Effect of moisture content and loading orientation on selected mechanical properties of cocoyam cormel

Abstract

Cocoyam, Xanthosoma sagittifolium, is a major staple food in many African countries including Nigeria. The crop has been under-utilized and there is need for more research input to fully exploit it. There is dearth of information especially in terms of the mechanical properties among other important engineering properties which are significant in designing equipment for handling and processing the cormels. This study therefore, investigated the effect of moisture content and orientation of loading on some mechanical properties of the cocoyam cormels. White- and pink-fleshed varieties of the X. Sagittifolium cormels were used for this study. Selected mechanical properties namely rupture force, compressive strength, stiffness and toughness of the cormels along the three mutually-perpendicular axes were determined at four moisture content levels using Universal Testing Machine (UTM). The rupture force, compressive strength, stiffness and toughness of the cocoyam cormels along the longitudinal, cross-sectional and transverse directions ranged between 361.40 and 1,093.60N, 0.53 and 2.51 Nmm-2, 3.03 and 11.70 Nmm-2 and 0.62 and 5.37 Nm respectively. The study further confirmed the moisture-dependence and anisotropic nature of cocoyam cormel as a biological material.