ABSTRACT

This study investigated some engineering properties of African oil bean kernel such as axial dimension, sphericity, surface area, bulk density, true density, weight, porosity, volume, moisture content angle of repose coefficient of friction, force at peak, deformation at peak, force at yield, deformation at yield, strain at yield, force at break, deformation at break, strain at break, energy to peak, energy to break and energy to yield which are essential in the design of the postharvest processing machines for the crop. Standard methods from the literature were adopted in carrying out the experiment. The properties were investigated at moisture content of 14.63% wet basis. The results obtained showed that the average values of major, intermediate and minor diameters were 47.34, 29.97 and 10.0mm, respectively. The volume, sphericity, porosity, surface area, bulk and true densities were obtained as 11.08cm3, 51.82, -0.16%, 1838.32cm2' 0.85g/cm3, 0.64g/cm3, respectively. The coefficient of friction of the kernels on wood, glass and metal were gotten as 0.88, 0.71, and 0.72, respectively while the angle of repose is 14.57°. It was found that the dimension and parboiling time affects the mechanical properties of the kernels. The force required to break the kernel increase from 127.437 to 3926.700N, 222.310 to 3612.233 and 126.50 to 198.780 as the size increase from 9.00 to 26mm, 11.50 to 27.10mm and 10.55 to 31.50mm respectively. The force and energy required to break the kernel decreases as the parboiling time increases from 10 to 30 minutes. Deformation on the other hand, increases as the parboiling time increases but decrease as the kernel size increase. The data obtained are useful in the design of postharvest machines for African oil bean kernel.