Characterization of M–F microcapsules
The infrared spectra of thyme oil and M–F microcapsules were
measured by a Fourier transform infrared (FTIR) spectrophotometer
(Jasco FT/IR 430, Jasco, Japan) to confirm successful encapsulation.
Scanning electron microscopy (SEM, JSM-5410LV,
JEOL, Japan) was used to visualize the morphology and surface
of the microcapsules. Each microcapsule was sprinkled on a brass
stub, which was adhered with double-sided tape and coated using
a gold/osmium coater (JSC-1100E, JEOL, Japan) at 10 mA for
5 min and then was observed using a microscope. Thermal properties
of the microcapsules were investigated using a differential scanning
calorimeter (DSC, Seiko instrument, Japan) under nitrogen
atmosphere. The samples of about 1.5 mg were heated to 300 ◦C
at a rate of 10 ◦C/min.