Aftertaste is important for human sensation and provides rich and sophisticated flavor. In general, foodstuffs with sufficient aftertaste are considered to be of high quality and impart a pleasant taste to most people. A taste sensing system(taste sensor) , that is, the electronic tongue, is effective for the evaluation of aftertaste of a variety of foods and drinks. However, for sake, sample differences in aftertaste data (CPA value)are so small that we cannot evaluate them adequately. The optimization of the measurement procedure for the sensor BT0, which is mainly used for the evaluation of the bitterness of hydrochloride medicines, enabled the evaluation of the aftertaste of sake in this study. Experiments on the concentration dependence of major tastants contained in sake revealed that the tastants detected by the sensor BT0 are peptides with some hydrophobic por

A sweetness sensor with lipid/polymer membranes has been developed for evaluating the sweetness of sugars and sugar alcohols. Among the constituents of lipid/polymer membranes, gallic acid has been used as the main substance involved in sucrose response in our group. In this study, as a step toward understanding the response mechanism of the sweetness sensor, functional groups of gallic acid, namely, carboxyl and hydroxyl groups, were focused on. The results demonstrated that the carboxyl group is essential for the sweetness sensor, whereas the hydroxyl group is not always necessary for the sucrose response. It was also revealed that the phosphate group may be a substitute for the carboxyl group. Then, for one of the sensors with the highest response to a 300 mM sucrose solution, named the sweetness sensor GL1, the basic characteristics such as selectivity and correlation with sweetness were investigated. The behavior of GL1 sensor outputs was relatively similar to the sweetness perception in humans.

A sweetness sensor with lipid/polymer membranes has been developed for evaluating the sweetness of sugars and sugar alcohols. In this paper, experiments were performed to compare the electric responses of the sweetness sensor with the chemical structure of various sugars. The results demonstrated that the presence of two adjacent hydroxyl groups in a sugar molecule is important and that the optimum distance between the two adjacent hydroxyl groups is approximately 3 Å. The interaction between the sweetness sensor and sugars is discussed.