The state-of-the-art on chitosan: historical perspectives and non-thermal modification technologies for sustainable packaging films

Abstract

Chitosan has garnered significant attention in the field of polymer science over the decades due to its associated characteristics, such as biodegradability, antimicrobial properties, and film-forming abilities. With increasing concerns, extensive research has been conducted to enhance the functional properties of chitosan using various modification techniques. Recently, the modification of chitosan-based materials using non-thermal technologies has drawn attention due to their ability to improve mechanical strength, barrier properties, and bioactivity without compromising environmental sustainability. This review discusses the historical discovery and development of chitin and chitosan and further emphasizes their growing significance in biomaterials science. A key focus of this study is to apply non-thermal modification technologies, such as cold plasma, irradiation, high pressure processing, ultrasonication, pulsed electric fields, and electrospinning, for the modification of chitosan-based materials for their application in active and intelligent packaging systems and shelf-life extensions, thereby aligning with the principles of green chemistry. Non-thermal modification technologies significantly enhance the structural and functional properties of chitosan films, making them viable alternatives to conventional plastic packaging. The mechanical properties, antimicrobial efficacy, oxygen barrier properties, and thermal stability of chitosan are among its key benefits, and the proposed material has been successfully used as a food packaging material for preserving fresh produce and increasing the shelf life of several types of food products. This approach not only supports the transition towards a circular economy but also contributes to a significant reduction in plastic packaging.