Recent advances in the improvement of protein-based edible films through non-thermal and thermal techniques

A major area of food research focuses on the study of food packaging, which plays a critical role in the containment and protection of foods. In the past, packaging materials have largely consisted of polymers derived from petroleum. However, consumers are more concerned with the environmental and health effects of synthetic polymers. Considering this, protein films may be useful in preserving food freshness due to their ability to insulate light and water. Nevertheless, they are not suitable for use in the food industry because of their limited mechanical strength, tendency to rupture, and poor water resistance. A variety of non-thermal techniques (such as microwave, ultrasound, cold-plasma, irradiation, and high-pressure processing) and thermal methods may be used to overcome this issue by modifying the properties of protein films. The use of these techniques improves protein film properties by reducing particle size, enhancing intermolecular electrostatic repulsion between molecules, and facilitating cross-linking. Further, modified protein films with excellent barrier properties can also be used to reduce food waste and environmental pollution, as well as to improve the quality, safety, and security of food. Thus, this review mainly focuses on the impact of non-thermal and thermal techniques on protein film properties and their applications.