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Barium sulfate is commonly used to prepare contrast media for videofluorograpy. The flow characteristics of thickened liquids formulated for oropharyngeal imaging are known to be greatly affected by the addition of barium. In this study, thickened barium liquids were prepared by mixing a commercial xanthan gum (XG)-based thickener (Visco-up®) at different concentrations (0.1%–3.0%) with barium powder (Baritop HD®), and differences in the viscosity between thickened non-barium and thickened barium liquids were investigated. In addition, the thickness levels of thickened barium liquids, which are based on the National Dysphagia Diet (NDD) and International Dysphagia Diet Standardization Initiative (IDDSI) guidelines, were classified by measuring the viscosity (NDD) and gravity flow through a syringe (IDDSI) with 0.1%–3.0% thickener concentrations. The apparent viscosity (ηa,50) values of thickened barium liquids were much higher than those of thickened non-barium liquids, indicating that the addition of barium to the XG-based thickener resulted in further thickening. Standard recipes for preparing thickened barium liquids with desirable thickness levels were also established, showing the different thickener concentrations corresponding to the different NDD and IDDSI levels.

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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, σoc, 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.