| Popis: |
Among many fungal species, Aspergillus flavus is still one of the most important food deteriorating species. Besides rapid growth on different substrates, production of mycotoxins makes it one of the best-known and easily recognized fungal species. Aspergillus oryzae, very similar species is used in food fermentation in China, Japan and other Far East countries. In this work, antifungal effect of thyme essential oil and its main component – thymol was tested on two strains of A. flavus (3.2758 and 3.4408) and one strain of A. oryzae in in vitro and in situ conditions. A. flavus 3.2758 was the most sensitive strain (MIC > 1000 ppm) while A. flavus 3. 4408 and A. oryzae were inhibited by > 2000 ppm. Thymol activity was considerably stronger since minimal inhibitory concentration, for all three tested species, was 250 ppm. In in situ experiments, apples of Granny Smith and Zlatni delišes were treated with different concentrations of thyme essential oil (250, 500 and 750 ppm) or thymol (100, 150 and 200 ppm) and incubated at 20 or 25°C. Higher concentrations of tested compounds and lower temperature time acted synergistically and increased lag phase of colony growth. Fungal growth on Granny Smith apple was retarded compared to growth on Zlatni delišes apple slices. |
