Rheological properties of thickened barium liquids prepared with xanthan gum-based thickener and barium powder used in the diagnosis of dysphagia: Effect of thickener concentration and serving temperature

In this study, thickened barium liquids (TBL) were prepared by mixing a xanthan gum (XG)-based thickener at different concentrations (1.0%–3.0%) with a barium powder. The rheological properties of TBL and thickened non-barium liquids (TNL) at different thickener concentrations were examined under steady and dynamic shear conditions. The values of flow and dynamic rheological parameters (K, σ_oc, G′, and G″) of TBL were considerably higher than those of TNL. The extents of the TBL thixotropy loops decreased with an increase in thickener concentration, showing that at higher concentrations, the degree of shearing-induced structure breakdown was lower than at lower concentrations. Compared with those of TNL, the rheological characteristics of TBL were more strongly dependent on thickener concentration, indicative of a strong molecular interaction between XG and barium at high thickener concentrations. These results could facilitate the development and preparation of videofluoroscopic contrast media with rheological properties suitable for the diagnosis of dysphagia. Practical applications: Thickened liquids (TL) prepared with XG-based food thickeners are widely used for the effective management of patients with dysphagia (difficulty of swallowing). In terms of clinical practice, the rheological characteristics of thickened barium liquids (TBL) prepared with both XG-based thickener and barium powder are very important for the preparing the contrast media used for videofluoroscopic swallow study (VFSS) which the swallowing safety and efficiency with a bolus are assessed. Our results showed that compared with those of TL without barium, the rheological characteristics of TBL were more strongly dependent on thickener concentration, indicative of a strong molecular interaction between XG and barium at high thickener concentrations. These results presented in this study will be useful for the development and preparation of videofluoroscopic contrast media with rheological properties suitable for the diagnosis of dysphagia.