Petrolomics-derived data interpretation to study acetaldehyde-epicatechin condensation reactions
Abstract
During red wine ageing or conservation, color and taste change and astringency tends to reduce. These changes result from reactions of flavan-3-ols and/or anthocyanins among which condensation reactions with acetaldehyde are particularly important. The full characterization of these reactions has not been fully achieved because of difficulties in extracting and separating the newly formed compounds directly from wine. Model solutions mimicking food products constitute a simplified medium for their exploration, allowing the detection of the newly formed compounds, their isolation, and their structure elucidation. In this work, the reactions of (-)-epicatechin in the presence of acetaldehyde were studied in model solution systems at wine pH by UPLC-LTQ-Orbitrap-high resolution mass spectrometry. High resolution mass spectrometry provides exact mass measurements thus leading to elemental composition assignment of molecules which is an essential step for identification of new-formed compounds. By applying petrolomics-derived data interpretation strategies such as the untargeted Van Krevelen diagrams and Kendricks mass defect plots, described earlier in black tea thearubigins (1), more than 40 compounds were found including the homogeneous bridged derivatives and the well-known vinyl and ethanol adducts (2,3). Other compounds from polymer series such as the hexamer and heptamer epicatechin bridged derivatives and several xanthylium salts were identified for the first time. Consequently, in this work, a structural model for acetaldehyde-mediated reaction cascades involving formation of ethanol adducts, vinyl adducts, ethyl brides, loss of water molecules to form xanthylium salts…was developed.
References 1. Kuhnert et al. Arch. Biochem. Biophys., 2010, 501, 37–51 2. Fulcrand et al. J. Chromatogr- A. 1996, 752, 85-91 3. Es Safi et al. J. Agric. Food Chem. 1999, 47, 2088-2095
Issue: Macrowine 2016
Type: Article
Authors
*INRA