Preparation and evaluation of food-grade nanoemulsion of tarragon (Artemisia dracunculus L.) essential oil: antioxidant and antibacterial properties.

This study aimed at to formulate a food-grade nanoemulsion of tarragon essential oil (NEO) and investigate its antioxidant and antimicrobial properties. Oil in water NEO was formed by blending 10% of tarragon EO (TEO), 85% water, and a mixture of 5% surfactants, then antioxidant and antimicrobial activities were evaluated. The main components of TEO were estragole, beta-cis-ocimene, beta-trans-ocimene, and l-limonene. NEO droplet had a diameter of 50 nm and a zeta potential of - 30 mV. Results of free radical DPPH scavenging activity revealed that hydrogen donating capacity of the nanoemulsion was significantly higher than TEO and at 2.5 µg/mL concentration it showed complete inhibitory activity against DPPH. The ferric reducing potential was almost similar for TEO and NEO. NEO showed higher antibacterial potential against Staphylococcus aureus and Listeria monocytogenes and Shigella dysenteriae. The results of this work indicated that NEO had higher antioxidant and antimicrobial activity compared with free TEO. © Association of Food Scientists & Technologists (India) 2020.