Trace elements in different brands of yerba mate tea.

Yerba mate (Ilex paraguariensis), a widely consumed beverage in South America, contains various biochemically active substances, among them are several minerals. This paper reports on the results of a survey of trace elements in the yerba mate infusions. Three different commercially available trademarks of I. paraguariensis were evaluated, simulating the popular mode of preparation. Atomic absorption analyses for cadmium, lead, copper, zinc, aluminum, iron, chromium, manganese, molybdenum, and silver were performed using a graphite furnace. The levels ranged from 0.03 to 0.06 mg/L for copper, from 0.41 to 1.0 mg/L for zinc, from 0.32 to 1.7 mg/L for aluminum, from 0.12 to 0.23 mg/L for iron, from 2.3 to 7.0 mg/L for manganese, and from 0.01 to 0.03 mg/L for silver. The levels of chromium did not exceed 0.005 mg/L, while molybdenum, cadmium, and lead were lower than <0.01 mg/L. Metal content in mate tea infusions depends on a number of factors, some of which are controllable and others not, but the differences among various sources are admissible. Trace elements in mate plants seem to be weakly bounded to the substrate. The concentration of biometals does not exceed the limits accepted by Brazilian and international legislation when available.