Unveiling the Impact of Withering Methods on Aroma Profile of White Peony Tea Through Integrating Metabonomics and Sensomics

Withering is a critical processing step that significantly influences the aroma quality of white tea. Although various withering methods are known to alter the aroma profile of white tea, the causal relationship between specific withering parameters and the resulting aroma signature remains elusive. This study systematically investigated the effects of sunlight withering (SW) and dark withering (DW) on the aromatic profile of white peony tea (WPT) made from three tea cultivars. Comparative analysis revealed that SW significantly attenuated the intensity of green aroma in WPT. Through orthogonal partial least squares-discriminant analysis (OPLS-DA) combined with odor activity value (OAV) evaluation, a total of 12 aroma-active compounds were identified. Aroma recombination models constructed using these compounds successfully reproduced the balanced sensory profile of WPT, encompassing green, fresh, sweet, and fatty notes. Omission experiments further elucidated the critical role of five volatile compounds in mediating withering-induced aroma variations: Linalool, ( Z )-3-hexen-1-ol, ( E )-2-hexenal, benzeneacetaldehyde, and β -ionone. These findings provide novel insights into the mechanisms of aroma modulation by different withering processes in WPT production.