Heat-induced denaturation and aggregation of β-lactoglobulin

Abstract

The heat-induced denaturation and aggregation of β-lactoglobulin in water can be quantitatively modeled by analogy with a radical polymerization reaction. The model contains an initiation, a propagation and a termination step and it predicts that linear polymeric aggregates of β-lg monomers will be formed. The β-lg monomers are assumed to be linked together via intermolecular disulphide bonds, which are formed via thiol group/disulphide bond exchange reactions. The decrease in in native β-lg is predicted to follow order 3/2, which is in full agreement with experimental results. The size of the protein polymer particles is predicted to be proportional to the square root of the initial β-lg concentration. The increase in scattered light intensity at the beginning of heating, which is proportional to the product of concentration increase and size of the protein polymer particles, should be proportional to the initial β-lg concentration squared, which is indeed found.