Rheological properties of heated cross‐linked waxy maize starch dispersions

Abstract

The effect of starch concentration on time‐dependent, steady shear, and dynamic shear rheological properties of heated cross‐linked waxy maize starch (CWM) starch dispersions was studied. The influence of storage time at 5°C on the rheological properties, the applicability of the Cox‐Merz rule, and the sol‐gel transition of a 5% (w/w) were also examined. The heated CWM starch dispersions exhibited antithixotropic and shear‐thinning with yield stress behaviors. The former behavior increased with both starch concentration and shear rate between 100s^‐1 and 400s^‐1. As expected, the apparent viscosity at a fixed shear rate and the yield stress increased with starch concentration. Because the Cox‐Merz rule was not applicable, the dispersions may be classified as weak gels. Both differential scanning calorimetry and thermo‐rheological data showed that the onset of starch gelatinization temperature was 63°C.