The present study aims to determine the influence of edible organic acids (ascorbic, citric, malic, and tartaric) at two concentrations (0.5, and 1 %) on the viscosity and rheological behavior of xanthan gum dispersion (0.2%, w/v). The results of this study showed that the apparent viscosity of xanthan gum dispersion reduced as the shear rate (SR) increased (shear-thinning behavior). Furthermore, the apparent viscosity of the xanthan gum dispersion decreased as the organic acid concentration increased. The highest decrease in viscosity was related to 1% citric acid and the lowest was related to 0.5% ascorbic acid. The rheological behavior of xanthan gum dispersion was successfully modeled using Power law, Bingham, Herschel-Bulkley, and Casson models, and the Power law model was the best one for describing the behavior of xanthan gum dispersion containing edible organic acids. The Power law model showed good performance with the maximum r-value (mean r-value=0.993) and least sum of squared error (SSE) values (mean SSE value=0.115) and root mean square error (RMSE) values (mean RMSE value=0.046) for all samples. The consistency coefficient values of the samples (Power law and Herschel-Bulkley models) reduced as the acid percent was increased. The sample containing 1% citric acid had the lowest consistency coefficient and the sample containing 0.5% ascorbic acid had the highest consistency coefficient. Based on the results of this research, the use of xanthan gum in food products containing high concentrations of citric acid is not recommended.
