Abstract
Microwave Clevenger or microwave accelerated distillation (MAD) is a combination of microwave heating and distillation, performed at
atmospheric pressure without added any solvent or water. Isolation and concentration of volatile compounds are performed by a single stage.
MAD extraction of orange essential oil was studied using fresh orange peel from Valencia late cultivar oranges as the raw material. MAD has been
compared with a conventional technique, which used a Clevenger apparatus with hydro-distillation (HD). MAD and HD were compared in term
of extraction time, yields, chemical composition and quality of the essential oil, efficiency and costs of the process. Extraction of essential oils
from orange peels with MAD was better in terms of energy saving, extraction time (30 min versus 3 h), oxygenated fraction (11.7% versus 7.9%),
product yield (0.42% versus 0.39%) and product quality. Orange peels treated by MAD and HD were observed by scanning electronic microscopy
(SEM). Micrographs provide evidence of more rapid opening of essential oil glands treated by MAD, in contrast to conventional hydro-distillation.
© 2005 Elsevier B.V. All rights reserved.