title: Simultaneous determination of ketoacids and dicarbonyl compounds, key Maillard intermediates on the generation of aged wine aroma.
abstract: The aim of this work was the simultaneous determination of both ketoacids and dicarbonyl compounds in wine. To detect ketoacid compounds in wine, a method based on the quinoxaline derivatives by the reaction with diaminobenzene, currently employed to detect alpha-dicarbonyl compounds, was developed. The quinoxaline derivatives were detected by RP-HPLC with UV detection, which allows the determination of the major dicarbonyl compounds in wine: glyoxal, methylglyoxal, diacetyl and pentane-2,6-dione, and the quinoxaline/quinoxalinol derivatives of alpha-keto-gamma-(methylthio)butyric acid and beta-phenylpyruvic acid (intermediate ketoacid compounds of methional and phenylacetaldehyde) were simultaneously detected by a fluorescence detector. The identification was performed by comparison with standards and also by using LC-MSMS. The levels found in 15 wines analyzed (white wines, Madeira wines, and Port wines) diverge according to the type and the age of the wine. The ketoacid compounds ranged from 0.2 to 5.7 mg/L for alpha-keto-gamma-(methylthio)butyric acid and 0.1 to 9.6 mg/L for beta-phenylpyruvic acid. The quantities observed for dicarbonyl compounds were similar to those already reported.
authors.affiliation: Escola Superior de Biotecnologia, Univ. Católica Portuguesa, R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
authors.forename: António César
authors.initials: AC
authors.lastname: da Silva Ferreira
authors.forename: Sofia
authors.initials: S
authors.lastname: Reis
authors.forename: César
authors.initials: C
authors.lastname: Rodrigues
authors.forename: Carla
authors.initials: C
authors.lastname: Oliveira
authors.forename: Paula Guedes
authors.initials: PG
authors.lastname: de Pinho
mesh_terms: D005524:Food Technology; D006571:Heterocyclic Compounds / Q000032:analysis* / Q000737:chemistry; D006838:Hydrocarbons / Q000032:analysis; D007651:Keto Acids / Q000032:analysis* / Q000737:chemistry; D015416:Maillard Reaction; D009812:Odorants / Q000032:analysis*; D013997:Time Factors; D014920:Wine / Q000032:analysis*
chemical_list: D006571:Heterocyclic Compounds; D006838:Hydrocarbons; D007651:Keto Acids