Sustainable Use of Essential Oil Nanoemulsions to Control Postharvest Spoilage in Fruits and Vegetables: A Review

Background: Postharvest losses of fruits and vegetables represent a critical global challenge. While synthetic fungicides have traditionally served as the primary preservation strategy, their environmental persistence, toxicity to non-target organisms, and potential for resistance development have intensified research into sustainable alternatives. Scope of Review: This review examines the emerging technology of essential oil nanoemulsions as a promising solution for postharvest fruit preservation. Essential Oil Properties and Limitations: Essential oils, extracted from citrus fruits, herbs, and spices, possess potent antimicrobial and antioxidant properties attributed to terpenes, terpenoids, and phenolic compounds. However, their direct application faces significant limitations: high volatility, poor water solubility, and intense sensory impact at effective concentrations. Nanoemulsion Technology: Nano-encapsulation technology addresses these challenges by creating oil-in-water nanoemulsions with droplet sizes of 20-200 nm through high-energy methods (high-pressure homogenization, microfluidization, ultrasonication) or low-energy approaches (phase inversion techniques). The antimicrobial mechanism involves the disruption of microbial cell membranes through hydrophobic interactions, while the antioxidant activity occurs through free radical scavenging and the inhibition of lipid peroxidation. Nanoemulsion systems enhance bioavailability, enable controlled release, improve water dispersibility, and protect bioactive compounds from degradation. Research Findings: Research demonstrates substantial shelf-life extensions across various fruits and vegetables, with nanoemulsions showing superior antimicrobial efficacy at lower concentrations than conventional formulations. Current challenges limiting commercial adoption include high production costs, scalability issues, complex regulatory frameworks for nano-structured food materials, and formulation optimisation requirements. Future Perspectives: Future research must prioritise cost-effective production methods, mechanistic elucidation, synergistic preservation combinations, and comprehensive sensory-nutritional assessments. Essential oil nanoemulsion coatings represent a paradigm shift toward sustainable postharvest preservation, offering enhanced food safety, extended shelf life, and maintained nutritional quality with significant promise for reducing global food waste.