Moisture-dependent physical properties of Karanja (Pongamia pinnata) kernel

The moisture-dependent physical properties are important to design post harvest equipments of the product. The physical properties of Karanja kernel were evaluated as a function of moisture content in the range of 8.56-22.22% d.b. The average length, width, thickness and 1000 kernel mass were 25.29mm, 15.58mm, 7.88mm and 1036.45g, respectively, at moisture content of 8.56% d.b. The geometric mean diameter and sphericity increased from 14.55 to 15.97mm and 0.57 to 0.6 as moisture content increased from 8.56 to 22.22% d.b., respectively. in the same moisture range, the bulk density decreased from 663 to 616 kg/ml, whereas the corresponding true density and porosity increased from 967 to 1081 kg/ml and 31.44 to 43.02%, respectively. As the moisture content increased from 8.56 to 22.22% d.b., the angle of repose and surface areas were found to increase from 27.69 to 37.33 degrees and 665.74 to 801.63 mm(2), respectively. The static coefficient of friction of Karanja kernel increased linearly against the surfaces of three structural materials, namely plywood (28.72%), mild steel sheet (29.88%) and aluminium (18.86%) as the moisture content increased from 8.56 to 22.22% d.b. (C) 2008 Elsevier B.V. All rights reserved.