Spatiotemporal evolution of aroma compounds in egg white and yolk of preserved eggs during pickling.

Preserved eggs (PEs) are a traditional Chinese pickled product known for the distinctive flavor. However, the formation mechanisms of such iconic flavor remain unclear. In this study, electronic nose (E-nose), gas chromatography-ion mobility spectrometry (GC-IMS), gas chromatography-mass spectrometry (GC-MS), and metabolomics analysis were performed to investigate the spatiotemporal flavor evolution of preserved eggs during pickling. Temporal patterns were observed in pH changes, protein degradation and oxidation as well as lipid oxidation. A total of 3 key aroma compounds were identified in egg white while 23 were identified in egg yolk, among which 1-octen-3-ol contributed most to the overall flavor. Lipids and amino acids may serve as the main precursors for the formation of key aroma compounds. This is the first study that reveals the spatiotemporal evolution of key aroma compounds in the egg white and yolk of preserved eggs, laying a solid flavor chemistry foundation for targeted flavor control.