How wrapping-twisting methods shape the aroma of spring oolong tea: a case study of Anxi Huangjingui

While mechanical processing is known to influence tea aroma, the targeted regulation of key odorants by specific wrapping-twisting methods remains poorly understood. The headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) method was employed to analyze the characteristic aroma compounds of extruding-rolling tea (ERT) and wrapping-rolling tea (WRT). Integrated analysis of differential compounds, VIP values from the OPLS-DA model, and ROC curve analysis identified 16 key aroma compounds that effectively differentiated WRT from ERT. Combined OAV and ACI analyses revealed that seven key aroma compounds contributed to ERT, imparting floral, green, and sweet notes. The 11 aroma compounds, especially β-ionone, methyl salicylate, hexanal, and 2-pentylfuran, were conducive to the floral, green and fruity aroma characteristics of WRT. Molecular docking demonstrated that the four key WRT aroma compounds were stabilized by hydrophobic interactions with olfactory receptors, elucidating the molecular basis for their "Qingxiang" perception. These findings revealed that different wrapping-twisting methods regulated aroma formation through selective accumulation of compounds and combined activation of receptors, providing a theoretical basis for the targeted regulation of oolong tea aroma profiles.