Sensory Properties of Extruded Blends of ‘Acha’ and Soybean Flour – A Response Surface Analysis

Abstract

Blends of ‘acha’ and soybean flours with moisture contents of between 15 and 35% were extruded in a single screw extruder. A response surface design (central composite nearly orthogonal) was used in the investigation with four independent variables comprising of feed moisture content (FMC), feed composition (FC), screw speed (SS) and barrel temperature (TP) combined at 5 levels. The extruded products were subjected to sensory evaluation using a 20-man panelist. The results of the study showed that maximum aroma and colour rating of extrudate blends were observed at high SS with FC playing the determinant factor. Increased feed composition and barrel temperature resulted in decreased texture rating of extrudates. Extrudates of 37.5: 62.5% (soybean: acha) had the highest sensory rating compared to other blend ratios evaluated. This indicated that acceptable extruded blends of ‘acha’ and soybean products could be obtained at 37.5% soybean addition. This is was higher than the 30% already reported in literature for cereal/legume mixes.