Evolution of physicochemical and antioxidant properties of whey protein isolate during fibrillization process.

Whey protein isolate (WPI) fibrils have great potential for applications in future food manufacture due to their improved properties. However, the evolution of their properties during fibrillization is still not fully understood. Here, we investigate variational characteristics of WPI fibrils during formation process. WPI fibrils with a semiflexible and linear structure were formed and showed high aspect ratio after heat treatment. The conversion, fluorescence intensity and isoelectric point of WPI were increased with heating time. Moreover, the antioxidant activity of WPI was improved after fibrillization and was dependent on heating time. This could be attributed to the structure transformation of protein and the exposed amino acids with sulfur groups or aromatic side chains in the fibrillated system. Our findings move a step forward for a detailed understanding on the dynamical changes of WPI properties during fibrillization, which would provide a guidance for WPI fibril applications and future food technology development.