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Addis Ababa University Libraries Electronic Thesis and Dissertations: AAU-ETD! >
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Thesis-Food science and Nutriation >
Please use this identifier to cite or link to this item:
http://hdl.handle.net/123456789/3139
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| Title: | GROWTH INHIBITION OF GRAIN SPOILAGE FUNGI BY SOME HERB AND SPICE ESSENTIAL OILS GROWN IN ETHIOPIA |
| Authors: | Diriba, Chewaka |
| Advisors: | Dr. Dawit Abate |
| Keywords: | GROWTH INHIBITION
GRAIN SPOILAGE FUNGI |
| Copyright: | Jun-2009 |
| Date Added: | 22-May-2012 |
| Publisher: | ADDIS ABABA UNIVERSITY |
| Abstract: | Microbial food contamination is an on-going limiting factor in crop production that can
determine the shelf life of processed and unprocessed foods. Spice plants and herbs are
commonly used as food flavoring and seasoning agents. Their antimicrobial properties as food
preservatives are also well documented. In this study, essential oils of seven spice plants were
tested for their antimicrobial properties against Aspergillus flavus and A. niger, two of the most
important food and feed spoilage organisms. Agar disk diffusion assay was used for screening
of the most effective essential oils, agar dilution assay was used to determine Minimum
Inhibitory Concentration (MIC) of the essential oils and broth dilution assay was employed to
the spore germination inhibition assay. Tests were also conducted to examine the effects of the
essential oils for sorghum kernel protection against the tested fungi, and the optimal protective
dosages on the sorghum grains were also determined. From the preliminary tests, essential oils
of Cinnamomum zeylanicum (Cinnamon) and Thymus schimperi (thymus) were found to be the
most effective. However piper nigrum (black pepper) had no effect on the test organisms. In
MIC, spore germination inhibition and grain protection assay, cinnamon essential oil was found
to be superior where its MIC on the isolates was found to be 0.0156% and its optimum
protective dosage on the grain was 5%. It inhibited spore germination at a concentration of 3
L/ml. The effect of thymus oil was also very much comparable to these results (no significant
difference at P < 0.05).
Finally, it could be concluded that some plant essential oils can be a useful source of antifungal
agents for protection of grain spoilage by fungi. |
| URI: | http://hdl.handle.net/123456789/3139 |
| Appears in: | Thesis-Food science and Nutriation
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