Kinetics of Phase Transition of Waxy Corn Starch at Extrusion Temperatures and Moisture Contents

Thermal energy effect on the phase transition of a waxy corn starch, Amioca, with different amount of water was evaluated by using differential scanning calorimetry. For water content less than 40% (w/ w), the kinetics of the conversion of starch followed the pseudo‐zeroth order. An activation energy of 33.78 kcal/mol for 80% Amioca and that of 44.25 kcal/mol for 75% Amioca in the Amioca‐water system were obtained from the Arrhenius relation. A useful correlation between the rate constant of conversion and a nondimensional temperature parameter, T/T_p, was found from various sources and with various moisture contents.