Influence of Stimulus Temperature on Orosensory Perception and Variation with Taste Phenotype

Recently, the phenomenon of thermal taste, where thermal tasters (TTs) perceive taste sensations from the application of thermal stimuli to the tongue, was described. Thermal taster status (TTS) appears to function as a marker of individual variation in orosensory perception, as TTs are more responsive to prototypical orosensory stimuli and flavor attributes in complex beverages than thermal non-tasters. The main objective of this study was to examine the influence of TTS on the relationship between stimulus temperature and orosensory perception. Propylthiouracil (PROP) responsiveness has long been used as an index of individual variation in oral sensation, as general orosensory responsiveness to a variety of stimuli associates with the ability and degree to which individuals perceive PROP's bitterness. PROP taster status (PTS), an expression of individuals' PROP responsiveness, was also examined. Perceptually equi-intense stimuli eliciting sweet, sour, bitter, and astringent sensations were presented at 5 °C and 35 °C and evaluated using time-intensity methodology. Unexpectedly, an apparent trend of TTs reporting higher maximum perceived intensities for all stimuli was not statistically significant, and an examination of individual subjects' data suggests further examination of the influence of TTS on orosensory stimuli is warranted. PROP bitterness and the perceived intensity of orosensory stimuli were not associated at either temperature; however, some differences between PTS groups were found. As previously reported, TTS and PTS interactions were not observed. Interestingly, temperature influenced the maximum intensity perceived from astringent, bitter, and sour stimuli, but not from the sweet stimulus.