Rheological Characterization of Binary Combination of Gleditsia triacanthos Gum and Tapioca Starch

Abstract

In the current study, Gleditsia triacanthos gum and tapioca starch were combined and rheological characterization of the binary mixture was performed. Gleditsia triacanthos gum at four different concentrations (0.1, 0.4, 0.7, and 1.0%, w/v) was mixed with tapioca starch at a constant level (2.5%, w/v). Steady shear and dynamic shear rheological properties of samples were determined using a stress/strain controlled rheometer at a constant temperature (25C). Oswald de Waele model was used to describe the shear rate effect on apparent viscosity values of the samples. Increase in the Gleditsia triacanthos level increased the apparent viscosity and consistency coefficient of the samples. Similarly, dynamic shear rheological parameters of the samples increased with the increase of Gleditsia triacanthos gum. The concentration of 0.7% for Gleditsia triacanthos gum was determined to be cross point for the liquid-solid phase. From this level, the elastic behavior became more dominant compared to viscous behavior because tangent delta was equal to one in this concentration. To describe the effect of Gleditsia triacanthos level on the studied rheological parameters, the Power law and exponential type models were used.