Extraction of essential oils from Mentha piperita using advanced techniques: Microwave versus ohmic assisted hydrodistillation

Ohmic and microwave assisted hydrodistillation (OAHD and MAHD, respectively) are advanced hydrodistillation (HD) techniques utilizing ohmic and microwave heating processes for extraction of essential oils. OAHD and MAHD of essential oils from the aerial parts of peppermint were studied and the results were compared with those of the traditional HD. The results showed that OAHD and MAHD methods require less than half an hour for extraction process while HD require about 1 h. Scanning electron microscopy of mint leaves undergone OAHD and MAHD provided evidences as to a sudden rupture of essential oil glands. GC-MS analysis did not indicate any noticeable changes in the compounds of the essential oils obtained by novel studied methods in comparison with HD. The results introduced OAHD as the greenest technique in terms of energy consumption. MAHD was superior in terms of rate of essential oils accumulation and also extraction duration parameter.