Knowledge Bank

The olfactory sensory system encompasses two pathways that perceive odor molecules: the orthonasal pathway, through the nose, and the retronasal pathway, through the mouth. Although both pathways are theorized to activate the same receptors in the olfactory epithelium, they elicit different sensations and perceptions, which is referred to as the Duality of Smell hypothesis. Additionally, there are different cognitive strategies humans employ to identify different flavors that impacts their perception. In this study, a matching activity was employed to evaluate similarities and differences of these two pathways (orthonasal and retronasal) using a novel flavor set, being floral flavors. Four isointense aqueous floral flavors (honeysuckle, lavender, rose, and jasmine) were used to determine the impact of delivery route on flavor perception. To alter the cognitive strategies used by panelist, three different reference labeling methods were utilized for the same flavors at the same concentration levels, familiar (honeysuckle, lavender, rose, jasmine), unfamiliar (inodora, pedunculata, beggeriana , didymum), and generic (A, B, C, and D). Participants (n=34) were presented with a reference, either in a vial (orthonasal delivery) or a 2 oz. cup (retronasal delivery), and instructed to match the same aroma from four unknowns, evaluated either by the same delivery route (congruent) or different route (incongruent) than the reference evaluation. This was then repeated for all possible combinations of orthonasal and retronasal delivery (four total delivery conditions). From the results it was shown that panelist performed significantly better (p<0.05) in the congruent conditions (orthonasal-orthonasal, retronasal-retronasal) than in the incongruent conditions (orthonasal-retronasal, retronasal-orthonasal), which further supports the Duality of Smells hypothesis and proves that the duality of smell is retained even with samples with low retronasal familiarity. Overall, there was no significant difference in matching ability between the different labeling conditions, suggesting panelist's cognitive strategy was similar in all three conditions. Trends, however, show that there may have been an effect as labeling method was altered, indicating the need for further research in this space.