Profiling polar lipids in whey protein phospholipid concentrate by LC-HRMS/MS

Bioactive polar lipids in the milk fat globular membrane can be recovered and enriched during whey protein processing into a co-product called whey protein phospholipid concentrate (WPPC). A food-grade solvent successfully extracted polar lipids from powdered dairy products, and lipids can be fractionated under temperature-induced crystallization. This study investigates the specific lipid species present in ethanol extracted lipid residues from commercially available WPPC using a UPLC-Q-TOF-MS/MS lipidomics method. In general, sphingomyelins and phosphatidylcholines were retained in the polar lipid enriched fraction. Sphingomyelin was found to be a rich source of long chain fatty acids. Several glycosphingolipids, glucosyl-, galactosyl-, lactosyl-, and galabiosylceramide, were also detected in WPPC; these species were observed to crystallize away from other polar lipids during fractionation. Correlation analysis supported the claim that majority of polar lipids recovered in a total lipid extract using ethanol were retained in a polar lipid enriched residue after fractional crystallization.