Antimicrobial, Aflatoxin B1 Inhibitory and Lipid Oxidation Suppressing Potential of Anethole-Based Chitosan Nanoemulsion as Novel Preservative for Protection of Stored Maize

Abstract

Aflatoxins (AFs) are the most frequent contaminants of maize and maize-based products, and its consumption can cause severe adverse effects to humans and animals. The efficacy of essential oils (EOs) and their bioactive compounds as potential antifungal agents has been well documented against food-borne fungi. This study evaluates the preservative potency of anethole-based chitosan nanoemulsion (Ant-eCsNe) to control deterioration of stored maize samples from fungal infestation, aflatoxin B1 (AFB1) contamination and lipid oxidation. Release study indicated a relatively good sustainable release profile for the encapsulated anethole after 10 days. The Ant-eCsNe showed improved efficacy against A. flavus (AF-LHP-VS8) and other common food-borne moulds and inhibited growth and AFB1 biosynthesis at 0.8 and 0.4 μL/mL, respectively. Ant-eCsNe caused concentration-dependent inhibition of ergosterol content and increased efflux of cellular ions (Ca+2, Mg+2 and K+) and 260 and 280 nm absorbing materials, suggesting damage of fungal plasma membrane. Inhibition of methylglyoxal in fungal cells treated with Ant-eCsNe signifies its novel antiaflatoxigenic mechanism of action. Ant-eCsNe exhibited strong in vitro DPPH• and ABTS+• scavenging activity with IC50 value 89.36 and 45.05 μL/mL, respectively, and inhibited lipid oxidation in stored maize samples. Further, Ant-eCsNe exhibited reasonably strong efficacy in preserving maize samples from fungal and AFB1 contamination during in vivo investigations and did not change the sensory attributes as well. Overall results revealed that Ant-eCsNe holds good potential to be applied as food preservative to reduce fungal and aflatoxin contamination causing deterioration of stored maize.