Characterization of phospholipid profiles of egg yolks: Newly classified plasmalogens, distribution of polyunsaturated fatty acids, and the effects of dietary enrichment

Egg yolk phospholipids are commercially valuable products that are beneficial to human health. Previous research on phospholipids in egg yolk mainly focuses on phosphatidyl choline (PC), phosphatidyl ethanolamine (PE), and fatty acid compositions, and neglects the esterification position and other bioactive phospholipids. This study found a total of 19 classes of phospholipids and 275 subclasses using lipidomics. The study firstly found that egg yolks were also rich in glucosylceramides, galactosylceramides, lactosylceramides, gangliosides, and plasmalogens with polyunsaturated fatty acids (PUFAs) at the high bioavailable sn-2 position. Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), α-Linolenic acid (ALA), and arachidonic acid (ARA) were esterified at sn-1 position of PC and sn-2 position of PE, phosphatidyl inositol (PI) and phosphatidic acid (PA). Microalgae feeding contributed to the deposition of PUFAs at sn-2 position and increased the contents of plasmalogens. The results provided detail the phospholipid profiles of egg yolk to improve understanding of its nutrition.