Increasing xanthan gum content could enhance the performance of agar/konjac glucomannan-based system

Abstract

The properties (e.g., viscosity, sol-gel transition, and mechanical characteristics) of polysaccharides are crucial for their food applications. This work discloses how xanthan gum (XG) incorporation tailors the performance of an agar/konjac glucomannan (KGM) system. As reflected by rheological and thermal analyses, an increasing content of XG added could strengthen the chain entanglement in the resulting ternary solution with strong KGM-XG binding (an exothermic event). For example, a ternary system with a 16% XG content (AKX-16%) showed simultaneous increases in the zero-shear viscosity (about 5.5 times that of the binary counterpart AK), sol-gel transition point (about 48 °C; 10 °C higher than that of AK), and gel hardness (about 2300 g; 450 g higher than AK). Moreover, the AKX-16% composite showed lower crystallinity and enhanced hydrogen bonding and tensile strength (74 MPa) resulting from gel dehydration. Additionally, increasing the XG content showed a negligible effect on the morphology of the composite matrix, suggesting the excellent compatibility between these different polysaccharides.