Effect of Hull Content and Moisture Content on Oil Expression from Dehulled Jatropha Curcas Seeds

Oil Expression from Dehulled Jatropha Curcas Seeds

Abstract

Jatropha curcas is an ornamental, medicinal and a multipurpose shrub grown widespread throughout arid and semiarid tropical region of the world. The Jatropha seed contains 46.27% oil, 42 % hull and 58% kernel. Jatropha seed oil with viscosity of 8.2 cSt is close to that of diesel fuel, the oil is used as fuels for jet, transformer, and high hydrocarbon. The oil from the seeds can be extracted through solvent extraction, mechanical pressing. The solvent extraction method is most efficient, but it is costly and requires more resources. The mechanical pressing, especially hot pressing is more efficient than cold pressing. The seed parameters such as oil content, moisture content, hull content, etc. and machine operating parameters i.e. operating pressure, retention time, temperature, etc, affects the oil extraction efficiency. Jatropha curcas seeds with different levels of moisture content viz. 10. 14, 17, 20 and 23 and hull content viz.0, 10, 20, 30 and 40 percent were pressed through screw press. The additional moisture to the seeds having 7% moisture content was added using hot water sprinkling. The extraction, extraction efficiency, expeller throughput and the oil from the feed having 0% hull resulted in paste formation even at lowest moisture content and consequently, no oil extraction. The maximum oil expression was observed as 29.7 percent for 20 percent hull content mixture at 17.2 percent moisture content. The oil expression as well as the oil expression efficiency was reduced at the levels below and above the optimum moisture content.