Analysis of a milk membrane fraction isolated from whey protein concentrates

Abstract

Examination of a milk membrane fraction from whey protein concentrates (WPC) has shown that components originating from the skim milk membrane (SMM) system were present in lipoprotein complexes with beta-lactoglobulin and alpha-lactalbumin. This membrane fraction contained <3% of the total WPC protein, approx. 40% of the WPC phospholipid and <7% of the WPC triglyceride components. Isopycnic sucrose density-gradient centrifugation showed that the lipoprotein complexes isolated in the membrane fraction covered a broad density range but, in general, were higher in density than SMM lipoproteins and lower in density than the high-density fraction of milk fat globule membrane (MFGM) material. These complexes had apparently formed during processing in a manner similar to complexes between MFGM material and skim milk components observed in pasteurized milks and creams.