Quantitative Analysis of Dairy Phospholipids by ³¹P NMR

Abstract

Abstract 31 P NMR analysis of samples prepared in a sodium cholate detergent system was assessed as a method for the quantitative measurement of dairy phospholipids. Major phospholipid (PL) classes measured included: phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), sphingomyelin (SM) and dihydrosphingomyelin (DHSM). The 31 P NMR method was validated by comparison with a quantitative two‐dimensional thin‐layer chromatography (2D‐TLC) technique. The 2D‐TLC system was more sensitive, able to detect some minor compounds not observed by 31 P NMR. However, 31 P NMR is more suited to routine analysis, with sample analysis taking 36 min. The method was also more versatile and sample analysis was possible on high phospholipid containing materials without prior lipid extraction (e.g. buttermilk protein concentrate, beta serum liquid).