Associations between volatile flavour compounds and microbial communities during the fermentation of traditional mould-fermented Sufu

Traditional mould-fermented sufu develops its distinctive flavour through interplay between volatile compound formation and microbial succession, yet the underlying microbial basis remains unclear. This study profiled volatile compounds and microbial dynamics across six fermentation stages (days 1–15) using HS-GC–MS, ROAV analysis, and high-throughput sequencing. Of 105 volatile compounds detected, ROAV identified 13 potential key aroma-active compounds, including isoamyl alcohol, linalool, heptanal, d -limonene, and 2-pentylfuran, with key esters accumulating in later stages. Fungal richness exceeded bacterial richness in early-to-middle stages, and fungal Shannon diversity exceeded bacterial diversity from Day 3 onward. Ascomycota, Thermomyces , and Thermoascus dominated fungal communities, while Proteobacteria and Acinetobacter dominated bacterial communities. Pearson analysis showed Ascomycota, Thermoascus , Thermomyces , Pichia , and Proteobacteria positively correlated with these compounds, whereas Mucoromycota and Firmicutes showed negative associations. These findings suggest potential microbial associations with flavour formation, providing preliminary evidence for flavour regulation and quality improvement of traditional sufu.