Yeast metabolic activity is sufficient to create a wine like aromatic feature in a synthetic grape must -a sensory-driven approach

Wine is characterised by an underlying aromatic volatile profile, which allows human subjects to easily recognise the product as "wine" by smell alone. Yeast metabolism significantly contributes to wine organoleptic properties, and some yeast metabolism-derived compounds contribute to the vinous character of wine. However, the relative contribution of yeast and grape-derived metabolic compounds to the sensory perception of a product as "wine-like" remains unexamined. This study explores the possibility of creating a wine-like aroma by yeast metabolic activity alone. For this purpose, we fermented a simple synthetic media without any grape-derived aromatic compounds or precursors thereof. Fermentation products were evaluated for the degree of wine-like sensory perception. The synthetic grape juice nitrogen, sterol and fatty acid composition were altered to improve the recognition of this character. Initial fermentations resulted in products that were not recognised as wine-like, but over several reiterations, more wine-like associations were observed, with some products judged as similar to real wine. The data suggest that the wine-like character responsible for the recognition of a product as "wine" is largely the result of the de novo synthesis of aromatic compounds by yeast and does not require the contribution of grape-derived volatile compounds.