Comparison of formation and structural characteristics of amyloid fibrils of peanut protein isolate after hydration treatment at different pH

In this paper, the process of fibrillation and the structure of fibrils formed from peanut protein after hydration treatment at pH 5.0 (group Q) and pH 2.0 (group S) were studied. The results showed that compared with the peanut protein obtained after hydration at pH 5.0, the particle size of the peanut protein obtained after hydration at pH 2.0 increased, and the surface hydrophobicity and intrinsic fluorescence intensity decreased, indicating that the protein aggregated. During fibrillation, the maximum Thioflavin T fluorescence intensity of protein in group Q was higher than that in group S, and the time for group S protein to reach the maximum fluorescence intensity was slower than that in group Q protein. Besides, the Group Q protein first formed short worm-like fibrils and then long flexible fibrils, and the Group S protein first formed short rigid fibrils and then worm-like fibrils. In conclusion, hydration treatment at pH 2.0 led to the aggregation of peanut protein, reduced the fibrils forming ability of peanut protein and affected subsequent self-assembly processes. This study could provide new insights of the fibril formation mechanism and structural properties of peanut protein after hydration treatment at different pH.