Influence of prior pre-treatments on molecular structure and digestibility of succinylated foxtail millet starch

Influence of different pre-treatments (Ultra-sonication, heat-moisture treatment (HMT) and acid hydrolysis) on the functional properties, in vitro binding capacity and structural properties of succinylated foxtail millet starch were investigated. The degree of substitution was found to be higher in the succinylated starch pretreated by sonication (USFS-0.39). Pre-treatment of succinylated starch by citric acid (ASFS) had markedly increased the resistant starch content. In vitro studies have confirmed that USFS exhibited the highest cholesterol binding capacity at both pH 2.0 (1.86 mg/g) and pH 7.0 (3.12 mg/g) owing to the chemical bonding and entrapment of cholesterol molecules in the starch matrix. FT-IR had confirmed the cross-linking of succinic anhydride as indicated by the presence of a new peak at 1724 cm^-1. This study concludes that prior treatment of succinylated starch by ultra-sonication is an efficient way to improve the resistant starch content and principally in vitro cholesterol and bile acid/salts binding ability.