Mannoproteins and Protein Stability: From Yeasts to Commercial Additives

Technical Contents:

The presentation examines mannoproteins as a heterogeneous group of molecules (5-10 kDa to larger sizes) derived from yeast cell walls, composed predominantly of mannose (~90%). Stabilization mechanism: coating of protein particles to prevent aggregation and maintain them in solution. Typical wine concentrations: 100-150 mg/L.

Sources and Applications:

Distinction between mannoproteins produced during fermentation, released during autolysis in lees aging, and commercial mannoproteins extracted enzymatically or through physical processes from purified strains. OIV authorization in 2005 as stabilization additives. Multiple functions: protein and tartrate stability, sensory improvement (softness, roundness), impact on sparkling wine bubbles.

Non-Saccharomyces Yeasts:

Research on Schizosaccharomyces pombe: release of up to 7 times more mannoproteins compared to S. cerevisiae. Study on Starmerella bacillaris in sequential fermentations for production of more stable white wines with greater mannoprotein contribution.

Commercial Products:

Analysis of compositional variability in commercial products: non-standardized composition due to proprietary production processes. Effectiveness in partial stabilization with positive sensory effects, but rarely sufficient for complete stabilization except in wines with low requirements.