Volatile flavoromics and metabolomics reveal quality evolution mechanism of Zhenghe white peony tea during storage.

Abstract

Long-term storage (aging) is considered a crucial process for improving white tea quality, yet insights into the quality formation of Zhenghe white peony tea (WPT) during storage remain insufficient. This study systematically investigates the metabolite-driven quality evolution of WPT stored for 0-12 years. Newly produced WPT was characterized by high levels of amino acids, catechins, and volatile aldehydes, ketones and alcohols contributing to umami-sweet taste and grassy-fruity aroma, while cedrol, 3-methylbutanoic acid, and total flavonoids increased with storage, potentially promoting mellow taste and aged flavor. Metabolomics identified 2522 metabolites, predominantly flavonoids, amino acids, and peptides. Storage years 4, 8, and 10 were identified as critical periods for WPT quality transformation. Notably, while proanthocyanidins decreased during storage, functional flavonoids (e.g., astilbin, hesperetin glucuronides) and specific peptides, particularly those rich in glutamate, histidine, proline, and tyrosine residues, were enriched. Furthermore, metabolic pathway enrichment analysis highlighted glycerophospholipid metabolism and phenylalanine biosynthesis as key pathways potentially involved in the flavor development and quality formation of WPT during long-term storage. Finally, the transformation networks of key flavor-associated and non-volatile metabolites during storage were integrated to provide scientific insights into the quality evolution mechanism of Zhenghe WPT.