Preparation of enriched fractions of (α-lactalbumin and β-lactoglobulin from cheese whey using carbon dioxide

A new process for preparing enriched fractions of alpha-lactalbumin (alpha-La) and beta-lactoglobulin (beta-Lg) from whey protein concentrate was developed. To prepare the fractions, solutions containing from 7% (w/w) to 25% (w/w) whey protein concentrate (WPC75) were sparged with carbon dioxide (CO2) in a batch reactor. The effects of pressure, temperature, concentration, and residence time on the distribution of the individual whey proteins in each fraction were investigated. Best results were obtained for 7% (w/w) WPC75 solutions, at reactor fill pressures of 4140 kPa and 5520 kPa, temperature of 64C and reactor residence time of 10 min. Gel electrophoresis of unpurified enriched samples showed that recovery of alpha-La was approximately 55 % and that of beta-Lg was 78%. The resulting fractions have a pH of 6.0 and contain no added salts.