In two parts, this thesis examined retronasal perception of single odours, binary odour mixtures and odour-taste mixtures. Part 1, aimed to determine if perceived retronasal temporal order differs to that order perceived via the orthonasal pathway and if retronasal temporal order is a function of an odorant’s water solubility or nasal mucus solubility slowing the odorants progression to the olfactory epithelium via the longer retronasal route. Part 1 established that retronasal temporal perception of binary odour mixtures differs from orthonasal temporal perception and that nasal mucus solubility and the “stickiness”, mediated by volatility, are the factors determining the perceived retronasal order. It was further concluded that nasal mucus and not water was the most appropriate approximation to the composition of nasopharyngeal mucus. Part 2, aimed to determine if correct retronasal odour identification is a function of learned taste-associations and if correct retronasal odour identification is a function of the modality through which the odour is learned. Part 2, established that in simple binary odour-taste mixtures correct retronasal odour identification is not a function of learned taste-associations, nor do tastants suppress odours. However, it was concluded that mouth-learning experience does provide odours with an identification advantage retronasally, over odours that are not learned through the mouth. Overall, the Thesis demonstrated that differences exist between retronasal and orthonasal perception. Specifically, the perceived temporal order of components in binary odours mixtures is determined retronasally by an odour’s nasal mucus solubility and “stickiness”. The exploration of this mechanism in future research may provide a greater understanding of temporal odour perception and the means to increase odour mixture component identification beyond the current limit of three. Furthermore, retronasal odour and taste processing seem to occur independently of each other, as learned-associations between taste and odours do not impact on the accuracy of mixture component identification or intensity. It may be that it is mouth-learning experience or a relationship to food that is important to retronasal odour perception rather than any component congruency. Future research should aim to determine if it is mouth experience or the contribution of other stimuli such as tactile cues that contribute to the increase in retronasal identification accuracy. / Doctor of Philosophy (PhD)

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京都大学 / 0048 / 新制・論文博士 / 博士(農学) / 乙第13100号 / 論農博第2846号 / 新制||農||1051(附属図書館) / 学位論文||H29||N5032(農学部図書室) / (主査)教授 松村 康生, 教授 裏出 令子, 教授 谷 史人 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

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La perception rétro-nasale (arôme) lors de la mastication en bouche d’un aliment est un phénomène assez complexe. Les compositions physico-chimique et aromatique du produit, son état physique lors de la mastication en bouche, les interactions et réactions mises en jeu dans la cavité buccale sont autant de paramètres qui peuvent influencer cette perception. Dans le cadre de ce travail la mangue sera utilisée comme fruit modèle. Il s’agira de mieux comprendre l’influence du niveau de déstructuration du produit, de la texture ainsi que de la variabilité inter-individuelle d’un panel d’analyse sensorielle sur la perception de l’arôme. La libération des composés volatils lors de la mastication en bouche in vivo du fruit frais, du fruit en forme de purée et du fruit séché sera étudiée par le dispositif RATD(. Le profil aromatique des produits obtenus par la technique SAFE (Solvent assisted flavor evaporation) et les descripteurs aromatiques établis lors de l’analyse sensorielle seront confrontés avec les données RATD. / Retro-nasal perception of flavor during chewing food in mouth is a complex process. The physico-chemical and aromatic compositions of food, its physical properties, the interactions and reactions involved in oral cavity are the main parameters which can influence flavor perception. In this study, mango is used as model fruit. The study will be focused in better understanding of food disintegration effect, its texture and inter-individual variability on the flavor perception. Liberation of volatile compounds during the chewing of fresh fruit, puree fruit and dried fruit will be studied with RATD (Retronasal aroma trapping device). Fruit volatile profile obtained by SAFE (Solvent assisted flavor evaporation) technique and the aromatic descriptors established during the sensory analysis will be compared with the data from RATD analysis.