Effects of olfactory dysfunction on sensory evaluation and preparation of foods.

Aim of this study was to investigate the impact of olfactory dysfunction on behavior during sensory evaluation and self-preparation, as well as on sensory perception and pleasantness of green tea and coffee. We compared the intensities of overall odor, flavor, and bitter taste, respectively, and the pleasantness ratings for three different concentrations of green teas and coffees between three groups: young (n=30) and elderly (n=30) with normal olfactory function and elderly (n=30) with olfactory dysfunction. In addition, we compared the subject groups' behavior during sensory testing and preparation of green tea or coffee. As expected, elderly subjects with olfactory dysfunction rated the overall odor intensity less intense than subjects with normal olfactory function. Also, elderly subjects with olfactory dysfunction rated the intensities of overall flavor and bitter taste significantly lower rather than subjects with normal olfactory function in green tea, whereas this result was not obtained in coffee. Compared to young subjects with normal olfactory function, elderly with olfactory dysfunction used more green tea powder to optimize their own green tea. Moreover, olfactory function scores assessed by the "Sniffin' Sticks" test were positively related with sniffing frequency for green tea and with sniffing time for coffee during sensory evaluation. During preparation of the green tea, compared to elderly subjects, young healthy subjects tried to adjust the green tea more frequently by adding green tea powder or water. Such behavioral differences were not present during coffee preparation. In conclusion, our findings demonstrate that olfactory dysfunction affects odor perception and sniffing behavior. However, under the current conditions, it appeared to have no effect on hedonic ratings and self-preparation behaviors.