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. One of the
major problems with traditional methods is long extraction time. OAHD of essential oils from the aerial
parts of Thymus vulgaris L. (common thyme) was studied and the results were compared with those of the
conventional HD. The results showed that OAHD method had the extraction time of 24.75 min while this
value was about 1 h for HD. Scanning electron micrographs of thyme leaves showed a sudden eruption of essential
oil glands and their surrounding area 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. Results of this
study introduced OAHD as a green technology because of less energy required per ml of essential oil extraction.
Industrial relevance: The quality and quantity of essential oils extracted from herbs and other raw materials
are affected by the extraction method. In this research ohmic-assisted hydrodistillation (OAHD) was used
as an advanced and novel hydrodistillation (HD) technique and compared with traditional hydrodistillation
in extraction of essential oils from the aerial parts of Thymus vulgaris L. (common thyme). OAHD method was
quicker, more economical and environmentally friendly than hydrodistillation method. The results of this
study introduced OAHD as a green technology.