Supercritical extraction of essential oil from Juniperus communis L. needles: Application of response surface methodology

The extraction of oil from Juniperus communis needles was investigated using supercritical CO2. The extraction was carried out varying the pressure in the range of 10-30 MPa, the temperature within 308-328 K, with a solvent flow rate fixed at 0.42 kg h(-1), and a mean particle diameter equal to 0.5 mm or less than 0.315 mm. The operating parameters have been optimized using the response surface methodology where a second order polynomial expression was used to express the oil recovery, and the results were satisfactory. The maximum oil recovery relative to the initial mass was 6.55 wt%. It was obtained for an extraction under 328 K, 30 MPa and a particle diameter less than 0.315 mm. Selected samples of extracts were analyzed using gas chromatography-mass spectrometry (GC/MS) and the results show that the most concentrated compounds were germacrene D and 1-octadecene. (C) 2015 Elsevier B.V. All rights reserved.