Influence of brewing pots on mineral content of black tea infusions

Abstract

Purpose: The objective of this study is to analyze the minerals of different black tea infusions brewed in different pots. Material and Methods: Eight different samples of black tea were used in this study. Six mineral contents (Fe, Cu, Mn, Zn, Na and K) obtained by duplicate analysis of 64 samples (8 different samples – 4 pots – 2 infusions each) that were brewed two times under the same conditions in different pots (stainless steel, aluminum, porcelain and glass) were analysed. Fe, Cu, Mn and Zn contents in infusions were determined by atomic absorption spectrometer; Na and K contents were determined by flame photometer. The differences in mineral contents of infusions brewed in different pots were analyzed by analysis of variance (F-test) for randomized block design. Results: Fe, Mn, Zn and Na contents of infusions were found to be significantly different whereas no statistically significant differences were observed in Cu and K contents between brewing pots. The highest amount of mineral found in infusions was K. Fe contents were found to be similar in infusions brewed in stainless steel and glass pots which is less than the tea brewed in aluminum and porcelain pots. There was no significant difference in the Zn content of infusions brewed in aluminum and porcelain pots, however these were significantly higher than those in stainless steel and glass pots. The Mn content of tea brewed in glass pot was significantly lower as compared to the other three pots. The Na content was found highest in tea brewed in porcelain pot, and lowest in glass pot. Conclusion: Tea is an important source of some minerals especially for K. The mineral content of tea may differ according to the pot in which it is brewed. This is especially important in order to regulate the tea consumption of patients in illnesses where there should be restrictions on some mineral consumption.