Determination of total polyphenol content in different brands of tea

Ng, Helen Lee Ching (2006) Determination of total polyphenol content in different brands of tea. Universiti Malaysia Sabah. (Unpublished)

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Abstract

Polyphenol content are widely present in human diet as component of fruits, vegetables and is especially high in tea. Consumption of tea as a beverage exhibits significant health effects including antioxidative, anticarcinogenic, antimicrobial and protection against cardiovascular disease. Determination of total polyphenol concentration in seven brands (four types) of tea obtained from the local supermarket was carried out. The chosen brands were Boh tea, Sabah tea (Black tea), Shuang Long tea, Fairy tea (oo-long tea), China tea, Yu Xian Nu tea (green tea) and Borneo Rainforest (organic tea) respectively. Total polyphenol contents in each sample were analyzed by Folin Ciocalteu and Ferrous Tartarte method, following aqueous extraction and detennination using UV-Spectrophotometer. The range and means of total polyphenol content (mg/g) using Folin Ciocalteu method with different parameters respectively are as follows; plain tea leaves (18.34-20.98; 19.7), addition of 2g sugar (21.48-20.06; 20.6), addition of 1ml lemon (18.96-21.25; 20.18) and addition of 5ml condensed milk (21.39-24.61; 22.6). In addition, the range and means of total polyphenol content (mg/g) using Ferrous Tartrate method for respective parameters is as follows; plain tea leaves (19.55-45.74; 30.5), addition of 2g sugar (50.94-24.75; 34.8), addition of 1ml lemon (22.05-46.81; 31.6) and addition of 5ml condensed milk (31.61-63.83; 41.1). The percentage increment of all the parameters analyzed with respect to the plain tea leaves samples using Folin Ciocalteu method range from 2.4-9.4 (addition of 2g sugar), 1.1-3.4 (addition of 1ml lemon) and 12.2-17.3 (addition of 5ml condensed milk) respectively. For Ferrous Tartrate method the percentage of increment is range as follows; 8.6-31.2 (addition of 2g sugar), 2.3-12. 8 (addition of 1mllemon) and 24.8-61.7 (addition of 5ml condensed milk). ANOVA one-way test on all the tea brands analyzed clearly showed that green tea brand (China tea) yields higher polyphenol content as compared to black tea brand (BOH tea). Independent t-test showed there was a significant difference between two methods analyzed (p<0.05), but from linear regression test, positive correlation could be achieved between both methods and total polyphenol content. Suggestion to use Ferrous Tartrate method would be a better choice for tea analysis. Overall, the variations of value for total polyphenol content in all tea analyzed depends mostly on solvent used, method of extraction, parameters analyzed and the most crucial part is the tea plant itself.

Item Type: Academic Exercise
Uncontrolled Keywords: polyphenol concentration, tea, fruit, vegetable, method of extraction
Subjects: T Technology > TX Home economics > Nutrition. Foods and food supply
Divisions: SCHOOL > School of Food Science and Nutrition
Depositing User: MDM SITI AZIZAH IDRIS
Date Deposited: 24 Oct 2013 01:19
Last Modified: 17 Oct 2017 04:42
URI: http://eprints.ums.edu.my/id/eprint/7359

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