Research Progress on Delivery Systems of Plant Essential Oils and Applications in Fruit and Vegetable Preservation

Plant essential oils, which can effectively extend the shelf life of fruits and vegetables, possess antioxidant, antibacterial and insect repellent properties, demonstrating them as promising natural preservatives for fruits and vegetables. However, the applications of plant essential oils in fruit and vegetable preservation are limited due to their disadvantages such as high volatility, poor stability and weak hydrophilicity, as well as strong aroma. Stable plant essential oil delivery systems that can form a barrier to the external environment provide new methods and approaches to overcome these limitations. In addition, the delivery systems can improve biocompatibility and have controllable release function, thus enhancing the utilization rate of plant essential oils. In the present paper, we review the composition, antioxidant, antibacterial and insect repellent activity and mechanisms of action of plant essential oils, and summarize various delivery systems including nano-emulsions, microemulsions, microcapsules, and liposomes and their preparation methods, and discuss the major factors affecting the encapsulation efficiency, particle size and physical stability of plant essential oils such as preparation methods, emulsifiers, the type and concentration of wall material. Finally, we summarize the applications and prospects of delivery systems for plant essential oils in fruit and vegetable preservation with the aim of providing a theoretical foundation for the development of new, effective fruit and vegetable preservatives.