Phenotypic variation in oronasal perception and the relative effects of PROP and Thermal Taster Status

Abstract

Joanne (2014) Phenotypic variation in oronasal perception and the relative effects of PROP and Thermal Taster Status. Food Quality and Preference, 38. pp. 83-91. Abstract Individual variation in taste perception has long been investigated, particular in relation to PROP taster status (PTS). Recently, a new marker has been identified, Thermal Taster Status (TTS), whereby individuals are categorised as thermal tasters (TTs) or thermal non-tasters (TnTs) based on their ability to perceive taste solely from temperature stimulation. The aim of this study was to investigate the incidence of thermal tasters and relative effects of PTS and TTS on oronasal sensitivity across the whole perceptual range. Both detection thresholds (ASTM E679) and intensity measures at suprathreshold level (rated on gLMS) for stimuli from a range of modalities were determined from up to 124 subjects pre-screened for their PTS and TTS. No significant differences were found within either PTS or TTS groups at detection threshold level, with one exception; TTs has a lower threshold for sucrose (p<0.05). At supra-threshold level, PROP supertasters (pSTs) and medium tasters (pMTs) rated stimuli higher than non-tasters, and a consistent trend was observed that TTs rated stimuli higher than TnTs, although only ratings for temperature (warm and cold) reached significance. Global analyses applied across each modality, showed that in general TTs rated gustatory and trigeminal modalities significantly higher than TnTs, whilst this was not the case for olfactory stimuli, indicating that the mechanism for increased perception for TTs may be located in the oral cavity. PTS and TTS were shown to be independent phenotypes, but interestingly, ANOVA revealed significant interactions between TTS and PTS across the three modalities. Most notably, within pMTs, TTs rated stimuli intensity higher than TnTs, while the opposite trend was observed for pSTs. The intensity advantage gained by thermal tasters appears to be more apparent for pMTs than the already highly sensitive pSTs.

Variation in orosensation and liking of sampled foods with thermal tasting phenotype

“…Figure 1 shows the taste qualities (%) experienced by thermal tasters after application of the TED; the proportions are similar to those reported by Pickering and Klodnicki [18]. The proportion of participants classified as TTs in this study was 44 %, which is within the range found in other reports (27 % [9], 31 % [Thibodeau M, Bajec MR, Pickering GJ: Orosensory responsiveness, thermal tasting and alcohol behavior, Submitted], 50 % [11]). …”

“…While there was an overall effect of TTS, a significantly more limited range of food items varied with the phenotype than we expected, given the heightened intensity experienced by TTs for a wide range of orosensations reported in simple aqueous solutions [8,9,11,12], wine [14] and beer [15]. While it is possible the analyses were underpowered due to the sample size, it is noteworthy that this enhanced acuity has only been demonstrated robustly to date in solutions and not with solid or semisolid matrices, perhaps indicating that wider palate stimulation is necessary to recruit sufficient receptors to confer the greater responsiveness of TTs.…”

“…Thermal tasting is a taste phenotype with a likely genetic basis first noted by the Green lab in 2000 [7]; however, there have only been sporadic reports appearing in the literature since then. Thermal tasters (TTs) perceive a phantom taste when small sections of the tongue are cooled or heated [7][8][9]. The specific sensations elicited include sourness, sweetness, saltiness, bitterness and metallic, and vary with the area stimulated and the temperature regime used (i.e.…”

“…In addition to experiencing a phantom sensation on lingual thermal stimulation, TTs also tend to rate the basic tastes and most chemesthetic sensations more intense than thermal non-tasters (TnTs) in aqueous solutions [8,9,11,12]. With respect to orosensory detection thresholds, Yang et al [9] recently assessed whether thresholds varied with thermal-taster status (TTS) for sucrose, sodium chloride, caffeine and two trigeminal stimuli.…”

“…With respect to orosensory detection thresholds, Yang et al [9] recently assessed whether thresholds varied with thermal-taster status (TTS) for sucrose, sodium chloride, caffeine and two trigeminal stimuli. Only one difference was found: the detection threshold for sucrose was lower for TTs than for TnTs.…”