The Mechanics of Tasting

For a brief moment, think about your favorite food. Immediately, its taste overwhelms you. This intense nostalgia is all thanks to your tongue. Despite its rather odd and fuzzy appearance, the human tongue is the reason we can enjoy our favorite foods, detect when a substance is not fit for consumption, and distinguish between complex levels of flavor interactions.

Through the delicate perceptions of your tongue’s taste buds, located on the papillae on the upper side of your tongue, you are able to accurately distinguish between different chemical triggers that translate into flavors such as salty, sweet, sour, and bitter. The Creative Inquiry, The Electronic Tongue, has created a bioelectronic equivalent of the human tongue for the measurement of taste that spans far beyond our body’s capabilities. By combining advanced research methods, a team of highly talented students has engineered a robot called the Electronic Tongue that can “taste.”

The Electronic Tongue robot is made up of extremely sensitive, impedimetric receptors that respond with specific changes in electrical impedance both during
and after exposure to various types of chemicals. The electronic tongue itself, which looks similar to the tongue of a pit-viper snake, is a biosensor chip or biochip made up of a pair of interlocking comb electrodes that are capable of sensing the electrical properties of the fluid to which the electrodes are exposed. The electronic tongue can then be hooked up to devices, such as a flying drone, emulating a moth or a hummingbird in order to obtain its results. Using digital signal processing and data collected during test conditions, the sensor is able to gather information about the “taste,” or the chemical makeup, of a solution.

Similar to the human tongue, the Electronic Tongue uses prior experiences to sort new ‘tastes’ into categories. Dr. Guiseppi-Elie, professor of Chemical and Biomolecular Engineering engaged a team of students in both the creation and testing of the electronic tongue.

The students—who call themselves “the Vipers” due to the Electronic Tongue’s similarity in appearance to that of a viper’s tongue—run controlled experiments to gain the data set needed to compare future unknown results. Many of these tests include recording the results of the Electronic Tongue’s findings for different chemical media. So far, these include orange juice, cranberry juice, Pepsi®, Coke®, and a wealth of hand-made buffer solutions. By comparing the changes in the electrical impedance for each of these fluids, the students are able to chart the exact “taste” of each of these materials and develop classified protocols.

Haley Leslie, a sophomore Biomedical Engineering major, sees the Electronic Tongue Creative Inquiry as a way to give students a background in research techniques and laboratory procedures. “We have gained a lot of experience in running experiments and recording our data. Research and lab experience is a big part of our major as engineers. We are able to learn the correct laboratory procedures to use for future projects,” Leslie explains. Made up exclusively of chemical and bimolecular engineering majors, this Creative Inquiry provides the tools in both lab procedures and research necessary to make each of these young Clemson engineers successful in the future.

The application of the work these Creative Inquiry students are doing goes far beyond the fun of tasting different juices and sodas. Guiseppi-Elie states, “By detecting taste, the electronic tongue has a wide range of applications.” Using its ability to detect the presence and amount of specific chemical solutions, the Electronic Tongue has the potential to be used in a life-saving capacity. Further, by detecting the presence of contaminants or potentially deadly allergens within food, the Electronic Tongue’s tasting ability could mean a safer food industry.

The results of this Creative Inquiry will help lead the way in electronic “tasting.” While gaining skills in research, laboratory methods, and professional communications, the students in The Electronic Tongue project are exploring new territory in biochemical engineering. These Creative Inquiry students are developing a novel technological application to create life-saving taste sensors that will aid in a safer chemical future.