Dairy Lecithin from Cheese Whey Fat Globule Membrane: Its Extraction, Composition, Oxidative Stability, and Emulsifying Properties

An ethanol extraction method was studied for the production of dairy lecithin from cheese whey-derived milk fat globule membrane (MFGM). A two-step ethanol extraction of MFGM involving first extraction at pH 6.5, followed by second extraction at pH 4.5 yielded 17.2 % lipids. The extracted material contained about 90 % lipids, 4.5 % ash, and 1.2 % moisture. The phospholipid content of the ethanol extract was 31 % and the remainder was mostly neutral lipids. The phospholipid fraction contained 34 % sphingomyelin, 31 % phosphatidylcholine, 27 % phosphatidylethanolamine, 4.6 % phosphatidylserine, and 3.1 % phosphatidylinositol. Since the ethanol extract contained 31 % phospholipids, it can be technically termed as dairy lecithin. The major fatty acid components were linoleic acid (5.1 %), myristic acid (8.3 %), palmitic acid (29 %), stearic acid (14 %), oleic acid (25 %), and the remainder was minor fatty acids with chain length ranging from C4:0 to C22:5. The dairy lecithin was semi-solid at room temperature and exhibited a major phase transition at about 35 °C. Owing to its low polyunsaturated fatty acid content, the dairy lecithin was reasonably stable to oxidation as measured by the rate and extent of hexanal production during 35 days of storage at 45 °C. Oil-in-water emulsions made with less than 2 % dairy lecithin (relative to the total emulsion weight) were unstable; however, emulsions made with greater than 4 % dairy lecithin were very stable for more than 60 days at room temperature. The results of this study indicated that a highly functional dairy lecithin can be commercially produced using cheese whey-derived MFGM as the starting material.