Multi-omics combined with simulated fermentation model for elucidation of variation patterns of lipids and volatiles and its mechanism during black tea fermentation

458 lipids and 59 volatiles in black tea fermentation were analyzed by multi-omics. • 120 lipids and 27 FADVs were predominantly altered during black tea fermentation. • C18:2, C18:3-glycerophospholipids and glycolipids were potential aroma precursors. • Both non-enzyme auto-oxidation and enzyme oxidation formed FADVs in fermentation. • Simulated fermentation using crude enzyme and FA 18:2 yielded 9 FADVs with OAV > 1. Lipid metabolism and fatty acid-derived volatiles (FADVs) are crucial in black tea aroma formation. Herein, dynamic variations of 458 lipids and 59 volatiles during black tea fermentation were investigated by multi-omics using UHPLC-Q-Exactive/MS and GC–MS. 120 lipids and 27 FADVs were predominantly altered during fermentation. Glycerophospholipids and glycoglycerolipids harboring 18:2 and 18:3 fatty acyls were highlighted as potential aromatic precursors. Model experiments using linoleic acid revealed firstly that both non-enzyme auto-oxidation and enzyme oxidation participated in FADVs formation. 28 FADVs were generated at an abundance of 156.01 μg/L by non-enzyme oxidation. Whereas, 32 FADVs with an abundance of 215.01 μg/L were produced in simulated fermentation system containing crude enzyme, covering fatty aldehydes, esters, ketones, alcohols, furans, etc. Specifically, 9 FADVs exhibited odor activity value >1 in simulated fermentation, e.g., hexanal, 2-pentanone, heptanal, 2-pentylfuran, mainly imparting fresh, floral, fruity notes. This study provides novel insights into black tea aroma formation. Download: Download high-res image (290KB) Download: Download full-size image