3 documents found, page 1 of 1
Thermodynamic and Kinetic Properties of a Red Wine Pigment: Catechin-(4,8)-malv...
Frederico Nave; Vesselin Petrov; Fernando Pina; Natercia Teixeira; Nuno Mateus; Victor de FreitasCatechin-(4,8)-malvidin-3-glucoside, a red pigment adduct (at acid pH) found in red wine and resulting from the reaction between malvidin-3-glucoside and flavan-3-ols during wine aging, was synthesized. The thermodynamic and kinetic constants of the network of chemical reactions were fully determined by stopped flow: (i) Direct pH jumps, from thermal equilibrated solutions at pH = 1.0 (flavylium cation, AH(+)),...
The fate of flavanol-anthocyanin adducts in wines: Study of their putative reac...
Frederico Nave; Natercia Teixeira; Nuno Mateus; Victor de FreitasMethylmethine bridged flavanol-anthocyanin dimeric adducts (F-A) were synthesised by hemisynthesis using catechin, acetaldehyde and F-A adducts as precursors in order to simulate putative reactions undergoing in red wine. The products obtained, catechin-methylmethine-catechin-malvidin-3-O-glucose and methylmethine-(catechin-malvidin-3-O-glucose), were analysed by HPLC-ESI-MS. The fragmentation patterns allowed ...
Hemisynthesis and structural characterization of flavanol-(4,8)-vitisins by mas...
Frederico Nave; Natercia Teixeira; Nuno Mateus; Victor de FreitasVitisins constitute the major group of pyranoanthocyanins naturally occurring in red wines. Regarding their chemical structure, only carboxypyranoanthocyanins have been detected and quantified in red wines, but no vitisin with substitutions in the carbons of the A ring has been identified. However, considering the chemical reactions that take place in red wine, the existence of flavan-3-ol-(4,6/8)-vitisins is e...