Matter of taste
How do we recognise different tastes?
Different chemicals can give rise to five different types of taste. Sweet, sour, salty and bitter tastes have been known for some time. More recently, the savoury taste umami – think of soy sauce or the juices from a roasted joint of meat – has been added to the set.
Specialised taste cells send signals to the brain, triggered by a range of chemical sensors. Salty or sour substances act on proteins that form channels on the surface of the cells and control the movement of positive ions. Sweet- and bitter-tasting ones bind to different receptor proteins, as do molecules that we sense as umami. The brain interprets patterns of cell activation, as each taste cell responds to a range of chemicals with differing sensitivity. The final taste also depends on the texture and temperature of the food.
Old textbooks mention a ‘taste map’ on your tongue, with different regions picking up different tastes. However, detailed tests show that all parts of the tongue with taste buds can register all types of taste.Lead image:
Jamwhy/Flickr CC BY NC