Spreading Degree Modulates Floral Aroma Development in Green Tea: Integrated GC-E-Nose, Metabolomics, and Molecular Docking Reveals Key Odorants and Olfactory Receptor Interactions

The spreading process constitutes a pivotal stage in green tea manufacturing. This study integrated GC-E-Nose with targeted metabolomics to comprehensively elucidate the dynamic changes in sensory characteristics and aroma substances of green tea across varying spreading degrees. Our findings demonstrated that spreading degree significantly modulated green tea's aroma profile, with lighter degree particularly promoting the development of desirable floral aroma. GC-MS/MS quantification identified 70 volatile compounds, among which 38 exhibited spreading-dependent differential accumulation (VIP > 1.0, p < 0.05). Five key odorants, including indole, β-ionone, nerolidol, cis-jasmone, and β-damascenone, were highlighted as essential contributors to the floral aroma. Molecular docking simulations indicated stronger binding affinities between these five odorants and the olfactory receptor OR1D2 (<-6 kcal/mol), primarily via hydrogen bonding and hydrophobic interactions. These findings indicate that modulating the spreading degree is an effective processing strategy to enhance the development of floral aroma in green tea, offering valuable insights for precision-driven optimization of tea processing protocols.