Effect of Moisture Content and Loading Orientation on Mechanical Properties of Bush Mango (Irvingia gabonensis) Nut

Abstract

The use of inappropriate equipment to crack bush mango nut and obtain the kernel has adversely affected the efficiency of its processing operations. The manual method, which involves cracking the nut with stone or pestle and mortar, is not only slow and risky, but also wasteful. In order to develop appropriate processing equipment for the nut, knowledge of its mechanical properties is necessary. This study was undertaken to determine some strength properties of the nut at different moisture contents under lateral and longitudinal loading orientations, using Universal Testing Machine (UTM). In the moisture range of 7.52% - 20.6% (d.b) under both lateral and longitudinal loading orientations, results of tests showed that all the strength properties (bioyield point, yield point, rupture point, bioyield strength, rupture strength, compressive strength, modulus of elasticity, modulus of resilience and modulus of toughness) of the nut decreased significantly with increase in moisture content. Loading along the longitudinal axis had higher strength property values than lateral loading. This implies that the nut will be easier to crack when loaded on the lateral axis. These findings will be useful in the development of cracking equipment for bush mango (Irvingia gabonensis) nut.