Total and soluble contents of Mn
Using the F AAS technique it was possible to determine the total contents of Mn in the acid digested solutions of RM and GM and also in the hot infusions of their samples. Results for the total mass fractions of Mn determined in the acid digested mate samples and in their hot infusions are shown in Table 1. Regarding the total mass fractions of Mn in GM and RM samples, they ranged from 1287.4 to 1462.6 mg kg-1 and from 1454.9 to 1746.2 mg kg-1, respectively. In relation to the total mass fractions of soluble Mn leached to the hot infusions of RM and GM, they varied from 336.8 to 564.0 mg kg-1 and from 1015.6 to 1229.9 mg kg-1, respectively.
Table 1. Total mass fractions of Mn in the acid digested solutions of roasted and green mate samples and in their hot nfusions determined by F AAS (mean ± standard deviation, n = 4).
Samplese
|
Total mass fractions (mg kg-1)
|
Acid digested solutions
|
infusionsf
|
RM 1
|
1462.6b ± 4.6
|
511.9b ± 7.1
|
RM 2
|
1287.4a ± 38.1
|
564.0b ± 1.6
|
RM 3
|
1297.7a ± 5.9
|
336.8a ± 13.9
|
GM 1
|
1746.2c ± 82.1
|
1229.9c ± 25.7
|
GM 2
|
1454.9b ± 21.7
|
1015.6d ± 10.4
|
GM 3
|
1675.4c ± 84.3
|
1201.1c ± 66.5
|
e 1, 2, and 3 correspond to different brands of commercial samples of roasted and green mate; f infusions prepared by the mixture of minced and sieved mate samples with hot ultrapure water (80 °C for 3 min); different superscript letters (a, b, c, and d) presented in the same column iindicate significant difference at 95% by the Tukey’s test (p<0.05); RM and GM are the abbreviations used for roasted mate and green mate, respectively.
In addition, from the results shown in Table 1, it can be observed that the total contents of Mn in the RM were, in general, significantly different from those obtained in the GM samples (p < 0.05), except for the total contents found in the RM 1 and GM 2. In addition, it is important to note that there were also significant differences for the total Mn contents found among the roasted mate samples as well as among the GM samples. Moreover, the average total concentrations of Mn in the GM (1625.5 mg kg-1) were approximately 20.5% higher than those determined in the RM samples (1349.2 mg kg-1). On the other hand, in relation to the average total soluble contents of Mn of the RM and GM samples leached to their hot infusions, it can be observed that these contents in the infusions of GM (1148.9 mg kg-1) were consistently higher (approximately 144.0%) than those determined for the infusions of the RM (470.9 mg kg-1).
These results are in agreement with those found in previous studies. Rusinek-Prystupa et al. [40] analyzed six samples of RM and six of GM, and they reported that the average total concentrations determined for Mn were 1323.7 mg kg‑1 and 1657.3 mg kg-1 in the RM bags and GM, respectively. Milani et al.[41] also analysed samples of RM, and the average total Mn content determined for nine samples was 1405 mg kg-1, and 22% of this average total concentration was extracted to the infusions. Pozebon et al. [23] analyzed 54 samples of GM produced in Argentina, Brazil, Paraguay, and Uruguay, and reported that the contents of Mn ranged from 730 to 1445 mg kg-1 and, on average, 53% of this metal content was leached to their infusions. Ulbrich et al. [42] have also determined total constents of Mn in 35 samples of GM, and it was the element that showed the highest contents (523 – 2475 mg kg-1) among all of the micronutrients assessed in those samples, which showed an average soluble content of Mn of approximately 53% in aqueous infusions.
Moreover, it is worth mentioning that the industrial process of yerba mate is among the key factors responsible for the amounts of trace metals present in tea materials. Giulian et al. [43] evaluated the relationship between the chemical composition of mate and the process required to tea production. The samples were analyzed considering three situations: harvest, roasting, and bleaching (sapeco). It was noted that the levels of metals significantly differed among the aforementioned steps, with a difference of up to 56% in the Mn contents. Furthermore, an assessment of the effect of storage time before packaging and commercialization of mate demonstrated that the levels of K, Ca, Cl, and Zn decreased substantially over time whereas the opposite was observed for Mn, Al, and Si contents.
