Abayomi, Louise AnikeTerry, Leon AWhite, S. F.Warner, P. J.2008-02-132008-02-132006-05-15L.A. Abayomi, L.A. Terry, S.F. White and P.J. Warner, Development of a disposable pyruvate biosensor to determine pungency in onions (Allium cepa L.), Biosensors and Bioelectronics, Volume 21, Issue 11, 15 May 2006, Pages 2176-2179.0956-5663http://dx.doi.org/10.1016/j.bios.2005.10.024http://hdl.handle.net/1826/2326A 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 +150 mV (versus Ag/AgCl). A strong correlation between the biosensor response and untreated onion juice of known pyruvate concentration 2–12 μmol/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 μmol/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.enMeldolas blueFresh produceQuality assuranceSweet onionsPostprint