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Updated: Jul 11, 2025

Real-time In Vitro Monitoring of Odorant Receptor Activation by an Odorant in the Vapor Phase
Published on: April 23, 2019
Masking effects on iso-valeric acid recognition by sub-threshold odor mixture
Jianbo Huang1, Jiehua Lin1, Rachel Yueng1
1Department of Food Science, Cornell University, Ithaca, NY 14850, United States.
Abstract:
Masking unpleasant odors with pleasant-smelling odorants has a long history and is utilized in various industries, including perfumery and consumer products. However, the effectiveness of odor masking is idiosyncratic and temporary. In this study, we employed Sniff olfactometry (SO) to investigate the psychophysics of masking using brief 70 ms stimulations with mixtures of the mal-odorant iso-valeric acid (IVA) and different masking agents. IVA is a component of human sweat that can overpower its smell and is often associated with unpleasant descriptors such as "gym locker," "smelly feet," "dirty clothes," and so on. Traditionally, high concentrations of pleasant-smelling odorants are used to mitigate the unpleasantness of IVA in situations involving clothing or environments contaminated with IVA. To examine the masking effects of sub-threshold levels of various masking agents (neohivernal, geraniol, florhydral, decanal, iso-longifolanone, methyl iso-eugenol, and s-limonene) on IVA, we conducted experiments using SO to measure the probability of recognizing IVA after 70 ms stimulations with headspaces containing mixtures of super-threshold concentrations of IVA and sub-threshold concentrations of IVA suppressors. The study involved nine subjects, and on average, a single masking agent was found to decrease IVA recognition probability by 14-72%. Moreover, a sub-threshold odor mixture consisting of 6 masking agents demonstrated a substantial decrease in IVA recognition, with a reduction of 96%.
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