Determination of Physical and Mechanical Properties of Some Selected Varieties of Commonly Grown Maize in Nigeria

Abstract

Knowledge of physical and mechanical properties of maize grains is significant in designing a processing machine whose energy depends on these properties. The aim of this study is to determine the physical and mechanical properties of some commonly selected varieties of maize grown in Nigeria, namely SAMMAZ/14, SAMMAZ/15, SAMMAZ/17, SAMMAZ/37, and SAMMAZ/50. Linear dimensions (length, width (W), thickness (T)) and moisture contents of Undehusked maize (leaf) kernel and seeds of each variety were determined. Angle of repose, bulk density, geometric mean diameter, deformation, compressive strength, and rapture energy measurements were also performed on each of the maize seeds varieties. Results shows the average linear dimensions of Undehusked maize (leaf) kernel and seeds varieties determined in terms of length, width (major, minor), thickness (major, minor) of SAMMAZ/14, SAMMAZ/15, SAMMAZ/17, SAMMAZ/37 and SAMMAZ/50 are 457.7mm, W(31mm, 27mm), T(6mm, 9.4mm), 565mm, W(40mm, 31mm), T(7mm, 5.5mm), 7.450mm, W(32mm, 19mm), T(5mm, 9mm), 426mm, W(29mm, 23mm), T(6mm, 3.4mm), 610mm, W(46mm, 19mm), T(4.1mm, 2.4mm) and 11mm, W(9.6mm, 7.4mm), T(4.4mm, 6mm), 9.5mm, W(9.3mm, 6.9mm), T(4mm, 3mm), 9.0mm, W(9.2mm, 7mm), T(4.1mm, 2.9mm), 9.3mm, W(8.8mm, 2.3mm), T(1.4mm, 3.4mm), 6.1mm, W(8.6mm, 7mm) T(4mm, 3.5mm), while moisture contents for both undehusked maize (leaf) kernels and seed varieties were 16%, 17%, 20%, 16%, 21% and 17%, 16%, 16%, 11%, 12% respectively. Average angle of repose, Bulk density, geometric mean diameters, deformation, compressive strength and rapture energy of the maize seed SAMMAZ/14, SAMMAZ/15, SAMMAZ/17, SAMMAZ/37 and SAMMAZ/50 varieties are 22.2o, 0.71gcm-3, 8.4mm, 1.201mm, 2.7N/mm2, and 0.0840Nm, 20.1o, 0.72gcm-3, 8.1mm, 2.123mm, 6.6N/mm2, and 0.1907Nm, 24.0o, 0.70gcm-3, 7.1mm, 0.825mm, 8.8N/mm2, and 0.165Nm, 23.3o, 0.8gcm-3, 6.2mm, 0.132mm, 3.34N/mm2, and 0.066Nm and 22.5o, 0.76gcm-3, 6.3mm, 0.456mm, 3.4N/mm2 and 0.0228Nm. To prevent kernel damage during processing and handling, the measured rapture energy and compressive strength during compression can be used as the limit value for designing machine.