Functional Properties of Extruded Corn Flour

Effect of extrusion cooking on hydration properties (water absorption index (WAI), water solubility index (WSI)), and viscosity (peak viscosity (PV), final viscosity (FV)) of corn flour was studied. The preconditioned corn flour was processed using different extrusion cooking conditions at the variable moisture content (MC), temperature (T), and screw speed (SS). Statistical analysis showed that irrespective of variable processing parameters the hydration properties were improved after extrusion cooking. WAI and WSI were increased by 70 % to 268 % and 5 to 198 %, respectively over unextruded flour. The viscosity of extruded corn flour showed a significant (p<0.05) decrease, indicating high paste stability of corn flour after extrusion cooking. Overall, there was 72 to 86 % decrease in PV and 89 to 95% decrease in FV. The mild processing conditions (high MC, low SS, and low T) imparted better hydration properties, whereas severe processing conditions (low MC, high SS, and high T) imparted better paste stability to corn flour. Extruded corn flour with modified functional properties has the potential to be exploited in the development of various gluten-free ready-to-eat products, composite flours, bakery products, etc.