Influence of PROP-sensitivity on taste perceptions and hedonics in French women. A study performed without retronasal...

Detection threshold for the taste of PROP (6-n-propyl thiouracil) in aqueous solution was determined in 173 French Caucasian women deprived of retronasal olfaction by blowing an air stream into the nostrils. As expected, the detection thresholds were bimodally distributed, although as many as 73% of the subjects had thresholds above the antimode concentration and therefore qualified as non-tasters. Detection threshold, difference threshold, intensity perceptions and preference ratings were then determined for NaCl, sucrose, caffeine, Na saccharin and naringin in 20 tasters and 20 non-tasters. No differences were found between tasters and non-tasters for detection or difference thresholds of the various tastants. Intensity and preference ratings for solutions of NaCl, saccharin or caffeine were not influenced by taster status. Although ratings of sweetness intensity for sucrose solutions did not differ between tasters and non-tasters, concentrated sucrose solutions were more disliked by non-tasters than by tasters. Non-tasters rated naringin solutions as more bitter than tasters, but naringin preference ratings were independent of taster status. Some of these findings were unexpected and further studies are required to find out whether they stem from the odour-preventing procedure or are of biological or cultural origin.