Cold Plasma Technology in Food Packaging
Cold plasma (CP) is an effective strategy to alter the limitations of biopolymer materials for food packaging applications. Biopolymers such as polysaccharides and proteins are known to be sustainable materials with excellent film-forming properties. Bio-based films can be used as an alternative to traditional plastic packaging. There are limitations to biopolymer packaging materials such as hydrophobicity, poor barrier, and thermos-mechanical properties. For this reason, biopolymers must be modified to create a packaging material with the desired applicability. CP is an effective method to enhance the functionality and interfacial features of biopolymers. It etches the film surface allowing for better adhesion between various polymer layers while also improving ink printability. CP facilitates adhesion between two or more hydrophobic materials, resulting in significantly better water vapour permeability (WVP) properties. The sputtering of ionic species by CP results in cross-linkage reactions which improve the mechanical properties of films (tensile strength (TS) and elongation at break (EAB)). Cross-linkage reactions are reported to be responsible for the improved thermal stability of CP-treated biopolymers. CP treatment is known to decrease oxygen permeability (OP) in protein-based biopolymers. CP can also enable the blending of polymers with specific antimicrobial substances to develop active packaging materials. In this review article, we have presented an overview of the recent advancements of CP in the food packaging application. Furthermore, the influence of CP on the properties of packaging materials, and recent advancements in the modification of polymeric food packaging materials have been discussed.