Effect of Cold Plasma-mediated Amyloid Fibrous Aggregation on the Emulsification and Foaming Properties of Pea Protein Isolate

The potential of cold plasma (CP) treatment to promote the formation of amyloid fibrils of Pea protein isolate (PPI) was evaluated relative to acidic heat fibrillation condition. The changes of ThT fluorescence intensity, microstructure, molecular structure, particle size distribution, Zeta potential, surface hydrophobicity, surface free sulfhydryl, free sulfhydryl, total sulfhydryl, and disulfide bonds content, emulsifying activity and foaming capacity of PPI amyloid fibrils were determined. Results indicated that the formation of PPI amyloid fibrils was significantly accelerated by CP treatment. Compared to acidic heat-induced PPI amyloid fibrils (A-PF), CP-mediated fibrils (CP-PF) showed higher ThT fluorescence intensity, relative content of β-fold, and shorter maturation time. After 60 min of heating, CP-PF formed longer fibrils (961.35 nm) than A-PF (219.84 nm). Hydrophobicity, free sulfhydryl groups, and disulfide bond analyses revealed that hydrophobic interactions and disulfide bonds were the primary driving forces for the self-assembly and ordered stacking of β-sheet structures during fibrillation process. Furthermore, fibrillization markedly improved the functional properties of PPI: The emulsifying activity and foaming capacity of A-PF and CP-PF were significantly enhancing. Notably, CP-PF exhibited superior emulsifying and foaming properties compared to A-PF. This study demonstrated that CP is an effective technique for promoting PPI amyloid fibril formation and improving its functionality.