Abstract: In order to achieve the controlled release of thyme essential oil and prolong its bacteriostatic and antioxidant effects, N-FMoc-L-phenylalanine (Fmoc-F) hydrogel was used to encapsulate thyme essential oil. The structure and morphology of the hydrogel were comparatively evaluated before and encapsulation, and the mechanism of encapsulation was studied as well as the controlled release of the encapsulated oil and the effect of Fmoc-F on maintaining its antibacterial and antioxidant activities. The results indicated that the addition of thyme essential oil could significantly decrease the gelation time of Fmoc-F to 50 s, and increase the storage modulus (G’) of the hydrogel. Fmoc-F interacted with itself and with thyme essential oil mainly through hydrogen bonds, both contributing to the formation of hydrolgels with a fibrous network microstructure. The essential oil made the structure denser, thereby resulting in higher storage modulus of the hydrogel. The encapsulation rate of Fmoc-F hydrogel for thyme essential oil was 93.13%. At pH above 6.5, the hydrogel inhibited the volatilization of the encapsulated oil, and it was slowly broken down with the decrease of pH, thus maintaining the antibacterial and antioxidant activities of the essential oil.

Key words: thyme essential oil, N-FMoc-L-phenylalanine (Fmoc-F), hydrogel, controlled release, bacteriostasis, antioxidation