Effects of carboxymethyl chitosan on the gelling properties, microstructure, and molecular forces of Pleurotus eryngii protein gels

Protein-polysaccharide interactions play a crucial role in development of plant-based food products. This study aimed to investigate the effects of different carboxymethyl chitosan (CMCS) concentrations (0-5.0%) on the gelation, structural properties, molecular interactions, and microstructure of the Pleurotus eryngii protein (PEP) gels. The results showed that the addition of CMCS could improve the rheological, textural properties and water holding capacity of the PEP/CMCS composite gels. Fluorescence spectra, fourier transform infrared spectrum and chemical interaction forces analysis suggested that the formation of the CMCS/PEP complex occurred by static quenching mechanism. The addition of CMCS changed the secondary structure and molecular conformation of the protein, also significantly enhanced the hydrophobic interaction and disulfide bonds of PEP molecules, thus increased the gel properties of PEP. Scanning electron microscopy revealed a denser and uniform network structure with small pores in the CMCS/PEP composite gels. Overall, these results provided an important basis for CMCS to improve the heat-induced gel properties of PEP, and also provided information on the potential use of composite gel as meat analogs in the food processing industry.