Birinci, Meriç Doğa (2016) Differences in the total number of colonies that resist synthetic stomach environment of homemade and different brand of kefir samples. Other thesis, TED Ankara Koleji.
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Abstract
The aim of my extended essay is to investigate the probiotic benefits of homemade kefir and the four different brands (Ülker İçim, Altınkılıç, AOÇ, Eker) of kefir which can be easily found in the supermarkets exposed to synthetic stomach environment. The research question is: “Will there be a significant difference between the number of alive bacteria in homemade kefir and the four different brands of kefir bought from the store, with regard to their probiotic effects after incubating the cell suspensions from each sample at pH 2 by using Cell Viability Assay method?” My hypothesis is: “There is a considerable difference between the number of alive bacteria in homemade kefir and the four different brands of kefir bought from the supermarket after being exposed to stomach acid, known as hydrochloric acid. Homemade kefir will have the highest number of alive bacteria that resist stomach acid, while the other kefir types which are sold in the supermarkets will have lesser number of alive bacteria.” For the purpose of examining the hypothesis and answering the research question, Cell Viability Assay method was used. All homogenized 10 ml of five kefir samples were exposed to hydrochloric acid (pH: 2) and incubated for four hours at 37 °C. After incubation, serial dilutions were prepared with kefir samples and spread all over the petri dishes. The dishes were incubated for 72 hours at 30°C in an incubator. Lastly, the number of colonies were counted and results were compared to each other. The final results of the experiment indicated that, Ülker İçim has the highest mean number of alive bacteria colonies (313) left after being exposed to hydrochloric acid. The homemade kefir which was expected to have the largest number of alive bacteria, is in the second rank (296). Altınkılıç (strawberry flavoured) is in the third place (144). AOÇ has taken the fourth place (118), followed by Eker which has the lowest number of alive bacteria (49).These results showed that the homemade kefir doesn’t have the highest number of alive bacteria after being treated with hydrochloric acid and this doesn’t support the hypothesis. Hence, the mean results demonstrate that there is slight difference between Ülker İçim and the homemade kefir with regard to the number of alive bacteria. According to the ANOVA test results, there is a significant mean difference between the number of alive bacteria colonies in homemade and four different brands of kefir. The p-value of the test is 6.21x10-18, which is smaller than 0.05.
| Item Type: | Thesis (Other) |
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| Additional Information: | Supervisor: Demet İzgü |
| Subjects: | Q Science > QH Natural history > QH301 Biology |
| Depositing User: | Users 114 not found. |
| Date Deposited: | 23 Sep 2016 11:22 |
| Last Modified: | 23 Sep 2016 11:22 |
| URI: | http://tedprints.tedankara.k12.tr/id/eprint/796 |
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