Integrated microbial-metabolomic analysis reveals how fermentation contributes to the unique flavor of African...

Post-harvest fermentation is a decisive stage in shaping the flavor complexity of Arabica coffee. In this study, we mapped for the first time the microbial-driven flavor metabolic network underlying the fermentation of high-quality African coffee, using a combined metabolomic, meta-barcoding, and metagenomic approach applied to samples from Chimanimani National Park, Mozambique. Over 72 h of spontaneous fermentation, chemical analyses revealed rapid sucrose hydrolysis, lactic acid accumulation, and the formation of 74 volatile compounds. These transformations were driven by a previously unreported core microbiome (Leuconostoc-Hanseniaspora-Galactomyces axis), whose functional repertoire (1791 genes) highlighted the Ehrlich pathway and ester biosynthesis as central flavor routes. Among the volatiles formed, linalool, phenylethyl alcohol, and ethyl acetate were most abundant, emerging as predictive drivers of the floral and fruity notes identified in the resulting high-quality coffee beverage (score 87.25 ± 0.25). This study underscores microbial terroir as a key factor adding value to emerging African origins.