Immobilization of essential oils in biopolymeric matrices: recent approaches for controlled delivery systems

The essential oils extracted from plants have attracted high scientific interest owing to their beneficial biological properties, such as antifungal, antimicrobian, antiviral, and antioxidant. These bioactive substances have been used ancestrally as a resource for traditional healing systems and, recently, in food preservation. The applicability of these compounds has been limited since they exhibit low resistance to environmental factors, poor bioavailability, sudden release, and water insolubility. In this sense, diverse methods have been reported to incorporate essential oils into polymeric systems. Although many ways are available to modify natural products with high levels of selectivity, their construction within a complex, polyfunctionalized structure, such as a natural product, requires well-defined methodologies to avoid undesirable by-products and low-to-moderate selectivity. The present review summarizes the effort to collect novel strategies for integrating essential oils into biopolymeric matrixes, focusing mainly on the association mechanisms and the structure-function interplay. For this purpose, the latest derivatization methods of biopolymeric matrices are presented. New advances in design approaches to controlled delivery systems based on essential oil/biopolymer matrices and future application trends are also discussed.