Recent developments and prospective food-related applications of cellulose nanocrystals: a review

Cellulose nanocrystals (CNCs) with prominent mechanical properties are well known as the natural reinforcing elements in composites and have received considerable interest over the past decades. Numerous original resources and extraction methods were applied to obtaining CNCs, and the surface properties of CNCs were modified to improve the compatibility with polymeric matrices. Despite these different raw materials and treatments, various novel applications of CNCs have been developed in recent years. Among them, the food-related applications of CNCs have attracted more and more attention because of their renewability, outstanding mechanical properties, unique nanoscale structure, biocompatibility, and easy surface modifications. This review summarized the recent work on the extraction, modification, and food-related applications of CNCs. Traditional raw materials, such as cotton, wood, and tunicate, were still widely used, while there is a new trend to obtain CNCs from waste biomass. Different pretreatments, extraction processes, and surface modifications were compared and discussed. Moreover, the potential applications of CNCs in food packaging, food thickener, emulsion stabilization, quality sensor, and active compound immobilization were presented. Finally, concerns about safety and sustainability have been addressed.