Abstract
In the past, people used to preserve perishable food products, such as fish and oil, by utilizing their indigenous knowledge or technology. Due to consumer demand and the transportation of perishable foods from one country to another, different types of technology have been created to preserve food. The existing technologies for food preservation involve various types of artificial substances, which are injurious to humans. In addition, consumers, in recent decades, have had higher expectations and requirements of staying in good health. Thus, food preservation and food safety are now major concerns attracting increased attention. As a result, chitosan is gaining popularity globally as a potential food preservative because of its outstanding biocompatibility, bioactivity, biodegradability, polycationic nature, and nontoxicity. In general, chitosan is produced from the chitin (most abundant biopolymer nature next to cellulose) via a deacetylation process, and the skeletons of crustaceans, such as prawns, shrimps, krill, crabs, and lobster, are its main sources. However, chitosan exhibits novel attributes, including antibacterial, antifungal, antioxidant activity, and other wonderful characteristics, such as its film-forming capability. These make chitosan an additive for the food and agricultural industry. The use of chitosan for fish and fish-based products and oil solves some major issues, such as harmful lipid oxidation and food-borne pathogens. Additionally, chitosan is used to decrease the deterioration of products during storage periods, increase their sensory characteristics, and extend the products’ shelf life. In this chapter, recent works are highlighted on the uses of chitosan and nanochitosan as a food preservative, especially in the preservation of fish, and oil, which would be helpful for policymakers, consumers, and the food industry.