Fermantation
Brettanomyces Detection – Quality Control of Wine
A major problem in red wine production with high economical impact is the appearance of smells and off-flavours caused by Brettanomyces sp yeasts generating volatile phenols during maturation. Unwanted taste components known from enology as ‘bretty’, ‘leather’, ‘ink’, ‘gouache’, ‘horse sweat’ and ‘animal’ cause wine spoilage and reduce wine quality and price (see examplary aromatic profiles of six types of red wine at the following pages, with and without volatile phenoles caused by Brettanomyces spoilage). Up to 50% of red wines in barrels and up to 25% of bottled red wines are contaminated with Brettanomyces sp. (concentration:1 - 10,000 cells/ml).
Brettanomyces spoilage can be prevented by adding sulphur dioxide at an early stage of maturation before Brettanomyces sp. yeasts develop in reasonable quantities. Yeast proliferation reacts in particular sensitive on the presence of sulphur. Anyhow, sulphur dioxide treatment itself significantly influences the wines buquet and reduces sales prices significantly, especially for premium red wines.
Real - Time detection and quantification of brettanomyces yeasts
After finishing of the alcoholic fermentation by Saccharomyces yeast, therefore early, rapid and affordable detection and quantification of Brettanomyces sp. in maturating wine is required to ensure absence of this organism or to initiate sulphur or other treatments. Conventional assays in this field were based on PCR methods and cultivation, leading to prohibitive effective cost per test of up to EUR 100 (PCR) or EUR 35 (cultivation) and to long response times of 7 days(cultivation) or 0.5 to 2 days (PCR).
The CyFlow® Oenolyser and the dedicated Partec OenoYeast™ reagent kit for viability staining developed and manufactured by Partec in close scientific cooperation with the Institut Français de la Vigne et du Vin (IFV) in Beaune, for the first time offers a “real-time” analysis of unwanted Brettanomyces sp.yeasts in microbiological quality control of red wines which according to the oenological measures is highly suitable. Even smallest concentrations of Brettanomyces sp. can be detected and quantified within a few minutes while test cost are reduced to EUR 5, only. The CyFlow® Oenolyser therefore is now replacing conventional methods which have been too expensive and too time consuming in order to prevent wine spoilage by Brettanomces on a wide scale.
CYFLOW® OENOLYSER for sensitive, rapid and affordable detection of Brettanomyces
With the CyFlow® Oenolyser, wine producers profit from improved microbiological quality control and can therefore gain higher sales prices in the market for their products. Spoilage of red wines by even lowest concentrations of Brettanomyces sp. can now be quickly detected and quantified in an easy-to-perform, highly sensitive and affordable “real-time” method, leading to prevention of negative economical impact from the unwanted smell and taste components caused by Brettanomyces yeasts and the treatment of spoiled wines with sulphur.
Wine laboratories offering microbiological quality control as service to vineyards benefit from significantly reduced test cost and much quicker resulting of analysis. Last but not least, the consumer profits from significantly reduced risk of buying spoiled wine, especially in the premium sector.
The CyFlow® Oenolyser is based on the key technology of fluorescence-based flow cytometry which has been introduced by Partec as first manufacturer already in 1969. With flow cytometry, synchronously up to 16 different cell properties and characteristics can be automatically analyzed for several hundred thousands of cells per minute. By employing state-of-the-art components in optics, electronics, fluidics and laser technology, a sensitivity of < 100nm can be realized, especially required for detection and analysis of smallest particles and microorganisms.
PROCESS CONTROL, FERMENTATION FOLLOW-UP AND YEAST CULTURE CONTROL
Advantages and Interests:
Simplicity of the protocol. Easy-to-performand rapid: Only two preparatory steps are required prior to automatic analysis with the CyFlow® Oenolyser -adding the staining reagent and buffer to the wine sample.
Rapidity of the method (15 minutes). Classical enumeration alternatives on Petri dishes take from 2 to 10 incubation days, quantitative PCR about 24 hours.
Real-time information for a winery situation: screening of exposed “cuvées”,contaminated containers, emergency assessment of operation like microbiological wine stabilization (racking off, sulfite oxide treatment, filtration, flashpasteurization, centrifugation…).
