Extraction of phospholipids from beta-serum using switchable solvents and solid-phase extraction

We report the extraction of milk phospholipids (MPLs) from beta-serum with a tertiary amine (N-N dimethylcyclohexylamine, CyNMe2). The extraction time (3, 10, and 18 h), temperature (25, 40, and 60 degrees C), and sample-to-solvent ratio (1/3, 1/10, and 1/18 v/v) were evaluated according to a factorial design. The extracted lipids were fractionated with solid-phase extraction and quantified by HPLC-CAD. Extraction conducted at 60 degrees C yielded values of 14.86 +/- 2.95%, 69.79 +/- 3.19%, 79.39 +/- 5.55% after 3, 10, and 18 h and a ratio of 1/18 (w/w). Microstructure images showed significant damage to the solid matrix that released the inner MPLs into the aqueous medium. The highest extraction yields of MPLs (79.39 +/- 5.55%) were obtained after 18 h of extraction at 60 degrees C and a sample-to-solvent ratio of 18 (w/w). The recovered fraction was made of phosphatidylinositol (similar to 41%), phosphatidylserine (similar to 6%), phosphatidylethanolamine (similar to 34%), phosphatidylcholine (similar to 9%), and sphingomyelin (similar to 8%). This work outlines different extraction conditions for recovering MPLs from beta-serum, a dairy byproduct.