Gelation of food macromolecules: effects of sugars on the gelation of agarose and mixtures of konjac glucomannan and carrageenan

Abstract

Abstract Effects of sugars on gelation of agarose were studied by differential scanning calorimetry (DSC) and dynamic viscoelastic measurements. It was suggested that the number of junction zones was increased, and that the size of junction zones became smaller by the addition of sucrose. As a result of this, the rotational freedom of parallel links which constitute a zipper was decreased. The increment of melting or setting temperature per unit concentration of sugars was correlated linearly with the dynamic hydration number of the sugars. Small and large deformation rheological measurements on mixed systems of kappa-carrageenan and konjac glucomannan with different molecular weights suggested that gels of this mixture consist of a carrageenan network strengthened by weak interaction of konjac glucomannan with carrageenan. carrageenan-rich mixtures (CAR content> 70%) showed two exothermic peaks in the cooling DSC curves.