Erich von Borries Medrano
Instituto Politecnico Nacional, Mexico
Title: Starch-guar gum extrudates: microstructure, physicochemical properties and in vitro digestion
Biography
Biography: Erich von Borries Medrano
Abstract
Starch-guar gum mixtures were obtained by extrusion using a three-variable Box-Behnken statistic design. Morphology, expansion index, viscosity, crystallinity and digestion in vitro of the extruded samples were analyzed through response surface methodology (RSM). The extrusion temperature and the moisture content were the factors that significantly affected the physicochemical properties of the samples. Starch-guar gum samples showed expansion index and viscosity up to 1.55 and 1,400 mPas, respectively. The crystallinity of the samples was modified by adding guar gum to the extrudates showing correlation between long-range order (X-ray diffraction) and short-range order (FTIR spectroscopy). Guar induced micro-structural changes and its role in gelatinization-melting processes was significant. The rate of glucose release decreased from 0.47 to 0.43 mM/min when the extrusion temperature decreased. However, adding guar gum to starch had no significant effect on glucose release. Overall, the extrusion temperature and the moisture content were the factors that significantly affected the physicochemical properties of the extruded samples.