|Abstract or Summary
- The sensations of taste and smell are integral to our perception of food. Because the olfactory and gustatory systems are physiologically separate, scientists were once uncertain of whether information from these two systems interacted at the perceptual level. Recent studies suggest that taste and smell do indeed interact. Two interaction phenomena, taste enhancement by odor and odor enhancement by taste, are of particular interest to the food industry because they can alter the perception of food quality. In particular, retronasal odor enhancement by sweetness has proven to be a robust interaction effect. It is suspected that the enhancement capability of sweet may be related to its ability to signal the presence of a "nutritive" or "beneficial" substance. Salty and umami have a similar ability, yet their role in odor enhancement has not been tested. Therefore, the current study explored the role of salty and umami tastes in retronasal odor enhancement. Additionally, the roles of congruency and perceptual similarity, two factors which are considered important in taste and odor interactions, but have been often confused, were further explored. Finally, the relationship between hedonic enhancement and odor intensity enhancement was
examined in order to better differentiate between the two concepts. Subjects (n=35) rated: (1) the intensity of 4 tastants (NaCl, MSG, MPG, caffeine), 2 odorants (chicken, soy sauce), and all possible binary mixtures, (2) the degree of liking/disliking of the odorants in the absence and presence of tastants, (3) the degree of congruency of the 2 odorants alone and all possible binary taste-odor mixtures, and (4) the perceptual similarity between tastants and odorants. Results showed that salty and umami tastes were capable of enhancing both chicken and soy sauce odor (Tukey's test, p < 0.05). Additionally, congruency was shown to be considerably more predictive of the degree of odor enhancement than was perceptual similarity. Finally, though hedonic enhancement and degree of odor enhancement were related, it was shown that the two effects are conceptually different. These findings confirm that the quality of the taste dictates the ability to enhance retronasally perceived food odors and that congruency modulates the degree of retronasal odor enhancement by taste. Study findings will be discussed both in terms of their relationship to potential mechanisms underlying retronasal odor enhancement and their implications to food science.