Exploring the impact of diverse combinations of withering methods and drying temperatures on the quality characteristics of white tea

While withering and drying are key variables influencing white tea (WT) flavor, the combined effects of different withering methods and drying temperatures remain elusive. The current study investigated variations in sensory profiles, non-volatile and volatile compounds in WT under three withering methods and drying temperatures (55 °C, 80 °C, and 105 °C) combinations. Among groups, the tank withering groups yielded relatively better taste, including sweetness, freshness and sweet aftertaste, alongside lower bitterness. Increasing drying temperature elevated bitterness and baking aroma intensity while decreasing sweet aftertaste and sweetness. A prominent fresh floral aroma was observed under the medium drying temperature. In terms of non-volatile compounds, polyphenol levels increased with elevated drying temperature, while amino acid contents were mostly accumulated under medium drying temperature across all three withering methods. Additionally, non-targeted metabolic analysis revealed significant differences among combinations. Moreover, a total of 66 volatile compounds were identified across all groups, with phytol, methyl salicylate, benzaldehyde, benzeneacetaldehyde, and nonanal exhibiting higher odor activity values (OAV > 1), indicating their significant contribution to the aroma of WT. Furthermore, after optimization via optimal design analysis, the predicted optimal processing parameters for WT were tank withering combined with a drying temperature of 84 ℃. Overall, the findings underscore the crucial role of different combinations of withering methods and varying drying temperatures in shaping the flavor profile of WT, which provides a theoretical basis for WT processing.