Pre-fermentative supplementation of fatty acids alters the metabolic activity of wine yeasts

Grape juice contains over a thousand metabolites in a wide range of concentrations. Many metabolites – including major sugars, carboxylic acids and amino acids – have been well-studied. However, no comprehensive study has been done on the lipid and fatty acid composition of juices from different grape varieties, despite the important role fatty acids have been shown to play in wine yeast metabolism.

A recent study involving Plant & Food Research scientists looked at the effects of individual pre-fermentative supplementation of five different fatty acids on two commonly-used wine yeast strains during Sauvignon Blanc fermentation. The study used a metabolomics approach to determine different primary (sugars, sugar alcohols, amino, organic and fatty acids) and secondary (volatile) metabolites.

The study concluded that global metabolite profiling of wines by Gas chromatography–mass spectrometry (GC-MS) is a useful approach in determining metabolic changes of wine yeasts during fermentation and that the combination of primary and secondary metabolite data provides new insights on wine yeast metabolism. 

The study also found that pre-fermentative supplementation of different fatty acids influenced the growth and metabolism of wine yeasts in different ways. This suggests that when deciding what yeast strain to use for winemaking it’s important to consider the overall grape juice composition, including lipids and fatty acids. 

Given that the increase or decrease of particular fatty acids in the grape juice may be used to improve the aroma bouquet or to reduce the production of undesired characters in wine, the results of this study are relevant for the wine industry.

The funding for this project was provided by New Zealand Winegrowers Inc. and The New Zealand Institute for Plant & Food Research Limited. 

Journal Reference: 

Pinu, F, Villas-Boas, S, Martin, D 2019 Pre-fermentative supplementation of fatty acids alters the metabolic activity of wine yeasts, Food Research International, Vol 121, pp 835-844. https://doi.org/10.1016/j.foodres.2019.01.005