Glutamate is one of the most common amino acids found in nature. Glutamate is also produced in the human body and binds with other amino acids to form a structural protein.

When glutamate binds to a protein molecule it is tasteless. Fermentation, aging, ripening and cooking liberate free glutamate. Glutamate is a crucial component of the taste of cheese, seafood, meat broths, and many other foods.

Free glutamic acid is present naturally in meat, poultry, seafood and vegetables. Seaweed, cheese, fish sauce, soy sauce, fermented beans, and ripe tomato show high levels of free glutamic acid. Continue reading

The flavor enhancing properties of glutamate have been scientifically investigated in many contexts. For each food, there is an optimum glutamate concentration. Some foods, however, are not improved by the addition of glutamate – noticeably sweet foods and some particularly bitter foods. Like any seasoning, the optimal concentration of umami taste varies widely between individual consumers.

Studies carried out among Europeans suggest that the optimal concentrations (0.6–1.2 percent) tend to be higher than those reported by Asians; this may be due to the relative deficit in awareness of the distinctive umami taste in Western countries. It may also be due to genetic variation in taste.

Asian consumers learn to discriminate and appreciate the taste of umami from early childhood. In the the Western world, consumers have only recently learned to discriminate the umami taste, although they have enjoyed its contribution to food for centuries.

Excess glutamate does not make food taste better and it actually worsens taste. Generally, glutamate will work very well with salty or sour food. The optimum amount of added glutamate to enhance the taste of food is at 0.1–0.8 percent by weight.

For instance, 500 grams of food needs 0.5–4.0 grams of glutamate to bring a favorable taste, which is the same as that of glutamate naturally found in foods rich in umami flavors. For example, protein from meat contains 11–22 percent of glutamate.

Although glutamate is naturally occurring in many foods, it is frequently added as a flavor enhancer. Foods containing large amounts of free glutamate, such as tomatoes, mushrooms and cheese have long been used to obtain savory flavors in dishes.  In fact, we consume about 20–40 times more naturally occurring glutamate in the food that we eat than we do MSG.

Glutamate is often used to enhance the natural flavors of meats, poultry, seafood, snacks, soups and stews. When glutamate is added to foods, it provides a flavor profile similar to naturally occurring free glutamate.

The most popular glutamate-based flavor enhancer is monosodium glutamate (MSG). Monoammonium glutamate, monopotasium glutamate, and ribonucleotides compounds including disodium 50-monoinosinate (IMP) and disodium 50-monoguanylate (GMP) are also used as additives in foods.

Glutamate is present in foods not only as flavor enhancer, but also as a byproduct of hydrolyzed vegetable proteins, which are widely used as seasonings and flavoring agents in canned foods, dry mixes, sauces, and other manufactured products. Hydrolyzed vegetable proteins are often used as a substitute for MSG, because, although safe, consumers are wary of the food additive and its safety profile.

Glutamate is frequently added to processed foods and is shaken onto foods during preparation, particularly in Asian cuisine. The glutamate concentration in convenience foods adds up to 0.1–0.8 percent of weight, which is similar to the concentration of natural free glutamate in tomatoes or parmesan cheese.