Chitin nanocrystals – A new material with ice-shaping and ice recrystallization inhibition activities

Ice-binding materials that bind to ice and inhibit ice recrystallization can improve cell viability during cryopreservation and food quality during frozen storage. Recently several groups of amphiphilic materials were found to have ice recrystallization inhibition (IRI) activities. Like nanocelluloses, nanochitins are another group of natural materials demonstrating an amphiphilic characteristic. In this work, chitin nanocrystals (ChNCs) prepared by hydrochloride acid hydrolysis were studied for their ice-binding ability and ice recrystallization inhibition (IRI) activity. The ice-binding ability of ChNCs was demonstrated by an ice-shaping experiment at a concentration as low as 1 mg/g. In addition, the ChNCs were IRI active in sucrose and 1X phosphate-buffered saline (PBS) solutions at concentrations below 10 mg/g. Compared with the newly identified ice recrystallization inhibitor - cellulose nanocrystals (CNCs), ChNCs demonstrated much better ice-binding ability and IRI activity. Our data added ChNCs to the current list of ice-binding materials with IRI activity for many potential applications.