Additionaly, the yerba mate plant shows a strong tendency to absorb Mn and store it in its leaves. This process can be strengthened depending on the soil pH and strong acidic media (pH < 5.5) favors the absorption of metallic species by the roots [19, 44]. However, other factors may also impact the levels of trace elements in tea plants, such as leaves age, sunlight exposure, moisture, genetics, region of cultivation, use of fertilizer and pesticides containing Mn in their composition (dithiocarbamate fungicides), pollutants, air pollution, among others [19, 21, 43, 45]. Therefore, these mentioned factors could account for the differences in total Mn contents found in the RM and GM samples and in the hot infusions of mate analyzed in this work (Table 1).
Furthermore, different infusion conditions can also affect the leachability of metallic species to the tea infusions, such as volume of water, mass and grinding degree of the sample, amounts of twigs and leaves and their ratios, temperature and infusion time [20, 28, 46].
Concerning the water-soluble contents of Mn in the RM and GM samples, it can be observed from the results shown in Table S1, that 26.0%-43.8% and 69.8%-71.7% of the total Mn contents in the dried RM and GM samples, respectively, were extrated to their hot infusions (Table S1), and the extraction percentages of Mn for the roasted and green mate infusions were significantly different (p < 0.05). In addition, it can be observed that the average aqueous-soluble content of Mn in GM samples (70.6%) was 2 times higher than those found in the RM samples (34.9%), and therefore, this result indicates that the consumption of GM infusions provides a greater intake of this ETE in comparison to the RM infusions..
Furthermore, the reliability of the procedures used to determine the total Mn contents in the acid digested solutions of the RM and GM samples and their infusions was evaluated by performing addition and recovery experiments (Table 2). It is worth saying that the AOAC (The American Association of Official Agricultural Chemists) [47] Guidelines for Single Laboratory Validation of Chemical Methods for Dietary Supplements and Botanicals considers the use of recovery from spiked samples as an appropriate procedure for validating the accuracy of the results obtained for dietary supplements and botanicals, according to the following recommendation: minimum of nine determinations (low concentragion range x 3 replicates, medium concentragem range x 3 replicates, and high concentration range of 3 replicates). This recommendation was adopted in this study by adding three different levels of standard Mn concentrations (0.5, 1.0, and 2.0 mg L-1) in the acid digested solutions of mate samples and their infusions, before preparing them. According to the recovery results shown in Table 4, it can be observed that the recoveries obtained for the all the mate infusions ranged from 91.2%-108.5%, except for the RM infusions 2 and 3 with a lower level of added concentration (0.5 mg L-1 Mn), whose recoveries were greater than 110% (111.0%) and less than 90% (86.6%), respectively. Recoveries obtained for the acid digested solutions of the samples of RM and GM 1 ranged from 90.7%-92.8%. According to the AOAC [47], the acceptable recoveries for the range of concentrations used in this work for being added in the acid digested solutions of the mate samples and their infusions vary from 75%-120%. Consequently, it can be considered that all recovery results (86.6%-111.0%) obtained in this work can be considered adequate. In addition, it is worth saying that concerning the recoveries obtained for the acid digested mate samples, the addition/recovery experiments were only performed for the samples RM 1 and GM 1, considering that all the acid digested samples of RM and GM (1, 2, and 3) should have similar residual matrices. It could be due to the minimization of their organic matrix contents promoted by the application of the acid digestion procedure. On the other hand, the mate infusions were analyzed directly without submitting them the acid digestion procedure, and consequently, the addition/recovery experiments were performed for all of them, in order to evaluate the existence of matrix effects on the determination of their total contents of Mn. Moreover, all the relative standard deviation (RSD%) were lower than 5%, indicating that the precision of the Mn determinations was also good or adequate.
Table 2. Recovery (%, mean ± standard deviation, n = 3) and RSD (%) for the Mn determinations in the acid digested solutions of the samples of roasted and green mate and their infusions by F AAS.
