Large-scale preparation of β-lactoglobulin A and B by ultrafiltration and ion-exchange chromatography

Purification of beta-lactoglobulin A and B was carried out by ultrafiltration and anion-exchange chromatography under very gentle conditions; temperature and pH did not exceed 50 degrees C and 7.0, respectively, at any step of the process. Fresh. raw milk from cows homozygotic in beta-lactoglobuiin A or B was used. Two batches of beta-lactoglobulin B, 485 and 125 g, and one batch of beta-lactoglobulin A, 460 g, was produced with 96.3, 97.1 and 97.2% protein in dry matter, respectively. By performing ultrafiltration and diafiltration at pH 4 versus near neutral pH products with varying calcium contents were acheived. The products contained very little fat. Electrospray mass spectrometry showed that the products contained a small amount of mono lactosylated beta-lactoglobulin. Dynamic light scattering showed the particle size of 98, 99.8 and 99.8% of the protein in the three preparations to be with a hydrodynamic radius of 3.5 nm, which corresponds to the beta-lactoglobulin monomer. (C) 1998 Elsevier Science Ltd. All rights reserved.