title: A New Chemical Pathway Yielding A-Type Vitisins in Red Wines.
abstract: A new chemical pathway yielding A-type vitisins in red wines is proposed herein from the reaction between anthocyanins and oxaloacetic acid (OAA). This new chemical path is thought to occur in the first stages of the wine production even during the fermentation process. This is due to the revealed high reactivity of OAA with anthocyanins compared with the already known precursor (pyruvic acid, PA). In model solutions at wine pH (3.5), when malvidin-3-O-glucoside (mv-3-glc) is in contact with OAA and PA a decrease in the OAA concentration is observed along with the formation of A-type vitisin. Moreover, part of the OAA is also chemically converted into PA in model solutions. The reaction yields were also determined for OAA and PA using different mv-3-glc:organic acid molar ratios (1:0.5, 1:1, 1:5, 1:10; 1:50, and 1:100) and these values were always higher for OAA when compared to PA, even at the lowest molar ratio (1:0.5). The reaction yields were higher at pH 2.6 in comparison to pH 1.5 and 3.5, being less affected at pH 3.5 for OAA. These results support the idea that OAA can be at the origin of A-type vitisins in the first stages of wine production and PA in the subsequent ageing process.
authors.affiliation: Laboratório Associado para a Química Verde, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal. paula.araujo@fc.up.pt.
authors.forename: Paula
authors.initials: P
authors.lastname: Araújo
authors.affiliation: Laboratório Associado para a Química Verde, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal. ana.fernandes@fc.up.pt.
authors.forename: Ana
authors.initials: A
authors.lastname: Fernandes
authors.affiliation: Laboratório Associado para a Química Verde, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal. vfreitas@fc.up.pt.
authors.forename: Victor
authors.initials: V
authors.lastname: de Freitas
authors.affiliation: Laboratório Associado para a Química Verde, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal. jsoliveira@fc.up.pt.
authors.forename: Joana
authors.initials: J
authors.lastname: Oliveira
mesh_terms: D000704:Analysis of Variance; D000872:Anthocyanins / Q000737:chemistry / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005638:Fruit / Q000737:chemistry / Q000378:metabolism*; D005960:Glucosides / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D053858:Metabolic Networks and Pathways; D008956:Models, Chemical; D015394:Molecular Structure; D062907:Oxaloacetic Acid / Q000737:chemistry / Q000378:metabolism; D019289:Pyruvic Acid / Q000737:chemistry / Q000378:metabolism; D027843:Vitis / Q000737:chemistry / Q000378:metabolism*; D014920:Wine / Q000032:analysis*
chemical_list: D000872:Anthocyanins; D005960:Glucosides; D062907:Oxaloacetic Acid; C458419:malvidin-3-glucoside; D019289:Pyruvic Acid
keywords: anthocyanins; carboxypyranomalvidin-3-O-glucoside vitisin; malvidin-3-O-glucoside; oxaloacetic acid; pyruvic acid; red wines