Kinetic parameters for heat-induced denaturation of lactoferrin under different conditions were determined over a temperature range 72-85°C. Denaturation of lactoferrin could be described by first-order reaction kinetics. Lactoferrin is denatured more rapidly in its apo form than in the iron-saturated form. Both apolactoferrin and iron-saturated lactoferrin are more heat-sensitive when treated in milk than in phosphate buffer. Values of change in enthalpy of activation of lactoferrin denaturation are high which indicates that a large number of bonds are broken. The association of lactoferrin with 8-lactoglobulin does not significantly influence the change in enthalpy of activation of lactoferrin denaturation.

beta-Lactoglobulin isolated from milk of cow, sheep, and goat had about 0.5 mol of fatty acids bound per mol of monomer protein. Fatty acids, mainly palmitic and oleic acids, were the major components (about 75% of total lipids). Albumin isolated from the same samples had about 4.5 mol of fatty acids bound per mol of protein. These two proteins were the only whey proteins able to bind labeled fatty acids in vitro. Interaction of beta-lactoglobulin and albumin with insolubilized fatty acids showed some differences, suggesting different structures of the respective fatty acid binding sites.

For heat denaturation of bovine milk immunoglobulins (IgG, IgA and IgM) in the temperature range 62 to 81ЊC, the D values were IgG Ͼ IgA Ͼ IgM at any temperature. The Z values were 6.29, 4.00 and 5.17ЊC for IgG, IgA and IgM, respectively. Heat denaturation of bovine milk immunoglobulins followed a reaction kinetics in the order of nϭ1.5. The highest value for apparent energy of activation was observed for IgA, and the lowest for IgG. Bovine milk immunoglobulins could resist the HTST pasteurization treatment at 72ЊC for 15 sec without affecting their structure.

Whey protein components were hydrolyzed with Corolase 7092'" (peptidases from Aspergillus strains), pepsin and Corolase PP'" (a mixture of pancreatic enzymes), either individually or in combination, in trials to eliminate protein allergenicity. The hydrolysates were characterized by physico-chemical and by immunological techniques using sera from patients allergic to milk proteins. Enzyme specificity rather than degree of hydrolysis or molecular mass distribution of hydrolysates determined the residual antigenicity of the whey proteins. Ultrafiltration was a prerequisite for obtaining hypoallergenic whey protein hydrolysates.

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