Effect of Extrusion Parameters on the Physical and Functional Properties of Cocoyam (Colocasia esculenta) Flour

Abstract

Cocoyam (Colocasia esculenta) flour was cooked and extruded in a single screw extruder (DD85G, 201132, IBG Monforts Gmbhi & Co, D-4050 Monchengladbach, Germany). A second order central composite response surface design was adopted in designing the experiment which generated 20 runs on selected process parameters including feed moisture (22,24,26%), screw speed (60,70,80rpm) and barrel temperature (200,220,240 0 C) on the functional and physical properties (density, expansion, water absorption index (WAI), water solubility index (WSI) and textural characteristics) of the extrudates. At high feed moisture content there was increase in extrudates density, decrease in expansion, increase in WAI, decrease in WSI and increase in hardness while high barrel temperature lead to decrease in extrudates density, WAI and hardness but increased the expansion ratio and WSI of the extrudates.