Enhancing the aromatic profile and sensory properties of wine via interactions between Zygosaccharomyces bailii and Saccharomycescerevisiae.

Zygosaccharomyces bailii is a non-conventional wine yeast, traditionally recognized for its spoilage potential in food and beverages. However, strain-level variability within this species presents an opportunity to identify efficient, non-spoilage strains with promising applications as wine starter cultures. The aim of this study was to investigate the interaction between indigenous strains of Saccharomyces cerevisiae and Z. bailii used as fermentation starters within the wine environment, emphasizing their impact on the aromatic profile and sensory characteristics of the final product. In an initial fermentation assay, pure and mixed cultures of Z. bailii and two S. cerevisiae strains were separately inoculated, while fermentation kinetics and population dynamics were monitored. Furthermore, in order to evaluate the impact of different inoculation strategies, the most efficient S. cerevisiae strain was selected for a second fermentation assay, where sequential and simultaneous co-inoculations were compared to pure cultures of Z. bailii and S. cerevisiae. Fermentation kinetics, microbial dynamics, and oenological properties were analyzed. The wine's aromatic profile was assessed via Gas Chromatography-Mass Spectrometry (GC-MS), while sensory analysis provided a holistic evaluation of inoculation modality effect. Overall, the mixed cultures of Z. bailii and S. cerevisiae enhanced the fermentation rate and promoted the growth of Z. bailii population, suggesting cooperative behavior. Moreover, Z. bailii revealed interesting oenological properties such as, tolerance to alcohol, fructophilic behavior, ability to consume malic acid, and liberation of varietal thiols. In conclusion, co-inoculation modality proved to be the most effective inoculation strategy, producing wines with enhanced citrus, passion fruit, and floral notes.