Microwave‐assisted hydrodistillation of essential oil from Zataria multiflora Boiss

Microwave‐assisted hydrodistillation (MAHD) has recently gained attention for the extraction of essential oils. A concern with the use of MAHD is the possibility of sample deterioration during the extended exposure to microwave irradiation. In this study, MAHD was applied as a new and green technology for the extraction of essential oil from Zataria multiflora Boiss. (Shirazi thyme) aerial parts. Superior results were obtained with the proposed method in terms of extraction time [1 h vs. 4 h in hydrodistillation (HD)] for an essential oil recovery of 3.66 and 3.44%, respectively. Images obtained from thyme leaves using scanning electron microscopy indicated a sudden eruption of essential oil glands undergoing MAHD. GC‐MS analysis of the essential oils did not indicate any new or missing compounds in the essential oil obtained by MAHD in comparison with that by HD. Therefore, a microwave oven can be safely used for the extraction of essential oil from Shirazi thyme.