The co-inoculation ratio of Hanseniaspora vineae-to-Saccharomyces cerevisiae correlates with aroma metabolic features in wine

Hanseniaspora vineae is a non-Saccharomyces yeast used in winemaking to increase the complexity of wines. However, the fermentation rate in sequential inoculations may be challenging, particularly in industrial winemaking settings. This study aimed to assess how different co-inoculation protocols involving H. vineae and S. cerevisiae affect the fermenting performance and aroma of white and red wines. White and red wines were co-fermented with varying H. vineae-to-S. cerevisiae ratios (67%, 80%, 90%, 95%, and 98%). Results were compared to sequential and pure S. cerevisiae inoculation. Co-inoculation mitigated the inhibitory mechanisms associated with sequential inoculation, resulting in a reduction of 30 days and 6 days of fermentation for white and red wines, respectively. Moreover, the fermentation time in co-inoculation was similar to that of the controls, thereby avoiding the slowdowns typically observed in sequential inoculation. Five yeast-derived metabolic markers, two of which characterizing H. vineae metabolism, were studied to evaluate the processes. In white wines, β-phenylethyl acetate and benzyl alcohol were increased by H. vineae up to 64-fold and sevenfold, respectively, while ethyl hexanoate was fourfold higher in S. cerevisiae. In addition, 2-phenylethanol was up to twofold higher in S. cerevisiae. The results for isoamyl acetate varied depending on the co-inoculation ratio. At 67% and 80%, the H. vineae protocols showed the highest concentration, even exceeding that of S. cerevisiae pure inoculation. All compounds correlated linearly with the H. vineae-to-S. cerevisiae ratio at inoculum. The same trends were observed in red wines, but to a different extent.