Discrimination of Umami Tastants Using Floating Electrode-Based Bioelectronic Tongue Mimicking Insect Taste System

An umami taste represents the taste sense of amino acids such as glutamate. L-monosodium glutamate (MSG) is known to elicit the umami taste via umami receptors, and understanding its mechanism is important for basic research and practical applications. Thus, many researchers have tried to detect MSG through various sensors. However, these methods can be only employed to detect glutamate-based tastants, and they have limitations to characterize a synergism that is the hallmark of umami. Herein, we developed a floating electrode-based bioelectronic tongue mimicking an insect taste system for the discrimination of umami tastants. In this strategy, nanovesicles containing honeybee umami taste receptors, gustatory receptor 10 of Apis mellifera, were immobilized on the floating electrodes of a carbon nanotube field-effect transistor. This strategy allows us to discriminate between MSG and non-umami tastants. It also allows us to detect MSG in real foods. Furthermore, we quantitatively demonstrated the synergism between MSG and disodium 5’-inosinate by utilizing bioelectronic tongues. The floating electrode-based bioelectronic tongue could provide an important insight regarding the insect taste system, and it can be a powerful platform for various applications like food screening.