Volatile profile characterization during the drying process of black tea by integrated volatolomics analysis
Lilei Wang, Jialing Xie, Yuliang Deng, Yongwen Jiang, Huarong Tong, Haibo Yuan, Yanqin Yang
Abstract
Drying plays an important role in the development of high-quality aroma in black tea. In this study, changes in the volatile profiles of Congou black tea samples subjected to different drying times were comprehensively characterized via gas chromatography-electronic nose, gas chromatography-mass spectroscopy, and gas chromatography-ion mobility spectroscopy (GC-IMS) analyses. Different drying times generated different aroma types (e.g., floral and sweet aromas, etc.). Forty-five minutes of drying treatment was identified as a critical time point for the formation of tea aroma quality, since at this point additional drying caused a decline in aroma quality. Here we identified a total of 90 volatile organic compounds, mainly alcohols and aldehydes, using GC-IMS. Based on the volatile fingerprints generated by GC-IMS, an authentic orthogonal partial least squares discriminant analysis model with credible parameters (R2Y = 0.921, Q2 = 0.817) was established. Moreover, using variable importance in projection >1.35 and p < 0.05 as filtering criteria, four key differential components were identified. This study provides a new perspective for understanding the dynamic changes occurring during drying and lays a theoretical foundation for precise and quality-oriented processing of Congou black tea.