Co-migration of phytate with cereal β-glucan and its role in starch hydrolysis in-vitro

Abstract

This study investigated the mechanisms of the co-migration of phytic acid during β-glucan isolation and its contribution to the retardation of starch hydrolysis in vitro. During the isolation, phytic acid precipitated together with β-glucan when ethanol was added as the precipitation solvent. The precipitation of phytic acid was reduced by lowering the pH or the ethanol concentration. When 20% (NH4)2SO4 was used as the precipitation solvent, only minor phytic acid was found in isolated β-glucan, because phytic acid did not precipitate by this solvent. In the in vitro starch hydrolysis test, the isolated oat β-glucan (OBG) containing 3.9% co-migrated phytic acid showed better retardation effect than OBG containing 0.6% phytic acid. Therefore, we concluded that the co-migration of phytic acid was dependent on the chosen isolation procedure and conditions, and both intrinsic phytic acid and viscosity contributed to the retardation of starch hydrolysis.