Effects of corn fiber gum with different molecular weights on the gelatinization behaviors of corn and wheat starch

Abstract Corn fiber gum (CFG) is a novel arabinoxylan hydrocolloid and recent research indicates that it has a considerable potential in food processing. In this study, composite systems consisting of starch and CFG with different molecular characteristics have been evaluated. The pasting and thermal properties, microstructure and leached amylose of corn and wheat starch have been studied. When compared with the starch suspensions alone, CFG addition led to lowering of peak viscosity, breakdown and final viscosity of corn starch. It also led to lowering of peak viscosity and final viscosity, but increase of breakdown of wheat starch The changes in rapid viscosity analyzer (RVA) characteristics were less pronounced as the M w of CFG was increased. The amount of leached amylose of corn/wheat starch gels decreased as the M w of CFG increased. The thermal characteristics of corn starch/CFG mixtures varied insignificantly as determined in differential scanning calorimetry (DSC) heating process. Confocal laser scanning microscopy (CLSM) confirmed changes in gel microstructure as starch components tended to be inhibited from leaching out of the granules. CFG addition also led to a well-defined morphology of wheat starch granules after gelatinization, suggesting a leaching-inhibition effect of CFG on the granule structure.