Assessment of the nutritional value of various teas infusions in terms of the macro- and trace elements content

Herbal teas are a good alternative to traditional green, black, red and white teas. Herbal teas infusions are also consumed for therapeutic purposes. Teas are the source of many valuable, biologically active compounds, including elements. Infusions drawn up from various teas may be one of the minerals sources in a daily diet. In the study, an attempt was made to assess infusions prepared from popular teas in terms of the content of elements in them.

In the work, the amounts of elements such as Ca (calcium), Cr (chromium), Cu (copper), Fe (iron), K (potassium), Mg (magnesium), Mn (manganese), Na (sodium), Ni (nickel) and Zn (zinc) were determined in herbal teas infusions as well as yerba mate and rooibos by atomic absorption spectrometry method (AAS). Their participation in covering the daily nutrient requirements for particular elements was also estimated.

The average amount (mg/g) of elements that passed from 1 g of teas to their infusions was following: Ca - 5.73 ± 3.33, K - 18.14 ± 9.50, Mg - 1.79 ± 3.47, Na - 1.34 ± 0.85, and (μg/g) for: Cr - 0.14 ± 0.14, Cu - 2.56 ± 1.53, Fe - 18.45 ± 11.90, Mn - 64.20 ± 88.82, Ni - 0.49 ± 0.30 and Zn - 10.77 ± 13.89. Among the tested teas, the infusions of hibiscus, horsetail, nettle, rooibos and yerba mate contained the largest quantities of minerals. A significant positive correlation was determined between the pH value of infusion and Mg content, as well as some pairs of correlating elements (Ca-K, Ca-Mg, Cr-Mg, Cu-Zn and K-Mg) were found in the analyzed brews.

Generally, the infusions of herbal teas to a small extent cover the daily allowance for elements, however they are a valuable complementary source of them.