Toward Separating Alpha-lactalbumin and Beta-lactoglobulin Proteins from Whey through Cation-exchange Adsorption

This paper describes the cation‐exchange adsorption of the two major whey proteins, alpha‐lactalbumin (ALA) and beta‐lactoglobulin (BLG) with the purpose of establishing a process for isolating them from cow's milk whey. The single‐ and two‐component adsorption of 1.5 mg/ml ALA and 3 mg/ml BLG to the cation‐exchanger SP Sepharose FF at 20° C using 0.1 M acetate buffer of pH 3.7 was studied. Langmuir isotherm parameters were determined for the pure proteins. In two‐component systems, BLG breakthrough curve exhibited an overshoot phenomenon that gave evidence for the presence of a competitive adsorption between the two proteins. Complete separation occurred and it was possible to obtain each of the two proteins in a pure form. The process was then applied to a whey concentrate mixture where incomplete separation took place. However, BLG was produced with 95% purity and a recovery of 80%, while ALA showed an 84% recovery with low purity.