The differential analysis of volatile substances from Gucong green tea

Gucong tree leaves ( Camellia sinensis var. assamica ) are conventionally processed into white or oolong tea, with limited application in green tea production. This study aims to investigate and elucidate the quality and aroma characteristics of green tea manufactured from Gucong tree leaves, focusing on the influence of bud-to-leaf ratio and thermal processing parameters (drying and roasting) on aroma development. The volatile substances, including both free and bound forms, were analyzed using the headspace solid–phase micro-extraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS). And the aroma characteristics were further examined through the multivariate statistical analyses, including principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA), and the odor activity value (OAV) calculations. A total of 51 volatile compounds were identified in fresh leaves and derived green tea, with 11 key aroma-active compounds discerned. Geraniol and linalool emerged as the most abundant constituents, while alcohols dominated the volatile fraction. Notably, there were 11 compounds, including 1-octen-3-ol, geraniol, and benzene-acetaldehyde significantly contributed to the overall aroma. Aroma radar plots further defined Gucong green tea by its distinct floral, sweet, and green notes. The origin of the raw materials and the drying processes were identified as the critical factors influencing the generation of the green aroma. These findings significantly enhance our understanding of the production and processing of Gucong leaves.