Affiliation: University of Warsaw, Department of Chemistry, Pasteura 1, 02-093 Warsaw, Poland.
The mineral content of commercially available different types of teas (premium black, flavored black, green and fruit tea) and the infusions produced from them with different type of water (distilled, spring and tap) were determined. Studied teas differed in contents of elements between their raw materials and infusions. Iron and copper exhibited the lowest efficiency of extraction by hot waters. There was a marked influence of the kind of water quality used for brewing on the release of Co, Ni, Zn and Mn. In most cases, tap water gave the highest released percentage. For the most popular black tea brand (Lipton yellow label) the efficiency of metal extraction decreased in the order: Co > Mn > Ni > Zn > Cu > Fe. The content of Pb in the infusions was very low or below the detection limit of ICP MS method.
Citrus tea infusion has relatively high content of Cu, Co and Ni and could be a good source of these trace elements.