Lipidome analysis reveals the salting-induced lipid liberation in duck egg yolk

Salted duck eggs are a traditional preserved egg product produced via a curing process. During the salting process, approximately 50% to 60% of the lipids in the duck egg yolk transform from a bound state to a free state, playing a critical role in flavor and texture development. However, the specific lipid profiles released from lipoproteins during this process remain unclear. This study employed quantitative lipidomics to systematically compare free and bound lipids in salted egg yolks. A total of 1297 lipid molecules were identified, including 350 triglycerides, 254 ceramides, and 122 phosphatidylcholines. The analysis revealed that free lipids were enriched in glycerolipids and prenol lipids, whereas bound lipids were dominated by glycerophospholipids. Glycerophospholipids remained stably bound to lipoproteins, contributing to the maintenance of the gel network structure of the yolk, while the release of glycerolipids contributed to the characteristic oily and grainy texture. This study elucidates the molecular mechanisms underlying the quality formation of preserved egg yolks and provides a theoretical foundation for the processing and quality enhancement of traditional egg products.