Design of a discriminating taste sensor using mutual information

A device closely mimicking the mammalian tongue is the electronic tongue or the taste sensor. It is composed of several kinds of lipid or polymer membrane for transforming information of a taste substance into an electric signal. In order to discriminate the tastes in a mixture, the mutual information has to be maximized by maximizing the determinant of the covariance matrix. We have developed a novel technique called the technique of determinant inequalities to maximize the mutual information by obtaining the upper and lower bounds of the correlated elements of the covariance matrix and applied it to an experimental taste sensor to demonstrate how certain tastes can be selectively suppressed.