Laurus nobilis essential oil nanoemulsion-infused chitosan: A safe and effective antifungal agent for masticatory preservation

Abstract

The present study reports the first time investigation on encapsulation of Laurus nobilis essential oil into chitosan nanoemulsion (CS-Ne-LNEO) and assessment of its efficacy to inhibit fungal infestation and aflatoxin B₁ (AFB₁) contamination in stored masticatories food system. Gas chromatography mass spectrometry (GC-MS) analysis revealed m-Eugenol (46.23%) and D-Limonene (8.89%) as the most abundant components of LNEO. The CS-Ne-LNEO was physico-chemically characterized through scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and x-ray diffractometry (XRD) analyses. The CS-Ne-LNEO exhibited broad range of antifungal activity against food contaminating fungi including inhibition of toxigenic Aspergillus flavus (AF-LHP-PE-4) and AFB₁ production at lower concentrations as compared to unencapsulated LNEO. The CS-Ne-LNEO caused impairment in ergosterol biosynthesis and enhancement in leakage of Ca²⁺, Mg²⁺, K⁺ ions and 260, 280 nm absorbing materials along with inhibition of methylglyoxal production suggesting the antifungal and antiaflatoxigenic mechanism of action. The DPPH antioxidant activity of CS-Ne-LNEO was noted with IC₅₀ value of 0.004 µL/mL. In addition, the CS-Ne-LNEO caused complete protection of stored Phyllanthus emblica (model masticatories) fruit samples against fungal and AFB₁ contamination without altering their sensory characteristics and exhibited high LD₅₀ value (13,504 µL/Kg body weight) mammalian system. Overall, these results indicated that LNEO loaded chitosan nanoemulsion could be promoted as an eco-friendly preservative for complete protection of stored plant masticatories against fungal and AFB₁ contamination.