Effect of moisture content on selected physical properties of shea kernel of varying slice thickness

Bulk density, kernel density, particle porosity and shrinkage of sheanut krnel slices were determined as a function of moisture content and slice thickness in order to establish preliminary design parameters for drying in an indirect solar dryer. Solid density increased linearly while bulk density decreased non-linearly during drying as the moisture content decreased from 150 to 5 %d.b. The porosities of the kernels ranged from 60.12 -67.91, 57.05-64.87  and 56.88-62.49%, respectively, for the 5, 10 and 15 mm slices. The volumetric shrinkage of the shea slices reduced with decrease in moisture content for all the particle sizes evaluated in this study. Among the shrinkage models tested, the empirical quadratic model gave the best fit of the experimental data. It is proposed that the mechanism of shrinkage in sheanut kernel slices is linked to the removal of water that leads to structural collapse. Key words: Density, porosity, volumetric shrinkage, sheanut kernel, slices.