Interfacial and foaming properties of sulfydryl-modified bovine β-lactoglobulin

The effects of a control blocking of free cystein by N-ethylmaleimide on the interfacial behavior (kinetics of adsorption at the air/water interface, rheology of the interfacial layer) as well as on the foaming properties (density, stability) of β-lactoglobulin were investigated. Compared to native β-lactoglobulin (unmodified β-lactoglobulin), sulfydryl-modified β-lactoglobulin exhibited higher surface hydrophobicity, adsorbed faster at the air/water interface, had the capability to develop rapidly an interfacial layer with high shear elastic constant but exhibited a considerably lower shear elastic constant plateau value. Moreover, sulfydryl-modified β-lactoglobulin exhibited better foaming properties especially regarding the short-term foam stability suggesting that the initial rheology of the interfacial film is at least as much important for the general mechanism of foam stabilization as the potential viscoelasticity the interfacial film could reach on aging.

The kinetic of protein adsorption and the initial viscoelasticity of the interfacial film is more important than the viscoelasticity the interfacial film can reached on aging for explaining the stability of native and sulfydryl-modified β-lactoglobulin foams.Figure optionsDownload as PowerPoint slide