Electronic Tongue Resembling Human Tongue... 10 Times More Sensitive Than Sommeliers

[Asia Economy Reporter Junho Hwang] Domestic researchers have developed an electronic tongue that is about 10 times more sensitive to astringent tastes than wine tasters. This electronic tongue is expected to be utilized for various purposes such as objectifying taste in food and pharmaceutical development. Ulsan National Institute of Science and Technology (UNIST) announced on the 8th that Professor Hyunhyup Ko’s research team from the Department of Energy and Chemical Engineering developed an electronic tongue that detects astringent taste using a polymer gel with numerous tiny pores.

Electronic Tongue Detecting Astringent Taste

Flexible Electronic Tongue Mimicking the Astringent Taste Detection Mechanism of the Human Tongue

The research team developed an electronic tongue that mimics the human tongue to sense astringent taste. In humans, astringent taste is perceived through the pressure of aggregates formed when astringent molecules bind to tongue mucosal proteins.

The team applied this concept by creating an electronic tongue using an ion-conductive hydrogel that forms hydrophobic aggregates (substances that do not mix with water) when binding with astringent molecules. This polymer gel contains mucin, which acts as the tongue mucosal protein, and lithium chloride ions, and has a large number of tiny pores. When astringent molecules bind with mucin to form hydrophobic aggregates inside the pores, the conductivity of lithium chloride ions changes, which can be detected as an electrical signal.

Co-first author Ahyoung Choi, a combined master's and doctoral course researcher, explained, "Due to the hydrophobic aggregates, the pore walls of the hydrogel change from hydrophilic to hydrophobic. At this time, the electrostatic interaction between the pore walls and the ions flowing inside decreases, enhancing ion flow and increasing the current flowing through the conductor."

10 Times More Sensitive Than Sommeliers

Principle of Taste Molecule Detection in Porous Artificial Tongue

The research team conducted experiments detecting astringent tastes in wine, unripe persimmons, and black tea using the electronic tongue. The results showed that the electronic tongue quantitatively distinguished the degree of astringency in various wines such as red, white, and ros?. Notably, the newly developed electronic tongue not only has a wide detection range for astringency (minimum detectable concentration 2×10^-6 M~) but also identifies the degree of astringency immediately upon contact with the sensor.

First author Junghui Yeom, a combined master's and doctoral course researcher, said, "While experts can detect astringent tastes at concentrations of several tens of micromoles (μM), the electronic tongue developed this time can detect astringency at levels as low as 2 to 3 micromoles."

Professor Hyunhyup Ko stated, "The electronic tongue developed this time is simple to produce, requires no complicated sample preparation for analysis, and is inexpensive, so it is expected to be applicable not only in the food and alcoholic beverage industries but also in various fields such as agriculture."

Meanwhile, the research results were introduced in 'Science Advances,' a sister journal of Science published by the American Association for the Advancement of Science (AAAS).

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