Human Oral Sensitivity to and Taste Modulation by 3-Mercapto-2-Methylpentan-1-ol.

INTRODUCTION

3-Mercapto-2-methylpentan-1-ol (3 M) is a key onion flavor (aroma), but past sensory work has focused primarily on ortho-nasal presentation. A series of experiments was conducted to characterize human sensitivity to oral 3 M solutions, then determine how 3 M impacts perception of basic tastes.

METHODS

Detection thresholds were measured for a food grade, racemic mixture using a forced-choice staircase procedure ( = 19). Recognition was measured by presenting a single stimulus per trial (3 M, vanillin, or water), with "onion," "vanilla," or "water" as responses ( = 18). Supra-threshold intensity ( = 20) was measured for various concentrations using the general labeled magnitude scale (gLMS). Odor-taste interactions were studied using mixtures of 3 M and exemplars of basic tastes. Participants rated the intensity of basic tastes, or both taste and aroma, using the gLMS ( ranged from 10 to 15). All stimuli were in aqueous solution.

RESULTS

Participants detected oral 3 M at about 0.90 ppb and recognized 3 M as "onion" at about 5 ppb. Supra-threshold intensity increased roughly as a cumulative logistic function of concentration. 3 M enhanced the rated savory intensity of monosodium glutamate, but did not enhance the dominant qualities of exemplars of the other four basic tastes. Under a response-context more favorable to an analytic approach, savory enhancement was reduced but not eliminated. Savory enhancement was eliminated with nose-clips.

CONCLUSIONS

Oral sensitivity was lower than previous retronasal studies would suggest, but roughly consistent with concentrations in cooked allium varieties. Oral 3 M selectively enhanced savory intensity, an effect likely due to retronasal aroma rather than taste or mouthfeel.

IMPLICATION

3 M is a promising candidate aroma to enhance or impart a savory flavor.