Ortho- and Retronasal stimulations with specific food odours: Hedonic and familiarity ratings are related to chemosensory pleasure scale (CPS) scores

Volatile compounds can reach olfactory epithelium though the nose (orthonasal olfaction) or the mouth (retronasal olfaction). Although differences have been found between these two pathways in terms of odour sensitivity and identification, few studies have examined ortho- and retronasal differences taking into consideration the three main dimensions of olfactory perception (i.e. hedonicity, intensity and familiarity). Olfactory perception, and particularly odour hedonic perception, is influenced by several factors such as sex or age. Another variability factor worth considering, especially regarding food-related odours, is the ability to experience pleasure simulated by smell or taste, which can be measured with the Chemosensory Pleasure Scale (CPS). Thus, the aims of this study were (1) to compare odour sensory ratings in response to ortho- and retronasal presentation and (2) to examine the relationship between CPS scores and odour sensory ratings in ortho- and retronasal pathways. Participants rated ten food odours in ortho- and retronasal conditions using visual analogue scales and were divided into two subgroups based on the median CPS score (CPS+ and CPS− groups). Results revealed similar sensory responses to food odours between ortho- and retronasal pathways for the three main dimensions of olfactory perception. Interestingly, when CPS scores were considered, clear differences in odour familiarity and hedonicity were shown, particularly for the retronasal pathway (i.e. odours were perceived as more pleasant and more familiar in CPS+ group than in CPS− group). Overall, these findings suggest that differences in odour perception between ortho-and retronasal pathways may be related to specific individual characteristics such as chemosensory hedonic capacity.