E622 (Monopotassium glutamate) is a chemical compound, potassium salt of glutamic acid. 

It appears as a white powder soluble in water, insoluble in ethanol or ether.

What it is used for and where

Food

Ingredient included in the list of European food additives as E622 as a flavour enhancer and salt substitute 

Safety

EFSA's Panel on Food Additives provided a scientific opinion reviewing the safety of glutamic acid-glutamates (E620-625) used as food additives.  The Panel assessed the suitability of human data to be used for the derivation of a health-based guidance value. Although human effects were identified, human data were not suitable due to the lack of dose-response data from which a no-effect dose could be identified. Based on the NOAEL of 3,200 mg MSG/kg bw per day from the neurodevelopmental toxicity study and applying the default uncertainty factor of 100, the Panel calculated a group Acceptable Daily Intake (ADI) of 30 mg/kg bw per day, expressed as glutamic acid, for glutamic acid and glutamates (E620-625). The Panel noted that exposure to glutamic acid and glutamates (E620-625) exceeded not only the proposed ADI, but also the doses associated with adverse effects in humans for some population groups (1).

This study finds that monopotassium glutamate and magnesium diglutamate have 'clastogenic, mutagenic, aneugenic and cytotoxic effects, particularly at high concentrations in human lymphocytes in vitro' (2).

• Molecular Formula  C₅H₈KNO₄ · H₂O
• Molecular Weight    203,24 g/mol  
• CAS  19473-49-5
• UNII    GQ82EXX32T
• EC Number  243‐094‐0

Synonyms: 

• Monopotassium l‐glutamate monohydrate  CAS  6382‐01‐0
• l‐glutamic acid, potassium salt, monohydrate (1:1:1)
• monopotassium glutamate monohydrate

References_____________________________________________________________________

(1) EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS); Mortensen A, Aguilar F, Crebelli R, Di Domenico A, Dusemund B, Frutos MJ, Galtier P, Gott D, Gundert-Remy U, Leblanc JC, Lindtner O, Moldeus P, Mosesso P, Parent-Massin D, Oskarsson A, Stankovic I, Waalkens-Berendsen I, Woutersen RA, Wright M, Younes M, Boon P, Chrysafidis D, Gürtler R, Tobback P, Altieri A, Rincon AM, Lambré C. Re-evaluation of glutamic acid (E 620), sodium glutamate (E 621), potassium glutamate (E 622), calcium glutamate (E 623), ammonium glutamate (E 624) and magnesium glutamate (E 625) as food additives. EFSA J. 2017 Jul 12;15(7):e04910. doi: 10.2903/j.efsa.2017.4910. 

(2) Avuloglu-Yilmaz, E., Yuzbasioglu, D. and Unal, F., 2020. In vitro genotoxicity assessment of monopotassium glutamate and magnesium diglutamate. Toxicology in Vitro, 65, p.104780.