Sweet, sour, salty, bitter … and umami? - health matters - meaty/monosodium glutamate - Brief Article

We were all taught in grammar school that there are four tastes the human tongue can detect: sweet, sour, salty and bitter. But in recent years, food scientists have been studying a fifth taste, umami, which roughly translates into "delicious" or "meaty." Scientists are divided about whether this fifth taste really exists or not. It is said to be associated with monosodium glutamate, or MSG, which is the salt form of the amino acid glutamic acid.

In 1959, the FDA classified MSG as a safe food additive, although many people claim to have an MSG sensitivity.

Although it doesn't have a distinct taste of its own, MSG is said to enhance the flavors of foods. Many scientists believe that this is because it stimulates the glutamate receptors in the tongue, hence the fifth taste.

Glutamate is found naturally in protein-containing foods, such as meat, milk and cheese, and MSG is typically made from fermented starch, sugar beets, sugarcane or molasses.