Physical Properties of Jatropha curcas L. Fruits and Seeds with Respect to Their Maturity Stage

Jatropha curcas L. is a multipurpose bioenergy crop. Physical properties of J. curcas fruits and seeds are a fundamental knowledge required for the design of processing machinery. Therefore, this research investigates the physical properties at different maturity stages as indicated by pericarp color of the fruits (green, yellow, and black). Rupture force, hardness, deformation at rupture point, deformation ratio at rupture, and energy used for rupture were measured in the length and width direction of the fruits and in the length, width, and thickness of the seeds. During the course of maturing, a decrease in the unit mass and the surface area of the fruits was observed with a simultaneous increase for the seeds. Moisture content decreased during maturing. Bulk density and solid density were considerably different among maturity stages. The lowest porosity was observed in black fruits as well as “black” seeds. The highest dynamic and static angle of repose was detected for black fruits, while no substantial difference was observed between “yellow” and “black” seeds. The highest and lowest coefficient of static friction for all fruits and seeds was found on rubber and plastic surfaces.