title: Development of a disposable pyruvate biosensor to determine pungency in onions (Allium cepa L.).
abstract: 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 +150 mV (versus Ag/AgCl). A strong correlation between the biosensor response and untreated onion juice of known pyruvate concentration 2-12 micromol/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 micromol/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.
authors.affiliation: Plant Science Laboratory, Cranfield University at Silsoe, Bedfordshire MK45 4DT, UK. l.a.terry@cranfield.ac.uk
authors.forename: L A
authors.initials: LA
authors.lastname: Abayomi
authors.forename: L A
authors.initials: LA
authors.lastname: Terry
authors.forename: S F
authors.initials: SF
authors.lastname: White
authors.forename: P J
authors.initials: PJ
authors.lastname: Warner
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004566:Electrodes; D009812:Odorants / Q000032:analysis*; D019697:Onions / Q000737:chemistry*; D010078:Oxazines; D010376:Pediococcus / Q000201:enzymology; D011771:Pyruvate Oxidase; D019289:Pyruvic Acid / Q000032:analysis*
chemical_list: D010078:Oxazines; C005559:Meldola blue; D019289:Pyruvic Acid; D011771:Pyruvate Oxidase