| dc.description.abstract | One of the largest problems in the Texas wine industry is a sensory flaw due to methoxypyrazines (MP). A precise method or material for the remediation of excessive levels of MP in finished wine has not been reported. Wine makers, enologist, and research scientist have been experimenting for years to find a material or method that will selectively reduce MP concentrations in wine or bind them into solution reducing aromatic volatility. MP when present in wines in excessively high concentrations occasion flawed wines; even to the extreme of making them unmarketable to be discarded as waste. Winemakers have developed various solutions to this problem allowing some salvageability. Most winemakers review MP changes subjectively, using before and after sensory tests. If sensory perception for the aromatic profiles of MPs in wines does not indicate the presence of MP quantitative analysis may be used to confirm this observation.
The overall objective of this project was a quantitative investigation of the binding capacity of various materials for 3-alkyl-2-methoxypyrazines in model wine.
Several materials currently used as fining agents have previously been reported to reduce the sensory perception of MP in wine. A material screening was conducted for alumina oxide, diatomaceous earth, copper sulfate, activated carbon, Isinglass, Bocksin, bentonite, toasted oak, untoasted oak, Amberlite XAD-4, FXP H0320, fibresol-2, aluminum foil, and polyvinylopolypyrrolidone (PVPP) using GC-MS SPEME on a model wine systems spiked with MP. The various fining agents and alternative materials chosen were found to have reduced MP concentrations in the model wine. For the first study quantitative assessments were recorded before and after treatment.
The second objective of this work was an investigation of the time it takes for the reduction in MP levels to occur. The time involved in fining wines is variable depending on the type of wine, the winemaking method, the fining material used, the condition of the wine, and the winemaker’s decision. The goal of these time trials is to establish the amount of time it takes for fining agents to bind MPs; in order to provide information to aid winemakers in implementing the selected materials into their wine making method. | en |
