Continuous centrifugal separation of selectively precipitated α-lactalbumin

The whey proteins α-lactalbumin (α-la) and β-lactoglobulin (β-lg) are valuable proteins for various food, nutraceutical, and medical applications. Their fractionation is, however, still a challenging task on industrial scale. This study describes a novel separation approach using selective thermal precipitation of α-la under acidic conditions, followed by high-throughput continuous centrifugation. The obtained α-la enriched sediment presented pseudoplastic flow behaviour with strong dependency on dry matter. As the sediment still contained residues of soluble β-lg and buffer salts, two steps of reslurry washing were performed. Along the three centrifugation steps, a slight susceptibility to particle fragmentation was recognised, however, separation efficiency was rarely impaired by it. Finally, two high purity protein fractions were obtained, the supernatant contained 99.7% pure and native β-lg, while the washed α-la sediment fraction was 99.4% free of β-lg.