Ilex paraguariensis (yerba mate) is a plant species of the holly genus Ilex native to South America from the family Aquifoliaceae and is used for the production of yerba mate infusion. The leaves of the plant are steeped in hot water to make a beverage known as mate.
1. Introduction
Ilex paraguariensis A. St.-Hil. (ang. Paraguay holly, yerba mate) is a plant species of the holly genus Ilex native to South America from the family Aquifoliaceae and is used for the production of yerba mate tea (
Mate folium). Mate was first consumed by the indigenous Guaraní people, and the practice of Mate consumption then spread to the Tupí people, who lived in the department of Amambay and the Alto Paraná territory of Paraguay. The plant was also primarily found in the southern regions of Brazil, Argentina, and Uruguay. In the mid-17th century, the Jesuits managed to domesticate the plant and establish plantations. It is also a medicinal plant known since pre-Columbian times and was used by the Indians to reduce the feeling of hunger, fatigue, and stress; as a diuretic; and as a physical and mental stimulant
[1][2][3][4][1,2,3,4].
Mate products also have the property of detoxification and possess precognitive, hypocholesterolemic, anticancer, and slimming activities. The presence of a large number of chemical compounds and elements in yerba mate indicates the potential antioxidant properties of the raw material.
The leaves of the plant are steeped in hot water to make a beverage known as Mate. Both the plant leaves and the beverage contain purine alkaloids, such as caffeine, and a variety of polyphenols, such as the flavonoids quercetin and rutin, saponins, vitamins, and bioelements. These substances are responsible for the bioactivity of Mate
[5][6][7][8][9][10][11][12][13][5,6,7,8,9,10,11,12,13].
I. paraguariensis infusions show protective activity against the oxidation of low-density lipoprotein by free radicals. It also reduces the number of products formed in the process of lipid peroxidation and increases the level of antioxidants in human blood serum.
[14] In vivo studies have demonstrated that the aqueous extract of yerba mate shows a potent anti-obesity effect by modulating the expression of several obesity-related genes. Positive effects of Mate inhibiting the proliferation of colon (HT-29), esophageal, and bladder cancer cells have also been found
[1][14][15][1,14,15]. Moreover,
I. paraguariensis infusions have anti-inflammatory effects, as they inhibit the production of nitric oxide, prostaglandin 2, interleukin-6, and interleukin-1ß
[16]. Mate is, however, most often consumed for its stimulating properties. yerba mate extract, when consumed in quantities not exceeding 2.5 L/day, has proven health-promoting effects. A study conducted in Uruguay showed an association between the consumption of more than 2.5 L/day of hot aqueous yerba mate extract and an increased risk of esophageal cancer
[17].
The name “yerba mate” originated in Spain. The word “yerba” means a drink made from the herb, while the word “mate” means drinking from a calabash mate gourd. The raw material is pre-dried directly over the hearth at temperatures ranging from 250 °C to 550°C for several seconds or several minutes. The leaves are then dried until they reach a moisture content of 3–6%, which usually takes 8 to 24 h. The dried leaves are then subjected to an aging process that can last up to several months. The aging process produces the distinctive flavor of the
I. paraguariensis leaves. In the next stage, the obtained dried product is grounded and packed. The conditions of all the abovementioned steps have a significant impact on the taste, aroma, quality, and contents of biologically active substances in the final product
[1][4][1,4].
Yerba mate can be brewed in several ways that vary from country to country or region to region. The leaves of
I. paraguariensis are brewed differently in Argentina and Brazil, and Paraguay and Uruguay also follow different methods to brew the leaves. The simplest method of preparing an infusion involves placing a bombilla in a container, adding dried leaves of
I. paraguariensis to fill one-half to three-quarters of the container, and pouring hot, but not boiling, water. Ideally, the water temperature should be around 85–95 °C
[18]. Infusions prepared from pure dried holly leaves are usually greenish or greenish-brown in color and have a bitter taste. This taste is very specific to the infusion and is both liked and disliked by consumers. Presently, to improve or mask the bitter taste, several producers add various kinds of fruits, flowers, or herbs to the brewed infusion. Sometimes, such additives not only change the taste of the brew but also enhance its properties; for example, the addition of grounded guarana (
Paullinia cupana) leaves increases the stimulating properties of yerba mate as the caffeine content of the brew increases.
