Voltage and NaCl concentration on extraction of essential oil from Vitex pseudonegundo using ohmic-hydrodistillation

Abstract

Ohmic-assisted hydrodistillation, as an emerging green technology, can be used for the extraction of essential oils. In this study, the effects of different input voltages (100 V, 200 V, and 300 V) and NaCl concentrations (1%, 2%, and 3%) on the extraction of essential oil from Vitex pseudonegundo were investigated. Also, the composition of extracted essential oil was evaluated by the aid of a gas chromatography–mass spectrometry (GC-MS). Besides, the antibacterial activities against Staphylococcus aureus and Escherichia coli were assessed. The obtained results showed that the higher voltages could positively affect the performance of the ohmic system in terms of inhibition zones of examined bacteria, extraction onset time, initial temperature, and extraction performance. However, the used technique improved the compositional profile of the extracted essential oil by an increase in the proportion of some active components such as β-selinene and α-pinene. According to free radical scavenging assay the IC50 of oils also increased. Addition of NaCl significantly shortened the onset time of essential oil accumulation and reduced the required temperature for extraction (P < 0.05). The results of this study demonstrated that voltage and salt concentration are the important factors in the extraction of Vitex pseudonegundo by ohmic-assisted hydrodistillation, which their appropriate adjustment can remarkably improve the quality of essential oil and optimize the performance of this emerging green system.