Modeling starch gelatinization kinetics of milled rice flour

Milled long-grain rice samples were evaluated by differential scanning calo rimetry (DSC) to determine the kinetics of starch gelatinization. The exper iments were conducted with milled rice flour with a 10.6% degree of milling . DSC thermograms were obtained from 35 to 110 degrees C using heating rate s between 1 degrees C/min and 15 degrees C/min. The rate constants were eva luated, and two activation energies were found for different temperature ra nges. At <70.1 degrees C gelatinization was not completed. It was assumed t hat at <70.1 degrees C gelatinization would only affect the amorphous regio ns. During the subsequent phase the crystalline regions destabilized by the amorphous component begin to gelatinize. For moisture content of 70%, wet basis, and a heating rate of 12 degrees C/min, the enthalpy of gelatinizati on reaches a constant value of 7.3 J/g.