Chitosan-based hydrogel beads: Preparations, modifications and applications in food and agriculture sectors – A review

Chitosan is produced by deacetylation of chitin, the second-most abundant biopolymer on earth. With three types of reactive functional groups, one amino group and both primary and secondary hydroxyl groups, chitosan has been used as a popular biomaterial for synthesis of three-dimensional and flexible hydrogel beads that swell in water and biological fluids. Chitosan-based hydrogel beads have been found in a wide range of applications in food and agriculture sectors. This review first provides an overview of traditionally used and recently developed methods for preparation and modification of chitosan-based hydrogel beads, and then discusses the advances in the most recent five years in their applications for delivery of food bioactive compounds and treatment of agricultural recycled wastewater.