Herbal essential oils such as Cuminum cyminum are natural antifungal agents consisting of many different
volatile compounds. In the present study, encapsulation by chitosan (CS)–caffeic acid (CA) nanogel was
used to improve antimicrobial activity and stability of the C. cyminum essential oils against Aspergillus
flavus. An encapsulation efficiency of 85% based on the optical density spectra of the essential oil was
achieved and as revealed through the release kinetics studies, 78% of the encapsulated oils were released
during 1 week. The results obtained indicated that due to the volatility and instability of the oils when
exposed to environmental factors, its encapsulation considerably improved its performance. More specifically,
the minimum inhibitory concentration of free and encapsulated C. cyminum essential oils against
A. flavus under sealed condition were at 650 and 350 ppm, respectively. Moreover, the encapsulated oils
performed better (800 ppm), when tested under non-sealed condition while the free oils failed to caused
fungal growth inhibition within the concentration range tested (up to 1000 ppm). This finding could be
of great significance in medicinal plant remedies in order to achieve improved performance of herbal
essential oils at lower concentrations and during longer time frames.