Characterization of Key Odorants in Xinyang Maojian Green Tea and Their Changes during the Manufacturing Process

Xinyang Maojian (XYMJ) green tea is a famous high-grade Chinese green tea, but the key odorants contributing to its aroma have been poorly understood. In this study, solid-phase microextraction and solvent-assisted flavor evaporation were used for sample preparation, and gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) were used for both qualitative and quantitative analysis. A total of 50 volatile compounds of five chemical classes were identified in XYMJ tea infusion. Among them, nine odorants including nonanal, β-ionone, octanal, E-nerolidol, linalool, cis-3-hexenyl hexanoate, geraniol, decanal, and β-cyclocitral were identified as key odorants of XYMJ based on GC-O, odor activity values, and aroma combination experiments. Changes in the content of these aroma-active compounds during the manufacturing process of XYMJ (fresh leaves, fixing, rolling, shaping, and drying) were also determined. Most aroma-active compounds decreased after the fixation process, with the exception of cis-3-hexenyl hexanoate. This is the first study to investigate the key odorants in XYMJ using the sensomics approach. The findings of this study provide novel information on the aroma quality of XYMJ.