Tropentag 2008 Stuttgart-Hohenheim, October 07 - 09, Conference on International Agricultural Research for Development Physical, mechanical and chemical properties of Jatropha curcas L. seeds and kernels Karaj, Shkelqim*, Huaitalla, Roxana Mendoza a , Müller, Joachim a a Institute of Agricultural Engineering 440e, University of Hohenheim, Garbenstrasse 9, 70593 Stuttgart, Germany, Email: *karaj@uni-hohenheim.de . Funded by: BMBF Introduction Jatropha curcas L. is a drought – resistant shrub/tree belonging to the family Euphorbiaceae [1, 2]. Cultivated in Central and South America, Jatropha curcas was distributed by Portuguese seafarers in Southeast Asia, India and Africa [3]. Propagated by cuttings, is widely planted as a hedge to protect fields from browsed animals. The plant and its seeds are non edible to animal and humans; toxicity of seeds is mainly due to the presence of curcine and deterpine [2, 4]. The existing distribution of Jatropha curcas shows that introduction has been most successful in drier regions of the tropics. It grows on well-drained soils with good aeration and is well adapted to marginal soils with low nutrient content [2]. The potential use of extracted oil from Jatropha curcas as transesterified oil (biodiesel), or as a blend with diesel have been studied [1, 5-7]. The calorific value and cetane number of Jatropha curcas oil are comparable to diesel, but the density and viscosity are much higher [8]. Since the density of oil is high, the engine performance, emissions and combustion parameters can be reached by optimizing the injector opening pressure, injection time, injection rate and enhancing the swirl level of the operated engine [1, 6]. High viscosity of the Jatropha curcas oil is not advantageous for the compression ignition engine. Pramanik (2003) has studied the performance of the engine using blends and Jatropha oil in a single cylinder (compression ignition) engine and made comparison with the performance obtained with diesel. Adequate thermal efficiencies of the engine were obtained with blends containing up to 50 % volume of Jatropha oil. 40–50 % of Jatropha oil can be replaced without any engine modification and preheating of the blends [1, 6]. In the oil industry, different processes must be done before oil extraction occurs. When Jatropha curcas fruits arrive for oil extraction different processes are conducted before: (a) dehulling, separating hull from nut, (b) deshelling, separating shell from kernel, (c) drying and than (d) oil extraction. Physical, mechanical and chemical properties of seed and kernel are needed for the design of equipment to handle, transport, process, store and assessing the product quality [1, 9, 10]. The aim of this study was to investigate the physical, mechanical and chemical properties of Jatropha curcas L. seeds, as part of optimization of de-shelling and oil extraction of Jatropha curcas L. for direct use in plant oil stoves. The considered parameters were bulk/solid density, volume, porosity, surface area, specific surface area, coefficient of friction, static angle of repose, rupture force, deformation at rupture point, deformation ratio at rupture point, hardness, energy used for rupture, moisture content, crude lipids, oil density, kinematic viscosity, gross calorific value, iodine value, water content of oil, C – impurities and acid value. These parameters will be useful in designing of handling and processing equipment.