18
1 Yerba Mate Tea, a Traditional South American …
1.5 An Introduction to Chemical Profiles of Yerba Mate
Products
From the chemical viewpoint, the compositional profile of different yerba mate products influences the resulting infusion, both in the hot and in the cold versions. Anyway,
because of the safety importance of these preparations as a daily consumption for
million South American consumers (similarly to the growing coffee consumption
worldwide), the best strategy is surely the examination of biomolecules with antioxidant and positive heath effects, provided that these compounds are sufficiently
extracted in water. A complete discussion is found in Chap. 4.
By a general viewpoint, the following molecule classes have to be considered
when speaking of I. paraguariensis infusions (Heck and Mejia 2007):
(1) Polyphenols, chlorogenic acid above all
(2) Xanthines (purine alkaloids)
(3) Saponins (a group of natural glycosides)
(4) Minerals: potassium, magnesium, manganese iron, aluminium, and zinc.
With relation to the first class, polyphenols, it has been reported that their amount
is strongly dependent on:
(a) The quality of yerba mate
(b) Particle sizes (the higher the dimension, the lower the superficial interface
between grinded leaves and water, and consequently the lower the quantity of
extracted molecules)
(c) And the possible mixture between different yerba mate selections.
Consequently, the amount of extractable polyphenols in water is reported to
be approximately 92 mg equivalents of chlorogenic acid per each gram of dried
leaves, on condition that yerba mate belongs to a selection only (no mixed selections). Otherwise, the amount of extractable polyphenols should be reduced (Heck
and Mejia 2007). In the ambit of antioxidant capability, yerba mate has notable
importance because the important polyphenol amount, similar to green tea values
(and related performances). However, the analytical determination can give different
results depending on the solvent: in fact, organic solvents such as acetone can
give significantly higher quantities of extractable polyphenols. The problem is that
researchers are generally interested to consumable (and water-extractable) polyphenols, and this amount is a minor fraction of the total quantity of present phenolics (Heck and Mejia 2007; Turkmen et al. 2006). In particular, the most abundant polyphenol in I. paraguariensis infusions is chlorogenic acid, while another
important class—catechins—is substantially absent (Heck and Mejia 2007).
With reference to xanthines, these substances are common also in tea, chocolate
products, and coffee (Heck and Mejia 2007). The most commonly found xanthines
in yerba mate are caffeine and theobromine above all. Other molecules of interest
can be caffeic acid, caffeoylshikimic acid, several caffeoyl derivatives, kaempferol,
quercetin, quinic acid, and rutin. The detection of similar phenolics is common to
1 Yerba Mate Tea, a Traditional South American …
1.5 An Introduction to Chemical Profiles of Yerba Mate
Products
From the chemical viewpoint, the compositional profile of different yerba mate products influences the resulting infusion, both in the hot and in the cold versions. Anyway,
because of the safety importance of these preparations as a daily consumption for
million South American consumers (similarly to the growing coffee consumption
worldwide), the best strategy is surely the examination of biomolecules with antioxidant and positive heath effects, provided that these compounds are sufficiently
extracted in water. A complete discussion is found in Chap. 4.
By a general viewpoint, the following molecule classes have to be considered
when speaking of I. paraguariensis infusions (Heck and Mejia 2007):
(1) Polyphenols, chlorogenic acid above all
(2) Xanthines (purine alkaloids)
(3) Saponins (a group of natural glycosides)
(4) Minerals: potassium, magnesium, manganese iron, aluminium, and zinc.
With relation to the first class, polyphenols, it has been reported that their amount
is strongly dependent on:
(a) The quality of yerba mate
(b) Particle sizes (the higher the dimension, the lower the superficial interface
between grinded leaves and water, and consequently the lower the quantity of
extracted molecules)
(c) And the possible mixture between different yerba mate selections.
Consequently, the amount of extractable polyphenols in water is reported to
be approximately 92 mg equivalents of chlorogenic acid per each gram of dried
leaves, on condition that yerba mate belongs to a selection only (no mixed selections). Otherwise, the amount of extractable polyphenols should be reduced (Heck
and Mejia 2007). In the ambit of antioxidant capability, yerba mate has notable
importance because the important polyphenol amount, similar to green tea values
(and related performances). However, the analytical determination can give different
results depending on the solvent: in fact, organic solvents such as acetone can
give significantly higher quantities of extractable polyphenols. The problem is that
researchers are generally interested to consumable (and water-extractable) polyphenols, and this amount is a minor fraction of the total quantity of present phenolics (Heck and Mejia 2007; Turkmen et al. 2006). In particular, the most abundant polyphenol in I. paraguariensis infusions is chlorogenic acid, while another
important class—catechins—is substantially absent (Heck and Mejia 2007).
With reference to xanthines, these substances are common also in tea, chocolate
products, and coffee (Heck and Mejia 2007). The most commonly found xanthines
in yerba mate are caffeine and theobromine above all. Other molecules of interest
can be caffeic acid, caffeoylshikimic acid, several caffeoyl derivatives, kaempferol,
quercetin, quinic acid, and rutin. The detection of similar phenolics is common to