QUANTIFICATION OF LIPIDS IN LOW FAT-CONTENT DAIRY-PRODUCTS WITH LIGHT-SCATTERING DETECTOR

The four major lipid classes: triacylglycerols (TG); phosphatidylethanolamines (PE); phosphatidylcholines (PC); and sphingomyelins (SM), were quantified in skim milk, whey and buttermilk by liquid chromatography (HPLC) with a light-scattering-detector (LSD) on a Lichrospher Si 60 column using two elution gradients. Calibrations were performed with triolein, purified milk TG and commercial standards for PE, PC and SM. LSD's response factors in the linear range of calibration were in the ratio 1, 2 and 3 for SM, glycerophospholipids and TG respectively. They were unrelated with fatty acid composition in TG and glycerophospholipid classes, but varied widely depending on SM sources.