Advances in green solvents for production of polysaccharide‐based packaging films: Insights of ionic liquids and deep eutectic solvents

• Published in: Comprehensive reviews in food science and food safety 2023-03, Vol.22 (2), p.1030-1057
• Main Authors: Yu, Jiahao, Liu, Xuwei, Xu, Shanlin, Shao, Ping, Li, Jiandong, Chen, Zhirong, Wang, Xuanpeng, Lin, Yang, Renard, Catherine M. G. C.
• Format: Article
• Language: English
• Subjects: Antibacterial activity; Bioactive compounds; biobased plastic; Cellulose; Deep Eutectic Solvents; Evaporation; extraction; food packaging; green solvents; Ionic Liquids; Life Sciences; Plasticizers; Polysaccharides; Solvents
• ISSN: 1541-4337; 1541-4337
• DOI: 10.1111/1541-4337.13099

The problems with plastic materials and the good film‐forming properties of polysaccharides motivated research in the development of polysaccharide‐based films. In the last 5 years, there has been an explosion of publications on using green solvents, including ionic liquids (ILs), and deep eutectic solvents (DESs) as candidates to substitute the conventional solvents/plasticizers for preparations of desired polysaccharide‐based films. This review summarizes related properties and recovery of ILs and DESs, a series of green preparation strategies (including pretreatment solvents/reaction media, ILs/DESs as components, extraction solvents of bioactive compounds added into films), and inherent properties of polysaccharide‐based films with/without ILs and DESs. Major reported advantages of these new solvents are high dissolving capacity of certain ILs/DESs for polysaccharides (i.e., up to 30 wt% for cellulose) and better plasticizing ability than traditional plasticizers. In addition, they frequently display intrinsic antioxidant and antibacterial activities that facilitate ILs/DESs applications in the processing of polysaccharide‐based films (especially active food packaging films). ILs/DESs in the film could also be further recycled by water or ethanol/methanol treatment followed by drying/evaporation. One particularly promising approach is to use bioactive cholinium‐based ILs and DESs with good safety and plasticizing ability to improve the functional properties of prepared films. Whole extracts by ILs/DESs from various byproducts can also be directly used in films without separation/polishing of compounds from the extracting agents. Scaling‐up, including costs and environmental footprint, as well as the safety and applications in real foods of polysaccharide‐based film with ILs/DESs (extracts) deserves more studies.