Infusionsa
|
Added Mn concentrations (mg L-1)
|
0.5
|
1.0
|
2.0
|
RM 1
|
103.9 ± 1.4 (1.3)
|
104.3 ± 1.5 (1.4)
|
99.0 ± 0.6 (0.6)
|
RM 2
|
111.0 ± 4.0 (3.6)
|
108.5 ± 1.0 (0.9)
|
106.1 ± 2.9 (2.7)
|
RM 3
|
86.6 ± 0.7 ((0.8)
|
95.4 ± 0.3 (0.3)
|
97.1 ± 0.5 (0.5)
|
GM 1
|
92.7 ± 1.2 (1.3)
|
93.5 ± 1.7 (1.8)
|
91.2 ±1.3 (1.4)
|
GM 2
|
96.2 ± 1.5 (1.6)
|
97.4 ± 2.2 (2.2)
|
93.5 ± 1.8 (1.9)
|
GM 3
|
94.7 ± 3.5 (3.7)
|
92.2 ± 2.3 (2.5)
|
95.0 ± 0.6 (0.6)
|
Acid digested solutions
|
Recovery (%)
|
RM 1
|
92.8 ± 1.1 (1.2)
|
90.9 ± 0.4 (0.4)
|
90.7 ± 0.3 (0.3)
|
GM 1
|
91.7 ± 0.3 (0.3)
|
91.8 ± 1.0 (1.1)
|
92.8 ± 1.3 (1.4)
|
a RM and GM are the abbreviations used for roasted mate and green mate, respectively.
Additionally, it is worth mentioning that in a nutritional and toxicological viewpoint, it is important to know about the adequate intake (AI) as well as about the tolerable upper intake (UI) of Mn, respectively. The AIs established according to the life-stage of males are: 1.9 mg/day (9-13 years), 2.2 mg/day (14-18 years), 2.3 mg/day (19 years and older), and for the life-stage of females are: 1.6 mg/day (9-18 years), 1.8 mg/day (19 years and older). In addition, the UIs stablished according to the life-stage of males and females are: 6 mg/day (9-13 years), 9 mg/day (14-18 years), and 11 mg/day (19 years and older).
In this context, the assessment of the contribution of the prepared hot infusions of the RM and GM to the recommended values of AI for Mn, was carried out considering the average masses of Mn found in the mate infusions as well as the recommended AI values established by the literature [48] (Table 3).
Table 3. Average masses of Mn in the hot infusions of roasted and green mate (mean ± standard deviation, n = 3), and their contribution to the recommended adequate intake for adult females and males.
Infusionsa
|
Masses of Mn (mg)
|
Contribution to the recommended adequate intakeb of Mn (%)
|
|
|
females
|
Males
|
RM 1
|
0.76 ± 0.01a
|
42.2
|
33.0
|
RM 2
|
0.85 ± 0.01a
|
47.2
|
37.0
|
RM 3
|
0.51 ± 0.02b
|
28.3
|
22.2
|
GM 1
|
1.83 ± 0.04c
|
101.7
|
79.6
|
GM 2
|
1.53 ± 0.02d
|
85.0
|
66.5
|
GM 3
|
1.82 ± 0.10c
|
101.1
|
79.1
|
a Infusions prepared by the mixture of minced and sieved mate samples with 40.0 mL of hot ultrapure water (80 °C for 3 min); b Adequate intake of Mn stablished for adult (19 years and older) females (1.8 mg Mn/day) and males (2.3 mg Mn/day) [48]; RM and GM are the abbreviations used for roasted mate and green mate, respectively; different supercript letters (a, b, c and d) presented in the same column indicate signicant difference at 95% by the Tukey’s test (p < 0.05).
According to Table 3, it could be observed that the hot infusions of RM could contribute on average with 39.2% and 30.7% in relation to the value established in the literature for the adequate daily intake of Mn for adult (19 years or older) females and males, respectively. In addition, it was also observed that the hot infusions of GM can contribute with 95.9% and 75.1% for adult females and males, respectively. Furthermore, it was found that hot infusions of GM can contribute with 56.7% and 44.4% more than hot infusions of RM. Furthermore, it also can be observed that the contributions of the RM and GM infusions for the adequate daily intake of Mn were different, considering that the extraction percentages of Mn from the RM and GM samples to their infusions (Table 3) were significantly different (p < 0.05). Moreover, it was also possible to observe that the average masses of soluble Mn in the infusions of GM and RM were always below the value established for the UI of Mn, which is 11mg/day for adult females and males [48].
