Properties of Starch Isolated from Wet-milled Rice after Steeping at Elevated Temperatures for Annealing Effect

Rice was steeped at elevated temperatures of for 2 hr, and physicochemical properties of starches isolated from wet-milled rice flour were investigated. Steeping at elevated temperatures slightly decreased lightness of rice starch, while increased yellowness and redness. Average granule size of rice starch was decreased by steeping treatment. Swelling power and solubility increased as temperature increased. Starch from rice steeped at displayed highest swelling power and solubility. Differential scanning calorimetry data of starch obtained from steeped rice at showed increased onset and peak temperatures, with narrower gelatinization temperature range, suggesting partial annealing effect. Pasting properties of starch measured by Rapid Visco-Analyzer indicated increased peak viscosity due to rice steeping at . Peak and breakdown viscosities decreased at , whereas setback and final viscosities increased.