Black tea which contains polyphenol is important for health benefits and it is
considered as antioxidant contents .
The extraction parameters, time and temperature and kind of solvent extraction, can
Influence the polyphenol concentrations of Blac
k tea, and were investigated in this study.
The purpose of the study was to quantify the polyphenols (catechin, epicatechin,
epigallocatechin, epicatechin gallate, epigallocatechin gallate)
in different kinds of teas ( Lipton , Alrabee , Layalina ) which are available in Syria
market.The study was conducted using two types of solvents methanol 70% the adoption
of the reference method adopted ISO14502-1 and water 100% , at different extraction
times (1, 3, 5, and 10 minutes) and extraction temperatures (60°C , 70 °C , 80°C, 90°C,
100°C). the total polyphenols content was determined using the phenol reagent (Folin
Ciocalteu reagent) adoption gallic acid as standard compound
the overall content values of polyphenols have been monitoring in extracts methanol
70% and water 100% .
Twenty two samples of black tea were collected from local Syrian markets
during 2009-2010 to study the quality characteristics of tea in terms of
moisture، water extract، caffeine، total ash، water soluble ash، alkalinity of
soluble ash, insoluble
ash in diluted hydrochloric acid in addition to
microscopic examination.
Results showed that all tested samples were identical to the Syrian Standard
No. 286/2003 for all above quality specifications، except for caffeine percent
which was less than the standard in 4 samples. The results also showed that
there was no adulteration with foreign plants nor exhausted tea leaves.
