Insight into the dynamic metabolic transformations and flavor characteristics during solid-state fermentation of Huangjinya dark tea by Eurotium cristatum PW-1

A novel Huangjinya dark tea was developed via Eurotium cristatum PW-1 fermentation. • Dynamic flavor shifts were identified throughout the dark tea fermentation process. • Significant metabolic transformations occurred at stage D9, shaping dark tea quality. • Pearson correlation and molecular docking analyses unveiled key taste compounds. Motivated by the escalating prevalence of high-end dark tea products, exploration into novel tea cultivars and optimized fermentation methodologies has seen a substantial upsurge. Here, we report the first systematic application of Eurotium cristatum PW-1 fermentation to the albino tea cultivar Camellia sinensis cv. Huangjinya for dark tea production, with a core focus on delineating the quality profile of this novel Huangjinya dark tea product. We systematically delineated temporal dynamic changes in metabolite profiles and flavor characteristics throughout the entire fermentation cycle. Day 9 of fermentation (D9) was recognized as the crucial quality inflection point for the product, characterized by significant metabolite disparities, a marked elevation in theabrownins, and concomitant reductions in total phenols, flavonoids, and amino acids. Volatile compound and taste analyses suggested that E. cristatum PW-1 fermentation may contribute to a distinctive chemical profile with compounds associated with floral, sweet, and minty aromas, alongside umami and mildly astringent taste attributes. Correlation analysis and molecular docking further linked key differential metabolites to these flavor attributes, offering preliminary insights into the molecular features that may shape the unique sensory profile of E. cristatum PW-1-fermented Huangjinya dark tea. Download: Download high-res image (361KB) Download: Download full-size image