The taste sensing system can be used to detect the interaction between taste substances, as described in Section 5.6 in detail. It is known that cooking oil generally makes the taste of foods milder. The changes in taste when cooking oil was added to solutions with various tastes such as sourness, bitterness, and astringency were measured [29], [62]. The results revealed that the responses to bitterness and astringency markedly decreased. In contrast, the responses to other tastes including umami and saltiness remained unchanged. These results indicate that cooking oil suppresses bitterness and astringency, which are relatively stimulating and sustained, to make the taste of foods milder.