Responses of PROP taster groups to variations in sensory qualities within foods and beverages.

Despite increasing evidence that variations in sensitivity to the bitterness of 6-n-propylthiouracil (PROP) are also reflected in responses to other tastes in solution, there has been little research examining the impact of PROP sensitivity on responses to sensory qualities in foods or beverages. The present studies examined responses of PROP taster groups to systematic variations in tastes and oral irritation in different foods and beverages. In Experiment 1, PROP groups were asked to discriminate variations in bitterness, sweetness, or sourness within two foods (yogurt and cream cheese) and a beverage (orange juice). In most cases, tasters and especially supertasters (STs) were able to discriminate smaller variations in tastant concentration than PROP nontasters (NTs). Differences were most evident with variations in bitterness and sourness. In Experiment 2, PROP taster groups rated the sweetness, sourness, and oral irritation in carbonated fruit drinks that systematically varied in citric acid (CA) and CO2 concentrations. Ratings of sourness and irritation were highest for STs and lowest for NTs, although there were no group differences for sweetness ratings. These data are some of the first to show PROP taster group differences in tastes and irritation within foods and provide a basis for reported differences of PROP groups in their hedonic responses to foods.