Effect of cinnamaldehyde incorporation on the structural and physical properties, functional activity of soy protein isolate‐egg white composite edible films

Cinnamaldehyde (CIN) was added to edible composite films of soy protein isolate (SPI) and egg white (EW) to develop active food packaging. The effects of adding 2%–10% CIN on the structural, physical, and functional properties of the SPI/EW films were systematically evaluated. Fourier-transform infrared spectroscopy and X-ray diffraction suggested the excellent compatibility of the components because hydrogen bonding occurred. Scanning electron microscopy indicated CIN affected the structure of the films. The incorporation of CIN significantly improved the antioxidant and antimicrobial activities of the films, but reduced the tensile strength and water vapor permeability. In particular, the addition of CIN at different concentrations significantly increased the elongation at break, water resistant, and UV–vis light barrier properties of the films. Therefore, SPI/EW/CIN films can be used as eco-friendly bioactive materials in food packaging. Practical applications In recent decades, many studies were devoted to the development of biodegradable and edible natural biopolymers to replace petroleum-based polymer packaging. The edible bioactive packaging film can be prepared by adding active substances to the food packaging materials instead of directly adding it to the food, which not only maintains the original characteristics of the food, but also delays the deterioration and autoxidation of the food. This study evaluated the Microstructural, physical, and functional properties (antioxidant and antimicrobial activities) of composite films for use in food packaging and it is proved that it is possible in practical application.