Gelatinisation of sage starch in the presence of sucrose and sodium chloride as assessed by differential scanning calorimetry

The inhibitory effect of sucrose and sodium chloride on sage starch gelatin isation was investigated by differential scanning calorimetry (DSC). The te mperature of gelatinisation of starch in the presence of low levels of wate r and high levels of sucrose was found to increase in the presence of sucro se, whereas the gelatinisation enthalpy was unaffected. The gelatinisation temperature range was not as broad in the presence of sucrose as without su crose. Furthermore, the shape of the gelatinisation endotherm was changed b y the addition of sucrose. The double endotherm obtained in limited water:s tarch systems was changed into a single endotherm, similar to the endotherm obtained in excess water:starch systems at a higher temperature. DSC was a lso used to examine the effects of water and sodium chloride content on the phase transitions of sage starch. Samples were adjusted to starch:water ra tios of 2:3 and 3:2 in sodium chloride concentrations of 0.0, 1.0, 2.0, 3.0 , 4.0, 5.0 M. The gelatinisation temperatures of sage starch increased and then decreased as the sodium chloride concentration increased. Sodium chlor ide created similar effects on the endotherms in excess water content and o n the first endotherm with limited water content. In the presence of sucros e and sodium chloride, gelatinisation shifted to higher temperatures, and e nthalpy associated with the endothermic process decreased. The extent of te mperature shift and enthalpy change was dependent on the water to starch to solutes ratios. (C) 2001 Elsevier Science Ltd. All rights reserved.