Multi-omics integration unveils fungal succession and volatile metabolite dynamics in spontaneous fermentation of Beibinghong icewine: Identifying yeast strains critical for flavor development

The indigenous fungal community plays a crucial role for flavor development in Beibinghong icewine. This study investigated the fungal composition and dynamic succession, along with changes in volatile metabolite. Key yeast species influencing flavor formation were identified. High-throughput sequencing detected 2154 fungal operational taxonomic units (OTUs), with 13 genera exhibiting relative abundances exceeding 1 %. Through culture-dependent methods, 629 strains spanning 13 genera were isolated. A total of 77 flavor compounds were identified, of which 62 showed significant concentration variations (<i>p</i> < 0.05). Correlation network analysis revealed strong positive associations between <i>Saccharomyces</i> and volatile phenols such as 4-ethylguaiacol and eugenol, whereas non-<i>Saccharomyces</i> yeasts like <i>Metschnikowia</i> and <i>Hanseniaspora</i> were significantly linked to γ-lactone production. These findings demonstrate that spontaneous fermentation drives fungal succession and the development of characteristic aroma profiles, providing a foundation for flavor regulation.