Chapter 5 - Chitosan as an antimicrobial agent to increase shelf life of foods

Abstract

One of the current challenges faced by the food industry involves the production of natural foods, which are safe and have extended shelf life. Consumers and public health agencies are concerned about the adverse toxicological effects of using synthetic food additives. Among the critical issues involved in this context are microbial growth, enzymatic browning, and lipid oxidation in food products. Thus the search for safe, bioactive, and natural additives has attracted the attention of researchers. Chitosan is one of the most promising emerging multifunctional additives due to its biological properties such as antimicrobial, antiviral, and antioxidant. In addition to direct application to foods as a preservative, chitosan is commonly used as a coating on fruits and vegetables to increase their postharvest shelf life. Chitosan is also suitable for making active and sustainable films for food packaging, encapsulation of bioactive compounds, and clarification of fruit juices. Recent trends in new concepts of chitosan-based nanoparticles and other forms of chemical modification of this biopolymer with novel properties and applications in the food industry have also been in evidence. Besides the biological potential of chitosan, another aspect that appeals to more attention is the possibility of using waste from the fishing industry precisely through the production of chitosan. This possibility of obtaining a natural additive as a value-added product from an agro-industrial residue appears to be an interesting environmental strategy, aligned with the principles of green chemistry and circular economy. This chapter reviews chitosan and its derivatives’ main sources and techniques for production, along with the polymers’ chemical, physical, and biological characteristics. Focusing on the antimicrobial activity of chitosan, this chapter discusses the action mechanisms for their application as antibacterial and antifungal, as well as diverse forms of adding chitosan in food matrices and how it can promote the shelf life extension in these products.