Macromolecules, Vol.32, No.8, 2610-2616, 1999
Light scattering and viscoelasticity of aggregating and gelling kappa-carrageenan
We have studied the evolution in time of the shear modulus and the scattered light intensity of aqueous kappa-carrageenan solutions at various concentrations and temperatures. Aggregation was induced by cooling solutions containing 0.01 M KCl. The ionic strength of the solutions was fixed by adding 0.1 M NaCl. The time dependence was found to be similar at all concentrations and temperatures investigated. Equilibrium was not attained even after 12 h maturation. The temperature dependence is mainly kinetic and diverges at a temperature close to the temperature of the coil-helix transition of kappa-carrageenan. Varying the concentration influences both the aggregation kinetics and the strength of the gels. No critical minimal concentration for gelation is observed.
Keywords:IOTA-CARRAGEENAN;CONFORMATIONAL TRANSITION;RHEOLOGICALBEHAVIOR;AQUEOUS-SOLUTION;GELS;SUSPENSIONS;HYDROLYSIS;GELATION;HELICES;CATIONS