Flavor Jolt: Japanese Researchers Invent Electric Chopsticks that Make Foods Taste Saltier

Lifestyle Health Technology

Tricking the Tongue

Diners in Japan may soon be able to cut their salt intake without needing to sacrifice flavor. In a world first, researchers at Meiji University recently announced they have developed electric chopsticks that increase the perceived saltiness of foods. Miyashita Hōmei, professor at Meiji University’s Department of Frontier Media Science, led the research team, which together with Kirin Holdings has since 2019 looked at ways to enhance flavors artificially with very weak electrical currents.

Working on the idea that different sodium ions convey flavors like saltiness and savoriness, the group developed a device that uses an electric charge, one too weak to harm the body, to transmit sodium ions to the mouth, making foods taste saltier. The device is so effective at this that the same sensation of saltiness can also be produced just by placing the chopsticks in the mouth alone.

With the help of a wearable minicomputer (not pictured), a weak electric charge is transmitted from the chopsticks to the mouth. (© Meiji University Department of Frontier Media Science/Miyashita Hōmei)
With the help of a wearable minicomputer (not pictured), a weak electric charge is transmitted from the chopsticks to the mouth. (© Meiji University Department of Frontier Media Science/Miyashita Hōmei)

The Taste Test

Researchers tested the chopsticks on 36 individuals aged 40 to 65 who had previously or were currently reducing their sodium intake. Participants compared a gel containing 0.8% sodium, representing the normal salt content of foods, against one with 0.56% sodium, a reduction of 30%. Using the chopsticks, test subjects found the low-sodium gel to be 1.5 times saltier when an electric current was applied compared to when the device sent no charge, showing that the electric current produced a sensation of saltiness on a par with the gel containing the higher sodium content.

The research team conducted a similar experiment with miso soup made with low-sodium miso. Participants reported that the chopsticks not only made the soup taste saltier, but also boosted the dish’s richness and savoriness, enhancing the overall flavor.

Miyashita believes that the chopsticks can help prevent or reduce the severity of lifestyle diseases. Experts recommend adults eat no more than 6 grams of salt a day, but the average daily intake of a Japanese person is more than 10 grams. However, many people are reluctant to reduce the amount of salt in their diet, pointing to the lack of flavor of low-sodium foods. The chopsticks eliminate this concern by enhancing the taste of foods that have less added salt.

Kirin Holdings says it has plans to start selling the chopsticks next year, marketing them as a tool to help people cut back on their salt intake while continuing to enjoy their favorite foods. Research is also underway to develop other eating utensils like spoons and forks using the technology.

Changing Tastes

Miyashita believes that computers can help humans enhance their sensory experiences, and for more than a decade he has been studying ways to electronically enrich the flavor of foods with specially designed cutlery and even plates. “The field has the potential to revolutionize people’s eating habits,” he says. “There has been a great deal of research in different areas. However, the chopsticks are the first device with which we’ve been able to quantitatively demonstrate how electrically enhancing saltiness can help people who are following a low-sodium diet.”

According to Miyashita, scientists have known for more than two centuries that weak electric current can be used to control how taste buds perceive flavors. He notes that a positive flow will cause taste buds to register saltiness. However, a negative flow can be used to increase or decrease the intensity of flavors. Running a weak current moves ions of sodium chloride or sodium glutamate away from the tongue, decreasing the sense of saltiness and savoriness, respectively. When the current is cut, though, the ions rush to the taste buds, boosting the flavor sensation. This is why people who used the chopsticks sensed an increase in saltiness.

Kirin and Meiji University are currently in the process of patenting their flavor-enhancing technology.

Potentially Great Taste

The chopsticks send a current that is only a fraction of that utilized by electrotherapy machines or home electrical stimulation devices for treating injured muscles or to help reduce nerve pain. Researchers found that raising the current increased the sensory effect. However, it also resulted in a tingling sensation on the tongue, making it unsuitable for everyday use. They tried out different electrical strengths, eventually finding that a weak current produced the desired effect while remaining barely perceptible to the eater.

Miyashita asserts that the chopsticks are also able to increase the flavor of foods beyond just saltiness. “The electric current can control umami and sourness too,” he explains. “When test subjects used the device to eat miso soup, it increased the umami component of the soup along with saltiness. Moreover, as salt is a flavor enhancer, increased saltiness magnified the overall taste of the dish.”

A researcher tests the electric chopsticks. (© Meiji University Department of Frontier Media Science/Miyashita Hōmei)
A researcher tests the electric chopsticks. (© Meiji University Department of Frontier Media Science/Miyashita Hōmei)

However, he is quick to point out that the device does have its limits. ”Sugar does not have an ionic bond as salt does, making it extremely difficult to control sweetness electronically,” he explains. He insists there are workarounds, though. Another sweetening agent, glycine, is ionically bonded and can potentially be manipulated. “Increasing the saltiness of sweet foods, like sprinkling salt on a piece of watermelon, can also make foods seem sweeter.”

Miyashita is confident that with further development, the chopsticks can help people make better decisions about their diets. “I want to overturn the idea that low salt means no flavor,” he declares. “The chopsticks make it possible to keep enjoying the foods we love, but in a healthier way.”

(Originally published in Japanese on FNN’s Prime Online on April 21, 2022. Translated and edited by Nippon.com.)

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