Antifungal activity of CS, CA, CS–CA nanogel, free and CS–CA nanogel-encapsulated C. cyminum essential oils were determined against A. flavus. No fungal growth was observed using the essential oils in their free and encapsulated forms but at different concentrations of 650 and 350 ppm, respectively (Table 1). In fact, based on the results obtained the fungi static rate was directly proportional to the concentration of the tested materials in the medium. Interestingly, considerable differences were also observed when the impacts of sealed and non-sealed conditions were compared. More specifically, when used in non-sealed flasks, the free oilsfailed to prevent the fungal growth (even up to the high concentration of 1000 ppm), and the encapsulated form managed to do so at 950ppm which was much higher than its effective concentration
under sealed condition (350 ppm)(Table 2). The deteriorating effect of open (non-sealed) condition could be ascribed to the evaporation of the oils. Hence, higher concentrations would be required to prevent the fungal growth under open condition. Moreover, the superior performance of the encapsulated oils when used in both sealed and non-sealed flasks, in comparison with that of the free oils could be explained by the positive effects of the encapsulating CS–CA nanogel i.e., slow release of the oils in the medium as well
as less evaporation of the oils