| Abstract: | Relationships between the structural properties of raw and extruded corn starches and their functionalities were investigated using mixtures of these starch types. Extruded starch had higher water absorption and water solubility indices, and produced lower RVA viscosity profiles when compared with raw starch. It also had no differential scanning calorimetry (DSC) endotherm. Gel cohesiveness and adhesiveness of both starch types were similar, while extruded starch gels were softer. Extruded starch produced lower Rapid Visco Analyser (RVA) viscosity profiles than raw starch due to starch degradation during extrusion. The raw and extruded starch components had negative interaction coefficients, thus RVA viscosity parameters were lowered as the fraction of extruded starch in the mixture increased. Starch degradation in the extruded starch was a likely significant factor associated with low viscosity profiles. Mixtures of raw and extruded starches could be commercially prepared to obtain finished starch products with a range of functional attributes. |
