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Register a new userDetermination Total polyphenol Conten in different Black Teas commercially in Syria
تحديد محتوى البوليفينولات الكلية في بعض أنواع الشاي الأسود المتوفرة في الأسواق السورية
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تكمن أهمية الشاي الأسود في الفوائد الصحية المرتبطة بمحتواه من البوليفينولات و التي تعتبر مضادات أكسدة, تم التحقق من خلال عمليات استخلاص أن كمية هذه المضادات تتعلق بمتغيرات مثل زمن النقع و درجة الحرارة و نوع المذيب المستخدم في الاستخلاص و أن هذه المتغيرات تؤثر في تراكيز البوليفينولات المستخلصة من الشاي الأسود المدروس . تمّ تحديد كمية البوليفينولات ( كاتشين، إيبيكاتشين،إيبيغاللوكاتيشين، إيبيكاتشين غاليت، إيبيغالوكاتيشين غاليت) في أنواع مختلفة من الشاي الأسود ( ليبتون , الربيع , ليالينا ) المتوافرة في الأسواق السورية.أجريت الدراسة باستخدام نوعين من المذيبات الأول : ميتانول 70% حسب الطريقة المرجعية المعتمدة ISO14502-1 الثاني ماء الصنبور 100% و أزمنة استخلاص (أزمنة نقع) مختلفة (1, 3, 5 و 10 دقائق ) و بدرجات حرارة استخلاص (60, 70, 80, 90 , 100 درجة مئوية ) . تم تحديد المحتوى الكلي للبوليفينولات في أنواع الشاي المدروسة باستخدام كاشف الفينول ( فولين سيكالتو) و اعتماد حمض الغاليك كمركب عياري . تم رصد قيم المحتوى الكلي للبوليفينولات الموجودة في مستخلصات ميتانول 70% و الماء 100%.
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 Black 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% .
References used
YUENGAN GZU.Simultaneous Determination of Catechins,Caffeine and gallic acid in Green ,Oolong ,Black and pu-ersh Teas using HPLC.Talanta(2002)307-316
(ANKITA SOOD..Extraction,purification and Extraction of Tea Catechins.Institute of Himalayan Biore Source Technology(2007-2009
RUCHI VERMA ;LALIT KUIMR.Characterization of Caffeine Isolated From Camellia Sinensis Leaves of Sikkim Himalayan Region .Journal of Chemical and Pharmaceutical ,Research.J.Chem.pharm.Res;2010,2(4):194-198.ISSN NO:0975- 7384,CODEN(USA):JCPRC5
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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.
This research concludes an determination of some Culicinae mosquitoes
distributed in south of Syria.
The study show that there are 14 species, 3 of them were recorded for the
first time in the study area, these 3 species were described, illustrate
d , and
distinguished from related species ,the seasonal reproduction and the habitat
types of these were studied .
(Culex perexiguus , Cx.sinaiticus , Cx.territans).
Four different brands of black tea and one brand of green tea commonly
available in Syrain markets were tested to measure the level of fluoride
contained in their liquid using four different methods of infusion and utilizing
the spectrophotometer
technology: A. Infusion without boiling. B. Infusion with
boiling. C. Repeated infusion. D. Continuous infusion.
The results have indicated that the average level of fluoride in the samples
of black tea liquid is higher than the one in the green tea sample regardless of
the infusion method used. Also, it was found that the level of fluoride released
from all samples is higher when boiling them in water from 1 to 5 minutes. In
addition, it was proved that the level of fluoride in tea liquids is higher when
it’s prepared using repeated infusion, but it’s lower when the tea has been
prepared using the continuous infusion method. Tea brands (2) and (4) released
the highest level of flouride 7.37mg/L and 5.01mg/L respectively, which are
very high levels comparing to the other brands which released between 1.5mg/L
to 2.7mg/L. To prevent fluoride from reaching poising levels, the total daily
consumption of black tea liquid of brands (2) and (4) should not exceed 1.76L
and 2.58L respectively and to avoid preparing them using the repeated and
countinous infusion methods.
Ten medicinal plants were chosen from various plants in Syria which
used as spices or cooked and Syria traditional medicine. Their names
Rosemary, Damask rose, Chamomile, Sumac, Silver linden, Black
cumin, Thyme, Mint, Laurel and lemon balm.
Mois
ture, yield of extraction, total phenolic content (TPC) and
antioxidant activities of methanol, ethanol, acetone and aqueous extracts
of medicinal plants were investigated.
The TPC were measured by Folin-Ciocalteu method, and the antioxidant
activity was assessed by the scavenging activity towards 2, 2′-diphenyl-
1-picryl hydrazyl (DPPH)-radical.
Total polyphenols (TP), total flavonoids (TF) and (-)-epigallocatechin gallate
((-)-EGCG) were determined in five commercial tea infusions by continuous
infusion method, using the ratio 20g of tea to 1L of water at 85±5 °C and
brewing time between 5-180 min.
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