Chapter 2 - Chitosan-based coatings and plant extracts

Abstract

This chapter will discuss advancements in the use of chitosan (CH)-based edible coatings with active ingredients derived from aromatic plants, focusing on essential oils (EOs), their main biological activities, and their effects on the quality of a variety of foods. CH is becoming a recognized polysaccharide for the active protection and extension of the shelf-life of perishable foods due to its biocompatibility, biodegradability, and nontoxicity. Integration of functional compounds in CH is also a promising technique in modern barrier technologies to improve their performance, thereby assisting in the preservation of nutritive and sensory attributes as well as the shelf life of food products. Due to their potential antimicrobial and antioxidative effects, EOs have been studied as alternatives to chemical preservatives to protect foods and are generally recognized as safe (GRAS). The application of edible coatings of CH incorporated with EOs has been shown in studies to reduce, inhibit, or delay the growth of spoilage and pathogenic microorganisms in food, increasing its post-harvest/post-manufacturing shelf-life. The studies also revealed that foods coated with CH and EOs maintain the balance of oxidation metabolism due to their ability to clear cytotoxic compounds via enzymatic and nonenzymatic antioxidants. Because perishable foods are more vulnerable to microbial attack and quality-altering biochemical reactions, coatings are primarily used in these products. However, there are still issues with the use of CH and EOs in food coatings, primarily in terms of mechanical and sensory properties. Encapsulation of EOs and CH nanoparticles is emerging as an alternative, where nanometer-scale control of material properties will allow for the exploration of new functionalities.