Measurements of shoyu (soy sauce) with multichannel taste sensor

Tastes of shoyu (soy sauce) were investigated using the taste sensor with lipid/polymer membranes. Stable measurements were made by synthesizing a standard solution for shoyu. Twenty five kinds of shoyu were measured with the sensor, but classification to conventional three groups, i.e., koikuchi, usukuchi and sashimi, could not be made. On the other hand, it was found that tastes of three types of shoyu, which were produced in the same manufacturer, resembled each other. The similarity of shoyu in the same manufacturer was also confirmed by an amino acid analysis and a sensory test. The taste sensor will contribute to automated shoyu brewing.