Hydration level significantly impacts the freezable - and unfreezable -water contents of native and modified starches

Abstract The freezable- and unfreezable-water contents of corn and waxy corn starches (native, pregelatinized and retrograded) were analyzed at various hydration levels (25, 35, 45, 55, 65, 75, 85%) using Differential Scanning Calorimetry (DSC). The unfreezable water contents and also the temperature of onset (To), peak (Tp) and endset (Te) of the peaks' in all samples were increased with increasing hydration level. Water absorption index (WAI) and water solubility index (WSI) values of the pregelatinized and retrograded starch samples were significantly higher (p<0.05) than their native counterparts. RVA profiles revealed that modified starches had higher viscosity values than natural starches.