Assessment of Fluoride in the Ethiopian and Imported; Black and Green Tea (Camellia sinensis) Infusions: Measurement and Safety Evaluation
| dc.contributor.advisor | Chandravanshi B.S. (Professor) | |
| dc.contributor.author | Zerabruk Samuel | |
| dc.date.accessioned | 2018-06-22T05:45:32Z | |
| dc.date.accessioned | 2023-11-09T16:17:47Z | |
| dc.date.available | 2018-06-22T05:45:32Z | |
| dc.date.available | 2023-11-09T16:17:47Z | |
| dc.date.issued | 2009-07 | |
| dc.description.abstract | The fluoride contents in the infusions of 21 commercially available Ethiopian and imported black and green tea brands; in leaf and bag forms was determined by fluoride ion-selective electrode. Of the samples analyzed 12 of them were products of Ethiopia. It is found that fluoride level increases with increasing brewing time (3, 5 and 10 min). The present study revealed wide differences in fluoride levels. Fluoride level of black tea leafs after 5 min brewing, which is the common time used to prepare tea infusions, was in the range of 117 – 682 mg/kg, for green tea bags it was between 111 – 190 mg/kg and that of black tea bags fluoride concentration was in the range of 141– 246 mg/kg. While the Ethiopian black tea leafs fluoride level ranges from 248 to 682 mg/kg with mean concentration of 458 mg/kg among ten brands. Of the imported products, teas of the same brand, the fluoride content was greatest in black tea bags, presumably because black tea bags are made from low cost older tea leaves. While the fluoride level in green tea was found lesser, as green teas are made from young shouts of the plant which contain less amount of fluoride. On the basis of the results obtained, the daily intake of fluoride provided from tea was estimated for an adult person and for children in comparison with the WHO guide line for daily fluoride in take thresholds Which is 2 mg for children and 4 mg for adults. Assuming that one consumes 4 cups of tea everyday (400 mL) and each cup uses 2.5 g of tea leaf or one tea bag, daily fluoride intake through taking the black tea leafs may be 1.11 – 6.82 mg, 1.00 - 1.38 mg through green tea bags and from the black tea bags it may range from 0.86 – 1.81 mg. from the Ethiopian black teas alone, the daily fluoride intake may range from 2.48 – 6.82 mg. Thus according to the WHO, 2002 recommendation for daily fluoride intake threshold and no or very less amount fluoride from other sources; all the black and green tea bags; and imported black tea leafs were safe for all age groups. From the 10 Ethiopian black tea leaf brands none of them were safe for children but 30% of them were safe for adults. Thus, the control of tea quality is important to protect human against too high uptake of this element from black tea, which is the most popular beverage. Excessive intake of fluoride with black tea, especially in the regions with its high level in the drinking water, increases the risk of dental fluorosis in children during the years of tooth development. The long-term exposure to large amounts of fluoride can lead to potentially skeletal fluorosis. Keywords: Black Tea Infusion, Green Tea Infusion, Fluoride, Brewing Time, Safety Evaluation, ISE | en_US |
| dc.identifier.uri | http://etd.aau.edu.et/handle/12345678/2838 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa Universty | en_US |
| dc.subject | Black Tea Infusion; Green Tea Infusion; Fluoride; Brewing Time; Safety Evaluation; ISE | en_US |
| dc.title | Assessment of Fluoride in the Ethiopian and Imported; Black and Green Tea (Camellia sinensis) Infusions: Measurement and Safety Evaluation | en_US |
| dc.type | Thesis | en_US |