Structure and properties of carboxymethyl cellulose/soy protein isolate blend edible films crosslinked by Maillard reactions

Edible films based on carboxymethyl cellulose (CMC) and soy protein isolate (SPI), compatibilized by glycerol, were prepared by solution casting. The effects of CMC content on blend structure, thermal stability, water solubility and water sorption, and mechanical properties were systematically investigated. Fourier transform infrared (FTIR) spectra showed that Maillard reactions occurred between CMC and SPI, and X-ray diffraction (XRD) scans indicated that the Maillard reactions greatly reduced the crystallinity of SPI. According to differential scanning calorimetry (DSC) analysis, CMC/SPI blends had a single glass transition temperature (T_g) between 75 and 100 °C, indicating that CMC and SPI form one phase blends. Increasing the CMC content improved the mechanical properties and reduced the water sensitivity of blend films. The results indicate that the structure and properties of SPI edible films were modified and improved by blending with CMC.