Colorimetric determination of monosodium glutamate in food samples using l-glutamate oxidase

Abstract

A rapid, sensitive and simple chromogenic method was developed for quantitative determination of monosodium glutamate MSG in food samples. The method incorporated a glutamate oxidase and peroxidase. The librated H 2O2 from a glutamate sample as a result of enzymatic action was measured using 4-aminoantipyrine and phenol as a chromogenic reagent at 502 nm. Glutamate calibration curve was linear up to 125 mmol L-1 with a detection limit of 2 mmol L-1. The results of analyzing L-glutamate in various food samples using the approach were compared to those of a standard procedure employing HPLC method. MSG concentration in different samples ranged from 0.93 to 4.9 g/kg. This method is relatively sensitive and specific, without the need of pre-treatment for sample. Fig 5, Tab 1, Ref 25.