Abstract

The properties of multiplier onion bulbs were studied for design of equipment for processing, sorting, transportation and heat transfer processes (heating and cooling). The equatorial diameter, polar diameter, thickness, geometric mean diameter (D gm ), arithmetic mean diameter (D am ) frontal surface area (Af.s) and cross sectional areas (A s.c ) of the fresh and three months stored Co-4 cultivar were determined. Spherical shapes of bulbs were indicated by values of shape index and sphericity. Surface area ranged from 14.04 ± 6.93 cm 2 for fresh onion and 11.18 ± 2.40 cm 2 for three months stored onion. The roundness values were 0.87 ± 0.04 and 0.84 ± 0.08 for fresh and stored samples respectively. Mass, volume, true density, bulk density and porosity were also determined. The emptying angle of repose for fresh and three months stored onion bulbs was higher than the filling angle of repose. The coefficient of friction was high in rubber surface and lowest in polished wooden card board surface.

Keywords: Multiplier onion, Geometrical properties, Physical properties, Frictional properties