Effect of Moisture Content on some Engineering properties of Groundnut Pods and Kernels

Abstract

Effect of moisture content on some engineering properties of groundnut pods and kernels were investigated. Two groundnut varieties were used namely; Manipintar and Ex-Dakar. The properties investigated were principal dimensions, porosity, bulk density, true density, angle of repose and static coefficient of friction as dependent variables while moisture content is the independent variable. At an increasing moisture content of 7.3 – 25.2 % d.b., the mean length, thickness, width, geometric mean diameter, arithmetic mean diameter and surface area for Ex-Dakar pods were 30.6 - 33.46, 12.55 - 14.89, 12.8 - 14.03, 16.88 – 18.71, 18.61 - 20.75 mm and 904.86 – 1099.73 cm², respectively. The corresponding mean values for the Manipintar pods were 18.60 – 30.89, 11.62 – 15.01, 11.72 – 14.05, 13.63 – 18.68, 13.98 - 19.98 mm and 583.78 – 1095.80 cm², respectively. However, for Ex-Dakar kernels, the mean length, thickness, width, geometric mean diameter, arithmetic mean diameter and surface area recorded within moisture range of 8.5 – 28.1 % were 12.92 – 13.01, 8.81 – 9.35, 10.73 – 11.71, 10.72 – 11.14, 10.82 – 11.36 mm and 360.96 – 389.68 cm², respectively. Similarly, mean values for the Manipintar kernels were 18.60 – 30.89, 11.62 – 15.01, 11.72 – 14.05, 8.97 – 11.03, 9.19 – 11.38 mm, and 252.89 – 382.16 cm², respectively. The porosity for Ex-Dakar pods increases from 30.23 – 61.77 % and from 11.65 – 18.63 % for the kernels, from 31.37 – 59.41 % and 11.65 – 33.82 % for Manipintar pods and kernels. True density increases from 0.35 – 0.72 and 0.84 – 1.13 g/cm³ for Ex-Dakar pods and kernels, from 0.39 – 0.62 and 0.98 – 1.29 g/cm³ for Manipintar pods and kernels. However, the bulk density shows a decrease from 0.33 – 0.24 and 0.92 – 0.55 g/cm³ for Ex-Dakar pods and kernels, and from 0.53 – 0.21 and 1.12 – 0.75 g/cm³ for Manipintar pods and kernels. Angle of repose increases from 25.1 – 28.9^o and 24.7 – 27.1^o for Ex-Dakar pods and kernels, and for Manipintar pod and kernels, it increases from 26.3 – 29.5^o and 25.0 – 29.0^o. The mean static coefficient of friction on plywood, galvanize sheet and glass increased at varying moisture content for both pods and kernels. The establishment of these parameters would serve as reference that is required to achieve the desired results in successful design and operation of groundnut processing equipment.