Chromatographic fractionation of α-lactalbumin and β-lactoglobulin with polystyrenic strongly basic anion exchange resins

Abstract

Adsorption characteristics of α-lactalbumin (α-La) and β-lactoglobulin (β-Lg) onto 11 strongly basic anion exchange resins were evaluated by contacting the resins columnwise with sweet whey (pH 6.5), from which lipoproteins and caseinomacropeptides had been largely removed. The resins were based on a polystyrene-divinylbenzene copolymer matrix. Two of the resins were gel-type, the rest were macroporous. The adsorption capacity of the gel-type resins was inferior compared to macroporous resins, of which two had a β-Lg adsorption capacity large enough to enable protein fractionation. Significant fractionation was obtained only with Diaion HPA 75 (α-La:β-Lg = 1.9, when 9 and 82% of α-La and β-Lg were adsorbed, respectively). Optimum fractionation conditions (pH 6-7, β-Lg load of 16-20 mg/cm3 resin, degree of demineralization 0-50) were determined by batch experiments with Diaion HPA 75. Within these conditions, α-La:β-Lg (2.0-2.2) with 75-80% recovery of a-La was obtained. ©1996 Academic Press Limited.