Hydraulic pressing optimization and physicochemical characterization of Jatropha curcas seed oil

Jatropha curcas seed oil can be used for numerous purposes including fuel, soap and cosmetics. Better quality oil is obtained by cold pressing, the effectiveness of which is unfortunately limited by a low extraction rate. The objective of this study was to optimize cold hydraulic extraction parameters of Jatropha curcas seed oil by increasing the oil recovery and characterising the extracted oil. The key extraction parameters (dwell time, pressure, compression speed, and press cage charge) were determined using a laboratory hydraulic press. The results show that the unhulled and dehulled seeds contained 5.1 and 2.9% moisture, as well as 33.6 and 51.7% fat, respectively. Under the optimal operating conditions and at ambient temperature (25 °C), the oil recovery from whole (crushed) material was 38.2 (42.5)% unhulled seeds and 71.3 (69.5)% dehulled seeds. The physicochemical characteristics of cold-extracted Jatropha oil were 10ppm phosphorus, 1.9 ppm iron, 0.0 ppm copper, 0.15% water-volatile matter, 0.918 (15 °C) density, and 37.72 cSt (37.8 °C) kinematic viscosity, respectively. In conclusion, the optimized cold hydraulic extraction of jatropha seed oil leads to high oil recovery and good oil quality suitable for industrial applications.