Advances in the application of ionic liquids and deep eutectic solvents in chitosan-based packaging systems: Trends...

With the environmental concerns over non-biodegradable plastics, chitosan has attracted substantial research focus in the field of sustainable and eco-friendly food packaging owing to its intriguing characteristics. In recent years, there has been a dramatic boom in publications focusing on the utilization of ionic liquids (ILs) and deep eutectic solvents (DESs) in chitosan-based packaging systems, and these studies are systematically reviewed in this article. The employment of ILs as solvents or plasticizers for chitosan film fabrication are summarized. Compared to ILs, DESs offer advantages such as lower production costs, simpler synthesis with 100% atom economy, better biodegradability, and higher environmental benignity, thereby presenting a new choice for optimizing the functional performance of chitosan films. Thus, recent developments regarding the integration of DESs in chitosan-based films are comprehensively discussed, with special focus on the plasticization, barrier, antioxidant, antibacterial properties, and biosafety assessment. Furthermore, the application of DES natural extracts as ready-to-use products in the chitosan-based packaging systems are also outlined. The efficacy of DES-integrated chitosan films and coatings is further verified in the preservation of fruits and meat. Future directions are proposed toward scale-up production, cost reduction, environmental footprint minimization, and multifunctional integration to promote the development of sustainable chitosan-based packaging.