Sensory and chemical changes of young white wines stored under oxygen. An assessment of the role played by aldehydes and some other important odorants

The aroma of young white wines altered by oxygen was described by a sensory panel which defined the terms: cooked vegetables, liquor, woody, cider and pungent. Twenty-seven young white wines stored under oxygen for 1 week were analyzed by the sensory panel and were further analyzed by gas chromatography (GC)-Ion trap mass spectrometry (MS) to determine their contents in hexanal, 4-hydroxy-4-methylpentanone, 2-nonanone, 2-buthoxyethanol, t-2-octenal, 1-octen-3-ol, furfural and 5-methylfurfural, benzaldehyde, t-2-nonenal and eugenol. The degrees of aroma degradation induced by oxidation and the acetaldehyde concentration of the wines were measured before and after the oxidation process. The sensory analysis showed that wine aroma degradation is primarily caused by the appearance of a cooked-vegetable odour nuance. The acetaldehyde content of the wines did not vary significantly during the oxidation process, and thereby, cannot be related to the appearance of any of the aroma nuances. Regression data confirm the important role played by eugenol in the woody aromatic nuance, but suggest that important odorants, responsible for the other aromatic nuances, remain unidentified. Some of the compounds analyzed may be used as chemical markers for wine oxidative deterioration. The cooked-vegetable odour nuance can be satisfactorily predicted with quantitative measurements of t-2-nonenal, eugenol, benzaldehyde and furfural. (C) 2002 Elsevier Science Ltd. All rights reserved.