Spent yeast polysaccharides in mixed alcoholic fermentation between Pichia kluyveri, Pichia fermentans and Saccharomyces cerevisiae retarded wine fruity ester hydrolysis

Abstract

Synthetic grape juice was fermented with Pichia fermentans Z9Y-3 and Pichia kluyveri PK-19, along with S. cerevisiae of different antagonistic abilities, to investigate their impact on aroma stability. During 12-month storage, wine was stored for 2 months with lees and for 10 months without lees. Levels of fruity esters and polysaccharides were monitored using gas chromatography (GC)-mass spectrometry and GC-flame ionization detector, respectively, and wine aroma attributes were quantified by trained panelists. Results showed that co-fermentation elevated fruity ester content during fermentation and retarded fruity ester hydrolysis during storage, which increased the intensity of fruity traits, especially in the highly antagonistic group. Spent yeast from co-fermentation released more polysaccharides, which was predominantly composed of 50 % glucose, 30 % galacturonic acid, and 20 % mannose. During storage, the polysaccharide content decreased until it reached equilibrium at 6 months. Pearson analysis revealed that polysaccharide content correlated positively with fruity ester content and profile.