Tracking the driving forces for the unfolding and folding of kidney bean protein isolates: Revealing mechanisms of dynamic changes in structure and function

Tracking the dynamic changes in the structure of kidney bean protein isolate (KPI) during extreme pH-shifting can reveal the different mechanisms that drive the unfolding and refolding of the protein from a conformational perspective and elucidate the relationship between its structure and function. The secondary and tertiary structures of KPI were analyzed using multispectral techniques. The results showed that acidic-shifting affected the hydrophobic interactions of KPI molecules, whereas alkaline-shifting affected hydrogen bonding and electrostatic interactions of the molecules. Therefore, alkaline-shifting was more likely to affect KPI conformation. SEM revealed that pH-shifting transformed the sheet structure of KPI into spheres and rods; moreover, it improved the surface hydrophobicity, thermal stability, emulsification, foaming, and antioxidant properties of KPI. In summary, each pH-shifting stage disrupts a different intermolecular force, resulting in protein conformational diversity, while structural changes further affect function. Therefore, pH-shifting treatment broadens the applications scope of KPI in the food industry.

Automated summary

Tracking the dynamic changes in kidney bean protein isolate (KPI) structure during extreme pH-shifting reveals mechanisms driving unfolding and refolding from a conformational perspective and its relationship with function. Acidic-shifting affects hydrophobic interactions, while alkaline-shifting affects hydrogen bonding and electrostatic interactions. pH-shifting transforms KPI into spherical and rod-like structures, improving its physical and functional properties. pH-shifting treatment expands the application scope of KPI in the food industry.