Nano-Delivery System for the Prevention and Control of the Disease

Kiwifruit soft rot is a major cause of postharvest loss owing to rapid fruit decay during storage. This study focused on kiwifruit soft rot during the postharvest storage stage, when fungal development may be promoted by room temperature and high humidity. Soft rot symptoms were observed in the pericarp and fruit flesh. In this study, carvacrol-loaded nanoliposomes (CAR@NL) were prepared by an O/W emulsification–solvent evaporation method to control kiwifruit soft rot. The physicochemical properties of CAR@NL were characterized by laser particle size analysis, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). Their antifungal activity and preservation efficacy were evaluated by in vitro antifungal assays and fruit storage experiments. The prepared CAR@NL showed an average particle size of approximately 280 nm, an encapsulation efficiency of 85.75%, and a drug loading capacity of 20.14%, along with favorable sustained-release properties. CAR@NL exhibited strong antifungal activity, with an EC50 value of 41.76 mg/L. DAPI staining indicated no obvious effect on fungal DNA, whereas propidium iodide (PI) staining revealed increased fluorescence intensity with increasing concentration and treatment time, indicating disruption of hyphal membrane integrity and severe structural damage. Flow cytometric analysis further showed that, at 50 mg/L, the total apoptosis rate was 2.96% in the untreated control group, 5.22% in the CAR@NL-treated group, and 33.6% in the carbendazim-treated group, demonstrating the lower cytotoxicity of CAR@NL toward mammalian cells. In addition, CAR@NL showed good stability and preservation performance during fruit storage. Overall, CAR@NL may serve as a safe and effective postharvest agent for the control of kiwifruit soft rot.