Refined single-interval adjustment matrix yes-no task for estimating the absolute thresholds of sweet-tasting molecules

Abstract

Determining the in vivo gustatory thresholds of sweet-tasting molecules is more difficult and laborious than other sensory analyses. In this study, we refined the single-interval adjustment matrix (SIAM) yes-no task to produce threshold estimates accurately and efficiently. Experimental procedures were optimized such that tasters provided bias-free results and achieved maximum performance. We found that the refined SIAM yes-no task accurately estimated the threshold values of the sweet-tasting protein brazzein within the sensitive threshold range, which was confirmed using the two-alternative forced-choice task. Threshold values of various artificial sweeteners were also investigated using the SIAM yes-no task. Our results suggest that the refined SIAM yes-no task is advantageous for obtaining thresholds and comparing the biological activity of various sweet-tasting molecules. Practical applicationsThe refined SIAM yes-no task suggested in this study would enable researchers to accurately obtain thresholds of various sweet-tasting molecules, in order to develop potential sugar substitutes and elucidate interactions with their corresponding sweet-taste receptors T1R2-T1R3 for sweet-taste mechanism studies.