Familiarity and Retronasal Aroma Alter Food Perception

When participants eat foods, they direct their attention to the particular taste quality that is the target of evaluation and subsequently perceive the intensity of the attended taste quality. We defined the ease with which participants pay attention to a particular taste quality as the “noticeability” of that quality. In our previous study, Japanese participants evaluated noticeability and intensity of five fundamental taste qualities (sweetness, umami, saltiness, sourness, and bitterness) under open- and closed-nostril conditions, using a popular traditional Japanese confection, yokan. The correlation between noticeability and intensity of sweetness was significantly reduced when participants were tested with open nostrils. Therefore, we hypothesized that high familiarity with a food and its olfactory information is necessary to decrease the correlation between these two scales.

In order to verify this hypothesis, we asked Japanese and German participants, who have different food cultures, to subjectively evaluate yokan, which is familiar to Japanese but unfamiliar to Germans. In a control condition, marshmallows were used which are familiar to all participants. Participants consumed each food under open- and closed-nostril conditions and evaluated the noticeability and intensity of the five fundamental taste qualities.

There were significant differences between the participants’ groups as the correlation between noticeability and intensity was reduced significantly only for sweetness of a familiar food under open-nostril condition.

These results support our hypothesis that high familiarity with a food and its olfactory information might be necessary to decrease the correlation between noticeability and intensity of a particular taste quality.

This finding suggests that perception of a food is influenced by its familiarity and retronasal aroma. These results suggest when a food is unfamiliar, the noticeability and intensity of a particular taste quality are not much altered by the retronasal aroma, but when a food is highly familiar, retronasal aroma serves to decouple noticeability and intensity of a given taste quality.