Heat denaturation of whey proteins. Comparative studies with physical and immunological methods

Samples of a single batch of milk or whey were subjected to various heat treatment and the rates of denaturation of whey proteins (beta-lactoglobulin and alpha-lactalbumin) evaluated by both immunological (radial immunodiffusion using specific antisera) and physical methods (G 100 filtration chromatography and polyacrylamide gel electrophoresis) in order to assess the utility and limitation of these techniques, and to clarify some conflicting resulted previously published. G 100 chromatography and radial immunodiffusion give very good results but the latter is very less time consumming and more quantitative. Polyacrylamide gel electrophoresis must be discarded for quantitative purpose since beta-lactoglobulin B peak is heavily contaminated by polymers of beta-lactoglobulin A, and alpha-lactalbumin peak by polymers of beta-lactoglobulin A and B.