Total phenolic contents and antioxidant activities of selenium-rich black tea versus regular black tea
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Date
3/04/2017
DOI
Open Access Location
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Journal ISSN
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Publisher
DIILI
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Abstract
Two black aqueous tea extracts of Camellia sinensis, (seleniumrich
black tea (Se-BTE) and regular black tea (R-BTE)) were
assessed for their total phenolic content (TPC) and antioxidant
properties. Aqueous tea extracts were prepared using different
extraction temperature and time. TPC was measured using the
Folin-Ciocalteu method, while antioxidant activity was measured
by ferric-reducing antioxidant power (FRAP) and 2,2-diphenyl-1-
picrylhydrazyl (DPPH) assays. The R-BTE showed significantly
higher TPC (P < 0.05) and antioxidant activity (P < 0.05) than the
Se-BTE, which may be due to these being different cultivars, or
differences in growing conditions. Our findings demonstrate that
both extraction temperature and time are important determinants of
extracted TPC and antioxidant activities of these teas. In addition
and in contrary to our expectations, the high level of organic
selenium in black tea did not enhance the antioxidant activity when
compared with black tea containing very low level of organic
selenium. Other elements and minerals may contribute to the high
antioxidant activity detected in the regular black tea.
Description
Keywords
selenium-rich black tea, regular black tea, total phenolic contents, ferric-reducing/antioxidant power, DPPH-scavenging activity
Citation
American Journal of Life Science Researches, 2017, 5 (2), pp. 40 - 50 (11)