Esterification of carboxymethyl debranched waxy corn starch, its characterization and performances

Abstract

A combination of pullulanase debranching, chloroacetic acid etherification, and sodium tripolyphosphate esterification was selected for the modification of waxy corn starch (WCS) to ameliorate its properties and expand its application. The results showed that the carboxymethylation and phosphorylation were chiefly completed on the big particles. The crystalline structure of WCS was an A-type, but the crystalline structure of debranched waxy corn starch (DWCS) was a C-type. The carboxymethylation destroyed the crystal structure of DWCS. The debranching could result in the reduction of the swelling capacity of WCS, while the carboxymethylation and esterification improved the swelling capacity. The characteristic absorption peaks of carbonyl bonds at 1736.8 cm− 1 and P = O bonds at 1301.2 cm− 1 confirmed that WCS was successfully etherified and esterified. Phosphate carboxymethyl debranched waxy corn starch (PDWCS) could be used to remove Zn2+, and at suitable adsorption conditions, the removal rate of Zn2+ could reach 72.9%