Isolation of glycoproteins from bovine milk

Abstract

A process isolates and recovers glycoprotein fractions in dry or solution form. Glycoproteins are recovered from deproteinized whey, preferably micro-filtered to remove large molecules and aggregates. The resulting retentate is then diluted for further processing. The resulting liquid is heated to coagulate whey protein and then cooled sufficiently to precipitate coagulated whey protein. The preparation can then be completed by centrifuging the resulting cooled solution and separating resulting supernatant containing glycoproteins from fat and precipitate. The product glycoprotein concentrate can be dried, such as by freeze drying, or recovered and stored in liquid form. In a preferred aspect, saline is employed to dilute the microfiltered concentrate prior to heating to improve the recovery of a liquid glycoprotein fraction that can be sterilized, such as by autoclaving. In another aspect, glycoprotein free of a majority of glycomacropeptides (GMP) can be recovered by adjusting the solution to alkaline pH and subjecting to ion exchange extraction. Preferred liquid products are stable to autoclaving and free of separation after storage in a sealed container at 20° C. for a period of at least one month.