Moisture Dependent Physical Properties of Nutmeg (Myristica fragrans) Relevant for Design of Processing Machines

Abstract

This study investigated the degree of influence of moisture content on some physical properties of nutmeg. The nutmeg seeds were subjected to six different levels of moisture content (5, 7, 9, 11, 13 and 15% db). Moisture content had a significant effect on the physical properties (p <0.05). A decrease in moisture content led to a decrease in length, width, thickness, geometric, arithmetic, square and equivalent mean diameters. Moisture content had a linear relationship with sphericity, projected and surface area, bulk and true density while it had an inverse relationship with porosity and angle of repose. Moisture content had a significant effect on coefficient of friction of nutmeg on the four surfaces considered (glass, stainless steel, plywood and rubber). Glass, stainless steel, plywood and rubber have an increasing coefficient of friction respectively; this implies that materials will move easily with lesser resistance on glass and stainless steel compared to more resistance on plywood. The data obtained will guide engineers, food processors and technicians in accurate selection of machine parts in design and constructions of sorting, separating, cleaning equipment and post harvest machines which will eventually aid commercialization and efficient processing of the spice crop.