Forschungs- & Entwicklungsinformationsdienst der Gemeinschaft - CORDIS

At-line methods of cork analysis

Chloroanisole contaminants in cork that give rise to the characteristic "corked” wine taint are largely associated with contamination by 2,4,6,trichlorophenol (TCA). In mature wines there is considerable evidence that TCA contamination arises largely from chlorophenolic contaminants in cork. Chloroanisoles are known to be produced by the methylation of chlorophenols by chemical and microbiological processes on storage. These chemical changes are very slow and it may take many years for the impact of chlorophenol contaminantion to be experienced in the final product.

In the wine industry cork taint has been shown to be a major problem and is a significant contributor to production and sales losses due to contaminated wine. In view of this cork production methods will require significant improvements to production and quality control procedures to enable the production of taint free material that is acceptable in a modern competitive marketplace.

Methods have been developed in Foodsafe to allow the determination of the chlorophenol and chloroanisole content of cork samples. The developed procedures are suitable for the analysis of chlorophenol contaminants in a laboratory location where the use and disposal of small quantities of flammable solvents is not permitted.

Two sample extraction procedures are offered, both compatible with the use of the high sensitivity ELISA procedure developed under Foodsafe:

Extraction method 1: PRESCREENING METHOD FOR THE EXTRACTION OF CHLOROPHENOLIC CONTAMINANTS FROM CORK SAMPLES, in which a large number of cork samples are cut and ground and amalgamated to give an overall screen with respect to chlorophenol levels.

Extraction method 2: QUALITY CONTROL OF CHLOROPHENOLIC CONTAMINANTS IN CORK SAMPLES in which a single cork sample is extracted without ant cutting.

In both cases, samples of cork are extracted using alkaline detergent and purified using steam distillation into dilute sodium carbonate. The pH-adjusted extracts are then tested for chlorophenols using the FOODSAFE- high sensitivity ELISA procedure.

FOODSAFE- high sensitivity ELISA procedure:
This ELISA assay is based on competitive antibody binding between the antigen (PCP) and a synthetic antigen-enzyme conjugate produced by chemically bonding horseradish peroxidase to a tetrachloro-hydroxy-phenyl (HRP-conjugate) moiety. The retained HRP conjugate is determined using the fluorescent substrate Pierce, QuantaBlu (TM) with fluorescence detection.

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Reported by

Cranfield University
MK45 4DT Bedfordshire
United Kingdom
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