The analysis of natural cork stoppers in transversal sections as an effective tool to determine the origin of the taint by 2,4,6-trichloroanisole

Abstract

The distribution of several chlorophenols (CPs) and chloroanisoles (CAs), including 2,4,6-trichloroanisole (TCA), the main compound responsible for fungal taint of wines, was analyzed in four independent batches of natural cork stoppers that were dissected into three transversal slices. The contaminants were homogeneously distributed in the slices analyzed. All the stoppers were contaminated with at least one single CP or CA, although most of the corks contained several CPs and CAs. Pentachlorophenol was the more abundant contaminant, detected in 89.2% of the corks analyzed. The analysis of releasable CPs and CAs showed that most of the contaminants present in the stoppers cannot be released into wine. The same compounds were analyzed in a different batch of natural cork stoppers that had been used to close wine bottles in a winery whose facilities were contaminated with CPs and CAs. In this case, the highest amounts of contaminants were accumulated on the heads of the stoppers in contact with the winery environment. Bottled corks were able to efficiently absorb deuterium-labeled TCA (TCA-d 5) and/or deuterium-labeled pentachloroanisole (PCA-d 5) from an artificially tainted wine during 40 months. In this case, most of the TCA-d 5 and PCA-d 5 was located in the basal slices of the closures in direct contact with wine. These data, and also data from other authors, indicate that the distribution in transversal slices of the CPs and CAs contaminating cork stoppers is in direct relationship with the origin of the taint, and therefore that the analysis of cork stoppers by transversal sections could be an effective tool to clarify the origin of the taint.