Preparation and characterization of a novel pH-response dietary fiber: chitosan-coated konjac glucomannan.

The purpose of this study was to prepare a kind of novel pH-response dietary fiber from chitosan-coated konjac glucomannan (KGM) powders (KGM/Chitosan or K/C powders) by a physical grind method. The K/C powders were selectively soluble in aqueous solutions of different pH. Meanwhile, the coated chitosan could largely decrease the viscosity of KGM in neutral condition, which is the main limitation for KGM application in food industry. Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), swelling ability and rheological measurements were utilized to characterize the performance of K/C powders. K/C powders exhibited much higher viscosity and swelling ability in acidic condition than in neutral condition. Therefore, this study will extend the application of KGM in food industry and in other pH-specific applications as well.