**Abstract**

Encapsulated essential oils (EO) by different techniques have demonstrated antimicrobial activity against bacteria, compared to the nonencapsulated ones. The study of the EO release is important, in order to predict the time in which it will be available to exhibit its antimicrobial activity to inhibit or inactivate specific microorganisms. The objective of this study was to analyze and model the release of cinnamon essential oil (CEO) and rosemary essential oil (REO) encapsulated by emulsification using high-frequency ultrasound. A concentration of 10 μL/mL was obtained for OEO after 60 min in aqueous solution under stirring, while for REO, a concentration of 60 μL/mL was obtained after 360 min. The CEO microemulsion droplet size was smaller than in REO microemulsion, thus enhancing its release in the aqueous solution. The release profiles were fitted to different kinetic models; a first-order kinetic described CEO microemulsion release, while a second-order kinetic was used for REO microemulsion release. The encapsulated EO by high-frequency ultrasound can be applied as water-soluble natural antimicrobial additives in different food systems with long-term release periods.

**Keywords:** natural antimicrobials, release kinetics, encapsulation, high-frequency ultrasound
