LARGE-SCALE PREPARATION OF BETA-LACTOGLOBULIN-A AND BETA-LACTOGLOBULIN-B BY ULTRAFILTRATION AND ION-EXCHANGE CHROMATOGRAPHY

Purification of beta-lactoglobulin A and B was carried out by ultrafil tration 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 p roduced with 96.3, 97.1 and 97.2% protein in dry matter, respectively. By performing ultrafiltration and diafiltration at pH 4 versus near n eutral pH products with varying calcium contents were acheived. The pr oducts contained very little fat. Electrospray mass spectrometry showe d that the products contained a small amount of mono lactosylated beta -lactoglobulin. Dynamic light scattering showed the particle size of 9 8, 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-lactogl obulin monomer. (C) 1998 Elsevier Science Ltd. All rights reserved.