Effects of Viscosity Modification on Sensory Perception, Hedonic Evaluation, and Expected Fullness of Whey-Based High-Protein Beverages Under Blind and Informed Conditions

This study investigated the effects of xanthan-gum-induced viscosity on sensory perception, expected fullness, and panelists’ acceptance of whey-based high-protein beverages under sequential blind and informed evaluation conditions. Four formulations containing 0%, 0.08%, 0.12%, and 0.16% xanthan gum were evaluated by 131 panelists using 30 mL tasting samples. Linear Mixed Models (LMMs) were applied to account for repeated measurements and inter-individual variability. Increasing viscosity systematically increased expected fullness while reducing overall liking and prospective hypothetical consumption volume. Panelists showed higher acceptance and greater prospective hypothetical consumption volume during the informed evaluation condition, although these differences were interpreted cautiously because the evaluation conditions were administered sequentially. Nevertheless, higher viscosity remained associated with lower hedonic ratings, indicating that oral texture continued to play a dominant role in product acceptance regardless of information disclosure. Taste liking was the strongest predictor of overall acceptance, whereas perceived viscosity was associated with lower prospective hypothetical consumption volume, particularly at higher xanthan gum concentrations. These findings highlight the importance of immediate sensory attributes, particularly taste and viscosity-related expected fullness, in shaping panelists’ acceptance and prospective hypothetical consumption volume. Differences between the sequential blind and informed evaluations, however, were interpreted cautiously because they may also reflect session-order and repeated-exposure effects.