GC−MS Study of Volatiles of Normal and Microbiologically Attacked Cork from Quercus suber L.

The volatile compounds of cork were studied by gas chromatography and combined gas chromatography?high-resolution mass spectrometry using simultaneous distillation?extraction to prepare the samples. To assess the origin of the volatiles, three different types of samples were analyzed:? ?normal?, attacked by Armillaria mellea, and infested by molds. The study of the volatiles of these different types of corks allowed the identification of the chemical modifications which may occur in cork polymers. The cork attacked by A. mellea showed higher amounts of phenols, vanillin, benzaldehyde, benzyl alcohol, and chlorinated compounds than normal cork; this may indicate lignin degradation. The cork infested by molds contained higher levels of 3-methyl-1-butanol, 1-octen-3-ol, 1-octanol, 2-methylisoborneol, chlorinated compounds, and methyl ketones. These components resulting from microbial metabolism were also present in cork attacked by A. mellea. The use of cork attacked by A. mellea is not recommended in the manufacture of cork stoppers, since these types of cork have volatile compounds likely to cause off-flavors in wine. For the same reason it is important to reduce the likelihood of mold development during the standing period. Keywords: ?Normal? cork; Armillaria mellea; molds; volatile components; musty and moldy odors