Ohmic accelerated steam distillation of essential oil from lavender in comparison with conventional steam distillation

A new extraction process, i.e., ohmic accelerated steam distillation (OASD), was designed and developed in this study. A packed bed of lavender inflorescences was subjected to OASD and extraction parameters, physical, and chemical properties of the extracted essential oil were compared to that of SD. The proposed extraction technique yielded the same amount of extract as SD (3.3–3.8% v·w−1) with the similar IC50 value (100 μg·mL−1). Gas chromatography-mass spectrometry (GC–MS) analysis showed that OASD did not negatively affect the valuable compounds of lavender essential oil and the major components of both extracted essential oil were Linalool, 1,8-cineole, and camphor. Likewise, the extracted essential oils had similar relative densities (0.88) and color values. On the other hand, OASD was superior to SD in terms of rapidity (total extraction time of 50.3 ± 2.1 min vs. 112.7 ± 5.9 min) and consumed energy (0. 4 kWh vs. 0.9 kWh for 1 mL essential oil). OASD can be considered as a potential energy- and time- saving alternative to SD for industrial units after further process optimization and up-scaling studies. Industrial relevance This paper describes the first research on using ohmic heating, as a volumetric heating method, to accelerate conventional steam distillation (SD). Ohmic accelerated steam distillation addressed the drawbacks of the previously proposed ohmic-assisted hydrodistillation method including the possibility of electrochemical reactions between electrode and extraction medium, limited range of applied frequency, the necessity of using costly corrosion resistant electrodes. Therefore, this method is potentially applicable to SD which is the preferred industrial extraction technique for many essential oils. The proposed method in this study has the potential of enhancing the production capacity and reducing the production expense for distillatory and essential oil industries.