Ohmic-assisted hydrodistillation (OAHD) is an advanced hydrodistillation (HD) technique utilizing ohmic heating process and could be considered as a novel method for the extraction of essential oils. Long extraction time is one of the major problems with traditional methods. OAHD of essential oils from the aerial parts of peppermint was studied and the results were compared with those of the conventional HD. The results showed that OAHD method had the extraction time of 19.71 min while this value was about 55.88 for HD. Scanning electron micrographs of mint leaves showed a sudden eruption of essential oil glands for OAHD samples. GC-MS analysis did not indicate any noticeable changes in the compounds of the essential oils obtained by OAHD in comparison with HD. Furthermore, both extracted essential oils were shown to have approximately same antioxidant activity using DPPH and β-carotene bleaching methods. The results introduced OAHD as a green technology.

Keywords