METABOLIC INTERACTIONS OF SACCHAROMYCES CEREVISIAE COCULTURES: A WAY TO EXTEND THE AROMA DIVERSITY OF CHARDONNAY WINE

Abstract

Yeast co-inoculations in winemaking have been investigated in various applications, but most often in the context of modulating the aromatic profiles of wines. Our study aimed to characterize S. cerevisiae interactions and their impact on wine by taking an integrative approach. Three cocultures and corresponding pure cultures of S. cerevisiae were characterized according to their fermentative capacities, the chemical composition and aromatic profile of the associated Chardonnay wines. The various strains studied within the cocultures showed different behaviors regarding their development. More than half of the 67 volatile compounds quantified were modulated by interactions, including 18 relevant wine aroma compounds. The main families affected were higher alcohols and their associated esters, vinyl phenols, and fatty acids. Coculture makes it possible to obtain new aromatic expressions that do not exist in the original pure cultures attributed to yeast interactions. The sensory profile of the wines related to the cocultures differed from the wines associated with the pure cultures. However, they also differed from the blends (50/50 v/v) of post AF wines from pure cultures. Based on the exometabolome, this was confirmed. The cocultures were revealed as not being simple additions of two wines represented by blend, thereby indicating complex interactions. High resolution mass spectrometry allowed to highlight thousands of cocultures biomarkers. Most of these biomarkers belonged to metabolic pathways involved in nitrogen metabolism. The latter is therefore a marker of changes associated with interactions between two strains of S. cerevisiae. Despite of preserved fermentative properties, the described interactions in- duced a modification of the chemical composition and sensory profile of the wines from the cocultures. A comprehensive approach by combining different techniques is essential to understand yeast interactions and describe the consequences on wine.