Cyclodextrins improve grape must fermentability through their detoxifying effect on medium-chain fatty acids

Area of Science:

• Enology
• Fermentation Science
• Food Chemistry

Background:

• Medium-chain fatty acids (MCFAs) are primary culprits behind stuck and sluggish fermentations in winemaking, particularly affecting white grape must.
• Current mitigation strategies often involve adding yeast hulls to counteract the inhibitory effects of MCFAs on yeast metabolism.

Purpose of the Study:

• To investigate alpha, beta, and gamma-cyclodextrins as novel alternatives for mitigating MCFAs' inhibitory effects.
• To evaluate the potential of cyclodextrins to encapsulate non-polar molecules like MCFAs, thereby reducing their toxicity to yeast.

Main Methods:

• Studied the efficacy of alpha, beta, and gamma-cyclodextrins in a winemaking context.
• Assessed the encapsulation capabilities of cyclodextrins towards medium-chain fatty acids.
• Evaluated the impact of cyclodextrin treatment on yeast metabolism in the presence of MCFAs.

Main Results:

• Alpha-cyclodextrins demonstrated significant ability to encapsulate MCFAs.
• Encapsulation by alpha-cyclodextrins effectively mitigated the toxic effects of MCFAs on yeast in high-MCFA concentration media.
• Yeast metabolism was less inhibited in the presence of alpha-cyclodextrins and MCFAs.

Conclusions:

• Alpha-cyclodextrins represent a promising strategy for preventing sluggish and stuck fermentations caused by MCFAs in winemaking.
• The encapsulation mechanism of alpha-cyclodextrins offers a viable alternative to traditional methods for managing MCFAs during fermentation.