Modelling of system parameters of extruded sorghum–cowpea breakfast cereal using response surface methodology

AbstractBlends of sorghum and cowpea flour (10%, 20% and 30%) were extruded at 20%, 22.5% and 25% moisture and 120°C, 140°C and 160°C barrel temperatures respectively, using a single-screw extruder. A central composite face-centered (CCF) design was used to model the specific power consumption (SPC), torque, mass flow rate (MFR) and apparent specific volume (ASV) of the sorghum–cowpea extrudates. The SPC, torque, MFR and ASV varied from 201.71 to 229.28Kwh−1kg−1, 85 to 97Nm, 1.94 to 2.31gs−1 and 4.01 to 6.36cm3, respectively. The SPC was significantly (p<0.05) influenced by the linear effect of feed composition and the interaction effects of feed moisture and extrusion temperature. The torque was however significantly (p<0.05) influenced by the linear effect of feed moisture and the interaction effects (p