Production of monosodium glutamate

By far the most important amino acid in food biotechnology and the first amino acid to be produced by fermentation is glutamate (monosodium glutamate, MSG).

It is monosodium glutamate that plays the largest role in food and in particular flavoring enhancing. Monosodium glutamate is used in a wide range of foods, including canned meat and fish, spreads, soups and other processed foods.

Monosodium glutamate is an odorless, white, crystalline substance that resembles salt. It has property of enhancing the flavor of meat and other protein foods.

Originally MSG was extracted from natural materials and hydrolyzed proteins but from the late 1950s it has been made by fermentation.

In the production of L-glutamate, only Corynebacterium glutamicum is used, although E- coli and other organism are also able to excrete glutamate.

Glutamate is synthesized from 2-oxoglutarate by one –step reaction catalyzed by the NADPH dependent glutamate dehydrogenase, which is the main pathway for glutamate formation when the ammonium concentration is sufficiently high.

Therefore, ammonium is added in a low concentration at the beginning of the fermentation and is then added continuously during the course of the fermentation.

Yield of between 60 and 70% is based in the glucose used. At the end of the fermentation the broth contains L- glutamate in the form of its ammonium salt.
Production of monosodium glutamate

Flavor enhancers

Flavor enhancers
Flavorings either impart a particular flavor to foods or modify flavors already present. Flavor enhancers intensify flavor already present, especially when desirable flavors are relatively weak.

Monosodium glutamate is one of the beat known and most widely used flavor enhancers. This compound occurs naturally in many foods and in certain seaweed that was used for centuries as a flavor enhancer for soups and other foods. It is only within the last hundred years that the reason for the effectiveness of the seaweed was discovered to be MSG (Monosodium glutamate). The way in which MSG enhances flavor is mot fully understood.

While it is effective at relatively low levels (parts per thousand), there are other compounds called flavor potentiators that also enhance flavors but are extremely powerful, effective in parts per million and even per billion. These compounds have been identified as nucleotides and their effect is attributed to their synergistic properties (properties that intensify the effect of natural flavor components).
Flavor enhancers