Pasting Characteristics of Cassava at Different Extrusion Conditions

Abstract

The ability of a starch-containing food to form a paste or a gel is one of the principal factors that determine the texture and the quality of that food product. In this study, the pasting characteristics (cold and hot paste viscosity) of the extrudates of the flour and starch of cassava which are grown in Nigeria in large quantity processed from a locally developed extruder (Length to diameter ratio, L/D 12:1; compression ratio, CR 4.4:1) were determined. This was to serve as a means of finding alternative processing options for the crop. Stepwise regression and other follow up tests were employed to a factorial experiment in completely randomized design. Generally, both Hot Paste Viscosity (HPV) and Cold Paste Viscosity (CPV) vary inversely with duration of operation and decreased with increase in moisture content. The most stable of the products is Cassava Starch at 40% moisture content. Also, retro-gradation decreased with increasing extrusion time and moisture content (m. c.). The equations relating the various dependent and independent variables were established to predict the performance of the machine and the pasting properties of the products.