Monoammonium glutamate

Monoammonium glutamate is the ammonium salt of glutamic acid, functioning as an umami flavour enhancer in the same manner as monosodium glutamate and its related salts. Its use is less common than the sodium and potassium forms but it appears in some condiments and seasonings, particularly where both sodium and potassium reduction are desired. The ammonium cation is a normal metabolic product of amino acid breakdown in the human body.

JECFA classified the ADI for monoammonium glutamate as "not specified" in its 1987 review, consistent with the treatment of all glutamate additives. Glutamic acid is a ubiquitous amino acid and metabolic participant, while ammonium is readily processed through the urea cycle in healthy individuals. No upper intake limit is considered necessary at the concentrations encountered in food additive applications.

Monoammonium glutamate is approved in the EU and in other jurisdictions for specific food applications as a flavour enhancer. Consumers monitoring total glutamate intake from additives should note that E624 belongs to the same functional class as E620–E621 and other glutamate salts. Individuals with liver or kidney conditions that impair ammonia metabolism should be aware of the ammonium component, though the quantities provided by this additive in food are modest compared with the ammonia released during normal protein digestion. Like other members of the glutamate family, it may be used alongside nucleotide enhancers to achieve synergistic umami amplification.