Physical properties of cassava (Manihot Esculenta Crantz) root

The processing of cassava has relied mainly on equipment used for other crops in most developing countries. Also there is a dearth of information regarding the engineering properties of cassava root and its products. Some selected engineering properties of ‘Oko Iyawo’ (TME-7), a popular cassava cultivar in south-western Nigeria, were studied. The study focused on some physical properties of cassava root which include mass, dimensions, peel thickness, and peel proportion by weight (PPW). Also studied were the frictional properties of stainless steel, galvanized sheets, and wooden surfaces at a moisture content range of 0.40-0.60 g H2O/g of wet mass which is necessary information required in machine design for processing equipment. Fifty freshly harvested cassava roots selected at random were used. The mass, length, diameters and peel thicknesses at the head, middle and tail, ranged respectively from 64-1480 g, 110-500 mm, 15-70, 17.5-76.0 and 12.5-67.0 mm, and 1.5-5.0, 1.3-5.9 and 1.1-5.9 mm while the PPW ranged from 12.80-38.13%, respectively. The coefficient of internal friction (CIF) ranged from 0.56-0.61 over the range of moisture content studied. The coefficient of rolling resistance (CRR) obtained using the periderm, cortex and flesh against the three surfaces were 0.15, 0.23 and 0.29; 0.12, 0.20 and 0.24; and 0.07, 0.13 and 0.18, respectively, while the coefficient of friction (COF) ranged from 0.18-0.25, 0.37-0.48 and 0.57-0.70 on stainless steel, galvanized sheets and wood surfaces respectively over the range of moisture contents studied. The influence of moisture content on the coefficients of friction and internal friction as well as on the periderm, cortex and flesh on the three surfaces were significant (p<0.05). An oval root shape was established. All this is useful information for the development of more efficient cassava processing, handling and harvesting machines.