Selected physico-chemical properties of extrudates from white yam (Dioscorea rotundata) and barn bara nut ( Vi~na subterranean) blends

Abstract

This study was conducted to investigate effects of extrusion conditions on physicchemical properties of blend of yam and bambara nut flours. Blend of white yam grit (750 pm) and Bambara nut flour (500 pm) in ratio 4: 1 respectively was extrusion cooked at varying screw speeds 50-70rpm, feed moisture 12.5-17.5% (dry basis) and barrel temperatures 130-150 OC. Extrusion variables employed included barrel temperature (BT), screw speed (SS) and feed moisture content (FM), while physico-chemical properties of extrudates investigated were expansion ratio (ER), bulk density (BD) and trypsin inhibition activity (TIA). The results revealed that all the extrusion variables had significant effects (p