Thyme essential oil loaded in nanocochleates: Encapsulation efficiency, in vitro release study and antioxidant activity

Essential oils (EOs) are widely used as natural preservatives in foods to control lipid oxidation and spoilage by microorganisms. In this study nanocochleates (NCs), based on phosphatidylcholine, cholesterol and calcium ions were loaded with 1 mg or 0.5 mg/100 ml of TEO and fully characterised. Particle size of TEO NCs were ca. 250 nm and 210 nm, respectively, and all were negatively charged. Thymol and carvacrol encapsulation efficiencies were, 463 +/- 0.01 and 50.9 +/- 0.02 respectively, using 1 mg/ml of TEO. In vitro release studies of thymol and carvacrol indicated a steady release in the first h and after 6 h ca 41% and 31% for thymol and carvacrol were released. Free TEO showed a strong antioxidant activity (75.2%) at the concentration of 1 mg/ml and also TEO-loaded NCs maintained this high scavenging activity (72.2%), indicating that this innovative formulation was able to preserve the antioxidant activity of TEO constituents. Nanochocleates could represent an innovative, completely biodegradable approach for the prolonged and sustained release of the EO, preserving functional properties. (C) 2016 Elsevier Ltd. All rights reserved.