Studies on Rupture Characteristics of Drum-Roasted Cashew Nut

Abstract

Conventional manual cashew nut shelling is very labour intensive and needs urgent attention for mechanization. The basic design of any cashew nut sheller would require a basic knowledge of its rupture properties. An investigation was therefore conducted to study the effect of moisture contents (6.75, 7.33, 8.84, 9.41, 10.20, 11.57 and 13.52% w.b.) and direction of loading (perpendicular to the plane of the concave and convex edges, parallel to the longitudinal axis and perpendicular to the planes of the flanks) on the impact (with flat and spherical object) and compression energy at rupture. The total impact energy at rupture in all the three directions of loading was found to increase with the increase in moisture content. The impact energy required for rupture with a spherical striking load was found to be less than that of a flat shape-striking load irrespective of moisture content and direction of loading. The compression energy at rupture increased upto the moisture content of 10.20% and decreased thereafter. The energy required for rupture by impact was found more than that by compression. Moisture content, orientation and their interaction were found to have a significant effect on both impact and compression energies at rupture. The failure pattern indicated application of impact load with a spherical striking load in lengthwise direction resulted in a crack along the natural line of cleavage, which was good enough to break open the outer shell and produce whole cashew kernels.