Metabolomic insights into seasonal variations in Darjeeling orthodox tea: implications for quality, flavor, and...

Tea, one of the most widely consumed non-alcoholic beverages, holds global acclaim, with Darjeeling tea renowned for its unique flavor and aroma. This study provides a comprehensive, untargeted metabolomic analysis of Darjeeling orthodox tea to understand the impact of seasonal variations on its physiochemical properties and metabolite composition. Six tea samples from two elevations and three plucking seasons (spring, summer-monsoon, and autumn) were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). Key physiochemical parameters, including moisture content, ash content, and pH, were evaluated, revealing variations influenced by factors such as soil nutrients and environmental conditions. Multivariate statistical analyses, including PCA and PLS-DA, showed significant differences in metabolite profiles across seasons in the two selected gardens. Amino acids, organic acids, sugars, and phenolic compounds were identified as critical contributors to these variations. Metabolites such as aspartic acid, L-proline, catechins, and sugars like sucrose and raffinose demonstrated seasonal patterns, serving as potential biomarkers. The study highlights the influence of seasonal variations on metabolite accumulation, contributing to the characteristic quality of Darjeeling tea. These findings provide valuable insights into optimizing cultivation practices and enhancing the sensory and nutritional qualities of black tea.

The online version contains supplementary material available at 10.1007/s13197-025-06310-2.