Impact of glucansucrase treatment on structure and properties of maize starch

A glucansucrase isolated from Leuconostoc citreum SK 24.002 has the ability to catalyze transglycosylation and/or hydrolysis reactions on differently linked alpha-glucose polymers. In this study, maize starch was modified using L. citreum glucansucrase, and its structure and properties were investigated. The total content of oligosaccharides was 2.72% for glucansucrase-treated starch. The modified starch had a higher amylose level and molecular weight than did native starch. The chain-length distribution showed a greater number of short (degree of polymerization, DP< 13) and long (DP> 30) branched chains in the modified starch. Compared with the native starch, the modified starch displayed a lower gelatinization enthalpy and a wider melting temperature range. The Englyst assay revealed that enzymatically modified starch had higher SDS and RS contents. Both the changes in molecular weight and the fine-chain structure in the treated starches likely contribute to its low digestion capacity.