Rheological properties of mixtures of kappa-carrageenan from Hypnea musciformis and galactomannan from Cassia javanica.

Mixed gels of kappa-carrageenan (kappa-car) from Hypnea musciformis and galactomannans (Gal) from Cassia javanica (CJ) and locust bean gum (LBG) were compared using dynamic viscoelastic measurements and compression tests. Mixed gels at 5 g/l of total polymer concentration in 0.1 M KCl showed a synergistic maximum in viscoelastic measurements for kappa-car/CJ and kappa-car/LBG at 2:1 and 4:1 ratios, respectively. The synergistic maximum obtained from compression tests carried out for mixed gels at 10 g/l of total polymer concentration in 0.25 M KCl was the same for both kappa-car/CJ and kappa-car/LBG gels. An enhancement in the storage modulus (G') and the loss modulus (G") was observed in the mechanical spectra for the mixtures in relation to kappa-car. The proportionally higher increase in G" compared with G', as indicated by the values of the loss tangent (tandelta), suggests that the Gal adhere non-specifically to the kappa-car network.