Monosodium glutamate Formula
Monosodium glutamate, also known as sodium glutamate is the salt of glutamic acid (one of the more important amino acids). It is a very important flavoring agent in the food-processing industry.
Formula and structure: The molecular formula of monosodium glutamate is C5H8NNaO4 and its molar mass is 169.11 g mol-1. Monosodium glutamate has the same basic structure of amino acids, with an amine group (-NH2) and carboxylate ion instead the carboxylic group (-COO-). Moreover, the monosodium glutamate has other carboxylic group in the side chain. Its chemical structure can be written as below, in the common representations used for organic molecules.
Occurrence: Monosodium glutamate is largely found in nature, especially in food as tomatoes and cheese.
Preparation: Nowadays, monosodium glutamate is obtained from bacterial fermentation using Corynebacterium species feeding with ammonia and different carbohydrates sources. Bacteria excrete different amino acids and then, sodium is added to neutralize and monosodium glutamate is isolated. Chemical synthesis methods are available to produce monosodium glutamate, but these have been substituted by bacterial fermentation mainly because the yield is higher.
Physical properties: Monosodium glutamate is a white crystalline powder with a slightly peptonelike odor. Its melting point is 232 ºC and it is highly soluble in water. Its insoluble in common organic solvents. Monosodium glutamate is used to impart the umami (meat-like) taste to food.
Chemical properties: Monosodium glutamate is very stable to high temperatures, thus it can be used in industrial food-processing conditions. It is important noting, glutamic acid has two carboxylic groups in its structure but monosodium glutamate corresponds to the deprotonation of the ɑ-carboxylic group, which has the most acidic hydrogen.
Uses: Monosodium glutamate is one of the most important flavoring agents, thus is largely used in the food industry. Monosodium glutamate was first prepared in Japan, where the meat-like taste is present in many dishes.
Health effects/safety hazards: Monosodium glutamate is safe and there are not risks associated with its manipulation. In the past decade, it was thought, monosodium glutamate caused headaches and other side effects, but at the moment, any test has proved it.