New genera of yeasts for over-lees aging of red wine

The osmophilic yeast genera Schizosaccharomyces and Saccharomycodes, and the primary fermentation-phase genera Pichia, were studied for possible use in the over-lees aging of red wines. The molecular architecture and chemical composition shown by the cell walls of these yeasts is quite unusual within the family Saccharomycetaceae. Their kinetics of cell wall polysaccharide release were examined by HPLC-RI molecular exclusion chromatography; two columns were coupled in series to increase the capacity of resolution since these yeasts all show an early elution peak corresponding to the largest polysaccharides. The anthocyanin content was determined by HPLC with photodiode array and mass spectrometry detection (HPLC-PDAD/ESI-MS). During aging over the lees of these yeasts, colour was monitored by UV–VIS spectrophotometry. In order to quantify any anomalies of potential sensorial importance, the change in the profile of the majority volatile compounds was monitored using gas chromatography with flame ionisation detection (GC-FID).