Biohybrid Chitosan–Curcuma aromatica essential oil nanoplatform for oxidative stress-mediated suppression of Aspergillus ochraceus and ochratoxin A

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Ochratoxin A (OTA) contamination by Aspergillus ochraceus is a major food safety concern due to its severe toxicological effects and persistence in stored food. In this study, we developed a novel hybrid chitosan-encapsulated Curcuma aromatica essential oil nanoplatform (Ch-CAEO-NPs) and evaluated its oxidative stress-mediated antifungal and anti-ochratoxigenic activities against A. ochraceus . GC–MS analysis revealed that C. aromatica essential oil (CAEO) has a sesquiterpene-rich profile dominated by ar-curcumene (26.93%), β-caryophyllene (9.74%), and β-curcumene (9.18%). The hybrid nanoformulation showed high encapsulation efficiency (93%), loading efficiency (16.9%), sustained release, average hydrodynamic particle size of ∼210 d. nm, and positive zeta potential (+29.61 mV), indicating good colloidal stability. FTIR, XRD, and SEM analyses confirmed the successful encapsulation of CAEO within the chitosan matrix and the formation of stable spherical nanoparticles. The hybrid Ch-CAEO-NPs exhibited potent antifungal activity against A. ochraceus , with MIC and MFC values of 72 and 116 μg/mL, respectively. Mechanistic investigations revealed a significant concentration-dependent induction of intracellular reactive oxygen species (ROS), disruption of membrane integrity, intracellular DNA and protein leakage, and severe ergosterol depletion, indicating that oxidative stress-mediated membrane damage is the primary antifungal mechanism. Furthermore, the hybrid nanoplatform significantly inhibited fungal biomass and OTA production in potato dextrose broth and maize grain storage. Principal component analysis (PCA) confirmed strong correlations among ROS generation, membrane disruption, ergosterol depletion, fungal growth suppression, and OTA production inhibition. Compared to in vitro conditions, higher concentrations were required in maize grains because of the complex matrix and reduced nanoparticle diffusion. Overall, the findings demonstrate that hybrid Ch-CAEO-NPs possess strong sustained-release behavior, potent oxidative stress-mediated antifungal activity, and remarkable anti-ochratoxigenic efficacy against A. ochraceus . This is the first report describing a chitosan-encapsulated C. aromatica essential oil hybrid nanoplatform for OTA contamination suppression in stored food systems, highlighting its potential as a sustainable and eco-friendly nano-preservative for post-harvest food protection.

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