Synergy of the kappa-carrageenan-carob galactomannan blend inferred from rheological studies.

Rheological measurements have been used to investigate kappa-carrageenan-carob galactomannan mixed gels at different ratios, in particular for very low kappa-carrageenan concentrations. The viscoelastic properties of the gels were explored using sinusoidal tests on dynamic rheometers and compression tests between parallel plates. The properties of the binary gels were compared with the kappa-carrageenan gels and with the carob galactomannan solutions. These measurements display significant synergy for very low kappa-carrageenan concentrations. From these data, it appears that the synergy is based on a gel structure defined by a coupled network with specific junction zones. However, above a total polysaccharide concentration of 8-10 g l-1, self-association of galactomannan chains could also take place.