The protective role of phytate in the oxidative degradation of cereal beta-glucans.

This study investigated the role of phytate in the Fenton reaction induced oxidative degradation of cereal ß-glucan. Viscosity analysis showed that the degradation rate was high in the beginning of oxidation, which fitted to the second order kinetic model. Oat ß-glucan contained significant amount of residual phytate and after the residual phytate was removed, faster degradation was shown compared to the original oat ß-glucan. Adding the same amount of phytic acid (PA) to the phytate removed ß-glucan sample also retarded the degradation but not as efficiently as the residual phytate. Considerable retardation of viscosity loss was shown when the PA to iron ratio was high. The presence of ascorbic acid weakened the retardation effect of phytic acid. Thus, phytate can significantly improve the oxidative stability of ß-glucan when the ratio of phytic acid to transition metals and the presence of ascorbic acid are taken into consideration.