The role of additives on the functional properties of chitosan-starch-based films and coatings for food preservation

The growing demand for sustainable and functional food packaging has spurred interest in chitosan–starch films and coatings. This review systematically examines recent literature (2020–2025) on the incorporation of plasticizers, nanofillers, and antimicrobial agents into starch–chitosan matrices. Plasticizers, such as glycerol, improve flexibility and homogeneity, whereas nanofillers such as ZnO nanoparticles and cellulose nanofibers enhance mechanical strength, barrier properties, and bioactivity. Natural antimicrobial additives, including phenolic compounds and anthocyanins, provide microbial inhibition and antioxidant activity, supporting food preservation. This review highlights the role of additive-matrix interactions, microstructure, hydrogen bonding, and dispersion in determining final film and coating performance. Emphasis is also placed on the potential use of GRAS-compliant, locally sourced additives and liquid-phase formulations. Collectively, these insights provide a framework for designing chitosan-starch materials with synergistic improvements in structural, functional, and bioactive properties for sustainable food packaging applications.