A novel approach to the evaluation of hydrophobicity of food proteins

Abstract

Different approaches used in the determination of surface hydrophobicity of proteins based on measurements of their partial heat capacity are discussed. They include the determination of the hydration heat capacity of a protein both in the unfolded and the native state and the determination of the increase in accessible to the solvent non-polar surface at the denaturation. The hydration heat capacity of a protein characterizes its net surface hydrophobicity or hydrophobic-hydrophilic balance. There was evaluated surface hydrophobicity of faba bean legumin and the product of its limited proteolysis with trypsin - legumin-T. It is shown that legumin-T in the native state has a higher hydration heat capacity and, hence, highcr net surfacc hydrophobicity than legumin, whereas hydration heat capacity of both proteins in the unfolded state does not differ significantly. The denaturation of legumin is accompanied by a grcater increase in accessible to the solvent non-polar surface than the denaturation of legumin-T. This differencc predetermines the higher conformational stability of legumin-T at temperatures below 310K compared to legumin.