Functional improvement of beta-lactoglobulin by conjugating with alginate lyase-lysate

Bovine beta-lactoglobulin-alginic acid oligosaccharide (beta-LG-ALGO) conjugate was prepared by the Maillard reaction to improve the function of beta-LG. The molar ratio of beta-LG to ALGO in the conjugates was 1:7. The isoelectric point of the conjugate was 4.55, which is lower than that of beta-LG. Fluorescence studies suggested that the conformation around Trp had changed in the conjugate and that the surface of the conjugate was covered with saccharide chain. Structural analyses with monoclonal antibodies indicated that the conformation around Va115-Ile29 (beta-sheet) in the conjugate had changed, while native structure was maintained around Thr125-Lys135 (alpha-helix). By conjugation with ALGO, beta-LG was endowed with high heat stability. The emulsifying activity and the aggregating property of beta-LG was improved in the conjugate.