Taking its name from Japanese, umami is a pleasant savoury taste imparted by glutamate, a type of amino acid, and ribonucleotides, including inosinate and guanylate, which occur naturally in many foods including meat, fish, vegetables and dairy products. As the taste of umami itself is subtle and blends well with other tastes to expand and round out flavors, most people don't recognize umami when they encounter it, but it plays an important role making food taste delicious.
Food Acceptability and umami
When humans eat, they use all of their senses (sight, hearing, smell, touch and taste) to form general judgments about their food, but it is taste that is the most influential in determining how delicious a food is. Conventionally, it has been thought that our sense of taste is comprised of four basic, or 'primary', tastes, which cannot be replicated by mixing together any of the other primaries: sweet, sour, salt and bitter. However, it is now known that there is actually the fifth primary taste: umami.
How Humans Experience Their Food