Isobaric and isothermal kinetics of gelatinization of waxy maize starch

Abstract

Thermal and high-pressure parameters describing the kinetics of gelatinization of a waxy maize starch solution at 25% solids were quantified using modulated differential scanning calorimetry (MDSC). Starch solutions were subjected to a range of temperatures (55-70 °C) and pressures (350-500 MPa) for pre-set times. In isobaric treatment, samples were placed and sealed hermetically in aluminum pans. These were heated instantaneously to various end points within the aforementioned temperature range from 3 to 300 s. In isothermal treatment, samples were sealed in plastic pouches and subjected to various levels of pressure indicated above up to 90 min. Thermal and high-pressure treated samples were then subjected to MDSC routines in order to evaluate the degree of starch gelatinization. Experimentation had an effect on the temperature of starch gelatinization, which followed first-order kinetics. The temperature and pressure dependence of the reaction rates was thus modeled using the Arrhenius and Eyring equations. This afforded collection of numerical values for the rate constants describing the combined time-temperature-pressure effect on starch gelatinization. © 2007 Elsevier Ltd. All rights reserved.