Corky off-flavour compounds in cork planks at different storage times before processing. Influence on the quality of the final stoppers.

BACKGROUND: Cork companies store cork planks before processing for a minimum of 6 months to dry up and to stabilize their texture and chemical composition, although many companies extend it up to 12 months. However, there is no information about the influence of this seasoning period on their "corky" off-favours content. For this reason, the main compounds responsible of the "cork taint" of planks stored in the company before processing from 6 to 12 months, and of their corresponding stoppers were investigated.

RESULTS: Four haloanisoles and three halophenols were identified, 2,4,6-trichloroanisole (TCA), 2,3,4,6-tetrachloroanisole (TeCA), pentachloroanisole (PCA), 2,4,6-tribromoanisole (TBA), 2,4,6-trichlorophenol (TCP), 2,3,4,6-tetrachlorophenol (TeCP) and 2,4,6-tribromophenol (TBP). All the planks presented some haloanisole or halophenol after 6 and 9 months of storage, which practically disappeared after a year of storage. These compounds were only detected in the cork stoppers made from planks with 6 and 9 months of storage. Within alkylmethoxypyrazines, 2-methoxy-3,5-dimethylpyrazine (MDMP), 3-isopropyl-2-methoxypyrazine (IPMP) and 3-isobutyl-2-methoxypyrazine (IBMP) were identified. MDMP was detected in a larger number of planks with 6 months of storage and at higher concentrations than IPMP and IBMP. However, MDMP was not detected in the cork stoppers made from planks at 6, 9 and 12 months of storage.

CONCLUSION: A storage time before processing of raw cork planks in the company for 6 months would be sufficient to obtain cork stoppers with low concentrations of corky off-flavour compounds. Although an increase in storage up to 9 or 12 months would result in practically "cork taint" free natural stoppers. This article is protected by copyright. All rights reserved.