DETERMINATION OF SOME PHYSICAL AND MECHANICAL PROPERTIES OF ONION

Abstract

Lack of sufficient knowledge about the physical and mechanical properties of onion can result in higher waste during harvesting and post-harvesting. The objective of this work was to determine some physical and mechanical properties of onion cultivated in China. These properties include linear dimensions, mass, shape index, pull-out force, compression and shear forces. The mean longitudinal diameter of bulb (BLD), transverse diameter of bulb (BTD), bulb weight (BW), pull-out force of bulb (BPF), depth of the bulb buried in the soil (BSD), bulb shape index (BSI), diameter of cauloid (CD), circumferential distribution of root systems (RCD), longitudinal length of root systems (RLL) and weight of root systems (RW) were 78.1±9.6 mm, 89.6±10.1 mm, 333.0±101.7 g, 43.9±21.6 N, 35.7±8.7 mm, 1.2±0.1, 15.3±3.7 mm, 89.2±19.7 mm, 42.9±10.0 mm and 0.8±0.4 g. In the study of mechanical properties of onions, the maximum compression force (MCF) required for compression deformation 10mm of bulb was 462.2N, and the maximum shear failure force (MSF) required for shearing of cauloid was 113.8 N. The results of the research will be very useful in the design and optimization of harvest and postharvest machines with reduced waste and damage.