The Impact of Cold Atmospheric Plasma on Physicochemical, Microbial, and Mechanical Properties of Protein-based Edible Packaging Films: A Review

Quality and safety, both in objective product characteristics and subjective consumer perception terms, are essential factors for the success of any food product. Therefore, the history of using the packaging goes back to protecting food and foodstuffs in the distant past (Shashi K. Pankaj et al., ۲۰۱۸). Food packaging is concerned with preserving and protecting all types of foods and their raw materials, mainly from microbial spoilage, and extending their shelf-life. Therefore, increasing the use of packaging materials, especially synthetic packaging for their excellent gas and liquid barrier characteristics, has led to severe ecological problems due to their total non-biodegradability (Tharanathan, ۲۰۰۳)(Mihalca et al., ۲۰۲۱). Nowadays, one of the synthetic materials produced in different types and applications is plastic and plastic composition, such as plastic packaging films (Zhong et al., ۲۰۲۰). Some efforts and awareness by environmentalists about the bio-pollution of polymers and the importance of their safety introduce new consumption patterns that include packaging products with biodegradable materials (Mirzaei-Mohkam et al., ۲۰۲۰). So biodegradable polymers from renewable resources have shown significant potential in packaging applications due to their environmental benefits. There are two types of biopolymers; one is a mixture of natural and synthetic plastics, such as a mixture of gelatin and polypropylene films, which destroy partially after some time. Another group is films that destroy entirely in the environment, which is named edible biodegradable film (Tian et al., ۲۰۲۱). Thus, biopolymers are degradable, renewable resources and made of cheap and readily available raw materials. The second category includes animal or plant-based proteins, polysaccharide-based films like starches, cellulose derivatives, chitosan/chitin, gums, and lipids (Mellinas et al., ۲۰۱۶). In designing a package, many factors must be considered. Most of these factors depend on the chemical nature of the film, the type of food, and the target microorganism. Among the critical factors related to the chemical nature of the packaging film, water vapor permeability, tensility, water solubility, and other factors that vary depending on the chemical nature. It is noticeable that the efficiency of edible films is related to their quality indicators (transparency and light absorption or their thickness) (H. Chen et al., ۲۰۱۹). For example, compared to polysaccharides and lipids, proteins have some advantages, such as relative abundance, good film-forming ability, and high nutritional value, which make proteins be used extensively for preparing biodegradable packaging films like whey protein-based, zein-based, and gelatin-based films (Calva-Estrada et al., ۲۰۱۹).