Effect of Salt on the Thermal Stability of Storage Proteins from Fababean (Vicia Faba)

The influence of various salts on stability of proteins in a fababean protein isolate were examined using differential scanning calorimetry (DSC) to monitor denaturation temperatures (Td). The ability of some salts to increase Td values, or stabilize the protein, was described as a biphasic linear relationship. The two distinct phases were attributed to two established stabilization mechanisms, electrostatic interaction and preferential hydration. Ranking of salts in terms of ability to stabilize or destabilize fababean proteins followed the lyotropic series for both major structural proteins present in the isolate. In most salt environments responses of the two proteins, legumin and vicilin, were slightly different; these differences were attributed to differences in electrostatic profiles and response to water availability for the two proteins.