Fabrication of mung bean protein isolate nanofibrils and calcium ions induced hydrogels

Protein nanofibrils have excellent functional properties due to their unique fibrous structure and high aspect ratio. This article focused on the formation processes, microscopic morphology and aggregation mechanisms of mung bean isolate protein nanofibrils (MPNFs), as well as the formation of MPNFs hydrogels induced by Ca 2+ . Mung bean isolate protein (MPI) could self-assemble into long and curly MPNFs via a partially unfolded conformation-aggregation model when heating at pH 2.0 and 90 °C for 11 h. Hydrophobic forces, electrostatic forces and disulfide bonds drove the hydrolysis and structural rearrangement occurring simultaneously resulting in MPNFs. MPNFs could formed self-supporting hydrogels. As expected, Ca 2+ could affect the network structure of the hydrogel by decreasing the electrostatic repulsion and the salt bridges between protein molecules, which can affect its water-holding capacity, texture and rheological properties. The MPNFs hydrogels formed with MPNFs of 0.050 g/mL and Ca 2+ of 100 mmol/L at 90 °C for 60 min had a denser and more homogeneous gel network, with a highly cross-linked and uniform pore distribution. It is believed that this present work can give some insight into MPNFs and provide more potential applications of MPI as gelling agents in the food industry. • Mung bean protein isolate self-assemble to nanofibrils (MPNFs) with improved gel properties. • MPNFs formed via a partially unfolded conformation-aggregation model. • MPNFs can form self-supporting hydrogels at concentration as low as 0.050 (g/mL). • Ca 2+ has the ability to induce and modulate the gelling properties of MPNFs.