Advances and challenges in green extraction of chitin for food and agriculture applications: A review.

Chitin, the second most abundant polysaccharide in nature, offers numerous practical applications due to its versatile functional properties. However, its utilization is constrained by significant challenges in extraction, as well as low solubility and high crystallinity. While traditional chemical and biological fermentation methods can achieve high-purity chitin, these processes are often environmentally harmful or time/energy-consuming. Ionic liquids and deep eutectic solvents have emerged as more sustainable alternatives for chitin extraction, though both methods still face certain limitations, which are comprehensively discussed in this review. Besides extraction, chitin or modified chitin is increasingly being used to create a variety of chitin-based biomaterials, which have shown considerable potential in food applications, including food packaging, preservation, stabilization, and nutrient delivery and encapsulation. Furthermore, the applications of chitin-based materials are also reviewed in agriculture, where they are utilized as fertilizers, biocides, the elicitation of plants, or to treat seeds. This review not only provides a deeper understanding of the advancements and limitations in green chitin extraction methods but also highlights the broad potential of chitin-based materials in both food and agriculture.