1.5 An Introduction to Chemical Profiles of Yerba Mate Products
19
other species in South America and worldwide, including green and black tea leaves.
Interestingly, the caffeine amount is very similar to the quantity extractable from
coffee: however, 260 or more mg of caffeine per day may be consumed in South
America because the normal mate consumption is based on approximately 500 ml of
aqueous infusion. On the contrary, coffee cups should be very small. It has to be noted
also that processing methods obtaining yerba mate can cause the notable decrease of
caffeine contents (especially in the sapeco and barbaqua, or blanching and drying
steps), up to 30% if compared with the original quantity. Additionally, chlorophyll
decreases strongly with the notable colorimetric turning, as expected. However, and
with exclusive relation to caffeine, the repeated infusion and consumption cycle
(and the relevant loss of moisture in above-cited steps) can explain the reason which
caffeine is still a high amount for, if considered as daily consumption (Heck and
Mejia 2007).
With concern to saponins, their importance in vegetable plants such as ginseng
(Panax ginseng) roots is linked to their ability to disrupt vegetable membranes, being
so able to create large micelles with bile acids and steroids. In other words, these
compounds can act as surfactant agents. This fact may explain, in part at least, certain
features of folk medicines. Chemically, these compounds are subdivided in steroidal
and triterpenoid saponins, depending on the aglycone skeleton (Bastos et al. 2007;
Heck and Mejia 2007).
Finally, the inorganic (mineral) profile of extractable yerba mate remains to be
discussed with an introduction (the complete discussion is in Chap. 4). With relation
to extractable minerals (iron, aluminium, zinc, and manganese above all), it should
be clarified that (Bastos et al. 2007; Heck and Mejia 2007):
(1) The amount of available minerals depends on agricultural practices and
seasons. Consequently, a certain difference/variability between leaves from
only-harvested and cultivated/mixed plantations has to be taken into account,
partially explaining the limited data amount in the scientific literature
(2) Secondly, mineral extraction by yerba mate roots does not imply the same or
similar amount of extracted mineral in leaves. It has been reported that calcium
and sodium show opposite behaviours in this ambit, partially because of water
solubility.
This situation has to be considered when speaking of variable results concerning
yerba mate infusions: the temperature and water volumes notably influence the solubility of minerals such as potassium and chlorine, without further factors. Interestingly, it has been reported that the general quantity of extractable minerals in a mate
infusion increases if tannin amount decreases. Probably, more research is needed
in this ambit. On the other hand, it has been reported that yerba mate could act as
a lead reservoir, but available data should not be worrying, being lower than limits
proposed by the United States Environmental Protection Agency (EPA) in 2003
(Heck and Mejia 2007).
19
other species in South America and worldwide, including green and black tea leaves.
Interestingly, the caffeine amount is very similar to the quantity extractable from
coffee: however, 260 or more mg of caffeine per day may be consumed in South
America because the normal mate consumption is based on approximately 500 ml of
aqueous infusion. On the contrary, coffee cups should be very small. It has to be noted
also that processing methods obtaining yerba mate can cause the notable decrease of
caffeine contents (especially in the sapeco and barbaqua, or blanching and drying
steps), up to 30% if compared with the original quantity. Additionally, chlorophyll
decreases strongly with the notable colorimetric turning, as expected. However, and
with exclusive relation to caffeine, the repeated infusion and consumption cycle
(and the relevant loss of moisture in above-cited steps) can explain the reason which
caffeine is still a high amount for, if considered as daily consumption (Heck and
Mejia 2007).
With concern to saponins, their importance in vegetable plants such as ginseng
(Panax ginseng) roots is linked to their ability to disrupt vegetable membranes, being
so able to create large micelles with bile acids and steroids. In other words, these
compounds can act as surfactant agents. This fact may explain, in part at least, certain
features of folk medicines. Chemically, these compounds are subdivided in steroidal
and triterpenoid saponins, depending on the aglycone skeleton (Bastos et al. 2007;
Heck and Mejia 2007).
Finally, the inorganic (mineral) profile of extractable yerba mate remains to be
discussed with an introduction (the complete discussion is in Chap. 4). With relation
to extractable minerals (iron, aluminium, zinc, and manganese above all), it should
be clarified that (Bastos et al. 2007; Heck and Mejia 2007):
(1) The amount of available minerals depends on agricultural practices and
seasons. Consequently, a certain difference/variability between leaves from
only-harvested and cultivated/mixed plantations has to be taken into account,
partially explaining the limited data amount in the scientific literature
(2) Secondly, mineral extraction by yerba mate roots does not imply the same or
similar amount of extracted mineral in leaves. It has been reported that calcium
and sodium show opposite behaviours in this ambit, partially because of water
solubility.
This situation has to be considered when speaking of variable results concerning
yerba mate infusions: the temperature and water volumes notably influence the solubility of minerals such as potassium and chlorine, without further factors. Interestingly, it has been reported that the general quantity of extractable minerals in a mate
infusion increases if tannin amount decreases. Probably, more research is needed
in this ambit. On the other hand, it has been reported that yerba mate could act as
a lead reservoir, but available data should not be worrying, being lower than limits
proposed by the United States Environmental Protection Agency (EPA) in 2003
(Heck and Mejia 2007).