Influence of shear rate and concentration ratio on viscous synergism.: Application to xanthan-locust bean gum-NaCMC mixtures

A method is described that allows the development of an empirical approach to quantify synergistic interactions and their variations with shear rate. The approach is based on the definition of a viscous synergism index, I-nu. The method is applied to xanthan-locust bean gum gels, and an equation is developed for relating the synergism index to shear rate, gamma, and the locust bean gum/xanthan gum concentration ratio, z. The value of z at which that function has a maximum, I-V(M), is calculated. This value of z provided an estimation of the proportion of gums at which maximum synergism occurs. A decreasing exponential dependence of these I-V(M) on gamma is shown. The influence of the addition of a fixed proportion of a third gum (NaCMC) is also analyzed. The results obtained for the higher gamma values are analogous to those of other authors.