Microwave pretreatment of Moringa oleifera seed: Effect on oil obtained by pilot-scale supercritical carbon dioxide extraction and Soxhlet apparatus

The effect of microwave radiation (MW) at three levels of power (100, 200 and 400 W) and for three radiation time (30, 60 and 90 s) on Moringa oleifera seeds was studied as a pretreatment process prior to oil extraction by pilot-scale supercritical carbon dioxide (SC-CO2) extraction and Soxhlet apparatus. Extraction oil yield by Soxhlet increased with MW pretreatments at 100 W for 30, 60 and 90 s with respect to untreated seeds. Therefore, these MW conditions were selected for SC-CO2 extraction of oil, carried out at 40 °C and 300 bar. Combining MW pretreatment at 100 W for 30 s with SC-CO2 extraction, the maximum oil yield of 35.28% w/w was obtained. The chemical quality of oil extracted by SC-CO2 was higher than Soxhlet oil.