Metabolic profiling as a tool for revealing Saccharomyces interactions during wine fermentation

Area of Science:

• Oenology and Viticulture
• Microbiology
• Analytical Chemistry

Background:

• Wine fermentation involves multiple yeast strains, primarily Saccharomyces species.
• The impact of co-fermentation by different Saccharomyces strains on wine flavor remains largely uncharacterized.

Purpose of the Study:

• To investigate how multiple Saccharomyces strains interacting during fermentation influence the profile of aroma compounds in wine.
• To determine if observed differences in mixed-culture fermentations can be replicated by blending wines from monocultures.

Main Methods:

• Metabolic footprinting using gas chromatography-mass spectrometry (GC-MS) to analyze volatile compounds.
• Principal Component Analysis (PCA) to compare metabolic profiles of yeasts in monoculture, mixed culture, and blended wine scenarios.

Main Results:

• Mixed-culture fermentations produced distinct volatile compound profiles compared to monocultures.
• These distinct profiles could not be replicated by simply blending wines from individual yeast monocultures.
• Yeast metabolic interactions, not just the presence of strains, were responsible for the observed differences.

Conclusions:

• Co-fermentation by multiple Saccharomyces strains significantly impacts wine aroma complexity through metabolic interactions.
• Metabolic footprinting offers a novel approach to assess yeast population dynamics and interactions during wine fermentation.
• The contribution of individual yeast strains to volatile production in mixed fermentations is not predictable from monoculture data.