Use of chitosan for selective removal of beta-lactoglobulin from whey.

A method is described for selective removal of undenatured beta-lactoglobulin from cheese whey based on interactions between whey proteins and chitosan. Whey was previously clarified at pH 4.5 with addition of chitosan (25 mg/100 mL), and selective removal of beta-lactoglobulin was studied in the pH interval 4.6 to 6.5. Addition of chitosan caused selective precipitation of beta-lactoglobulin that increased with pH. The content of beta-lactoglobulin in whey decreased as the amount of chitosan added was increased. At pH 6.2, addition of 1.9 to 3.0 mg/mL of chitosan led to complete removal of beta-lactoglobulin, whereas at least 80% of the rest of whey proteins remained in solution. The production of cheese whey without beta-lactoglobulin could help to expand the applications of dairy by-products in food processing, and to isolate hypoallergenic whey protein concentrates.