A kinetic study of the release of vanillin encapsulated in Carnauba wax microcapsules

Thermal release of vanillin encapsulated in Carnauba wax microcapsules was studied by isothermal thermogravimetric analysis at 443, 453, 473, and 483 K. The thermal analysis data were analyzed kinetically and it was found that they can be satisfactorily described mathematically by the Avrami–Erofe’ev kinetic model A3. However, application of the isoconversional Friedman’s method showed that the activation energy of the vanillin release changes significantly with the degree of conversion, implying that the release is not a single-step reaction but a complex kinetic process. Nonetheless, the activation energies throughout the process remain relatively low (below 40 kJ mol−1), meaning that the Carnauba wax as a carrier can easily release vanillin in food processing.