Seminar - Uncovering the Boundaries of Olfactory Perception

The question of how to measure a smell has troubled scientists for over a century. Alexander Graham Bell challenged the scientific community: "We have very many different kinds of smells, all the way from the odor of violets and roses up to asafoetida. But until you can measure their likenesses and differences, you can have no science of odor". We addressed this by collecting 49,788 perceptual odor estimates from 199 participants to build a physicochemical measure of smell and derive a model of olfactory perceptual quality space. This measure, expressed in radians, predicts real-world odorant pairwise perceptual similarity from odorant structure alone, meeting Bell's challenge with accurate predictions for similarities between rose, violet, and asafoetida. Next, based on thousands of comparisons, we identified a cutoff in this measure, below 0.05 radians, where discrimination between pairs of mixtures becomes highly challenging. To assess the usefulness of this measure, we investigated whether it can be used to create olfactory metamers - non-overlapping molecular compositions that share a common percept. Like visual and auditory metamers before them, these could reveal olfaction's dimensionality and brain mechanisms, advancing towards its digitization. In this talk, I will present our data collection methods, modeling approach, and demonstrate novel applications using the measure and the metamers concept. I will also present recent efforts to apply this framework to food ingredients and flavor to guide F&B product development.

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