Comparison of microwave-assisted hydrodistillation with the traditional hydrodistillation method in the extraction of essential oils from Ziziphora clinopodioides Lam

Applying single stage microwave-assisted hydrodistilation (MADH) at power level 270 W, the essential oil of Ziziphora were extracted and results were compared with those of the conventional hydrodistilation (HD) technique in terms of extraction time, extraction yield/efficiency, chemical composition, quality of the essential oils and cost of the operation. The amount of essential oils extracted by MAHD at 270 W for 1 hr was similar to that obtained by conventionalHD for 4 hr. Scanning electron microscopy (SEM) of leaves undergone HD and MAHD provided evidences as to a suddenrupture of essential oil glands with MAHD. Gas chromatography–mass spectrometry analysis of the extracted essential oils indicated that the use of microwave irradiationdid not adversely influence the composition of the essential oils. MAHD was found to be a green technology.

Keywords:

Clevenger , Essential oil composition , Microwave assisted hydrodistillation , Scanning electron microscopy , Ziziphora