Distribution of 2,4,6-Trichloroanisole in cork stoppers

Background

Natural cork stoppers are commonly considered the main source of 2,4,6-trichloroanisole (TCA) in wine. However, little is known about how TCA is spread inside naturally contaminated cork stoppers. In the present work, the TCA distribution of 37 contaminated stoppers was assessed by slicing them into 3 mm discs and performing TCA analysis on each piece. Additionally, the distribution of TCA in artificially contaminated stoppers was investigated, after exposing clean stoppers to a controlled contaminated environment for 48 h.

Results

The results showed that TCA was concentrated either in small sections or distributed along the length of the stoppers. Regarding the artificially contaminated, it was found that TCA was present not only in the outer layer along the stopper length but some was found 6 mm below the surface.

Conclusion

In this study, no specific distribution pattern could represent TCA contamination in cork stoppers. An equal number of stoppers exhibited either a concentrated distribution or spread over the whole stopper. Lenticular channels are proposed to play a role in the dissemination of TCA from the surface to the interior of the stopper, as TCA was detected in the interior of the stopper within 2 h of exposure to an environment contaminated with TCA. However, the orientation of these channels does not contribute to the transportation of TCA to wine as they are perpendicular to the stopper's axis.