Effect of Vacuum Freeze-drying and Hot-air Drying on Volatile Components of Onion
Volatile components of fresh onion, vacuum freeze-drying onion and hot-air drying onion were obtained by simultaneous distillation-extraction (SDE) ,36,33,27substances were analyzed by GC-MS. The components included sulfide compounds, organic acids, ethers, aldehydes, esters andhydrocarbons. Through vacuum freeze-drying and hot-air drying, 14 and 12 kinds of substances were separately preserved, each total peak area was 55.59% and 53.16%. Vacuum freeze-drying is more favorable to the qualities of drying onion.