ABSTRACT
Response surface methodology was used to investigate the effect of extrusion process on proximate composition of noodles analogue from water yam, yellow maize, and African yam bean flour mixture. Flour blend from water yam, yellow maize, and African yam bean were produced and was used to extrude noodles analogue using a Brabender single screw laboratory extruder (Duisburg DCE 330 model) fitted with 3.0 mm die nozzle diameter. A central composite rotatable design (CCRD) with three variables, namely barrel temperature, feed moisture content and screw speed and five level coded – a, -1, 0, +1, +a, was used and data analyzed by regression analysis. Results showed that bulk density ranged from 0.41 to 0.09 g/cm water solubility index ranged from 4.41 to 6.36%; water absorption capacity ranged from 2.05 to 5.66% and expansion ratio ranged from 1.62 to 3.81respectively. The coefficients of determinations (R2) were high and ranged from 0.9039 to 0.9887 at 5% level. The response surface plots suggested that the models developed had a good fit and the CCRD was effective in explaining the effect of the process conditions on noodles analogue as influenced by barrel temperature, feed moisture content, and screw speed of the extruder. The data obtained from the study could be used for control of product characteristics. The study indicated that improved noodles analogue from available and cheap roots, cereal and legumes such as water yam, yellow maize, and African yam bean can be produced for possible projection for the commercial production of noodles analogue.