Bitterness in coffee
Did you know that on average we are more sensitive to bitterness and less sensitive to sweetness? And that bitterness sensitivity can vary from person to person?
In 1931, a chemist named Arthur Fox was pouring some powdered PTC into a bottle. PTC stands for phenylthiocarbamide, also known as phenylthiourea, the chemical structure of PTC resembles toxic alkaloids found in some poisonous plants. When some of the powder accidentally blew into the air, a colleague standing nearby complained that the dust tasted bitter. Fox tasted nothing at all. Curious how they could be tasting the chemical differently, they tasted it again. The results were the same. Fox had his friends and family try the chemical then describe how it tasted. Some people tasted nothing. Some found it intensely bitter, and still others thought it tasted only slightly bitter.
Soon after its discovery, geneticists determined that there is an inherited component that called. TAS2R38 that was discovered in 2003.
The shape of the receptor protein determines how strongly it can bind to PTC. Since all people have two copies of every gene, combinations of the bitter taste gene variants determine whether someone finds PTC intensely bitter, somewhat bitter, or without taste at all.