Dissolution behaviors of waxy maize amylopectin in aqueous-DMSO solutions containing NaCl and CaCl2

Abstract

Dissolution behavior and molecular conformation of waxy maize amylopectin in aqueous DMSO solutions containing different amounts of water and salts (NaCl or CaCl2 up to 0.2 M) were characterized using multi-angle laser light scattering (MALLS; micro-batch mode) and dynamic light scattering (DLS) detectors. The solubility of amylopectin decreased and the molecular size measured increased when the water content in the DMSO increased, indicating that amylopectin chains tended to be less dissociated or aggregate by the excess amount of water. The amylopectin in aqueous DMSO solutions (10-50% water) had a spherical shape with a regular star structure, but the individual amylopectin chains were not affected by water content. Minor addition of salts facilitated the dissolution of amylopectin in aqueous DMSO solutions, possibly due to water cluster formation by the salt ions. However, a minute presence of salts (0.01 and 0.05 M) could induce the chain association even in 90% DMSO solution. (C) 2013 Elsevier Ltd. All rights reserved.