Research on Properties of Edible Films Prepared from Zein, Soy Protein Isolate, Wheat Gluten Protein by Adding Beeswax

With the increasing awareness of environmental protection, the interest in the development of biodegradable materials has become increasingly popular. At present, wheat gluten protein (WGP), soybean protein isolate (SPI), and Zein have made some progress in the application of packaging materials. At the same time, beeswax (BW) is widely applied in the preparation of food coatings. In this study, composite films were prepared by adding BW to three different types of proteins. Various properties of the composite film, such as thickness, color, mechanical properties, and thermal stability, were tested. The thickness of the film was significantly increased after adding BW. Regarding the mechanical properties, the BW didn’t improve the composite film’s tensile strength. The results of the SEM indicated that the surface morphology of the composite films changed due to the interaction between BW and protein molecules. Besides, the addition of BW resulted in a decrease of thermal stability. The Td of the Zein film (77 ℃) and WGP film (106 ℃) were decreased to 72℃ and 98℃, respectively. The study shows that the composite films will have the opportunity to be applied in the food package field in the future and further replace the traditional petroleum-based films.