Determination of Some Engineering Properties of Dika Nut (Irvingia gabonensis) at Two Moisture Content Levels as Relevant to its Processing

Abstract

Samples of African bush mango (Irvingia gabonensis) were collected from the wild, sun dried for four days to a moisture content of 13.75% (at an average temperature of 38.160C and relative humidity of 40.60%) and the seeds were carefully split to release the kernels unharmed. The kernels were divided into samples A and B; sample B was sun dried for three days to obtain different moisture content level from sample A. Both samples were then used for the experiments. Some selected physical and mechanical properties of dika nut were determined at two moisture content levels. This study was done under approved standard laboratory conditions using standard engineering methods and instruments. The two moisture content levels of 13.75% and 8.74% were obtained. The result revealed higher values for the physical properties at moisture content level of 13.75% . The following values were obtained for samples A and B respectively: the average length, width, thickness, weight, geometric mean diameter, arithmetic mean diameter, surface area, sphericity, volume and density were 28.97mm, 19.49mm, 11.91mm, 2.23g, 18.77mm, 20.12mm, 1111.81mm2, 64,95%, 156.17mm3 and 14.44g/cm3, and 28.62mm, 18.20mm, 8.24mm, 1.15g, 16.07mm, 18.35mm, 819.02mm2, 56.46%, 115.61mm3 and 10.20g/cm3. The coefficient of static friction was highest on plywood and least on glass for both samples. From the values obtained, it appears the increase in sizes of dika kernel may aid a decrease in coefficient of static friction. The force required to fracture and compress sample A are 25N and 62.5N on axial loading and 12.5N and 45N on longitudinal loading respectively. The force required to fracture and compress sample B was also gotten as 37.5N and 95N on axial loading and 27.5N and 67.5N on longitudinal loading respectively.