Cellulose-Based Hydrogel Films for Food Packaging

Abstract

The use of fossil-based plastic in food packaging has increased the plastic-based waste, carbon footprint, and global warming, which has led to the development of alternatives such as hydrogels for biodegradable stringent food packaging industries. Hydrogels consist ofbiopolymers having three dimensional networks can trap a large quantity ofwater and formulation ofcellulose-based hydrogels have laid high impact for food packaging application with improved biodegradability, biocompatibility, mechanical properties, plasticizing effect, etc. Cellulose hydrogels can be imparted as thin layers onto the polymers to improve its wettability, appearance, degradability, and resistance towards environmental agents. Cellulose-based hydrogels are mainly formulated from cellulose, bacterial cellulose, and its derivatives. Further, use of cellulose and its derivatives with gelatin, low-methoxyl pectin, polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene glycol (PEG), protein, etc., provide a better property for packaging food products. Various bioactive compounds such as silver nanoparticles and other antioxidants, antifungal agents can be embedded onto hydrogel films to improve its properties. Use of cellulose hydrogel as packaging material mainly depends on its hydrophilicity, swelling property, molecular weight, stability, physical, mechanical and chemical properties. Cellulose hydrogels generally consist of various chemistry of hydrogels such as physical cross-linking, chemical cross-linking, interpenetrating hydrogels, which find significant importance in bio- degradable food packaging. Dry hydrogels from biopolymers can be used individu- ally or in conjugate with others. However, use of individual polymers for making hydrogel creates problems in hydration which enhance water-polymer interactions than polymer-polymer interactions. In contrast, blending and composites ofpolymers help in enhancing interactions between polymer-polymer matrices than water- polymer matrices. The tailored properties of blends or composites of hydrogel can be formed through electrostatic interactions between opposite charges, formation of cross-links through covalent bond, formation of physical networks, and interpenetrating polymer networks.