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Abstract
Thirty types of commercial Vietnamese-brand teas (21 green teas, 5 black teas, 4 oolong teas) in Ho Chi Minh city were investigated for total polyphenols content (TPC acid gallic equivalent), total catechins content (TCC-catechin equivalent) and DPPH (2,2 diphenyl-1-picrylhydrazyl) free radical scavenger activity (RSA - Vitamine C equivalent). It was found that green tea had the highest TPC (15.06 ± 0.53 ppm), TCC (7.33 ± 1.71 ppm) and RSA (288 ± 23 mg) in three grams dried tea, higher than those of oolong tea, whereas black tea had the lowest TPC, TCC, RSA. However, high inconsistency and high deviation from mean values were observed within green tea group. Unexpectedly, several green tea types had low TPC, TCC, and RAC, even as low as those of black tea. This evidence demonstrated the instability and unevenness of green tea quality in Vietnam market.
Issue: Vol 10 No 10 (2007)
Page No.: 5-11
Published: Oct 31, 2007
Section: Article
DOI: https://doi.org/10.32508/stdj.v10i10.2827
Copyright: The Authors. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 4.0., which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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