Extractability of Fluoride into Black Tea Liquors, Kenya

Abstract

Fluoride in food is currently a subject of immense interest globally as it is directly related to health and disease. Tea leaves are rich in fluoride, part of which is released into the tea liquor during the tea making process. Therefore, the main objective of this study was to determine the levels of fluoride in tea liquors prepared from different grades of black Cut, Tear and Curl (CTC) tea sourced from various tea growing regions in Kenya as well as other tea producing countries in East Africa (Rwanda, Uganda and Tanzania). The fluoride levels in tea liquors (1 g of black tea + 100 ml of boiling distilled water agitated on a mechanical shaker for 10 minutes) were quantified to be in the range between 0.11 and 1.35 µg/ml using a simple, reliable and cheap potentiometric method by a Fluoride Ion Selective Electrode (FISE). These results confirm that tea consumption is indeed an important dietary source of fluoride. Also, these data demonstrate regional variations in the fluoride contents as tea liquors of the black CTC tea samples from different regions varied widely in terms of their fluoride contents.