Tea infusions are a valuable source of bioactive compounds. They are also a source of minerals, but anti-nutritional factors present in the leaves of Camellia sinensis, such as soluble oxalates, limit their availability. Tea leaves, in particular red tea which undergoes fermentation, can also contain ochratoxin A (OTA). The aim of this study was to compare the content of selected minerals, total polyphenols, tannins, soluble oxalates and OTA in three popular types of Chinese tea (green, black and red – 100g packaged leaves) of five popular brands available on the Polish market. The antioxidant capacity (Trolox Equivalent Antioxidant Capacity) of tea infusions was also determined. Tea leaves differed significantly in their content of Cu, Mn, Fe, Mg, Na, K and P. Red tea leaves were characterized by particularly high levels of Na. The highest tannin content was found in red tea leaves. Red tea infusions were characterized by the highest antioxidant capacity, but the range of values for all tea infusions was relatively narrow: between 1.09 and 5.07 mM TE. The highest total phenolic content was noted in green tea infusions (114.3 mg in 200 ml). Black tea infusions had the highest content of compounds with adverse consequences for the consumers’ health, such as soluble oxalates, whereas red tea infusions were characterized by the highest content of OTA, which reached 21.67 ng in 200 ml.

23.1.2018