How the Measurement Works
The taste sensor outputs the change in potential relative to the membrane potential of a tasteless reference solution (e.g., Ag/AgCl saturated KCl solution of reference electrode). To perform electrochemically stable measurements, the reference-electrode electrolyte is a solution of 30 mM KCl and 0.3 mM tartaric acid.
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The taste sensor evaluates two types of taste: initial, which is the perceived taste when food first enters the mouth, and aftertaste, which is the taste persisting in the mouth after swallowing the food. First, the initial taste is measured as the difference in the potential of the sample liquid versus the potential of the reference solution* as zero. Then, the sensors are lightly washed, and the aftertaste is measured as difference in potential versus the reference solution.
*Reference solution: a nearly tasteless solution of 30 mM KCl and 0.3 mM tartaric acid used to mimic human saliva.