Forsythia suspensa flowers are a promising raw material for herbal infusions, but the effects of drying on their flavor and chemical composition remain unclear. Four drying methods, freeze-drying (FD), indoor shade drying (ID), sun drying (SD), and hot-air drying (HAD), were evaluated using an electronic nose, an electronic tongue, HS-GC-MS, LC-MS, sensory evaluation, and correlation analyses. Significant differences in aroma, taste, and overall acceptability scores were observed between drying treatments. HAD samples showed stronger sweetness, bitterness, and umami responses, whereas FD samples showed higher W1W (mainly responsive to terpenes) and W2W (mainly responsive to aromatic compounds) sensor responses. In total, 72 volatile and 148 non-volatile compounds were identified. Aldehydes were the main volatile class, showing the highest relative abundance in SD, whereas terpenes were highest in HAD. OAV analysis revealed 38 volatile compounds with OAV > 1, with nonanal as the major contributor in all groups. LC–MS screened 62 differential non-volatile compounds across the four drying treatments. Pairwise comparisons with FD showed 46 differential compounds, with HAD showing the most distinct changes. Overall, the flavor differences across drying treatments were closely associated with changes in volatile and non-volatile compounds, and HAD showed better potential for standardized processing.
Xie et al. (Fri,) studied this question.