Abstract: The antibacterial activity of encapsulated and non-encapsulated eucalyptus essential oil (EEO) was determined by the agar well diffusion method, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were studied by vapor diffusion method. Besides, the chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the EEO had antibacterial activity against all tested bacteria, yeast and mold irrespective of encapsulation. Its antimicrobial activity against yeast was the strongest followed by bacteria, and its antimold activity was weaker. The MIC and MBC of EEO did not significantly differ before and after encapsulation, and the major chemical components were identical, including terpenes and alcohols. The disappearance or decrease of some terpenes in the essential oil after encapsulation resulted in a slight decrease in its antibacterial activity; while its MIC remained unchanged, its MBC against Saccharomyces cerevisiae and Penicillium citrinum was slightly increased.

Key words: eucalyptus essential oil, encapsulation, antibacterial properties, vapor diffusion, chemical composition