Chitosan Nanoencapsulation of Angelica archangelica Essential Oil: In Vitro Sustained Release and Inhibition of Aspergillus flavus and Aflatoxin B1 in Stored Maize

Contamination of stored grains by Aspergillus flavus and aflatoxin B₁ (AFB₁) remains a major food-safety concern, highlighting the need for effective natural preservation strategies. This study developed a chitosan-encapsulated Angelica archangelica essential oil nanoformulation (CS@AAEO-NF) and evaluated its effects on fungal growth and AFB₁ accumulation. GC–MS identified 19 compounds representing 96.31% of AAEO, predominantly β-phellandrene (33.68%) and terpinen-4-ol (19.41%). Free AAEO exhibited MIC and MFC values of 85.50 ± 4.72 and 132.33 ± 11.83 μg/mL, respectively, and induced oxidative stress, membrane permeabilization, ergosterol depletion, biomolecule leakage, and hyphal damage in A. flavus . The optimized CS@AAEO-NF (nominal chitosan:AAEO ratio, 1:0.8 g:mL; corresponding mass ratio, 1:0.712 w/w) showed 63.14 ± 6.43% encapsulation efficiency, 14.18 ± 2.43% loading efficiency, a mean hydrodynamic diameter of 140.0 ± 3.74 nm, PDI of 0.15 ± 0.02, and zeta potential of +37 ± 1.89 mV. Approximately 69% of AAEO was released over 180 h, with the Korsmeyer–Peppas model providing the best empirical fit (R² = 0.9904; n = 0.742), descriptively consistent with anomalous release behavior. In the 28-day high-water-activity artificial maize challenge model, untreated grains contained 8.96 ± 0.25 log CFU/g A. flavus and 795 ± 15 μg/100 g AFB₁. At 150 μg AAEO-equivalent/g, CS@AAEO-NF reduced these values to 0.67 ± 0.52 log CFU/g and 98.5 ± 21.5 μg/100 g, respectively; both endpoints were below detection at 175 μg AAEO-equivalent/g, whereas free AAEO required 250 μg/g. Blank chitosan nanoparticles produced only partial reductions in fungal growth and AFB₁ accumulation. These findings show that CS@AAEO-NF reduced AFB₁ accumulation in association with inhibition of fungal growth and support its evaluation as a nano-preservation strategy for controlling A. flavus and reducing AFB₁ accumulation in maize, although further safety and validation under normal commercial grain-storage conditions are required before practical food application.