DIFFERENTIAL SCANNING CALORIMETRY OF STARCH12

ABSTRACT At high water‐to‐starch (2:1) ratios a single endotherm was obtained for starch gelatinization. As the water‐to‐starch ratio was decreased the endotherm area decreased and the peak developed a trailing shoulder. At high water‐to‐starch ratios birefringence is lost over a temperature range of about 7°C. That narrow range increases to about 30°C at a low water‐to‐starch ratio. Starch and flour gave essentially the same endotherm initiation temperatures. In low‐water systems the second DSC peak is much smaller with starch than with flour. It appears that in a starch system, water migrates during gelatinization. In dough, gluten limits that migration. As the level of sucrose was increased in a dough, the transition temperature increased and the gelatinization temperature range decreased. At the levels found in bread doughs both sugar and salt increase starch gelatinization temperatures.