Effects of different drying methods on the aroma and metabolic profiles of Chrysanthemum morifolium cv. Chuju

Chrysanthemum morifolium cv. Chuju is a high-value edible flower with unique aroma characteristics but is susceptible to quality deterioration during drying. This study systematically evaluated the effects of four drying methods, including natural drying (ND), hot-air drying (HAD), microwave drying (MD), and vacuum freeze-drying (VFD), on the aroma profiles and metabolic characteristics of Chuju using sensory quantitative descriptive analysis (QDA), electronic nose ( E -nose), gas chromatography-ion mobility spectrometry (GC–IMS), and untargeted metabolomics. A total of 90 volatile compounds and 2605 metabolites were identified. Drying treatments significantly altered volatile fingerprints and metabolic profiles. HAD exhibited higher signal intensities of several volatile compounds potentially associated with heat-induced transformations, whereas VFD showed relatively higher levels of aroma-related volatile compounds and thermolabile metabolites. Metabolite–volatile correlation analysis indicated that aroma differentiation among drying treatments was associated with amino acid metabolism, lipid oxidation-related pathways, phenylpropanoid metabolism, and flavonoid-related metabolism. These findings provide insights into the metabolic basis underlying drying-induced aroma variation and contribute to the optimization of Chuju drying strategies for quality preservation.