Effect of combination of dry heating and glucose addition on pasting and gelling behavior of starches

Normal corn, waxy corn, potato, and tapioca starches were subjected to dry heating by adding glucose at slightly alkaline conditions to investigate the impact of the combination of dry heating and glucose addition. After dry heating, normal/waxy corn and tapioca starches showed increased peak viscosity and decreased pasting temperatures, whereas potato starch exhibited decreased peak viscosity. The increase in peak viscosity of normal/waxy corn and tapioca starches became more significant after adding glucose to the dry heating process. Moreover, the starch gels became more rigid after dry heating with the addition of glucose than native and control starch. Dry heating alone decreased the melting temperatures and enthalpy of the starches assessed. Nevertheless, dry heating with glucose addition induced no significant changes in the melting characteristics of corn and tapioca starches; however, it significantly increased the melting temperature and enthalpy of potato starch compared to those by dry heating alone. Furthermore, dry heating in combination with glucose addition reduced paste clarity and induced slight thermal browning. These results clearly indicate that the combination of dry heating and glucose addition induces more intense changes in the properties of starch than those by dry heating or glucose addition alone.