Food additives Europe numbers:E621
Functional Category
Buffering agent; flavoring agent.
Applications in Pharmaceutical Formulation
Monosodium glutamate is used in oral pharmaceutical formulations as a buffer and a flavor enhancer. For example, it is used with sugar to improve the palatability of bitter-tasting drugs and can reduce the metallic taste of iron-containing liquids. It has also been used in subcutaneous live vaccine injections such as measles, mumps, rubella and varicella-zoster live vaccine (ProQuad). However, the most widespread use of monosodium glutamate is as a flavor enhancer in food products. Typically, 0.2–0.9% is used in normally salted foods, although products such as soy protein can contain 10–30%. The use of monosodium glutamate in food products has been controversial owing to the apparently high number of adverse reactions attributed to the substance, which gives rise to the so-called ‘Chinese Restaurant Syndrome’ The current consensus is that there is no clinically compelling evidence to suggest that monosodium glutamate may be harmful at the current levels used in foods.
Description
Monosodium glutamate occurs as white free-flowing crystals or a crystalline powder. It is practically odorless and has a meat-like taste.
Stability and Storage Conditions
Aqueous solutions of monosodium glutamate may be sterilized by autoclaving. Monosodium glutamate should be stored in a tight container in a cool, dry place.
Safety
Monosodium glutamate is widely used in foods and oral pharmaceutical formulations. It is generally regarded as moderately toxic on ingestion or intravenous administration. Adverse effects include somnolence, hallucinations and distorted perceptions, headache, dyspnea, nausea or vomiting, and dermatitis. The lowest lethal oral dose in humans is reported to be 43 mg/kg.(1) The use of monosodium glutamate in foods has been controversial due to the so-called ‘Chinese Restaurant Syndrome’ (see Section 18), although it is generally regarded as safe at intake levels of up to 6 mg/kg bodyweight.(2) In Europe, total glutamate intake from food ranges from 5–12 g/day.(2) There has been a report of a foreign body granuloma caused by monosodium glutamate after a BCG vaccination.(3)