Effect of moisture content on some physical properties of sheanut (Butyrospernum Paradoxum)
N.A. Aviara 1
F.A. Oluwole 2
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Department of Agricultural Engineering, University of Maiduguri, Maiduguri, Nigeria
Department of Mechanical Engineering, Ramat Polytechnic, Maiduguri, Nigeria
Int. Agrophys. 2005, 19(3): 193–198
The effect of moisture content on the physical properties of sheanut (Butyrospernum paradoxum) was determined to explore the possibility of developing its bulk handling and processing equipment. In the moisture range of 6 to 27.9% (d.b.), the major, intermediate and minor axes of the nut increased from 37 to 39.4, 26.8-28.3 and 25.9-26.8 mm, respectively. The arithmetic mean, geometric mean and equivalent sphere effective diameters determined at the same moisture level were significantly different from each other, with the arithmetic mean diameter being of the highest value and the equivalent sphere effective diameter yielding the volume that is closest to the experimentally determined value. In the above moisture range, one thousand nut weight and volume increased linearly with moisture content from 7.8 to 10.6 kg and 12 360 to 14 030 mm3, respectively. Particle density, bulk density and angle of repose increased logarithmically with moisture content from 643 to 782 g cm-3, 291.3-356.2 g cm-3, and 24.7-25.1°, respectively, while porosity increased with increase in moisture content to a maximum value of 56.5% at the moisture content of 22.7% (d.b.), and thereafter decreased to a value of 54.5% at the moisture content of 27.9% (d.b.). Static coefficient of friction increased linearly with moisture content from 0.300 to 0.394 in the above moisture range, and varied with structural surface. The maximum static coefficient of friction was on plywood with wood grains perpendicular to the direction of movement, while the minimum value was on formica (papreg). Regression equations that could be used to express the relationships existing between the physical properties and nut moisture content were established.