title: Dual laccase-tyrosinase based Sonogel-Carbon biosensor for monitoring polyphenols in beers.
abstract: A biosensor based on the bi-immobilization of laccase and tyrosinase phenoloxidase enzymes has been successfully developed. This biosensor employs as the electrochemical transducer the Sonogel-Carbon, a novel type of electrode developed by our group. The immobilization step was accomplished by doping the electrode surface with a mixture of the enzymes, glutaricdialdehyde, and Nafion-ion exchanger, as protective additive. The response of this biosensor, denoted the dual Trametes versicolor laccase (La) and Mushroom tyrosinase (Ty) based Sonogel-Carbon, was optimized directly in beer real samples and its analytical performance with respect to five individual polyphenols was evaluated. The Lac-Ty/Sonogel-Carbon electrode responds to nanomolar concentrations of flavan-3-ols, hydroxycinnamic acids, and hydroxybenzoic acids. The limit of detection, sensitivity, and linear range for caffeic acid, taken as an example, were 26 nM, 167.53 nA M (-1), and 0.01-2 microM, respectively. In addition, the stability and reproducibility of the biosensor were also evaluated in beer samples. The Lac-Ty/sonogel-carbon electrode was verified as very stable in this matrix, maintaining 80% of its stable response for at least three weeks, with a RSD of 3.6% ( n = 10). The biosensor was applied to estimate the total polyphenol index in ten beer samples, and a correlation of 0.99 was obtained when the results were compared with those obtained using the Folin-Ciocalteau reagent.
authors.affiliation: Departamento de Quimica Analitica, Facultad de Ciencias, Universidad de Cadiz, Apdo. 40, 11510 Puerto Real, Cadiz, Spain.
authors.forename: Mohammed
authors.initials: M
authors.lastname: ElKaoutit
authors.forename: Ignacio
authors.initials: I
authors.lastname: Naranjo-Rodriguez
authors.forename: Khalid Riffi
authors.initials: KR
authors.lastname: Temsamani
authors.forename: Manuel Domínguez
authors.initials: MD
authors.lastname: de la Vega
authors.forename: Jose Luis Hidalgo-Hidalgo
authors.initials: JL
authors.lastname: de Cisneros
mesh_terms: D001515:Beer / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004566:Electrodes; D004795:Enzyme Stability; D004800:Enzymes, Immobilized; D005419:Flavonoids / Q000032:analysis*; D007700:Kinetics; D042845:Laccase; D014442:Monophenol Monooxygenase; D010636:Phenols / Q000032:analysis*; D059808:Polyphenols; D015203:Reproducibility of Results
chemical_list: D004800:Enzymes, Immobilized; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D042845:Laccase; D014442:Monophenol Monooxygenase