Researchers at Ohio State University have developed a system called e-Taste that can replicate flavors like cake and fish soup in virtual reality. The device uses sensors to detect chemicals corresponding to five basic tastes – salty, sour, sweet, bitter, and umami – and sends digital readings to a pump that releases flavor-containing hydrogels under the user’s tongue. In tests, the system matched real sourness 70% of the time, paving the way for recreating flavors in virtual reality, but it still can’t replicate other factors influencing taste, such as smell.
Source: https://www.newscientist.com/article/2470348-electronic-tongue-could-let-you-taste-cake-in-virtual-reality