Effects of Cellulose Gums on Rheological Interactions in Binary Mixtures of Xanthan Gum and Locust Bean Gum

Abstract

The effects of cellulose gums (CG), such as carboxymethyl cellulose (CMC) and hydroxypropyl methylcellulose (HPMC), on the flow and dynamic rheological properties of binary mixtures of xanthan gum (XG) and locust bean gum (LBG) were examined at different XG/LBG/CG mixing ratios (50/50/0, 47.5/47.5/5.0, 45/45/10, and 42.5/42.5/ 15.0). All XG/LBG/CG ternary mixtures showed high shear-thinning behavior and the flow behavior index values of samples containing HPMC were lower than those of samples containing CMC. An increase in consistency index and apparent viscosity values was observed for ternary gum mixtures containing HPMC, indicating that the flow properties of the XG/ LBG binary mixture were affected by the content of HPMC. Storage modulus and loss modulus values of ternary gum mixtures decreased with an increase in CG content from 5 to 15%. The maximum viscoelasticity of XG/LBG/CG mixtures was observed at a mixing ratio of 47.5/47.5/5.0. These findings suggest that the rheological properties of XG/LBG binary mixtures were strongly influenced by the addition of CMC and HPMC.

Keywords: cellulose gum; rheological property; viscoelasticity; xanthan gum.

Fig. 1

Plots of shear stress versus shear rate of (A) xanthan gum (XG)/locust bean gum (LBG)/carboxymethyl cellulose and (B) XG/LBG/hydroxypropyl methylcellulose mixtures at different mixing ratios (50/50/0, 47.5/47.5/5.0, 45/45/10, and 42.5/42.5/15.0). ○, 50/50/0; □, 47.5/47.5/5.0; △, 45/45/10; ⋄, 42.5/42.5/15.0.