Bacterial Identification and Antioxidant Analysis on Puer Tea
| Autor: | LISA-CHEN, 陳麗莎 |
|---|---|
| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 Puer tea contains many proven antioxidants which can effectively prevent free radicals in the environment and have considerable benefits the human body. In this study, puer tea leaves collected from the market were used for randomly selecting 27 strains, and then the chromosomal DNAs of 27 strains were extracted. PCR was utilized to amplify the 16S rRNA sequences, then to compare gene sequences obtained from searching the NCBI database. The result showed that there are 8 different genus and 17 species. However, there are still 4 species with 6 strains classified in this study have no more 99% similarity of species distributed in the NCBI database. We speculate these lower 16S rRNA similarity may be some new species. In addition, the antioxidants were extracted from puer teas with methanol, and furthermore used for test the Free radical scavenging by DPPH. Reducing power and total polyphenols were also analyzed to understand their antioxidant capacities. About the results of free radical scavenging capacity, the maximum removal capability and minimum removal capacity are 2006’s and 2007’s puer tea. The two oldest ages in 1980, puer tea, powers of free radical scavenging capacity were 77% and 85.7%. About the results of reducing power, the highest and lowest reducing power abilities are the both two 2006's puer tea. The two 1980’s puer tea’s reducing powers are 435.5 and 451.4 μg/ml with relative ascorbic acid. About the results of total polyphenols, the highest and lowest total polyphenols are the 2007's and 1989’s puer tea. The two 1980’s puer tea’s total polyphenols are 1.7 and 2.9 mg/ml with relative gallic acid. According to the three results analysis, the year of puer tea production has no significant relevance. It may be related to the production process of fermentation conditions and the preservation ways of the environment. And further, to understand the impact of the fermentation process in temperature and humidity which changes by microbes will be able explored clearly. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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