Effect of Pre-Shelling Treatment on Physical and Mechanical Properties of Cashew Nut

Abstract

This study was conducted to investigate the effect of roasting in hot oil on physical and mechanical properties of large (26-35mm), medium (23-25mm) and small (18-22mm) cashew nuts at moisture content of 7.00% w.b. The physical properties considered were length, width, thickness, geometric mean diameter, sphericity, true density, bulk density, porosity, mass, and coefficient of friction. The mechanical properties considered were, rupture force, deformation at rupture point, energy used for rupture and young modulus determined from compression test carried out in three major direction of loadings. It was observed that all the dimensional characteristics, mass and densities of cashew nuts before roasting were significantly different (P < 0.05) from after roasting. The pre-treatment has significant effect on coefficient of friction of cashew nut which has higher values on mild-steel and wood than other materials. The compression test results showed that the rupture force decreases with decrease in nut size for the three loading directions, however the transverse loading requires higher force than longitudinal and lateral loading for the three nut sizes. For large and medium size nuts, the highest rupture energy was needed in transverse loading direction, followed by lateral loading direction. The compression along the longitudinal direction has the least deformation for the three nut sizes. For the three nut sizes, the highest Young Modulus was exhibited in longitudinal loading direction followed by transverse loading direction.