Impact of Aspergillus cristatus on microbial community and flavor profile of fermented white tea

This study systematically investigated the impact of Aspergillus cristatus inoculation on quality of white tea (WT) using multi-omics approach. Integrating metagenomics with gas chromatography-mass spectrometry (GC-MS) analysis, this study assessed its effects on microbial community structure, functional gene expression, and volatile flavor profile. Metagenomics revealed A. cristatus significantly reshaped the microbial ecosystem to be the dominant fungus. Functional annotation showed it enhanced the abundance of energy production and conversion genes, while concurrently reducing antibiotic resistance genes (ARGs) and virulence factor genes (VFGs). GC-MS identified 205 differential volatile compounds; fermentation increased esters, ketones, and heterocyclics, and decreased acids and aldehydes. Relative odor activity value (rOAV) analysis identified key aroma compounds, benzaldehyde, ethyl 2-methylbutanoate, and 1-octen-3-ol, imparting almond, fruity, and mushroom notes. A strong positive correlation was found between A. cristatus and key aromas. This work elucidates the mechanistic role of A. cristatus in improving FWT quality through microbiome-flavor metabolome correlations. • Multi-omics reveals how Aspergillus cristatus shapes white tea fermentation. • It dominated the microbiome and enhanced microbial energy metabolism genes. • Antibiotic resistance genes and virulence factor genes were significantly reduced. • Fermentation boosted esters and ketones, and lowered acids and aldehydes. • Key almond, fruity, mushroom aromas strongly correlated with Aspergillus cristatus.