Structural and Functional Properties of Ferulic Acid-Rice Residue Protein Composite Film

Effects of ferulic acid on the performance of rice residue protein films were studied by measuring the mechanical properties of the films,water vapor transmission rate and water solubility. The structural characteristics of the film were characterized by Fourier transform infrared spectroscopy,differential scanning calorimetry,X-ray diffraction,and scanning electron microscopy. Results showed that,with the content of 0.1%(W/V)ferulic acid,the tensile strength,the water vapor transmission rate and the water solubility of the composite RRP film were increased by 20.33% and decreased by 20.58% and 23.88%,respectively. Results of Fourier transform infrared spectroscopy(FTIR)showed that the amide band absorption peak was red-shifted,β-sheet was transformed into a flexible random helical molecular structure,and the secondary structure of the protein was changed by ferulic acid crosslinking. Differential scanning calorimetry(DSC)analysis showed that the ferulic acid enhanced the intermolecular interaction,it increased the glass transition temperature of the film,and the film had better thermal stability. X-ray diffraction(XRD)analysis showed that ferulic acid and protein molecules had covalent cross-linked,and the film crystallinity was increased. Scanning electron microscope(SEM)results displayed more uniform and smooth microstructure of the film. The addition of ferulic acid made RRP film indicated better performance and more stable spatial structure.