L-Glutamate determiation in food samples by flow-injection analysis

摘要

This work refers to the exploitation of green pepper(Capsicum annum)as an enzymatic source of L-glutamate decarboxylase for the development of enzymatic reactors for enzymatic reactors for automatic flow systems .The purified enzymatic extract was immobilised in glass beads, incoporated into an assembly with potentiometric detection and applied to the determination of L-glutamate in food formulas of commercial soups. The enzymatic reactor with 8 cm length and 4 mm thickness was filled with 400mg of beads containing the immobilised enzyme with a specific activity of 4.12 U mg~(-1) of protein and a useful life time of 78 days or 638 determinations. Optimisation of the flow system by response surface methodology allowed its application to the determination of L-glutamate in the rage 2.5-75 mmoll~(-1) for 200 #mu#l samples with a sampling rate of 60 samples per hour. The results obtained with the proposed methodology were compared with those obtained by spectrophotometric determination, showing relative deviations lower than 5%