Therefore, based on the results above, it could be concluded that the hot infusions of RM and GM can be good dietary sources of Mn, with the GM infusion being a richer dietary source of this ETE. However, there is a need for further researches to evaluate the bioaccessibility and bioavailability [30] of Mn from the GM and RM infusions, which are dependent on the physicochemical forms of this element, so that it could be possible to know more about the actual nutritional value of these infusions based on their Mn contents. In this context, Erdemir et al. [49] evaluated the bioaccessibility of Mn in different tea samples after an in vitro enzymatic digestion and found bioaccessible Mn levels ranging from 70–80%, 66–67%, and 73–84% in black, earl grey and green tea infusions, respectively. Milani et al. [40] assessed the bioaccessibility of trace elements in some ready-to-drink ice teas and found that most of the bioaccessible fractions of Al, Sr, Mn, and Zn were 50% of their total content. On the other hand, Alnaimat et al. [48] stated that Mn presented a low dialyzability in the tea infusions, suggesting that Mn has low bioavailability in the human organism probably because of the poor solubility of this inorganic ion in the gastrointestinal digestion process.
Moreover, it should be stressed that absorption of Mn is relatively low and for adult humans, dietary Mn ranges between 1% and 5%, and is dependent on the amount and form of Mn as weel as on other dietary components [50]. Therefore, this may indicate that yerba mate infusions, as well as other foods that have total Mn levels greater than those recommended for an adequate daily intake, may not be toxic to adult humans. Furthermore, it is important to highlight that in the case of neonates, infants, and children the recommended daily intake of Mn can be much higher than for adults, based on the greater demand for this element due to a less developed regulatory system in the early stages of development [51]. Besides, considering the higher absorption of Mn in neonates, toxic effects may be more important to occurr in newborn infants [52].
Polyphenolic compounds and melanoidins
It was carried out the evaluation of the TP contents and SM`s presence in the hot infusions of RM and GM (Table 4), which are known as complex forming compounds with metal ions. Concerning the TP contents, it could be observed that these contents in the hot infusions of GM were significantly different (p < 0.05) and consistently higher (2.2 to 3.5 times) when compared to those found in the RM infusions. The lower polyphenol contents found in the hot infusions of RM may be due to the losses of thermolabile compounds such as polyphenols, which can occur during the additional roasting step used in its industrial process [1, 53].
Table 4: Total polyphenols contents and the detection of the presence of soluble melanoidins in the hot infusions of roasted and green mate (mean ± standard deviation, n = 4).
Infusions
|
Total Polyphenols (mg GAe g-1)
|
Melanoidins A420 nmf
|
RM 1
|
53.0a ± 1.5
|
0.59a ± 0,01
|
RM 2
|
55.0a ± 5.2
|
0.46b ± 0,02
|
RM 3
|
33.5b ± 0.6
|
0.55a ± 0,03
|
GM 1
|
106.6c ± 3.5
|
0.28c ± 0,04
|
GM 2
|
117.0c ± 5.3
|
0.15d ± 0,01
|
GM 3
|
100.0d ± 6.8
|
0.13d ± 0,01
|
e GA: gallic acid; different superscript letters (a, b, c, and d) presented in the same column indicate significant difference at 95% by the Tukey’s test (p < 0.05); f absorbances at 420 nm; RM and GM are the abbreviations used for roasted mate and green mate, respectively.
Melanoidins are dark-colored polymeric compounds with high molecular weight, which are formed in the final steps of the Maillard reaction (MR), and they are associated with color, taste, and aroma in thermally processed foods, such as bakery products, cocoa, teas, wine, and coffee. The MR products also have a strong bioactive activity related to antioxidant, antimicrobial, antihypertensive, and anti-inflammatory activities [54–56].
Melanoidins' structure is not completed elucidated, however, it is well established that they are nitrogen-containing polymers formed by the reaction between reducing sugars with proteins or amino acids. It is important to notice that, during the roasting step, phenolic compounds can be incorporated into the high molecular weight melanoidins (HMWM) skeletons and these phenolics are predominantly chlorogenic acids (CGA) [54, 57]. Smrke et al. [58] reported a negative correlation between the content of CGA and the roasting time of coffee beans, and the CGA contents in the samples decreased during the occurrence of the roasting process. According to Coelho et al. [59] , the incorporation of phenolic acids into HMWM is an important pathway of the degradation of CGAs during the roasting process. Moreover, the MR products have a structure that is hydrophilic, anionic, and able to form bonds with positively charged substances with low molecular weight, and consequently they can form stable complexes with cationic species such as Mn2+ [55-56]. According to Welna et al. [28] in a chemical fractionation study of Mn and other elements in brewed grounds and soluble coffees by tandem solid phase extraction with reverse-phase and strong cation-exchange extraction tubes, it was found that the Mn was predominantly in the form of simple ionic species or stable cationic complexes.
