Physicochemical and structural properties of debranched waxy rice, waxy corn and waxy potato starches

Starch gels of waxy rice (WR), waxy corn (WC) and waxy potato (WP) were hydrolyzed with pullulanase, and the products obtained were analyzed for unit chain length distribution and certain physicochemical properties. Average chain lengths of debranched WR, WC and WP starches were 18.2, 19.2 and 25.6, respectively. The debranched starches had a greater ability to form complexes with iodine and possessed higher solubility but lower viscosity compared with their corresponding dispersed native starches. Their complexing abilities with fatty acids (palmitic and butyric acids) were found to be dependent on the unit chain length. Among the three debranched starches, debranched waxy potato starch exhibited the greatest ability to form complexes with iodine and fatty acids, while debranched waxy rice starch had the highest solubility and lowest viscosity. The debranched starches formed stable gels at high concentrations (10–20%) and formed precipitates at concentrations up to 5%.