Citrus essential oils' nano-emulsions: formulation and characterization

The use of citrus essential oils nano-emulsions (CEO-NE) plays a crucial role in enhancing food safety. This is achieved through various mechanisms such as the enhancement of organoleptic properties, increased bioavailability of bioactive components from essential oils, controlled release of key compounds for long-term efficacy, and extension of the shelf life of food and beverages (antioxidant and antimicrobial activity). In this work, CEO-NEs, formulated with different types of citrus essential oils, Tween 80, and alcohol, were obtained by magnetic stirring combined with ultrasound method. The main component of CEO-NEs was D-limonene (31.37 % bergamot-loaded nano-emulsions, 48.81 % tangerine-loaded nano-emulsions, 87.82 % orange-loaded nanoemulsions, 87.09 % grapefruit-loaded nano-emulsions, 48.53 % lemon-loaded nano-emulsions). The selected formulations demonstrated a mean droplet diameter of 47.285 nm. The nano-emulsions were stable even after 30 days of storage (except tangerine nano-emulsions). The bergamot-loaded nano-emulsion had the highest antibacterial activity against Escherichia coli, while Staphylococcus aureus and Listeria monocytogenes seemed to be more resistant to citrus nano-emulsions.