Identification of Volatile Flavor Compounds of Zaobaijian Black Tea Harvested in Different Seasons Based on HS-SPME-GC-MS and PLS-DA

By using headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), the volatile flavor compounds were determined for 15 Zaobaijian black tea samples harvested in spring, summer and autumn in Junlian, Sichuan Province. Subsequently, a discriminant model partial least square-discriminant analysis (PLS-DA) was used and a hierarchical cluster analysis of the dendroid heat map was drawn to determine the distribution of key aroma components from different harvest seasons. Results showed that the alcohol content (113.05 μg/g) and esters (34.92 μg/g) in the spring samples were significantly higher than those from the summer and autumn samples, while the aldehydes (23.85 μg/g) were significantly lower than those in the summer and autumn samples. The established PLS-DA model could distinguish between tea samples harvested in spring and those harvested in summer and autumn. Moreover, the heat map cluster analysis showed that hyacinthin, nerol and (Z)-geraniol were the key aroma component that distinguished the spring tea samples from the summer and autumn tea samples. Cis-linalool oxide and trans-linalool oxide (furanoid) were the key aroma components that distinguished the summer tea samples from autumn tea samples. This study provides basic research data for analyzing the aroma components of Zaobaijian black tea from different seasons and lays a foundation for further exploration into the key aroma formation mechanism of Junlian Zaobaijian black tea.