Physicochemical and sensory characteristics of extrudates from rice enriched with pumpkin

Abstract

The purpose of this work was to study the effect of pumpkin flour (10% and 20%), moisture content of initial mixture (14% and 20%) and working screw speed (180 min-1 and 220 min-1) on the physicochemical (expansion, density, hardness, colour) and sensory characteristics of rice extrudates enriched with pumpkin produced on a single screw extruder. The chemical composition before and after extrusion was also determined. The ash, lipids, reducing sugars, total sugars and total protein remained unchanged before and after extrusion while the carotenoids decreased after extrusion. The increase in the pumpkin flour led to a decrease in the expansion and lightness, and an increase in the density, hardness and redness of extrudates. The effect of the moisture content was inversely proportional on the expansion and redness, while it was directly proportional on the density, hardness and lightness. The screw speed increased the expansion, hardness and lightness of the extrudates, decreased the redness and had no significant effect on the density. The highest sensory score was achieved at a moisture content 14%, pumpkin flour 10% and screw speed 220 min-1. The moisture content had the most significant effect on the characteristics of the extrudates.