Viscoelastic characterization of gum arabic and maize starch mixture using the Maxwell model.

The aim of this study was the viscoelastic characterization of dispersions of gum arabic (GA) at 25 and 35% (w/v), maize starch (MS) at 3 and 5% (w/v) and their mixtures (GA/MS) using dynamic oscillatory and creep tests. The studied dispersions presented G′ values of up to 8.5, 12.7 and 3.5 greater than those of G″ in GA, MS and GA/MS dispersions, respectively, showing a predominantly elastic behavior. Creep curves revealed that in 5% (w/v) MS dispersions, recovery reached 96.7%; thus, they behaved as a viscoelastic solid. However, by adding gum arabic into the mixtures (GA/MS), no recovery was observed and they behaved as viscoelastic fluids. In relation to Maxwell model parameters, viscosity (η0) was approximately 6 Pa s for GA and GA/MS dispersions, and 1.12×106 Pa s for MS dispersions. Mixture relaxation time (λrel) was between 0.023 and 220 s and instantaneous compliance (J0) was greater than retarded compliance (J1) regardless of MS concentration.