"Electronic Tongue Appears" ... UNIST Develops Tongue to Detect Astringent Taste

Ulsan National Institute of Science and Technology Research Team Led by Ko Hyun-hyeop, Applicable to Food and Alcoholic Beverage Industries

Electronic tongue developed by the UNIST research team.

[Asia Economy Yeongnam Reporting Headquarters Reporter Kim Yong-woo] An 'electronic tongue' that senses astringency has been developed by a research team at Ulsan National Institute of Science and Technology (UNIST).

The research team led by Professor Ko Hyun-hyeop from the Department of Energy and Chemical Engineering at UNIST announced on the 8th that they have developed an electronic tongue that detects astringency using a polymer gel with numerous tiny pores.

Taste is a subjective and personal domain, but when developing food or pharmaceuticals, it is necessary to express taste as objectively as possible. This new tongue helps with the 'objectification' of taste.

This electronic tongue, which mimics the human body's taste detection mechanism, can quantitatively express astringency, making it widely applicable in various fields such as food and beverage development and fruit monitoring.

When eating wine or unripe fruit, one can feel an astringent taste that leaves the mouth feeling dry and rough. A substance formed when 'astringent molecules' like tannins bind to tongue mucosal proteins stimulates the mucosa, and the human body perceives this as astringency.

On the other hand, sweet or salty tastes are detected by taste buds, clusters of taste receptor cells located in the tongue papillae. Therefore, to detect astringency, an electronic tongue operating on a different principle from those already developed for detecting sweetness and other tastes was needed.

Professor Ko Hyun-hyeop's team succeeded in developing an electronic tongue using an 'ion-conductive hydrogel' that forms 'hydrophobic aggregates' when binding with astringent molecules. This mimics the astringency detection mechanism occurring in the tongue mucosa.

This polymer gel contains 'mucin,' which acts as the tongue mucosal protein, and lithium chloride ions, and has numerous tiny pores.

When mucin binds with astringent molecules, a 'hydrophobic aggregate network' forms inside the tiny pores, which changes the conductivity of lithium chloride ions, enabling the detection of astringency as an electrical signal.

Co-first author Choi Ah-young, a combined master's and doctoral course researcher in the Department of Energy Engineering at UNIST, explained, “Due to the hydrophobic aggregates, the hydrogel pore walls change from hydrophilic to hydrophobic, reducing electrostatic interactions between the pore walls and the ions flowing inside, which enhances ion flow and increases the current flowing through the conductor.”

UNIST Professor Koh Hyun-hyup's research team. From the right, Professor Koh Hyun-hyup, co-first author researcher Choi Ah-young, first author researcher Yeom Jeong-hee, and others.

The research team conducted experiments detecting astringency in wine, unripe persimmons, and black tea using the developed electronic tongue. The results confirmed that the electronic tongue could quantitatively distinguish the degree of astringency in various wines, including red, white, and ros? wines.

First author Yeom Jeong-hee, a combined master's and doctoral course researcher in the Department of Energy Engineering at UNIST, said, “The electronic tongue developed this time not only has a wide detection range for astringency but can also determine the degree of astringency immediately upon contact with the sensor.”

While trained experts can detect astringency at concentrations of tens of micromoles, the electronic tongue demonstrates excellent capability by detecting astringency at concentrations as low as 2 to 3 micromoles.

Professor Ko Hyun-hyeop said, “We developed a miniaturized electronic tongue using inexpensive and flexible materials. It is easy to manufacture and requires no complex sample preparation for analysis, making it applicable not only in the food and beverage industries but also in various fields such as agriculture.”

This research was published on June 6 in 'Science Advances,' issued by the American Association for the Advancement of Science.

This content was produced with the assistance of AI translation services.