Identification of the discriminatory chemical markers of different grades of Sri Lankan white, green and black tea (Camellia sinenesis L.) via metabolomics combined to chemometrics

Abstract

In the current study, seven Sri Lankan tea grades; Orange Pekoe, Flowery Pekoe, Broken Orange Pekoe Fannings, Broken Orange Pekoe black tea, green tea, silver tips and golden tips white tea grades were subjected to comprehensive metabolic profiling using UPLC-MS/MS combined with chemometrics. Theasensinin C and E, theaflavin and theacitrin were the main chemical markers of black tea type, catechin, epicatechin, epigallocatechin, methyl epigallocatechin were the main discriminatory markers of green tea type, while theanine, oolongotheanine and quercetin glycosides were the main chemical markers of white tea type. Theogalloflavin, epigallocatechin and flavonoid glycosides were the main down-accumulated metabolites while theaflavin gallate, and N-ethyl pyrrolidinone epicatechin were the chief up- accumulated metabolites between whole and broken black tea leaves grades while puerin A and C and gallic acid were the main down-accumulated metabolites and N-ethyl pyrrolidinone epicatechin gallate was the main up-accumulated one between broken and fanning black tea grades.