A new device could bring some flavor to virtual reality. Researchers studying thermal taste simulation have demonstrated for the first time that heating and cooling the tongue can simulate a variety of tastes.
VR systems already simulate visual and audio, but taste has typically been difficult to reproduce because it is derived from a chemical reaction on the tongue. While it is possible to incorporate chemicals in VR applications, it isn’t practical, as these chemicals need to be refilled and handled with care.
In recent years, research has demonstrated how thermal reactions can influence taste. Thermal tasters are a segment of the population that can perceive taste sensations when there is an increase in temperature on their tongue. By heating or cooling the TRPM5 (Transient receptor potential cation channel subfamily M member 5) taste channel of the tongue, researchers were able to produce taste sensations without chemicals.
Previous studies on thermal taste have produced sensations of sweetness in only half or fewer participants in their studies. A team from the Imagineering Institute in Malaysia and the City, University of London lead by Professor Adrian David Cheok has demonstrated for the first time that thermal reactions can produce a variety of different taste sensations using a novel thermal taste device called the “Thermal Taste Machine.” The device is composed of a microcontroller, a silver plate connected to a Peltier module, a liquid cooler system, an H-bridge motor driver, a current sensor, a temperature sensor, and a USB serial interface. To create the taste sensation, the system heats or cools the silver plate from -40°C to 80°C.
Figure 1: The thermal taste device and its components
“With the digitization of taste, the virtual experiences will become much closer to reality,” said Kasun Karunanayaka, researcher at the Imagineering Institute. “This will create more opportunities in fields such as human computer interaction, medicine and internet shopping. As this technology advances, the food industry will be able to make and share healthy virtual foods.”
To test their system, the researchers conducted three user studies. The first study found heating up the tongue induced sweet and fatty (or oily) tastes, while cooling the tongue produced minty and pleasant sensations.
Figure 2: User study set-up for the thermal taste characterization experiment
The next study involved the enhancements of sweet taste in solutions using thermal stimulation. The researchers used two different concentrations of sucrose solutions and water with the thermal taste machine. Users reported the device was able to affect the sweetness and intensity ratings of the solutions. The higher concentrated sucrose solution was liked more and viewed as more intense by test participants.
Finally, the third study evaluated the effect of different temperature rates on the sensation of sweetness, using three different rates of rising temperatures. The researchers found faster rates of temperature increases produced sweeter sensations.
Through these studies, the team confirmed their system could generate specific tastes in users as well as increase the intensity of certain tastes by speeding up the temperature increase on the tongue. Some modifications will be needed before they can make the system available to consumers.
“The main limitation we need to address is the lack of user friendliness for frequent use,” said Hanis Camelia, researcher at the Imagineering Institute. “Some users are hesitant to place the silver plate of the device due to concerns of burning their tongue or hygiene. We need to find more innovative ways to make users comfortable with receiving thermal sensations to the tongue.”
In addition to the user experience, the researchers are looking to improve the taste sensations and decrease the time of thermal taste activation. They would also like to improve this technology by collaborating with the experts from different fields such as food, nutrition and healthcare.
As this technology progresses, it would be possible to combine thermal taste technology with other digital taste and smell actuation technologies to produce complex VR flavor experiences. With this development, VR users could enjoy any of their favorite foods without having to worry about calories.
For more information on thermal taste, visit the IEEE Xplore Digital Library.
