Zein/Gum Arabic Nanoparticles for Cinnamaldehyde Delivery: Enhanced Antifungal Performance and Bread Shelf Life Extension.

Bread is highly susceptible to fungal spoilage, which limits its shelf life. The increasing interest in preservation strategies based on naturally derived antifungals is constrained by the instability of compounds such as cinnamaldehyde, the main component of cinnamon essential oil. This study evaluated cinnamaldehyde-loaded zein/gum arabic nanoparticles for bread preservation, focusing on physicochemical characterization, antifungal activity, in situ performance, and storage stability. The particles, prepared by antisolvent precipitation, showed a mean particle diameter in the nanometric range (∼255 nm), a narrow size distribution (polydispersity index < 0.2), good colloidal stability (zeta potential -21.8 mV), and suitable encapsulation efficiency (71%). Scanning electron microscopy (SEM) analyses revealed spherical particles with smooth and compact surfaces. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) confirmed the incorporation of cinnamaldehyde and the enhanced stability of the compound within the polymeric matrix. Small-angle x-ray scattering (SAXS) indicated nanoscale domains consistent with cinnamaldehyde incorporation, whereas x-ray photoelectron spectroscopy (XPS) confirmed surface zein, supporting encapsulation. Encapsulation maintained or enhanced antifungal activity against Penicillium citrinum, Penicillium roqueforti, Aspergillus niger, and Aspergillus flavus, particularly at subinhibitory concentrations. In situ assays showed a marked delay in fungal growth and reduced contamination in bread treated with encapsulated cinnamaldehyde compared with the cinnamaldehyde control dispersion and untreated bread. Storage studies demonstrated that refrigeration preserved nanoparticle stability and antifungal activity for up to 180 days. Overall, zein/gum arabic nanoparticles provided a stable delivery system for cinnamaldehyde, enabling sustained antifungal performance in bread and offering a promising strategy for controlling fungal spoilage and extending shelf life.