Thermal Tasting and Difference Thresholds for Prototypical Tastes in Wine

Abstract

Thermal tasting—the capacity to experience phantom taste sensations on thermal stimulation of the tongue—has been shown to associate with greater responsiveness to orosensations elicited in aqueous solutions and beverages. Here, we sought to determine if this heightened acuity extends to difference thresholds. An ascending two-alternative forced choice method was used to measure difference thresholds for sweetness (sucrose), sourness (tartaric acid), and bitterness (quinine) in a neutral white wine. Individual best-estimate thresholds (BETs) were calculated according to ASTM E-679-04. Group difference thresholds (g/L) for thermal tasters (TT) and thermal non-tasters (TnT), respectively, were sweetness, 3.52 and 5.24; sourness, 0.23 and 0.70; and bitterness, 0.0058 and 0.0060. There was an overall trend of TTs having lower difference thresholds than TnTs, but this was significant only for sourness (t = 3.95, p = 0.002). Additionally, wine expertise was inversely associated with the difference threshold for sweetness (rho = −0.470, p = 0.029) and was a significant source of variation in the analysis of covariance (t = −2.69, t = 0.016). These data provide some preliminary evidence that the supra-threshold intensity “advantage” in orosensory perception previously reported for thermal tasters may extend to difference thresholds and complex products such as wine. These results add to the evidence that thermal tasting represents a potentially important taste phenotype that may associate with food preference and consumption and should also be considered when populating sensory panels.