Insights into the flavor enhancement mechanism during dried bonito processing: An integrated analysis of flavoromics and untargeted lipidomics.

This study aimed to unravel the flavor enhancement mechanisms during dried bonito processing by focusing on five critical stages. Taste characteristics, key volatile compounds, and the role of differential lipids in flavor development were comprehensively evaluated. Results demonstrated that the progressive accumulation of glutamic acid during processing was the primary driver of significant enhancements in umami taste and richness. Through integrating flavoromics with multivariate statistical analysis, eight key flavor compounds were identified: hexanal and 2-furaldehyde contribute to the characteristic fatty notes; 1-hydroxy-2-methoxybenzene and 2-methoxy-4-methylphenol provide the core smoky aroma; ethyl 2-oxopropanoate and isobutyl 2-butenoate enhance freshness with fruity aromas; while 2-methylpyrazine and furfural impart roasted and caramel-like aromas. The dynamic changes in volatile compounds were influenced by lipid metabolism, Maillard reactions, and the transformation of phenolic compounds, which collectively construct the unique fatty-roasted-smoky composite flavor profile of dried bonito products. Untargeted lipidomics results showed that lipid oxidation, primarily driven by phospholipid degradation and fatty acid oxidation, was a major contributor to flavor formation. Phosphatidylcholine (PC), phosphatidylethanolamine (PE), and triglycerides (TGs) emerged as critical flavor precursors, PC and PE hydrolysis produces lysophospholipids and releases unsaturated fatty acids, which oxidize into characteristic volatile components like hexanal; TGs release free fatty acids through lipolysis, which serve as substrates for Maillard reactions and phenolic transformations. These findings provide novel insights into the mechanisms underlying flavor formation in dried bonito and offer a theoretical foundation for quality control and product optimization in industrial production.