According to the Table 4, it can also be observed that the absorbance measurements at 420 nm for the SM indicated that the presence of them in the RM infusions was 2.1 to 4.5 times higher than those observed in the GM infusions. Thus, this result is in opposition to that observed for TP in the hot infusions of RM and GM, in which the TP contents were higher in the GM infusions. In addition, the higher presence of SMs in the RM infusions, may be explained due to the use of phenolic compounds for their formation by the occurrence of the MR during the roasting process [57-58].
Moreover, considering that the TP and SM can form complexes with inorganic ions, it was evaluated the existence of correlation between the TP contents and SM with the soluble Mn contents in the hot infusions of RM and GM. From the results shown in Table 1 and Table 4, as well as based on their relationships established by the Pearson`s correlation coefficients, it was possible to observe that high correlations were obtained between the TP contents and soluble Mn in the hot infusions of both RM and GM. Furthermore, this correlation was direct for the RM infusions (r = 0.99) and inverse for the GM infusions (r = -0.87). Regarding to the relationship between the presence of SM and soluble Mn contents, it was observed that it was small in the hot infusions of both RM and GM, being negative for the RM infusions (r = -0.43) and positive for the GM infusions (r = 0.50). It is worth saying that positive correlation coefficients indicate that the higher the contents of TP contents and SM, the higher are the contents of soluble Mn. On the other hand, negative coefficient correlations indicate that the higher the TP contents and SM, the lower are the contents of soluble Mn. Moreover, it is also worth emphasizing that the high positive correlation (r = 0.99) observed for hot infusions of RM, may indicate that the soluble polyphenolics in the RM infusions probably contribute to the extraction of the Mn from the RM samples to their hot infusions, in the forms of aqueous-soluble polyphenol-Mn complexes.
Differently, the high negative correlation (r = -0.87) found for the GM infusions may suggest that probably the content of Mn in this type of infusion interact more with non-soluble polyphenols than with soluble polyphenols. Despite this, the consistently higher soluble TP contents in the hot infusions of the GM in comparison to those found in the RM infusions (Table 3), may account for the higher soluble Mn contents found in the hot infusions of GM.
Concerning the relationship between the SM’s presence and soluble Mn contents in the hot infusions of RM and GM, a small negative correlation (r = -0.43) was observed for the RM infusions and a small positive correlation (r = 0.50) was observed for the GM infusions. Consequently, based on these correlations, it may be suggested that the SM present in the RM and GM samples have a minor influence on the extractability of the Mn from these mate samples to their hot infusions. However, it is worth emphasizing that the molecular weight of MR products increases as the browning reaction proceeds, resulting in less soluble compounds such as the HMWM. Consequently, the Mn bound to HMWM may have its solubility decreased in the hot infusions of the RM depending on the time and temperature heating used in the roasting process [55]. Therefore, the probable presence of the insoluble HMWM in the RM samples may have contributed for the lower contents of soluble Mn found in the RM infusions (Table 1). Pohl et al. [14] observed in a physical fractionation study of Mn in ground coffee infusions that 61-68% of the soluble Mn was found associated to low molecular weight ligands (<5 kDa), 8-38% to high molecular weight ligands (5-10 kDa) such as melanoidins and proteins, and a very small part related to moderate and high molecular weight ligands (40-100 kDa).
Furthermore, it is important to highlight that the soluble Mn contents that showed a positive (direct) correlation with the TP contents in the hot infusions of RM, showed a negative (inverse) correlation with the TP contents in the GM infusions. Concerning the relationship between soluble Mn and SM in the hot infusions of the RM and GM, the soluble Mn that showed a negative (inverse) correlation with SM in the RM, showed a positive (direct) correlation with the SM in the GM infusions. Moreover, it is also important to note that there is room for further research to investigate the correlations of soluble forms of Mn with the TP contents and SM in hot infusions of RM and GM.
