Effect of Fermentation, Storage Sur Lie or Post-Fermentation Thermal Processing on White Riesling (Vitis vinifera L.) Glycoconjugates

Abstract

Four strains of Saccharomyces cerevisiae were evaluated for their influence on White Riesling glycoconju- gates. Fermentation resulted in a decrease in bound glycosides, as estimated by the analysis of glycosyl glucose. The greatest reduction occurred with the Fermiblanc strain, although the maximum difference among yeasts was only 7%. The concentration of bound monoterpene alcohols, oxides, and aromatic alcohols was diminished due to fermentation, although generally similar among yeasts. Following fermentation, the concentration of free terpenes and aromatic alcohols differed slightly among yeasts, but differences were below the sensory thresholds reported for each compound. Post-fermentation thermal processing reduced the glycoconjugates by an average of 33% for all treatments, with the greatest reduction occurring with the VL1 strain. Storing wines for 45 days sur lie lessened the glycoside content uniformly among treatments by 52%.