Extraction of essential oils from Bunium persicum Boiss. using superheated water

A comparative study of superheated water extraction (SWE) with two conventional volatile isolation methods including hydrodistillation and Soxhlet extraction was performed on Bunium persicum Boiss. Influence of operating conditions such as temperatures from 100 to 150 °C, mean particle size from 0.5 to 1.0 mm and flow rates from 2 to 4 mL/min on the extraction process was investigated. The experiments were carried out using a laboratory-built apparatus. Separation and identification of the components were carried out by GC-FID and GC/MS. The optimum extraction efficiency for SWE was determined at 125 °C, 4 mL/min and 0.5 mm. At these operating conditions, the extraction efficiency was lower than hydrodistillation and Soxhlet extraction methods, but SWE was quicker and with respect to the valuable oxygenated components, it was more selective.