Abstract:
The effects of four drying methods, sun drying, hot air drying, vacuum drying and vacuum freeze drying on physicochemical properties and essential oil quality of
Melaleuca alternifolia Cheel were studied. The results showed that the contents of flavonoids was the highest in
M. alternifolia after hot air drying and the contents were(2.68±0.27)%; the DPPH·and ABTS
+ scavenging activities of the
M. alternifolia after freeze-drying were the lowest and the scavenging rates were (53.74±4.58)% and (71.63±2.95)%, respectively. After drying by four methods, the extraction rates of essential oil decreased. The oil extraction rate was the highest after the freeze drying. The contents of terpinen-4-ol and 1, 8-cineole in the essential oil obtained were higher than 30% and less than 5%, respectively after drying process. The difference of the contents of terpineol-4-ol in the essential oil obtained after sun drying and hot air drying was significant, and the content obtained after the sun drying was the highest. The content of 1, 8-cineole in the essential oil obtained after vacuum freeze drying was the lowest.