Aroma modulation of pomegranate wine by non-Saccharomyces yeast: Insights from GC-IMS, GC-MS, and multivariate statistical analysis

This study investigated the role of non- Saccharomyces yeasts in modulating the aroma complexity of pomegranate wine, with a particular focus on sequential fermentation with Saccharomyces cerevisiae . Torulaspora quercuum X24-4 and Torulaspora delbrueckii X28-10 were employed in both pure and sequential fermentations. T. delbrueckii exhibited robust fermentative performance. Gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS) identified a total of 62 and 80 volatile compounds across all samples, respectively, with esters as the predominant class. Key differential volatiles across the different fermentation strategies, including ethyl hexanoate and 3-methyl-1-butanol, were identified by partial least squares discriminant analysis (PLS-DA) in both GC-MS and GC-IMS analyses. In addition, several high-odor-activity-value (OAV) compounds, including ethyl octanoate and β -damascenone, reached their highest levels in wines produced by sequential inoculation of T. delbrueckii and S. cerevisiae ( Td - Sc ). Sensory evaluation confirmed that wines produced with Td - Sc achieved the highest fruity and floral scores, consistent with the volatile profiles. Partial least squares regression (PLSR) analyses further revealed strong correlations between ester/alcohol accumulation and floral aroma perception. In conclusion, sequential fermentation with T. delbrueckii and S. cerevisiae synergistically enhanced the volatile composition and sensory quality of pomegranate wine, demonstrating the practical potential of mixed-culture fermentations for developing distinctive and aroma-rich pomegranate beverages.