Formation mechanisms, handling and digestibility of food protein nanofibrils

Background: Globular proteins including whey proteins, soy proteins and egg white proteins self-assemble into fibrillar structures with several nanometers thickness and several micrometers length by prolonged heating at very acidic conditions. These in vitro synthesized fibrils resemble amyloids associated with various neurodegenerative diseases and hence have received special attention by bioscientists. The synthesized fibrils are however of widespread potential for food and colloid sciences applications. Characteristics such as aspect ratio, and persistence and contour lengths of the artificially-synthesized fibrils could be elaborated by appropriate selection and employment of parameters of fibrils formation process. Scope and approach: The fibrillation process of whey proteins, proposed mechanisms and potent inhibitors of the process, as well as, alternative enzyme-based routes of fibrillation are overviewed in the present article. Then post-formation treatment and applications of globular proteins fibrils and their gastric digestibility behavior are briefly referred followed by representing some future trends in this field. Key findings and conclusions: The building units of protein fibrils are hydrolysis-generated polypeptides rather than parent intact protein monomers. It was hypothesized that proteins fibrillation is an oxidation-triggered process and may be inhibited by antioxidant agents that suppress the generation of reactive oxygen species. Whey protein-originated fibrils may be exploited in formation of heat-resistant protein-stabilized emulsions and nanoemulsions. However, more effort is required to characterize the interfacial behavior of fibrils in comparison with native and heat-denatured whey proteins. Gastric and intestinal digestion fate of protein nanofibrils is also a hot topic for upcoming research studies.