Retronasal odor of dried bonito stock induces umami taste and improves the palatability of saltiness.

Abstract

A traditional Japanese umami-rich stock, dried bonito stock, was reported to improve the palatability of a low-salt diet due to its characteristic aroma. Two pathways are available for the presentation of odors: the orthonasal and retronasal pathways. Aroma is perceived through the orthonasal pathway. In contrast, retronasal application of odors is thought to evoke different sensations from the orthonasal pathway, which is typically perceived as taste and modifies taste. Therefore, the effect of retronasal odor on salt-reduction might be different from that of aroma, that is, orthonasal odor. Thus, the effects of the retronasal odor of dried bonito stock on the enhancement and improvement of palatability upon salt reduction were examined using sensory evaluation. Moreover, the contributions to flavor expression and palatability of dried bonito stock were also investigated. Although the retronasal odor of dried bonito did not enhance saltiness, it improved the palatability of saltiness. In the presence of no tastants except 0.68% NaCl, a content 15% less than that of Japanese traditional soup, the retronasal odor of dried bonito generated umami, enhanced the suitability for dried bonito stock, and increased palatability. This indicates that the retronasal odor of dried bonito stock could improve the palatability of a salt-reduced diet. These findings can be applied to the development of new seasonings for improving the palatability of salt-reduced foods.