Chitosan and its composites-based delivery systems: advances and applications in food science and nutrition sector.

Natural bioactive ingredients have lower bioavailability because of their chemical instability and poor water solubility, which limits their applications in functional foods. Among diverse biopolymers that can be used to construct delivery systems of bioactives, chitosan has attracted extensive attention due to its unique cationic nature, excellent mucoadhesive properties and easy modification. In this review, chitosan and its composites-based food-grade delivery systems as well as the factors affecting their performance are summarized. Modification, crosslinking, combination with other biopolymer or utilization of coating material can effectively overcome the instability of pure chitosan-based carriers under acidic conditions, thereby constructing chitosan and its complex-based carriers with conspicuously improved performance. Furthermore, the applications of chitosan-based delivery systems in nutrition and health as well as their future development trends and challenges are discussed. Functional food ingredients, functional food packaging and biological health are potential applications of chitosan-based food-grade delivery systems. The research trends of nutraceutical delivery systems based on chitosan and its composites include co-delivery of nutrients and essential oils, targeted intestinal delivery, stimulus responsive/sustained release and their applications in real foods. In conclusion, food industry will be significantly promoted with the continuous innovation and development of chitosan-based nutraceutical delivery systems.