Regulatory mechanism of cellulose nanocrystal from tea residue in coordination with calcium ions on the thermal gelation of pea protein amyloid fibrils

This study was conducted to investigate the effect of tea residue cellulose nanocrystal (CNC) in coordination with Ca2+ on the thermal gelation of pea protein amyloid fibrils (PAFs) and its potential mechanism. The results showed that CNC (0.12%) inhibited the aggregation of PAFs molecules, reduced the surface hydrophobicity and increased the solubility of the solution, and further formed PAFs-based gels with high water holding capacity and high gel strength. However, Ca2+ (400 mM) promoted the aggregation of PAFs molecules, which made the solution have high surface hydrophobicity and low solubility, and finally formed a PAFs-based gel with low water holding capacity and high gel strength. The intermolecular force of PAFs-CNC/Ca2+ gel was enhanced, and the content of beta-sheet conformation was increased. CNC fragments bound to specific amino acid sites of PAFs through non-covalent forces (hydrogen bonding and van der Waals forces), and Ca2+ might enhance the crosslinking and interaction between CNC and protein, thus making the two synergies enhance the gel strength and viscoelasticity of PAFs. The research results will provide a new perspective for the diversified regulation of PAFs gel properties and the design and development of PAFs gel-based products.