Measurements of soy sauce using taste sensor

The taste of soy sauce was studied using a taste sensor with lipid membranes. Stable measurements were made by synthesizing a standard solution for soy sauce. Twenty-five kinds of soy sauce were clearly distinguished with the sensor, but classification into three conventional groups, i.e., koikuchi (high amino acid, low NaCl), usukuchi (low amino acid, high NaCl) and sashimi, could not be made. Contrary to this, it was found that the tastes of three types of soy sauce, which were produced by the same manufacturer, resembled each other. The similarity of soy sauce by the same manufacturer was also confirmed by amino acid analysis and a sensory test. The taste sensor will contribute to automated soy sauce brewing.