Dialdehyde carboxylated cellulose green crosslinked soybean protein isolate based on Schiff base reaction to improve the emulsification performance and stability of emulsion

To enhance the stabilization emulsion of soybean protein isolate (SPI), many strategies have been developed, such as modifying the properties of plant protein, using plant protein-polysaccharide complex, forming emulsion and so on. The purpose of this study was to investigate the response of SPI and dialdehyde carboxylated cellulose nanofibers (DCNFs) with Schiff base at different concentrations and its effect on the emulsification property of SPI were investigated. The results indicated that the α-helix and β-turn contents of the protein in the SPI/DCNFs conjugates decreased by 35.9 % and 2 %, respectively. The fluorescence intensity reduced as the addition of DCNFs, indicating that there was a static quenching between DCNFs and SPI. SPI was caused by DCNFs to reduce the surface hydrophobicity, expand the molecular structure of protein, and form the new covalent bonds (C=N). In addition, The average diameter of the SPI/DCNFs emulsion was reduced to 117 nm, the zeta potential was enhanced to −35.6 mV, and the emulsification performance and stability were increased by 40.9 % and 40.8 %, respectively. The results suggested that the Schiff base reaction generated the conformational change of protein and improved the emulsification function, which offered a possible way to control glycosylation and improve the emulsifying property of SPI.