The relationship between phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP) taster status and taste thresholds for sucrose and quinine Won-Ic Chang, Jin-Woo Chung, Young-Ku Kim, Sung-Chang Chung, Hong-Seop Kho * Department of Oral Medicine and Oral Diagnosis, School of Dentistry & Dental Research Institute, Seoul National University, Yunkeun-Dong 28, Chongro-Ku, Seoul 110-749, Korea Received 20 May 2005; received in revised form 15 September 2005; accepted 12 October 2005 Archives of Oral Biology (2006) 51, 427—432 www.intl.elsevierhealth.com/journals/arob KEYWORDS Phenylthiocarbamide (PTC); 6-n-Propylthiouracil (PROP); Supertaster; Taste Threshold; Quinine; Sucrose Summary Objective: The aim of this study was to investigate the relationship of taster status with taste detection and recognition thresholds for sucrose and quinine. Design: 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 solu- tions, which comprised a total of 15 grades, differed by 0.25 log 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 percep- tions. 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. Results: 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). * Corresponding author. Tel.: +82 2 2072 3989; fax: +82 2 744 9135. E-mail address: hkho@plaza.snu.ac.kr (H.-S. Kho). 0003–9969/$ — see front matter # 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.archoralbio.2005.10.002