Green natural deep eutectic agents (GNDEAs) for biocryopreservation: Syntheses, properties and advanced applications

Freezing, as a common method of food preservation, has been widely used in the food industry. However, with further research, the drawbacks it brings (such as ice crystal puncturing cells and osmotic pressure) have also become well-known at the same time environmental problems are becoming more and more obvious. Therefore, there is a need to seek green cryoprotectant agents (CPAs) for freezing. Green natural deep eutectic agents (GNDEAs) were first applied to biocryopreservation in 2018. This review aims to comprehensively understand the principles and prospects of GNDEAs as green CPAs by summarising the origin, development, synthesis methods, physicochemical properties related to cryoprotection, potential cryoprotection mechanisms, applications in the field of cryoprotection, current challenges and prospects for future development. GNDEAs have been proved to achieve freezing protection by regulating the freezing point and inhibiting the recrystallization of ice crystals. Compared to traditional CPAs, GNDEAs systems are natural, green CPAs that are non-toxic, environmentally friendly and have good biocompatibility, which are potential CPAs in the food industry.