Characterizing dynamic sensory properties of nutritive and nonnutritive sweeteners with temporal check-all-that-apply

Temporal check-all-that-apply (TCATA) is a rapid method where attributes are actively checked and unchecked to track sensations over time, so that the checked words fully describe the sample in any given moment. Here, we characterize the temporal profiles of sweeteners using TCATA. In two experiments, sweeteners were tested in water at concentrations known to elicit weak to moderate sweetness. Before evaluating the sweeteners, participants (n = ∼125 per experiment) were familiarized with the TCATA method with a guided example using imaginary samples of Kool-Aid. Participants then received 10 ml of each sweetener solution and were instructed to click “start” after he or she finished swallowing the sample. Incidence of six attributes obtained from prior literature—sweet, bitter, metallic, licorice, cooling, and drying—was obtained for 60 s. We observed similarities across temporal profiles of various sweeteners: sweet and bitter occurred first (∼10 s), then metallic and cooling (∼10–25 s), followed by drying much later (30–50 s depending on the stimulus). The presence of side tastes influenced how often “sweet” was endorsed: stimuli with fewer endorsements of side tastes showed more prominent sweetness. Finally, unfamiliar side tastes may lead to a smearing bias where participants check every attribute in an attempt to characterize those unfamiliar sensations. Practical applications: Traditional continuous time intensity methods only allow one or two attributes to be assessed at a time, while discrete multi-attribute time intensity methods may miss important changes in sensation, depending on the interval between ratings. The inclusion of multiple attributes in temporal check-all-that-apply allows continuous tracking of side tastes that are not the most intense/dominant sensation; this may be especially important for stimuli where a secondary attribute is still a strong driver of acceptability in spite of not being the most intense sensation, as with nonnutritive sweeteners.