This work outlines a rapid novel methodology for the direct quantitation of 12 volatile aldehyde compounds related to oxidative off-flavors in wine, by measuring the combined free and hydrogen-sulfite-bound forms of each aldehyde compound, consisting of four general aldehydes, four Strecker aldehydes, and four (E)-2-alkenals. The methodology requires minimal preparation of wine samples: the addition of internal standards and 6 g/L sulfur dioxide, and filtration prior to quantitation by liquid chromatography-triple quadrupole-mass spectrometery. Overall, the limit of detection, limit of quantification, accuracy (recovery, 97-114%), and precision (repeatability and reproducibility, RSD ≤ 10%) were satisfactory to enable routine measurement of the 12 aldehyde compounds in wine. The methodology was applied to 20 commercial white and red wines from various varieties and vintages. A general trend of higher concentrations of the aldehyde compounds in white wines compared to red wines was observed.
Keywords: oxidation; sulfur dioxide; volatile aldehyde compounds; wine.