Thermal taster status: An exploratory taste-specific stratification

Thermal Taster Status (TTS) is a taste phenotype where some individuals (Thermal Tasters, TTs) perceive tastes in response to thermal stimulation of the tongue. However, the classification of individuals as TTs, Thermal non-Tasters (TnTs), and Not Classified (NCs) has been inconsistent, often leading to a high proportion of NCs and limited insights into sensory variability. This study aimed to propose an exploratory taste-focused stratification of the traditional TTS classification to examine whether considering the specific thermally perceived taste provides additional insight. One hundred thirteen participants (60 % female; average age 27; 85.8 % Italian) assessed the intensity of five tastes and four chemesthetic properties in aqueous solutions at 5 °C and 55 °C. Each participant was categorized as TTs, TnTs, or NC once for each of the five tastes, based on whether they thermally perceived that specific taste. Unlike the currently mostly used approach, which revealed no significant differences between TTs and TnTs across tastes or chemesthetic perceptions, the taste-specific classification showed greater discriminative power. Bitter-TTs perceived significantly higher bitterness intensities than Bitter-TnTs and Bitter-NCs at both temperatures. Moreover, although previous studies found no association between TTS and PROP sensitivity, our approach revealed that Bitter-TTs reported significantly higher PROP bitterness, suggesting a taste-specific interaction. These findings highlight the value of a more in-depth taste-specific TTS analysis to better capture individual sensory differences. Despite preliminary, this method provides a promising framework for future research aimed at understanding the physiological mechanisms of TTS and its relevance in food perception and eating behavior.