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

## TL;DR

Cyclodextrins, especially α-cyclodextrin, can help prevent stuck fermentations in winemaking by reducing the toxic effects of medium-chain fatty acids on yeast.

## Contribution

This study introduces α-cyclodextrin as a novel alternative to yeast hulls for mitigating MCFA toxicity in winemaking.

## Key findings

- MCFAs delay yeast growth and cause sluggish or stuck fermentations.
- α-cyclodextrin encapsulates MCFAs and neutralizes their toxic effects on yeast.
- Using α-cyclodextrin is a promising strategy to prevent fermentation issues in enology.

## Abstract

Through their inhibitory effects on yeast metabolism, medium-chain fatty acids (MCFAs) are one of the most frequent causes of stuck and sluggish fermentations (especially white grape must fermentation) in winemaking. A common strategy in winemaking to mitigate or correct the inhibitory effects of medium-chain fatty acids (MCFAs) on alcoholic fermentation is the addition of yeast hulls. In this paper we study α, β and γ-cyclodextrins as alternatives for mitigating the inhibitory effects of MCFAs through their ability to encapsulate non-polar molecules. Our results suggest that α-cyclodextrins encapsulate MCFAs by mitigating the toxic effects on yeast in rich MCFA media. Using α-cyclodextrins may thus be a promising strategy for mitigating the toxic effects of MCFAs and preventing sluggish and stuck fermentations in winemaking due to the presence of these compounds in the fermentation medium.

•Medium-chain fatty acids (MCFAs) caused sluggish and stuck alcoholic fermentation.•MCFAs delayed yeast growth during alcoholic fermentation.•Supplementation with α-cyclodextrin in an MCFA-enriched medium may neutralize the toxic effects of MCFAs.•α-cyclodextrin appears to be a promising strategy for mitigating the toxicity of MCFAs and preventing sluggish and stuck fermentations in enology.

Medium-chain fatty acids (MCFAs) caused sluggish and stuck alcoholic fermentation.

MCFAs delayed yeast growth during alcoholic fermentation.

Supplementation with α-cyclodextrin in an MCFA-enriched medium may neutralize the toxic effects of MCFAs.

α-cyclodextrin appears to be a promising strategy for mitigating the toxicity of MCFAs and preventing sluggish and stuck fermentations in enology.