Multidimensional chromatographic approach applied to the identification of novel aroma compounds in wine: Identification of ethyl cyclohexanoate, ethyl 2-hydroxy-3-methylbutyrate and ethyl 2-hydroxy-4-methylpentanoate

A multidimensional chromatographic strategy has been developed and optimized with the purpose of identifying different odorants potentially relevant to the aroma and flavor of aged wines from Madeira or Sherry. Different techniques of extraction and fractionation were studied in order to get clear olfactometric and spectrometric signals from the target odorants. The best results were obtained with a dynamic headspace extraction followed by a fractionation on a normal phase medium pressure liquid chromatography on a silicagel column. Large volumes (50 μl) of the concentrated fractions were further analyzed in a dual gas chromatography–mass spectrometric system (GC–MS) equipped with two olfactometric ports. The strategy made it possible to identify in wine by first time the presence of the powerful strawberry-smelling compound, ethyl cyclohexanoate, and of two other novel fruity esters, ethyl 2-hydroxy-3-methylbutyrate and ethyl 2-hydroxy-4-methylpentanoate. Some other unidentified odorants could be isolated and their mass spectra are given.