Multi-omics insights into the formation mechanism of aging quality in white tea (Bai Mudan) during storage: integrating sensory evaluation, volatilomics, metabolomics, and metagenomics

White tea (WT) develops unique aged quality during long-term storage, characterized by progressive changes in sensory properties and chemical composition. However, integrated insights into the sensory, metabolites, and microbial contribution underlying this process remain limited. This study systematically investigated the quality evolution of Bai Mudan tea (a typical WT) over 0 to 11 years of storage using an integrated multi-omics approach. Sensory analysis revealed a flavor transition from fresh (grassy, fruity) to aged (woody, stale) characteristics. Volatilomics identified 72 volatile compounds, with cedrol and isophorone as aged characteristic aroma compounds (rOAV ≥ 1, VIP ≥ 1, p ≤ 0.05). Metabolomics identified 1146 non-metabolites, showing accumulation of fatty acyls and flavonoids, and a decrease in amino acids. Metagenomic sequencing analysis revealed that bacterial communities (mainly Sphingomonas, Pedobacter, Methylobacterium, and Chryseobacterium) dominated during the first 7 years of storage, followed by a potential shift toward a bacterial - fungal synergy pattern in later stages as the abundances of Monascus and Aspergillus increased. KEGG annotation highlighted the roles of carbohydrate metabolism and amino acid metabolism, and flavonoid biosynthesis was activated during storage. Multi-omics correlation networks demonstrated that fungi positively regulated volatile flavors, while bacteria may be involved in taste balance. Monascus, Sphingomonas, Sphingobium, and Novosphingobium were identified as core functional taxa that may contribute to WT quality formation during storage through aged flavor synthesis, flavonoid accumulation, and lipid degradation. In conclusion, this study provides a multi-dimensional scientific basis for a comprehensive understanding of the formation mechanism of aged quality in white tea during storage.