preparation and study of physical properties of zein based composite films as food coatings

background: demand for degradable and biocompatible polymers is rapidly increasing, especially in the food packaging sector where it is highly encouraged by environmental management policies. methods: this study aimed to prepare zein/montmorillonite (mmt) and zein/poly (vinyl alcohol) (pva) composite films by a high-power ultrasonic probe method for use as a food coating. the film was produced through solvent casting method. in all the films, glycerol and polyethylene glycol were used to improve the fragility properties. the biodegradability, color characteristics and surface roughness of the films were evaluated. results: based on the results of the statistical analysis, the clay dispersion method a, mmt and pva content significantly affected the mechanical and properties of the composite films. the results showed that mechanical properties of the nanocomposites were improved in the presence of small amounts (up to 3%) of mmt, while increased mmt percentage in the micro composite films weakened the mechanical properties of these films. it was also found that the addition of mmt and pva increased the porosity of the film. therefore, the use of high-power sonication is a suitable method for producing protein-based nanocomposites with an exfoliated structure. conclusions: as the nanocomposite films of zein, zein-pva and zein-mmt are highly biodegradable, natural and non-toxic, they are highly efficient in this field and can be used in food packaging.