Monitoring Laccase
Related Documents
Harvest Fee Schedule
Technical Bulletins - Monitoring Laccase in Juice and Wine
Close-up of Botrytis sp. spores.
Photo by Ed Hellman, OSU

New Capabilities at ETS

ETS announces the availability of an improved method for measuring laccase activity. The current commercially available laccase assay does not function reliably in the presence of moderate SO2 levels (20-50 mg/L). The new ETS assay is not compromised by these levels of SO2 and enables detection of laccase on incoming juice samples, as well as throughout the wine making process.

Significance of Laccase in wine
Laccase is a fungal enzyme primarily associated with rot on grapes caused by the grape pathogen Botrytis cinerea. Laccase can negatively impact wine by causing premature browning of bottled white wine and color degradation in red wine. This occurs when laccase converts phenolic compounds to quinones, and the quinones polymerize in the presence of oxygen. The polymerized quinones form pigmented compounds associated with laccase-induced browning and discoloration.

Consequences and Applications

 Wines identified as containing laccase should be maintained in a reductive state to minimize browning and discoloration, and should not be blended with wines that do not contain laccase. Early detection of laccase enables winemakers to take appropriate actions to minimize the impact on the final wine product.

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