RHEOLOGICAL STUDIES OF SYNERGISTIC KAPPA CARRAGEENAN-CAROB GALACTOMANNAN GELS

The mechanical properties Young's modulus and yield stress of different carob galactomannan-kappa carrageenan blends have been examined using an Instron testing machine as a function of the following parameters: (1) Constant total polysaccharide concentration. (2) Galactomannan concentration for a given carrageenan concentration. (3) Carrageenan concentration for a given galactomannan concentration. (4) Galactomannan molecular weight. (5) Carrageenan molecular weight. The properties of the binary gels were compared to the kappa carrageenan gels. From the results, two types of gel structure could occur: a coupled network defined by specific junction zones (and involving unsubstituted mannose residues of the galactomannan chains) and also a gel structure with both polysaccharides associating independently.