Authors : T.U. Nwabueze and M.O. Iwe
Abstract: Blends of African breadfruit (Treculia africana), defatted soybean and corn were extrusion cooked in a Brabender laboratory single screw extruder (DCE 330, NJ). Effects of extrusion and process variables on extrudate nutrient composition, mass flow rate, expansion ratio and bulk density, were investigated. Extrusion cooking resulted in significant (p 0.05) changes in moisture, fat, crude fibre and energy values but not in crude protein and carbohydrate. Mass flow rate ranged from 2.99 kg h 1 to 6.72 kg h 1 as feed composition shifted from African breadfruit towards soybean . Similar o bservation was made for bulk density from 0.62 g mL 1 at the centre point to 0.65 g mL 1 at the lower corner point and 0.59g mL 1 at the lower star point. A reverse effect of feed composition was observed in product expansion ratio. It ranged from 1.85 at the centre to 1.64 and 2.36 at lower corner and star point formulations, respectively. Regression analysis indicated that screw speed and feed composition were the only process variables showing significant (p 0.1) quadratic influence on mass flow rate and expansion ratio respectively. They also showed significant (p 0.05) linear and cross product effects on bulk density. All the process variables had significant (p 0.05) quadratic effect on bulk density.
T.U. Nwabueze and M.O. Iwe , 2006. Mass Flow Rate, Nutrient Composition and some Functional Properties of Single Screw Extruded African breadfruit (Treculia africana) Blends . Journal of Food Technology, 4: 50-58.