Typically, we are encouraged not to lick our electronic devices by manufacturers, as they probably don’t taste that great anyway. Researchers from Meiji University in Japan are looking to change that, not by making edible smartphone enclosures, but rather a Taste Display that simulates nearly any flavor on the user’s tongue. Most humans can detect four primary flavors — sweet, sour, salty, and bitter, along with a combination thereof. A fifth flavor, umami (savory), also plays a significant role in how we taste different foods, such as broth and cooked meats.
The engineers' new device, known as the Norimaki Synthesizer, can capture those five flavors, and use them to trick our brains into thinking we are tasting distinct foods, much in the same way our brains trick our eyes into seeing something that isn’t there. Think of it like looking at the display you are currently reading this article on — it uses pixels made up of red, green, and blue elements to make millions of different colors.
The Norimaki Synthesizer taste display was designed using five different color-coded gels made of agar packed into a tube shape, which uses glycerin for sweet, citric acid for acidic, sodium chloride for salty, magnesium chloride for bitter, and glutamic sodium for umami. When pressed against the tongue, users experience all of the flavors at the same time, however mixing those gels and adjusting their amounts and intensities creates specific flavors.
The tubes for the display are wrapped in copper foil, so when they are held in hand and make contact with the tongue, it creates an electrical circuit via the human body, which is known as ion electrophoresis. The process moves molecules in a gel when a current is applied, moving the molecules to the cathode side away from the tongue, resulting in a weak flavor for that particular gel.
It’s a subtractive process that removes certain flavors gradually to render a specific taste. In tests, the team found that they could replicate the flavors of everything from sushi to gummy candy without eating a single piece of food.