Due the various demands for processed foods with functional ingredients, a mixture of cassava starch and dried orange pulp was extruded under different conditions (0 to 20% of fibers in the mixture); (14.6 to 21.4% moisture); and (60.8 to 129 ºC temperature of extrusion) aiming at the use in high fiber instant products. The screw speed was kept constant (272 rpm), the diameter of die was 3 mm, the compression ratio was 3:1, and the feed rate was 150 g/minute. The following pasting properties of the extruded products were analyzed: initial viscosity, peak of viscosity, breakdown, final viscosity, and retrogradation tendency using a Rapid Visco Analyser (RVA) in view of the importance of these parameters for such use. The results showed that the percentage of fibers was the greatest variable of influence on the pasting characteristics. The conditions of low-fibre, high temperature, and low humidity may have promoted sharp degradation of starch and fiber solubilization leading to the reduction in the viscosity parameters values.
extrusion; orange; cassava; viscosity