2. Selected Elements Determined in Yerba Mate by Atomic Absorption Spectrometry
Presently, there is an increasing awareness among people with regard to the impact of food and its components on human health. Studies on the content of bioactive compounds in foods can be used in the rational planning of daily diets. Bioelements have many functions in the human body, and therefore, it is necessary to provide them through food. On the basis of the obtained results for the contents of bioelements in dried yerba mate and considering the Recommended Dietary Allowance (RDA) of the examined bioelements, dried samples with the highest and lowest contents of particular elements were selected for further analyses.
Table 1 shows the results of the determination of the selected metal ions in the prepared yerba mate infusions. Next,
rwe
searchers assessed the amount of the determined elements extracted from the dried fruit into the infusion and the extent to which these elements covered the RDA for humans, and the results are presented in
Table 2. Knowledge of the elemental composition of a given product allows the assessment of the products that can prevent deficiencies in macro- and microelements.
Table 1.
Mg(II), Zn(II), and Mn(II) contents of yerba mate infusions.
Element |
Sample |
Content (mg/L) |
% of Content in Infusions Compared to the Content in Dried Material |
Table 2.
Coverage of the daily recommended requirement when drinking 1 L of yerba mate infusion per day prepared using the described method.
Element |
Sample |
% RDA at Intake of Approximately 1 L per Day |
Men |
Women |
Mg |
YM-B1 |
144.75 ± 6.8 |
29.9% |
YM-P2 |
44.45 ± 13.7 |
Mg |
YM-B1 |
34.5% |
45.2% |
14.0% |
YM-P2 |
10.6% |
13.9% |
Zn |
YM-P1 |
Zn | 3.14 ± 0.0 |
27.8% |
YM-P1 |
28.6% |
39.3% |
YM-B1 |
1.00 ± 0.0 |
YM-B1 | 24.9% |
9.1% |
12.5% |
Mn |
YM-A1 |
3.67 ± 0.1 |
Mn |
YM-A1 | 18.9% |
159.8% |
204.1% |
YM-P2 |
1.70 ± 0.0 |
50.2% |
Several studies have investigated the elemental content of holly leaves. The contents of Mg, Ca, K, P, Cu, Zn, Mn, Fe, Na, Al, Cd, and Pb were found to vary significantly in available sources
[19][20][21][22][27,28,29,30]. In the present study, the concentrations of Mg in the infusion from samples YM-B1 and YM-P2 were 144.8 mg/L and 44.5 mg/L, respectively. The RDAs for Mg are 420 mg and 320 mg for adult men and women, respectively
[23][31]. Mg deficiency is becoming more common among people, and hence, Mg supplementation is recommended. Early symptoms that accompany Mg deficits include loss of appetite, chronic fatigue, and vomiting. By contrast, severe hypomagnesemia manifests as increased neuromuscular excitability in the form of muscle tremors, wrist cramps, and muscle spasms. Disturbances in heart rhythm, such as atrial and ventricular tachycardia, also occur. Mg deficiency very often accompanies deficiencies of other minerals, such as Ca or K
[24][32].
The concentrations of Zn in the infusion from samples YM-P1 and YM-B1 were 3.14 mg/L and 1.00 mg/L, respectively. The RDAs for Zn are 11 mg and 8 mg for adult men and women, respectively
[25][33]. Long-term intake of Zn ions from food in amounts lower than the recommended intake can lead to many diseases. In children and adolescents, these disorders include poor growth and delayed development. Cellular response mechanisms in patients with Zn deficiency are not as enhanced as those of patients with normal blood Zn levels. Numerous skin lesions appear, which become worse with increasing deficiency of Zn. Wound healing becomes more difficult. The condition of the hair and nails deteriorates, leading to increased brittleness and a tendency for hair loss. In more severe cases, the lingual papillae may disappear
[26][34].
