Quantification of phospholipids classes in human milk.

Phospholipids are integral constituents of the milk fat globule membranes and they play a central role in infants' immune and inflammatory responses. A methodology employing liquid chromatography coupled with evaporative light scattering detector has been optimized and validated to quantify the major phospholipids classes in human milk. Phospholipids were extracted using chloroform and methanol and separated on C18 column. Repeatability, intermediate reproducibility, and recovery values were calculated and a large sample set of human milk analyzed. In human milk, phospholipid classes were quantified at concentrations of 0.6 mg/100 g for phosphatidylinositol; 4.2 mg/100 g for phosphatidylethanolamine, 0.4 mg/100 g for phosphatidylserine, 2.8 mg/100 g for phosphatidylcholine, and 4.6 mg/100 g for sphingomyelin. Their relative standard deviation of repeatability and intermediate reproducibility values ranging between 0.8 and 13.4 % and between 2.4 and 25.7 %, respectively. The recovery values ranged between 67 and 112 %. Finally, the validated method was used to quantify phospholipid classes in human milk collected from 50 volunteers 4 weeks postpartum providing absolute content of these lipids in a relatively large cohort. The average content of total phospholipids was 23.8 mg/100 g that corresponds to an estimated mean intake of 140 mg phospholipids/day in a 4-week old infant when exclusively breast-fed.

Quantification of phospholipids in infant formula and growing up milk by high-performance liquid chromatography with evaporative light scattering detector.

Phospholipids (PLs) are well known for their excellent emulsifier properties and more recently for their biological functions, such as cell signing, brain development, immune function, heart health, and cancer prevention, besides their physiological role in membrane composition. In dairy products, PLs represent 0.2-1% of milk fat. The milk PLs comprise phosphatidylcholine (PC), phosphatidylethanolamine (PE), and sphingomyelin (SPH) as the major compounds; phosphatidylinositol and phosphatidylserine are minor PLs. A new generation of dairy products claiming PL family content, such as SPH, is being produced; therefore, a validated method for quantifying PL families in dairy products is needed. In this study, an HPLC-evaporative light scattering detector method to quantify the most abundant milk PL families, i.e., PC, PE, and SPH, in infant formula and growing up milk was developed and validated.