Rheological behavior and physical properties of aqueous solutions of carrageenan and acacia gum

Resumo

Polysaccharides are widely used as thickening, stabilizing, and gelling agents for the control of the texture, flavor, microstructure, and shelf-life of foods. This work contributes to the study of the physical properties and rheological behavior of binary and ternary solutions of carrageenan and acacia gum. Experiments were performed to determine properties such as density, refractive index, and viscosity. The results showed that those properties studied increased with increasing biopolymer concentration and decreased with increasing temperature. Experimental data were modeled to describe the combined effects of temperature and biopolymer concentration on the density, refractive index, and dynamic viscosity of these solutions. The properties were measured in the temperature range from 298.15 to 308.15 K. Suitable polynomial functions were successfully fitted to the experimental data. Classical rheological models (Bingham, power law, Casson, and Herschel-Bulkley) were tested for binary and ternary aqueous solutions containing carrageenan. Pseudoplastic behavior was observed, and the solutions were accurately modeled through a power-law model.