Abstract:A study was conducted to investigate the effect of varying moisture content levels on the physical properties of castor seeds namely, these physical properties include; seed dimensions, surface area, sphericity, geometric diameter, bulk and true density, repose angle, static coefficient of friction at varying moisture contents on glass, aluminium and plywood surfaces. The physical properties of Castor seeds were evaluated at moisture contents of 10 %, 12 % and 14 % d.b. The average major, minor and intermediate diameters were 15.509 mm, 12.4992 mm and 7.093 mm respectively at moisture content of 10 % d.b. The geometric mean diameter, sphericity and surface area increased from 11.116 to 11.8497 mm, 0.717 to 0.719 and 388.635 to 441.935 mm2 as moisture content increased from 10 to 14 % d.b. At the same moisture range, bulk density decreased from 0.4944 to 0.4632 g/cm3, true density decreased from 2.6632 to 2.5626 g/cm3, and the corresponding porosity increased from 0.0081 to 0.0082 %. The repose angle was found to increase from 29.67o to 33.76o and as the moisture content increased from 10% to 14% d.b., the static coefficient of friction increased on all three structural surfaces, from 0.364 – 0.445 for glass, 0.42868 – 0.52282 for aluminium and from 0.518 – 0.615. Knowledge of these properties constitute essential engineering data in the design of equipment, machineries, processes and controls for castor seeds.

Keywords: castor seeds, surface area, sphericity, geometric diameter, bulk and true density

| DOI: 10.17148/IARJSET.2025.12101