Structural and Physicochemical Properties of Cassava Starch Modified by Roasting Treatment with Citric Acid

Structural and physicochemical properties as well as digestibility of modified cassava starch produced by roasting treatment at 150 °C for 1−3 h in the presence of 1% citric acid were investigated. After roasting for 3 h, some starch granules  appeared to have minute cracks, and some displayed irregular and disrupted structures. Starch molecules were broken down into small ones during the roasting, and the degree of hydrolysis increased with time. Esterification had occurred between the citric acid and starch with a new peak appearing at around 1736 cm−1. Citric acid-roasted starches exhibited increased solubility in cold water and enhanced water-binding capacities. Whereas the ability of citric acidmodified to absorb oil did not differ from native starch. After cooking, thermally stable RS content in citric acid-roasted starches (16.2-17.2%) was higher than that in native starch (3.4%).