3.1. Characterization
SEM micrographs of the oil-encapsulated chitosan microsphereswere taken at 5000 X, 10000 X, 20000 X and 40000 X magnifica-tions, and are shown in Fig. 1. The diameters of the oil-encapsulatedchitosan microspheres were in the range 400 nm to 7 m. The bigspheres were pumpkin shaped, whereas the small ones were ovalshaped. There were pores with varying sizes between 20 and 70 nmon the surface of the microspheres. The pores were bigger on thesurface of the big spheres than on the surface of the small spheres.As seen from Fig. 1, the capsules were separated from each other.The surface morphology of the chitosan consists of nanofibers andnanopores [27]. We identified fibers and pores on the surface ofthe chitin and chitosan obtained from crayfish in the present study(Fig. 1). After encapsulation, the nanofibers were lost and only poreswere still present, but the size of the pores was observed to besmaller. These small pores could be very important for releasingthe oils from the capsule.The FTIR bands of chitin, chitosan, the capsule and corian-der essential oil are shown in Fig. 2. The recorded FT-IR bandsat 1654 cm−1, 1619 cm−1and 1550 cm−1show that the chitinextracted from the crayfish was in the form [28]. The observedbands appearing at 1659 cm−1 ( C O) in NHCOCH3group(Amide I band) and 1590 cm−1 (NH2) in NHCOCH3group (AmideII band) show that the chitosan was obtained after deacetylation ofchitin in an alkali solution [29]. The OH and NH stretching bandsat 3356 cm−1in the chitosan were shifted to lower wavenumbers,which indicated changes in the chitosan structure following theencapsulation procedure. These changes can be attributed to theinteractions of the OH and NH groups of chitosan with the C Oof the essential oils [11]. Furthermore, symmetric and asymmet-