Modelling temporal thermal taste responses: Variability, thermal taster subgroups and potential mechanisms

Thermal taste is a phenomenon where some individuals perceive taste sensations when temperature is applied to the tongue. Reported tastes vary across individuals and temperature ranges, but limitations in earlier phenotyping methods made it difficult to explore underlying mechanisms. The RapCoTT approach addresses this by capturing real-time taste reports at the approximate stimulation temperature. This study analysed data from three RapCoTT studies (including previously published data in Botha et al., 2021 ) to examine relationships between reported tastes and temperature, using model-based clustering to identify patterns in thermal taster responses. From responses of 230 respondents, three distinct subgroups emerged. C1 (C1) often reported salty taste, either with any taste except metallic (State 4) or with metallic (State 2). C2 (C2) showed sour (State 2), savoury (State 4), and metallic (State 3) responses. Cluster 3 (C3) featured bitter taste combined with dominant sweet (State 2), metallic (State 5), or sour (State 3). By identifying critical temperatures where specific tastes or combinations occurred, this study highlighted potential temperature-sensitive receptor mechanisms underlying thermal tastes, in particular TRPA1 and TRPM5, but also TRPM4, TRPV4, TRPV1 and TMC4 and the need for research to understand potential variation in the identified receptors and thermal taste phenotype.