Elemental Characterization of Commercial Mate Tea Leaves (Ilex paraguariensis A. St.-Hil.) before and after Hot Water Infusion Using Ion Beam Techniques

Abstract

Ilex paraguariensis A. St.-Hil. is used to prepare a traditional tealike beverage widely appreciated in Argentina, Paraguay, Uruguay, and southern Brazil. In these countries, the tea is popularly known as mate or chimarrão. The aim of this work is to characterize the elemental composition of commercial Ilex paraguariensis and determine the portion of each element present in the leaves that is eluted in the water during the infusion process and consequently ingested by the drinker. Using the particle-induced X-ray emission technique, we verified the presence of Mg, Al, Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, and Rb at different concentrations, which accounts for about 3.4% of the total mass. The results show a loss of about 90% of K and Cl, 50% of Mg and P, and 20% of Mn, Fe, Cu, Zn, and Rb by the leaves after the infusion. The volume of water used in the infusion affects only the concentration of elements such as Cl, P, K, and Mg until the first 600 mL of water, where a steep decrease in the concentration of these elements was observed in brewed leaves. Furthermore, higher water temperatures (typical temperatures used in infusions, between 80 and 100 degrees C) favor the extraction of K and Cl into the infusion, while the concentration of other elements remains practically constant as a function of temperature.

Trace Elements in Different Brands of Yerba Mate Tea

“…The only data available on this subject in Brazil are the studies carried out in the State of Paraná and in the neighboring State of Rio Grande do Sul, Brazil, where aluminum content was determined in infusions of roasted yerba mate samples. According to these authors, Al concentration in Parana varied from 0.5 to 1.67 mg/L [17,19], which is exactly the same value as determined in the present work. However, in Rio Grande do Sul, aluminum content in the infusions was incredibly high, e.g., 445 mg/L.…”

“…Zinc contents observed in the present study were 0.41±0.0007-1.0±0.0001 mg/L, while the zinc concentrations reported for the samples from the State of Rio Grande do Sul, Brazil are extremely higher, that is 59.0 mg/L [17]. As has been observed in a work dealing with different teas originated from China, climate and agricultural practices, including soil, water, and fertilizers, can be of great influence on the zinc composition of samples [26].…”

“…In the available Brazilian literature, copper content in mate tea infusion is reported as 11.0 mg/L [17]. Similar value, 9.0 mg/L, was found in Guanajuato, Mexico for the same drink [18].…”

“…As to mineral composition, several studies have been carried out to determine the content of bioactive metals in I. paraguariensis and its infusions [17][18][19], including a vast review on the matter [2]. These metals can be either toxic like lead or benefic like zinc.…”

Development of a Certified Reference Material (NMIJ CRM 7505-a) for the Determination of Trace Elements in Tea Leaves

“…4 Much research has been carried out to investigate the elemental concentrations in tea leaves from the viewpoints of both nutrition and toxicity. [5][6][7][8][9][10][11][12][13][14] In most cases, the investigations were accompanied by analytical method development or optimization, such as acid digestion, [5][6][7][8][9][10][11] extraction, 5,6,10-12 further preconcentration, 5 or solid sample analysis techniques. [12][13][14] Such kinds of research need proper CRMs for quality control of the analysis, evaluation or validation of analytical methods.…”