Which substance evokes the umami taste sensation in humans?

The fifth taste sense, umami, was recently added to the four classic tastes. This taste has actually been known for almost 100 years, and it became established once its receptor was identified. It is triggered by glutamate and paicularly by the monosodium glutamate (MSG) used so extensively in Asian cooking. The taste is pleasant and sweet but differs from the standard sweet taste.Ref: Ganong&;s review of medical physiology 23rd edition, Page no:224