Development of finger citron (Citrus medica L. var. sarcodactylis) essential oil loaded nanoemulsion and its antimicrobial activity

In this work, various surfactants and cosurfactants were selected to develop nanoemulsions of finger citron essential oil (FCEO). Five suitable mixtures of surfactants were obtained: Cremophor EL/1, 2-propanediol (1:1, m/m), Cremophor EL/glycerol (1:1, m/m), Tween 80/ethanol (3:2, m/m), Tween 80/PEG-400 (3:2, m/m) and Tween 80/1, 2-propanediol (3:1, m/m). These five nanoemulsions showed a good stability with average droplet sizes kept below 20 nm for at least 28 days. All of them had low polydispersity index. Antimicrobial activities of these five nanoemulsions against bacteria (E. coli, B. subtilis and S. aureus) and molds (A. niger and P. citrinum) were tested, in which the nanoemulsion with Cremophor EL enhanced the antibacterial ability. However, the antifungal activities of these nanoemulsions were weaker than expected. These developed FCEO loaded nanoemulsions have good physical stability and antibacterial activity, suggesting their potential application in food and beverage fields.