leaf plucking，withering，rolling，fermentation and drying) of‘Danxia 2’black tea and the impact of those metabolites on the formation of black tea quality，liquid chromatography coupled with a hybrid quadrupole linear ion trap orbitrap mass spectrometry（LC-Q-LIT-OT-MS）-based metabolomic study is performed. In‘Danxia 2’tea leaves，124 metabolites were identified，including 22 catechins，19 catechin polymers， 32 flavone and flavone glycosides. Multivariate statistical analysis of metabonomic data showed that during the black tea processing of‘Danxia 2’，there were 162，412，308，and 126 metabolites significantly changed from fresh leaves plucking to withering，withering to rolling，rolling to fermentation，and fermentation to drying，respectively. The type and content of metabolites of black tea quality characteristic components changed most significantly during rolling and fermentation. The content of catechins showed a downward trend as a whole. The relative contents of catechin polymers increased dramatically at the rolling period，and then decreased gradually during the fermentation and drying process. The content of flavone and flavone glycosides showed an increasing trend，mainly peaked at the rolling or fermentation stage. The contents of catechins，catechin polymers，flavone and their glycosides showed positive correlation with the contents of aspartic acid，glutamine，phenylalanine and soluble sugar.

Key words: black tea, processing, LC-Q-LIT-OT-MS, metabolomics