GC/MS coupled with MOS e-nose and flash GC e-nose for volatile characterization of Chinese jujubes as affected by different drying methods

Volatile compounds in Chinese jujubes dried by different methods – hot-air (HAD), heat-pump (HPD), infrared radiation (IRD), vacuum (VD), vacuum freeze (VFD) and instant controlled pressure drop (DIC) drying – were analyzed using GC–MS, MOS e-nose, and flash GC e-nose. Acids comprised more than 90% of the aroma compounds in the dried jujubes, of which acetic, butanoic, propanoic, hexanoic, octanoic and decanoic acids were the most common. Jujubes dried using VFD had the highest content of total aroma compounds (1061.6 µg/kg), while DIC-dried jujubes had the most diverse profile (26 species). HPD-, IRD-, HAD- and VD-dried jujubes had similar aroma profiles based on GC–MS and flash GC e-nose results. Although the results of GC–MS, MOS e-nose, and flash GC e-nose were significant different (p < 0.05), their combination could characterize aroma profiles more comprehensively.