Influence of glycosylation on foaming properties of bovine caseinomacropeptide

Bovine caseinomacropeptide (CMP) fractions, both glycosylated (gCMP) and non-glycosylated (aCMP), were studied in detail for their foaming properties. The aCMP-stabilised foams showed significantly higher foam rigidity and stability than foams stabilised with gCMP, whereas both fractions yielded a high foaming ability with overruns of around 600%. The gCMP-stabilised foams, in particular, were considerably influenced by pH and showed reduced foaming properties above the pI, but superior properties at strong acidic pH below the pI. This influence was less significant for aCMP. An increase in ionic strength did not appear to influence either fraction. The combination of electrical, steric and hydrophilic barriers caused by the glycosylation of gCMP appears not to allow an ordered adsorption at the air/water interface, whereas aCMP can build a stable network at the surface.