| Author: | Wong, Wan Yee |
| Title: | Total antioxidant content and polyphenol profile of a range of teas |
| Degree: | M.Sc. |
| Year: | 2013 |
| Subject: | Antioxidants. Catechin. Tea. Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Health Technology and Informatics |
| Pages: | xiii, 97 leaves : ill. (chiefly col.) ; 30 cm. |
| Language: | English |
| Abstract: | Tea (Camellia sinensis) is the second most consumed beverage in the world. Green tea (unfermented), oolong tea (semi-fermented) and black tea (fermented) are major categories of tea that are differentiated by their process of production and composition. It is not only a pleasant, popular and sociable beverage but also has been reported a potential association with health benefits such as anti-oxidant, anti-carcinogenic, anti-atherosclerotic and neuroprotective activities. Most of the benefits are attributed to its polyphenolic flavonoids, catechins. The aims of this work are to study the level of total antioxidant content of green, oolong and black teas in vitro and to analysis their catechin profiles. Ten types of green, oolong and black teas were chosen and carried out the ferric reducing/antioxidant power (FRAP) assay to measure the total antioxidant power of teas and catechin analysis using high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). It is found that all green teas have the highest antioxidant power compared with the others that agreed with previous studies. Catechin, epigallocatechin-3-gallate (EGCG) is reported its highest content among other analyzed catechins. Also, the highest content of EGCG has been shown in green teas. However, relatively high content of EGCG was found in some oolong teas that implied to an alternative of green teas. In addition, a linear relationship was shown between total antioxidant power and catechin content. This study provides more information on the level of total antioxidant power and catechin profiles in commercial tea bags and oolong teas might develop an alternative source of EGCG to green teas. |
| Rights: | All rights reserved |
| Access: | restricted access |
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| File | Description | Size | Format | |
|---|---|---|---|---|
| b26372332.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 1.81 MB | Adobe PDF | View/Open |
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