Selective extraction of native β-lactoglobulin from whey

Abstract

A method is proposed for the selective extraction from whey of β-lactoglobulin, the major allergenic component of cow milk. It represents an application of subunit exchange chromatography, which exploits the tendency of β-lactoglobulin to undergo reversible association—dissociation equilibria at slightly acidic pH values. Immobilized A and B β-lactoglobulin subunits are capable of interacting in a highly specific and reversible way with the soluble protein and can be used to extract A and B β-lactoglobulin from whey under conditions that favour subunit association. The soluble protein retained by the immobilized protein can be recovered under conditions that promote dissociation into subunits. The subunit exchange column, if coupled to an anion-exchange column, allows the complete deproteinization of whey. All the whey proteins are extracted in their native form and are of high purity; their functional properties are intact even after lyophilization. This important characteristic and the possibility of removing β-lactoglobulin selectively render the proposed method a potentially powerful tool in the processing of whey to produce human food products for specific end-uses such as hypoallergenic milk formulas.