Structure-activity relationship and regulatory mechanism of nanocellulose with different length-diameter ratio on the gelling behavior of soybean protein-derived amyloid fibrils

In this study, the effect of length-diameter ratio of nanocellulose on the gel properties of soybean protein amyloid fibrils (SAFs) and its regulatory mechanism were investigated. The results showed that the viscoelasticity, gel strength and water holding capacity of SAFs composite gel increased significantly with the decrease of length-diameter ratio of nanocellulose. The root cause of this phenomenon was that nanocellulose with small aspect ratio showed good dispersion stability in SAFs solution, which promoted the hydrophobic amino acids and aromatic amino acids residues in SAFs to be concealed in the protein to a greater extent. In addition, the nanocellulose with smaller length-diameter ratio promoted the composite gel to have more β-sheet conformation, and effectively induced the increase of ionic, hydrogen and disulfide bonds in the gel. In summary, precisely regulating the length-diameter ratio of nanocellulose could significantly affect the aggregation state, functional groups, structural characteristics and interaction forces of SAFs molecules, so as to achieve directional optimization of SAFs gel properties. This research result opens up new possibilities for the application of SAFs composite gel system in various fields such as functional protein substrate materials and food ingredients, and has important practical significance and promoting role.