Whey proteins limited proteolysis

Huang, X.L., Catignani, G.L., and Swaisgood, H.E. 1999. Modification of the rheological properties of whey protein isolates by limited proteolysis. Nahrung 43, 79-85. 

Lieske, B. Konrad, G. Physico-chemical and functional properties of whey protein as affected by limited papain proteolysis and selective ultrafiltration. Int. Dairy J. 1996, 6(1), 13-31. 

Although the volume of foam was increased by limited proteolysis, the stabilities of the foams, defined as the time required for one half of the weight of the foam to drain from the foam as free liquid, were greatly decreased by this same limited proteolysis. Presumably the increased initial polypeptide concentration in the hydrolysates favors more air incorporation. However, the polypeptides apparently do not have the surface activity required to give a stable foam. The decrease in foam stability becomes evident in the first 30 min of the enzyme reaction. Further hydrolysis results in peptides which lack the ability to stabilize the air cells of the foam. Thus a limited hydrolysis may be advantageous for utilizing whey proteins in foams since the specific volumes of the foams were increased 25% by such treatment. The decrease in foam stability which results from limited hydrolysis can be compensated for by adding stabilizers such as carboxymethyl cellulose (19,27). 

---