The concentrations of Mn in infusions from samples YM-A1 and YM-P2 were 3.67 mg/L and 1.70 mg/L, respectively. Drinking 1 L per day of infusions prepared using the method described in this
res
earchtudy can cover 34.5% of daily Mg requirements for men and 45.2% of those for women; 28.6% of Zn requirements for men and 39.3% of those for women; and 159.8% of Mn requirements for men and 204.1% of those for women. This implies that the amount of Mn in 1 L of the infusion exceeds the daily requirement of the human body for this element. The RDAs for Mn are 2.3 mg and 1.8 mg for adult men and women, respectively
[27][35]. Because of the significant presence of Mn in the diet, Mn deficiencies are very rarely found. Long-term supply of Mn ions to the human body in amounts higher than the recommended amount causes symptoms similar to those of Parkinson’s disease. Although epidemiological studies are lacking, intravenous injection of Mn has been shown to decrease heart rate and blood pressure and increase P-R and QRS intervals in electrocardiography
[28][36].
3. Organic Compounds in the Analyzed Yerba Mate Materials
Compounds found in plant materials with a protective effect against diseases caused by free radicals are ranked in the following order according to their antioxidant activity: phenolic acids > flavonoids > ascorbic acid > tocopherols > purines. In the analyzed material, the following organic compounds with significant antioxidant activity were detected: phenolic acids, flavonoids, and caffeine.
According to the macroscopic analysis of the samples, the most powdered one was YM-B1, and it had the highest content of organic compounds. Similar content was noted in yerba mate samples from Brazil (YM-B2 and YM-B4). An important point to note is that these samples contained mainly leaf blades and differed from the Argentina and Uruguay samples because stems formed a major part of this sample. Compared with the leaf blade, stems contain more cellulose than organic compounds. The lowest content of organic compounds was found in the roasted material (YM-B3, roasted), which was related to the degradation of these compounds by thermal processing (
Table 3). Industrial processing could affect the polyphenol content and their composition, as well as the antioxidant activity of Yerba Mate extracts
[29][37].
Table 3.
Content of organic compounds in yerba mate samples analyzed in the present research.
|
Neochlorogenic Acid |
Chlorogenic Acid |
Cryptochlorogenic Acid |
Caffeic Acid |
4-Feruloylquinic Acid |
isochlorogenic Acid |
Rutoside |
Astragalin |
Caffeine |
[mg/g dry mass] ± SD |
YM-B1 |
39.03 ± 0.64 a |
19.00 ± 0.29 a |
17.84 ± 0.29 a |
0.60 ± 0.02 a |
2.92 ± 0.10 a |
28.82 ± 0.47 a |
8.77 ± 0.26 a |
1.61 ± 1.10 |
1.17 ± 0.00 a |
YM-B2 |
24.46 ± 0.18 |
12.37 ± 0.06 |
12.18 ± 0.19 |
0.44 ± 0.01 |
2.20 ± 0.02 |
22.20 ± 0.20 |
6.53 ± 0.09 |
1.61 ± 0.01 |
0.74 ± 0.02 |
YM-B4 |
25.95 ± 0.20 c |
12.12 ± 0.30 |
13.59 ± 0.30 |
0.18 ± 0.00 |
ab |
YM-B3 * |
1.24 ± 0.03 |
1.77 ± 0.050 |
1.32 ± 0.01 |
0.05 ± 0.00 |
0.56 ± 0.02 |
0.45 ± 0.02 |
0.27 ± 0.01 |
0.14 ± 0.00 |
0.29 ± 0.01 |