Abstract:Fresh double-petalled jasmine was used as the raw material for the comparative analysis of the color, physicochemical composition, antioxidant capacity, amino acid components and volatile aroma components of the flowers dried by hot-air drying (HD), microwave drying (MVD), microwave combined with hot-air drying (MVD+HD), and vacuum freeze-drying (FD). The results showed that the jasmine dried by FD had the highest L*, lowest a*and ΔE, highest contents of chlorophyll and total phenolics, and highest hydroxyl radical-inhibitory ability. The jasmine dried by MVD+HD had the highest total amino acid content, essential amino acid content and essential amino acids ratio (8.32 mg/g, 2.67 mg/g and 32.09%, respectively). The relative contents of alcohols in the dried flowers were the highest. Among the four groups, the relative contents of alcohols, esters and aldehydes of the FD group were 53.37%, 5.40% and 17.99%, respectively. The HD group had the highest relative contents of ketones, alkanes and acids, and the MVD group had the highest relative contents of alkenes and other kinds of volatiles, indicating that FD could retain the main aroma substances of jasmine flower to the greatest extent, whilst HD caused the largest loss. In general, the jasmine dried by FD had the best color and aroma and could be developed into high-end jasmine products. Whereas, MVD+HD could preserve the aroma and nutritional quality of jasmine , thereby being suitable for industrial production and used as an ideal drying method for drying jasmine flowers.
