Optimization of supercritical fluid CO2 extraction of Opoponax essential oil (C. erythraea)

Essential oil of Opoponax (Commiphora erythraea) was extracted by means of steam distillation and supercritical CO2 (SFE-CO2) extraction. Experiments were performed using a Clevenger-type apparatus. On the other hand, SFE-CO2 runs were carried out using OCOLABS extraction unit at the operating conditions of 150, 200, and 250 bars and within temperature range from 50 to 65 °C. Other extraction parameters such as particle size and extraction period were also investigated in order to validate their effect on the processes and the oil yield. The extraction yields were almost similar (2.46%) for the optimized SFE-CO2 at 250 bar, 65 oC, and 2 hr, and 2.45% for the steam distillation. Our findings confirmed that the grinding of the material (particle size), pressure, and temperature had an important effect on the SFE-CO2 extraction process. GC/MS analyses revealed that major compounds, namely α-santalene, α and β-bisabolone, and trans-alpha-bergamotene were of similar quantities except for ocimene. α-Santalene concentration was 7.15% for steam distillation and 15.32% for SFE-CO2 at the abovementioned conditions.