Optimization of Jatropha Curcas oil extraction using microwave pretreatment prior to Soxhlet extraction

Abstract

Jatropha curcas is a multipurpose shrub with a variety of applications and enormous economic potentials for its seed oil, which can be converted into biodiesel. This study aims to demonstrate and compare the extraction of Jatropha oil by conventional method and those with assisted by microwave pretreatment. This research also aims to optimize the parameters in the microwave pretreatment process for obtaining a maximum yield of Jatropha seed oil. The present study deals with the extraction of Jatropha curcas seed oil by using microwave pretreatment prior to Soxhlet extraction. Samples were microwave treated at a frequency of 2450 MHz using a household microwave. Thirteen microwave pretreatments were suggested, combining the potencies of microwave power (300 W- 450 W) and pretreatment time (70 s – 180 s) by Design of Experiment (DOE) software. The extraction of Jatropha curcas oil was carried out using Soxhlet method by using hexane for 6 hours. It was found that extraction oil yield increased by 30.95 % with microwave pretreatments of Jatropha seed compared to untreated seeds as control. Optimum condition of 450 W and 180 s were obtained with the maximum oil yield of 91.3 %. The quality characteristics (e.g. acid value, peroxide value and saponification value), oil composition (e.g. fatty acids) were measured and compared to those of an untreated oil sample. The result showed that the Jatropha seeds contained acid value 1.67± 0.09 %, 0.78±0.02 miliequivalence/kg and 188 ± 0.37 mg/g respectively. This concludes that a microwave pretreatment could be applied to Jatropha Curcas oil extraction prior to Soxhlet method to improve the oil recovery about 91.3 %.