Physical properties of the African walnut (Tetracarpidium conophorum) from Nigeria

Abstract

In this research about 1,700 samples of the African walnut (Tetracarpidium conophorum) were measured for their axial dimensions, mass, geometric mean, sphericity index, surface area, aspect ratios, angle of repose on steel, wood and glass, porosity, bulk and true density of the nut, kernel and shell at five moisture levels and three size ranges. Various equations linking the nut moisture content with other physical properties for nut and kernel were established using regression models. The studies showed that at initial moisture content of 28.2% w.b, the African wild walnut fall mostly within the mass (m) range of 5.5 ≤ m ≤ 6.5 g with shell thicknes of 0. 135 ± 0.04 cm, kernel mass of 4.22 ± 0.26 g, kernel moisture content of 28.9% w.b, porosity of 45%, nut true density of 0.815 g/cm3, nut bulk density of 0.45 g/cm3, nut aspect ratio of 76% and nut surface area of 15.41 cm2. This various properties are affected by increase in moisture contents and change in nut mass.

Keywords

• nut size
• nut mass
• moisture contents
• sorting
• regression modeling