Solid phase chemical fractionation
A SPCF study based on a batch adsorption procedure using the chelating resin Chelex 100 (NH4+ form) was performed for evaluating the relative lability of the soluble Mn found in filtered fresh infusions of the RM and GM samples. Firstly, the amount of the Chelex 100 resin sufficient to promote complete adsorption of a Mn2+ concentration higher than those found in the hot infusions of the RM (17.0 mg L-1) and GM (36.6 mg L-1), and also higher than those reported in the literature for mate infusions [23, 40-43] was evaluated. The preparation of the resin Chelex 100 in an ammoniacal form was needed to kept constant the infusions pH during all the adsorption experiment, to avoid alterations of the soluble chemical forms of Mn in the hot infusions of the RM and GM. The suitable amount of the resin was determined by keeping a 40.0 mL of a 50.0 mg L-1 Mn standard solution with pH adjusted to pH 5.80 with a 0.30 mol L-1 sodium acetate-acetic acid buffer solution, in contact with different masses of Chelex 100 for 24h [6]. It was necessary to adjust the pH value of the Mn standard solution to 5.80 for keeping it within the range of pH values found for the infusions of the RM and GM, which ranged from 5.71-5.97.
From the results shown in Figure 1, it can be observed that a 0.45 g mass of the chelating resin was sufficient to promote the complete adsorption of the total Mn2+ concentration present in the standard solution.
After that, batch adsorption experiments using different adsorption times and the adequate mass of the resin Chelex 100 (NH4+ form), were performed to evaluate the rate of removal of Mn from the hot infusions of the RM and GM, so that the relative lability of the soluble forms of Mn in these infusions could be assessed. Based on the results obtained by performing the batch adsorption experiments for the infusions of the RM 1, 2, and 3 (Figure 2), it was observed that the adsorption equilibrium of Mn from these infusions on the Chelex 100 resin was reached after 5 min. From this adsorption equilibrium time, the average Mn removals for the infusions of the RM ranged from 98.4 ± 0.8% to 99.4 ± 0.2%, which were significantly different (p < 0.05) from the average Mn removal percentages obtained in the first evaluated adsorption time (2 min). Furthermore, theses results indicate that the total Mn content from the RM infusions, essentially corresponded to relatively labile or noninert chemical forms such as aquocomplexes of Mn ions (free Mn2+) and other Mn complexes with low relative stability formed with other ligands including polyphenols, melanoidins, among others from the matrix of the RM.
In relation to the results obtained for the batch adsorption experiments applied to the infusions of the GM samples (Figure 3), it could be observed that the adsorption equilibrium of the Mn from the GM infusions 2 and 3 was reached after 5 min, and the average Mn removal percentages ranged from 99.0 ± 0.2% to 99.7 ± 0.1%. These Mn removal percentages were significantly different (p < 0.05) from those obtained for these same GM infusions in the adsorption time of 2 min (98.1 ± 0.1% to 98.3 ± 0.1%). On the other hand, the adsorption equilibrium occurred faster (2 min) for the soluble Mn from the GM infusion 1, and from this equilibrium time, the observed removal ranged from 99.8 ± 0.3% to 100 ± 0.1%. Consequently, the results obtained from these adsorption experiments showed that the adsorption behavior for the Mn from the infusions of the RM and GM was similar, indicating that the soluble forms of Mn in these infusions were essentially related to the relatively labile or noninert soluble chemical forms, suggesting that these soluble Mn species have potential to be bioavailable. Moreover, based on the average Mn removal percentages found for the infusions of the RM and GM, it could also be observed that the removal percentages obtained for the GM infusion 1 showed a tendency to be higher than those obtained for all other infusions, although they were not significantly different from each other (p < 0.05). In addition, these results may suggest that the Mn soluble forms from the GM infusion 1 seem to be slightly more labile or noninert than those found in all other infusions analyzed, due to their shorter adsorption equilibrium time. Furthermore, it should be emphasized that any differences among the contents of the relatively labile Mn soluble forms in the hot infusions of the RM and GM could be due not only to the different heating degrees of their industrial processing, but also due to the different growing and harvesting conditions of the mate plants. Moreover, it is also worth saying that there are no reports in the literature comparing the relative lability of the Mn in the of RM and GM infusions using the Chelex 100 resin. In addition, it should also be emphasized that there is still room for further research to better understand the influence of polyphenols, melanoidins, and other ligands on the chemical forms of Mn and, consequently, on the lability, bioavailability, and bioaccessibility of this element in mate infusions.