Chapter 17 - Monosodium glutamate in foods and its biological importance

Abstract

Monosodium glutamate (MSG) is a food flavor enhancer used widely for its umami potency in different cultures. This chapter documents the biological importance of MSG and found that it constitutes sodium, glutamate, and water and occurs richly in protein foods and in the human body. As a major nonessential amino acid in the human body, it performs several functions including energy for gut cells, material for protein metabolism and key metabolites, and also a neurotransmitter in the central nervous system. It can be found free or bound to proteins and the free form has the unique taste quality (umami) that translates savory taste in foods. This umami taste is distinct to other basic tastes. Human beings have been shown to adequately metabolize food glutamate and flavor-enhancing glutamate. Double blind placebo-controlled studies reported that flavor-enhancing glutamate at normal dietary levels found in umami foods can considerably improve health of older population and poses no risk for other age groups. The European established acceptable daily intake of 30 mg/kg body weight is well above the no adverse effect level. Proper labeling is specified for MSG on product labels. More work on MSG as consumed in human diet is encouraged.