Must protection, sulfites versus bioprotection: A metabolomic study

Area of Science:

• Enology
• Wine Chemistry
• Microbiology

Background:

• Reducing chemical inputs like sulfites is a key challenge in the wine industry.
• Bioprotection using non-Saccharomyces yeasts offers an alternative to sulfites for preventing microbial spoilage.
• The impact of replacing sulfites with bioprotection on final wine characteristics requires further investigation.

Purpose of the Study:

• To characterize the impact of substituting sulfites with bioprotection on Chardonnay wine.
• To compare the effects of sulfite treatment versus bioprotection on wine's physico-chemical and metabolic profiles.
• To provide insights into the consequences of sulfite reduction in winemaking.

Main Methods:

• An integrative approach was employed to analyze Chardonnay wine.
• Physico-chemical analyses were conducted to assess oenological parameters.
• Phenolic compound analysis and untargeted metabolomic analyses were performed.
• Sensory profiling was used to evaluate the impact on wine's organoleptic properties.

Main Results:

• Physico-chemical analyses showed no significant differences in classical oenological parameters between sulfite and bioprotection treatments.
• Bioprotection offered less protection against oxidation compared to sulfites, as indicated by phenolic compound analysis.
• Metabolomic analyses revealed substantial changes in wine composition, particularly in nitrogen-containing compounds and antioxidant compounds like glutathione and melatonin.
• Despite chemical differences, sensory profiles of wines were not significantly impacted by the must treatment.

Conclusions:

• Substituting sulfites with bioprotection significantly alters Chardonnay wine's chemical composition and antioxidant capacity.
• Bioprotection impacts yeast metabolism, affecting nitrogen-containing compounds and the production of key antioxidants.
• The study highlights that while chemical profiles change, the sensory experience of wine may remain consistent, offering valuable insights for sulfite reduction strategies.