Interaction properties of beta-lactoglobulin and benzaldehyde and effect on foaming properties of beta-lactoglobulin

Quenching of tryptophan fluorescence intensity and absence of covalently bo und fluorescent products in beta-lactoglobulin solutions containing bt benz aldehyde at various molar ratios, indicated that beta-lactoglobulin monomer and benzaldehyde might associate through a non covalent binding mechanism. The affinity constant determined from perturbation of tryptophan spectrofl uorescence spectra was close to that previously observed by other authors f or retinol binding to beta-lactoglobulin. In parallel foaming properties of solutions of beta-lactoglobulin alone or in mixture with benzaldehyde were investigated through a conductimetric method. It was observed that additio n of benzaldehyde to beta-lactoglobulin led to enhanced foaming properties in comparison with beta-lactoglobulin alone. These results were discussed i n terms of formation of non covalently bound complexes with a specific surf ace activy. (C) 2000 Elsevier Science Ltd. All rights reserved.