title: Interaction of yeasts with the products resulting from the condensation reaction between (+)-catechin and acetaldehyde.
abstract: The condensation reaction between (+)-catechin and acetaldehyde was studied in model solutions in the presence and absence yeasts in order to evaluate its contribution to color changes in fermented drinks such as white wine. On the basis of the results, the yeasts retain the oligomers produced in the reaction, their retention ability increasing for higher polymerization degrees. As a result, the color of model solutions, measured as the absorbance at 420 nm, was found to decrease after the addition of yeasts. On the other hand, the yeasts exhibited no inhibitory effect on the condensation reaction, which took place at the same rate in their presence and absence. At acidity levels and reactant concentrations similar to those in wine, with acetaldehyde in high concentration as it is present in sherry wines, the reaction was found to occur very slowly. Taking into account that Yeasts are present during most of the winemaking process; consequently, they retain oligomers, and the studied reaction could mainly contribute to the alteration of the color of white wine after bottling.
authors.affiliation: Department of Agricultural Chemistry, Faculty of Sciences, University of Cordoba, Edificio C3, Campus de Rabanales, E-14014 Cordoba, Spain.
authors.forename: Azahara
authors.initials: A
authors.lastname: Lopez-Toledano
authors.forename: Debora
authors.initials: D
authors.lastname: Villaño-Valencia
authors.forename: Manuel
authors.initials: M
authors.lastname: Mayen
authors.forename: Julieta
authors.initials: J
authors.lastname: Merida
authors.forename: Manuel
authors.initials: M
authors.lastname: Medina
mesh_terms: D000079:Acetaldehyde / Q000737:chemistry*; D002392:Catechin / Q000737:chemistry*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D012996:Solutions; D013053:Spectrophotometry; D014920:Wine / Q000032:analysis
chemical_list: D012996:Solutions; D002392:Catechin; D000079:Acetaldehyde