Tracking the driving forces for the unfolding and folding of kidney bean protein isolates: Revealing mechanisms of dynamic changes in structure and function. (15th February 2023)

• Record Type: Journal Article
• Authors: Yan, Xinyue; Jia, Yijia; Man, Hui; Sun, Shiyan; Huang, Yuyang; Qi, Baokun; Li, Yang
• Is Part Of: Food chemistry. Volume 402(2023)
• Publication Date: 2023-02-15
• Subjects: Kidney bean protein isolate -- pH-shifting -- Driving force -- Dynamic changes -- Spatial conformation -- Functional properties; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2022.134230
• Languages: English
• ISSNs: 0308-8146

Abstract

Graphical abstract: Highlights: The pH-shifting is irreversible, causes KPI depolymerization and rearrangement. Alkaline-shifting disrupts hydrogen bonds and electrostatic interactions of KPI. Acidic-shifting disrupts intermolecular hydrophobic interactions of KPI. Both acidic- and alkaline-shifting improve structures and functionalities of KPI. Abstract: 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.