GCMS based metabolite profiling of first flush Darjeeling tea (orthodox) through the processing steps: First report.

Climatic and soil conditions affect the first flush metabolite composition of the economic crop Darjeeling tea, can impact flavour, nutrition and overall consumer preferences. We sampled Camellia sinensis var. sinensis grown in Darjeeling hills and from different processing steps.75 metabolites have been illustrated utilizing GC/MS based metabolomic and chemometric tool. Metabolomic profiling performed across production will aim identification of quality markers and establishing database applicable for Darjeeling tea authentication, the first GI product of India. PCA and PLSDA show differences in tea metabolites through the processing steps. The chemometric analysis elucidates the changes in important metabolites. The antioxidant activity showed significant changes. The amino acids enhanced significantly (p < 0.05), from fresh tea leaves to finally processed product. The organic acids, inorganic acids and fatty acid compounds decreased. Among the phenolic compounds, caffeic acids, epicatechin, epigallocatechin, chlorogenic acid, 3, 4-dihydroxybenzoic acid and 4-hydroxycinnamic acid showed increase in their concentration, whereas catechin, (-) - epicatechin, gallic acid, pyrogallol, quinic acid, shikimic acid, arbutin showed remarkable decrease in concentration in finally processed tea. The flavonoids kaempferol and taxifolin showed significant decrease in their concentration.During first flush meteorological parameters recorded along with variation of PM 2.5 , PM 10 , O 3 , NO 2 , and SO 2 concentrations and AQI.