Detection of catechins using a fluorescent molecule and its application toward the evaluation of astringent intensity

To evaluate sensory intensities of tastes, astringency, or pungency with ease and high reproducibility, the present study proposes a method using a fluorescent substance as a sensor. Unlike conventional taste sensors that each require a specialized system, this approach has the advantage in that it can be conducted using common analytical equipment such as a fluorescence spectrometer. In this report, a method to detect catechins and its application toward astringent evaluation is described. The binding of a sensor molecule with eight catechins revealed that the sensor molecule has higher affinity for catechins with stronger astringency. The complexation with the more astringent catechins showed larger fluorescence quenching. The change in the fluorescence intensity of a sample solution with the sensor molecule based on a reference solution was defined as the astringent intensity. Evaluation tests of green tea astringency demonstrated that the outputs of the sensor molecule correlate highly with the results by the human sense.