PROP (6-n-Propylthiouracil) tasting and sensory responses to caffeine,sucrose, neohesperidin dihydrochalcone and chocolate.
ABSTRACT The genetically determined ability to taste 6-n-propylthiouracil (PROP) has been linked with lowered acceptance of some bitter foods. Fifty-four women, aged 18-30 years, tasted and rated PROP-impregnated filter paper and seven solutions of PROP. Summed bitterness intensity ratings for PROP solutions determined PROP taster status. Respondents also tasted five sucrose and seven caffeine solutions, as well as seven solutions each of caffeine and PROP that had been sweetened with 0.3 mmol/l neohesperidin dihydrochalcone (NHDC). Respondents also rated three kinds of chocolate using 9-point category scales. PROP tasters rated caffeine solutions as more bitter than did non-tasters and liked them less. PROP tasters did not rate either sucrose or NHDC as more sweet. The addition of NHDC to PROP and caffeine solutions suppressed bitterness intensity more effectively for tasters than for non-tasters and improved hedonic ratings among both groups. PROP tasters and non-tasters showed the same hedonic response to sweetened caffeine solutions and did not differ in their sensory responses to chocolate. Genetic taste markers may have only a minor impact on the consumption of such foods as sweetened coffee or chocolate.
[show abstract] [hide abstract]
ABSTRACT: While past research has suggested an association between the ability to taste PROP and liking for the taste of sucrose, many aspects of this relationship remain ambiguous. To clarify this further, 60 volunteers (40 women and 20 men) were classified as PROP super-medium or non-tasters and as sweet likers or dislikers depending on hedonic and intensity ratings for PROP and sucrose. 67% of PROP super-tasters were sweet dislikers, compared to 12% of PROP non-tasters. PROP super-tasters also rated the intensity of salty and sweet tastes as greater than did non- or medium PROP tasters, but these differences in sweet intensity could not explain the group differences in sweet liking. The groups did not differ in restraint or BMI. Taste bud density was higher in PROP super-tasters and sweet dislikers than in PROP medium or non-tasters or sweet likers. Overall these data confirm that PROP super-tasters are more likely to be sweet dislikers, and that this cannot be explained as secondary to cognitive attitudes to sweetness (restraint) or enhanced sweet intensity.Physiology & Behavior 07/2007; 91(2-3):264-73. · 2.87 Impact Factor
Article: The relationship between phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP) taster status and taste thresholds for sucrose and quinine.[show abstract] [hide abstract]
ABSTRACT: The aim of this study was to investigate the relationship of taster status with taste detection and recognition thresholds for sucrose and quinine. Sixty-nine subjects (35 men and 34 women; mean age, 23.9+/-1.2 years) were included. Stimulus fluids were prepared, one each for phenylthiocarbamide (PTC), 6-n-propylthiouracil (PROP), sucrose and quinine HCl. In each series, successive solutions, which comprised a total of 15 grades, differed by 0.25log units of the molar concentration. Two concentrations of NaCl (0.32 and 1.0 M) were prepared. The subjects were classified as nontasters and tasters using their PTC and PROP perceptions. Tasters were classified as medium-tasters and supertasters by the ratio of perceived bitterness of above-threshold PROP relative to the perceived saltiness of NaCl (PROP ratio). Taste detection and recognition thresholds for sucrose and quinine were determined by standard two-alternative forced choice trials. A Student's t-test, a Pearson's correlation analysis and linear contrasts in a one-way analysis of variance (ANOVA) were used. The percentages of nontaster, medium-taster and supertaster were 13, 70 and 17%, respectively. There were no significant gender differences in the taste detection and recognition thresholds for sucrose and quinine. The threshold for PTC and PROP showed significant correlations with taste threshold for quinine. Linear contrast in one-way ANOVA showed that the greater the value of PROP ratio, the more sensitive to sweet and bitter tastes (p<0.001). The PTC and PROP taster status is closely related with taste detection and recognition thresholds for sucrose and quinine.Archives of Oral Biology 05/2006; 51(5):427-32. · 1.60 Impact Factor