Cellulose Nanocrystal/Chitosan Hybrid Bio-Composite Films for Food Packaging Application: A Review on Synthesis, Mechanisms, and Functional Properties

Food packaging often employs plastic films made from petroleum, as they generally present good mechanical, water-resistance, and barrier properties. However, their toxicity and non-biodegradability features cause significant environmental and health problems that need potential solutions. In response to those challenges, there has been an increasing interest in sustainable food packaging bio-composite films from renewable, non-toxic, biodegradable, and eco-friendly biopolymers, along with active agents. Cellulose nanocrystals (CNCs) are a promising nanomaterial that can enhance the functional properties of bio-composites due to their high strength, biodegradability, and compatibility with many biopolymers. This review discusses the role of CNCs in improving the mechanical and barrier properties of the CNC/chitosan (CS) hybrid bio-composite films employed in food packaging applications. Furthermore, the role of CS, essential oils, and metal nanoparticles in the bioactivity properties of CNC/CS films was discussed. Finally, the technical challenges, performance limitations, and industrial scalability issues were discussed, and potential solutions were provided. Although it requires further research and innovation, CNC/CS hybrid bio-composite film can prevent environmental pollution, align with global sustainability goals, promote the use of green packaging strategies, extend the shelf life of foods, and encourage circular economy practices.