Relation between PROP taster status and fat perception, touch, and olfaction.

We tested the hypothesis that fat perception (sensitivity to and preferences for fat) may be linked to 6-n-propylthiouracil (PROP) taster status as a result of differences in trigeminal innervation of the oral cavity. In addition, we examined the relationship between taster status and sensitivity to other taste attributes, as well as tactile and olfactory sensitivities. Subjects (40 nontasters, 67 medium tasters, and 40 supertasters of PROP) rated samples (potato chips, chocolate drink, mashed potatoes, and vanilla pudding) varying in fat and flavor concentrations for the intensity of fattiness, saltiness, and sweetness, first without and then with nose clips, and for liking. Tactile sensitivity of the tongue was assessed according to responses to stimulation with Von Frey filaments (2.36, 2.44). Olfactory thresholds were determined for two odors (diacetyl and phenylethyl methyl ethyl carbinol). In general, taster status was not related to the perceptions of fat, saltiness, and sweetness. Subjects were able to accurately assess the fat content of the samples. Increasing the flavor levels in the potato chips and mashed potatoes enhanced the perception of fattiness for these systems. Supertasters were more sensitive to stimulation on the median of the tongue with the no. 2.36 Von Frey filament, and the olfactory thresholds for diacetyl were lower for PROP tasters and supertasters than for nontasters.