Temperature thresholds and time-temperature dependence of gelatinization for heat-moisture treated corn starch

The time and temperature dependence at different stages of starch gelatinization has been poorly understood. In order to fill this gap in knowledge, we employed heat-moisture treated corn starch and developed a novel gradient gelatinization method with short (5 min) and long (20 and 30 min) isothermal holding within 64-95 °C to determine the relevant temperature thresholds. The increase in viscosity values (Δμ-values) during 5 min isothermal holding demonstrated the temperature-dependent behavior of corn starch gelatinization. The time-dependent nature of which was also evidenced with long-term heat-holding method. 70 and 76 °C were proposed as the two critical temperature thresholds TTS1 and TTS2, which were associated with amorphous swelling and disintegration of crystalline domains, respectively. Furthermore, the individual influence of time and temperature at different gelatinization stages were discussed based on a multi-stage gelatinization theory. The degree of time-dependence was different from different gelatinization stages occurring in between TTS1 and TTS2.