Functionalization of oilseed proteins via fibrillization: Comparison in structural characteristics, digestibility and 3D printability of amyloid fibrils

The functionalized modification of proteins from more sustainable resources is urgently required. Herein, the fibrillization of oilseed proteins derived from different sources was conducted, and the conformation-fibrillization relationship was further elaborated by systematically comparing the physicochemical and functional properties of amyloid fibrils. The results indicated that fibrillization-induced alterations in particle size and ζ-potential, ThT fluorescence intensity, surface hydrophobicity, flexibility and rheological property differed among proteins due to their diverse proportions of secondary structure and subunit compositions. Compared with soy proteins, walnut proteins were more likely to be hydrolyzed into peptides with a smaller particle size (108.6 nm) and fibrillated at a higher conversion rate (65.4%). The sesame proteins featured by a higher level of β-sheet exhibited increased surface hydrophobicity and flexibility of fibrils, resulting in higher viscosity due to the formation of cluster-like fibrillar aggregates. The rapeseed protein fibrils derived from cruciferin and napin demonstrated the lower digestibility (20.51%) as they displayed strong resistance against acid and proteolytic digestion during in-vitro digestion. Furthermore, among four oilseed proteins, short-flexible fibrils from sesame and walnut proteins could adhere firmly to oil/water interface, maintaining a gel-like structure of HIPEs with excellent printing accuracy and high self-supporting capacity.