Modeling the release of antimicrobial agents (thymol and carvacrol) from two different encapsulation materials

The release of microencapsulated natural antimicrobial (AM) agents (thymol and carvacrol) from two encapsulating matrixes [maltodextrin (MD) and soy protein (SP)] were evaluated for possible use in food packaging coatings. Microcapsules were prepared by oil-in-water (O/W) emulsions at different concentrations (10, 20% for MD and 2, 5% for SP). High encapsulation efficiency ranged from 96 to 99.95% for MD and 93.1 to 100% for SP, with average microcapsule diameters that ranged from 17 to 27.5 and 18.8 to 38 µm, respectively. The release rate with 20% MD-thymol [20MD-T] was faster than with 10% MD-thymol [10MD-T]. Similar results were obtained for carvacrol with the same concentration of MD. Korsmeyer-Peppas and Weibull mathematical models were successfully fitted to the release of the AM agents, describing the Fickian diffusion release of the components. Different release rates were obtained as a function of the chemical nature of the encapsulation material and its concentration.