Taste sensations are detected by chemical sensors on the tongue that convert chemicals into electrical signals.

“Now, most of us are familiar with the sense of bitterness that comes from something like a raw radish, sweet, which comes, obviously, from sugars of different kinds, fructose, glucose, et cetera, salty salty and sour, think lemon or lemon juice, for instance. And then I mentioned umami. The umami receptor is a receptor that responds to the savory taste of things. So that's what you might find in a really wonderfully rich tomato sauce. For those of you that eat meat, and like meat, a really well cooked ,not necessarily well done, but properly cooked, I should say, steak, if that's your thing. And umami is present in both plant and animal foods, and gives us that sensation of savoriness. It almost has a kind of little bit of a briny taste to it, or braised taste to it. And indeed, brazing of meats and brazing of vegetables is done specifically to activate that umami receptor. So we have those five basic tastes. Those are chemical sensors on the tongue that, what we call, transduce those chemicals. Those chemicals, literally, in food bind to those receptors, and it is transduced, meaning the binding of those chemicals to the receptors is converted into an electrical signal that travels in from the tongue along what's called the gustatory nerve.”

“And as you've all heard before, we have sensors on our tongue and elsewhere in our mouth that detect the various chemicals contained within food and lead to the senses of taste, which we call bitter, sweet, umami, salty, and sour.”

“So we have those five basic tastes. Those are chemical sensors on the tongue that what we call transduce those chemicals.”