Abstract
Previous research on food functionality has not focused on the relationship between food and its unique sensory characteristics, such as taste and smell. On the other hand, the mechanism of action of polyphenols, which are food components that exert strong physiological effects, has been unclear due to their low bioavailability. In the process of elucidating this issue, we focused on the bitter and astringent tastes, which are sensory characteristics of polyphenols. First, we evaluated the sensory characteristics using a panel of young adults and found that they could be divided into four clusters. Furthermore, we discovered that bitterness improves glucose tolerance and regulates appetite via the vagus nerve in the digestive tract, while astringency stimulates brain function and the circulatory and metabolic systems via the sensory nerves in the digestive tract. In addition, recent studies have shown that these sensory stimuli may also affect palatability. This paper proposes a reevaluation of food functionality, distinct from conventional drug-inspired product development. It starts with the unique sensory characteristics of food and considers three perspectives: 1) enhancing brain function to maintain and improve sensory capability, 2) improving autonomic imbalance, and 3) increasing preference for aversive tastes to compensate for age-related vulnerabilities. Research on the crosstalk between food's sensory characteristics, physiological regulation effects, and palatability is still in its early stages. However, further development in this area is expected to lead to the creation of new food categories and services within the food industry.
