Some Physical Properties of Pumpkin (Cucurbita pepo L. ) and Watermelon (Citrullus lanatus L.) Seeds

Some physical properties of pumpkin (Cucurbita pepo L.) and watermelon (Citrullus lanatus L.) seeds were determined at a moisture content of 9.87% and 2.87% (dry basis), respectively. The mean values of length, width, thickness and geometric mean diameter were 19.92, 11.30, 3.22, 9.71 mm for pumpkin seeds, and 13.28, 8.00, 2.64, 6.52 mm for watermelon seeds, respectively. The mean 1000 seed mass, sphericity, angle of repose, bulk and true densities, single seed volume, surface area, porosity values were obtained as 261.2 g, 60.55%, 23.9°, 321.3 kg/m 3 , 784.3 kg/m 3 , 0.11 cm 3 , 2.54 cm 2 and 58.9%, respecitvely for pumpkin seed; and 14.62 g, 49.2%, 19.1°, 412.2 kg/m 3 , 1543.3 kg/m 3 , 0.03 cm 3 , 0.48 cm 2 and 47.45%, respectively for watermelon seed. The mean values of dynamic coefficient of friction against galvanized steel, chipboard, mild steel, plywood and rubber surfaces were 0.29, 0.24, 0.32, 0.36 and 0.61 for pumpkin seed, and 0.21, 0.45, 0.41, 0.57 and 0.94 for watermelon seed; while the values of static coefficient of friction were 0.37, 0.38, 0.38, 0.43 and 0.74 for pumpkin seed and 0.27, 0.54, 0.48, 0.70 and 1.11 for watermelon seed, respectively. The maximum static and dynamic coefficients of friction was found for rubber surface.