Rheological characterization of thickened protein-based beverages under different food thickeners and setting times.

The effects of different setting times (15-120 min) on the rheological properties of cold thickened protein-based beverage (PBB) samples prepared with different xanthan gum (XG)-based food thickeners were examined. In this study, four commercial XG-based food thickeners (coded A-D) and three commercial PBB products (whole milk, skim milk, and soybean milk) were used to prepare thickened PBB samples at a 3% thickener concentration. The fastest increases in ηa,50 values of thickened PBB samples were observed at 15 min, and at longer time periods their ηa,50 values gradually increased or remained constant with an increase in setting time (15-120 min). The magnitudes of the rheological parameters (ηa,50 , K, G', and G″) of thickened PBB samples with thickener A were significantly higher compared with those with other thickeners (coded B, C, and D). The flow and dynamic rheological properties of thickened PBB samples prepared with different XG-based thickeners were significantly different (p < .05), demonstrating that their rheological properties were greatly affected by the type of PBB and thickener as well as the setting time. PRACTICAL STATEMENTS: Food thickeners have been commonly used in the preparation of various thickened fluids with desirable rheological properties for dysphagic patients to elicit an optimal swallow response. However, among various thickened fluids, there is limited rheological information on cold thickened protein-based beverage (PBB) (e.g., whole milk, skim milk, and soybean milk) prepared with various xanthan gum (XG)-based thickeners. Our flow and dynamic rheological results showed that the flow and viscoelastic properties of the thickened PBB samples prepared with different food thickeners were dependent on the PBB type, thickener type, and setting time. These rheological results presented in this study will provide both thickener manufacturers and clinicians with valuable information for thickened PBB products with desirable rheological properties for safe and easy swallowing. New knowledge of the different rheological characterizations of thickened PBB can be practically applied to develop the commercial dysphagia thickeners suitable for PBB in food industry.