Modelling release mechanisms of cinnamon (Cinnamomum zeylanicum) essential oil encapsulated in alginate beads during vapor-phase application

Abstract Encapsulation efficiency of Cinnamomum zeylanicum essential oil (EO, at 5% v/v) in sodium alginate beads and its controlled release was determined. Composition of vapors generated by the beads was assessed by solid-phase microextraction. Water and EO released from the beads in the vapor phase were determined at 59% or 88% relative humidity at 4 °C or 25 °C. First and second order dynamic models appropriately described release mechanisms of water and EO, demonstrating Fickian behavior in both cases, in which diffusion mainly depends on EO concentration gradients. Encapsulation efficiency was 85.43% ± 4.97%, volatile components (cinnamaldehyde, caryophyllene, and α-caryophyllene) were detected in the vapor phase. Water and EO release rates were higher at the higher temperature, while a higher relative humidity led to lower water release but greater EO diffusion. Furthermore, enhanced antifungal (against Botrytis cinerea, Penicillium expansum, Alternaria alternata, or Colletotrichum gloeosporioides) activity of encapsulated EO was observed in vapor phase.