RELEASE KINETICS OF CYMBOPOGON CITRATUS ESSENTIAL OIL FROM STARCH BEADS

ABSTRACT

The essential oil of Cymbopogon citratus was extracted using a green method (i.e. essential oil still), encapsulated into cassava starch matrix using sodium alginate as a binder. The encapsulated sodium alginate starch beads were characterized using Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectrophotometer (FTIR), release kinetics of the oil was monitored by UV-Visible Spectrophotometry from two (2) aqueous media, buffer of pH 4 and pH 9. The result for SEM showed the sodium alginate starch beads were spherical in shape, average radius of 5 µm, modal area of 0.10 µm2 and average size of 852.28 nm and were good absorbent of essential oil in which its volatility can be entrapped. Release kinetics showed it was at its maximum peak at 2 hours and data obtained spectrophotometrically were further fitted to the various Kinetics Models such as First Order, Pseudo Second Order, Zero Order and Higuchi Order Kinetics Model from which their equations gave (R2= 0.9991, 0.9188) (K= 0.1547, 0.0738), (R2= 0.9962, 0.9201) (K= -0.0071, -0.0038), (R2= 0.9929, 0.8059) (K= 0.0065, 0.0247) and (R2= 0.8389, 0.7216) (K= 0.033, 0.0392), respectively, from the two (2) aqueous media, buffer of pH 4 and pH 9, and it followed the First Order Kinetic Model, which indicated the absorption of the encapsulated essential oil into the porous material of the sodium alginate starch beads and its FTIR showed the functionalities such as OH, CO, CHO, C=C, =C-H and C-H present conformed to the structure of citral, starch and algin.