Advances in efficient encapsulation and controlled release strategies for citrus oils

Citrus oils (COs) are extremely popular food-grade natural flavors and are renowned for their health benefits and food preservation attributes. However, challenges related to their low solubility, instability, and intense volatility have impeded the controlled release of COs within food matrices. In recent years, encapsulation techniques have emerged as promising ways to overcome these issues. Citrus oil-loaded encapsulation systems designed using suitable biopolymers and encapsulation techniques enable safe usage, effective encapsulation, and controlled release. Encapsulated COs with controlled-release profiles have enhanced functionality in a range of food application scenarios, thereby increasing the commercial value of COs. This review summarizes the natural biopolymers that have been used as encapsulation materials (e.g., protein-based and carbohydrate-based). It also explores the encapsulation techniques, predominantly the non-thermal methods (e.g., low-energy emulsification, spraying, and electrospinning techniques), and the controlled release of CO-loaded encapsulation systems, including release profiles, release kinetics, and multiple factors affecting release. Finally, it provides a detailed summary of commercial applications and future potential of encapsulated COs. This review summarizes the available evidence and the technical supports needed to further guide the development of encapsulated COs as food additives, dietary supplements, and food preservatives.