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Monitoring the Reductive and Oxidative Half-Reactions of a Flavin-Dependent Monooxygenase using Stopped-Flow Spectrophotometry
Published on: March 18, 2012
Quinones as Strecker degradation reagents in wine oxidation processes
Carla Maria Oliveira1, Sónia A O Santos2, Armando J D Silvestre2
1QOPNA/Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; CBQF/Faculty of Biotechnology, Catholic University of Portugal, Rua Arquiteto Lobão Vital, Apartado 251, 4202-401 Porto, Portugal.
Abstract:
The Strecker aldehydes formed during the reaction between α-amino acids (phenylalanine or methionine) and either gallic acid, caffeic acid or (+)-catechin ortho-quinones were evaluated in wine-model systems. It was demonstrated that phenylacetaldehyde was formed by quinone intermediates at wine pH. The highest amounts of phenylacetaldehyde during the 10days of experiment (69±5µg/L/day; 7x>Control) were obtained from (+) catechin, followed by gallic acid (61±4µg/L/day; 6x>Control) and caffeic acid (41±4µg/L/day; 4x>Control). The intermediate structures delivered from the reaction of ortho-quinones with α-amino acids were demonstrated by MSn.
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