Optimisation of steam extraction of oil from maritime pine needles

International audienceEssential oil from pine maritime needles is generally extracted by steam distillation process at atmospheric pressure for more than one hour, or by solvent extraction process. In the last decade, there has been an increasing demand for new extraction techniques enabling automation, shorter extraction time and reduced consumption of organic solvent. In this study, Response Surface Methodology (RSM) was used to evaluate the effects of two processing parameters of an alternative extraction process: instantaneous controlled pressure drop: "Détente Instantanée Contrôlée" (D.I.C) on the yield and composition of oil isolated from maritime pine needles (Pinus pinaster). This process involves subjecting the substrate for a short time to steam varying from 1.5 to 5.5 bar (113 to 155 °C) for 4 to 20 minutes, followed by an instantaneous decompression to a vacuum (about 50 mbar). We studied the effect of processing pressure and processing time on the yield of oil and in three important compounds: -pinene, -pinene and germacrene D. Both the processing pressure and time had a significant effect on all responses studied. For the less volatile compound, -pinene, the maximum quantity was obtained at the lower processing pressure and time, while an inverse trend was observed for -pinene and germacrene D. The models displayed by the experimental design gave R2 higher than 0.92