Development of a disposable pyruvate biosensor to determine pungency in onions (Allium cepa L.)

摘要

A disposable prototype pyruvate biosensor was constructed using pyruvate oxidase immobilised on mediated meldolas blue electrodes to determine pungency in onions (Allium cepa L.). The optimum operating potential was +150mV (versus Ag/AgCl). A strong correlation between the biosensor response and untreated onion juice of known pyruvate concentration 2-12 mu mol/g fresh weight (FW) was demonstrated. The biosensor was able to differentiate between low and high pungency onions. The detection limit using 1 unit of pyruvate oxidase was 1-2 mu mol/g FW. Optimum concentrations of co-factors TPP, FAD and MgSO4 comprising the enzyme cocktail were determined as being 0.04, 0.1 and 30 mm, respectively. (c) 2005 Elsevier B.V. All rights reserved.