Characterisation of Properties for Karanj (Pongamia pinnata) Seeds and Kernels in Relation to Bulk Handling and Processing Applications

The present study was undertaken to investigate engineering properties (viz. mass, density, volume, porosity, surface area, specific surface area, coefficient of friction, angle of repose, mechanical properties and colour) and chemical characteristics (moisture, oil and protein content) of Karanj (Pongamia pinnata) seeds and kernels. The length (l), width (w) and thickness (t) values indicated that the kernels are more spherical than the seeds. Average sphericity values of seeds and kernels were, 0.42 and 0.63, respectively. Although bulk densities did not vary, the true density of kernels was almost 2.5 times that of seeds. Kernels exhibited less coefficient of friction compared to seeds over different surfaces. Oil and protein content of kernels were found to be 35 and 18%, respectively. Mechanical properties in terms of rupture force (R-F, N), hardness (H, N mm(-1)), deformation (R-D, mm) and energy for rupture (E-R, N mm) were measured. While R-F and E-R were marginally more for seeds, kernels were harder as registered from the H values. Pearson correlation coefficient indicated high (r = 0.847 at p < 0.001) correlation between t and unit weight (wt) of seeds. Statistically significant (R-2 > 0.9, p < 0.001) linear models could also be developed for kernels with t and wt as dependent variables, respectively.