3.1 Chemical Profiles of Yerba Mate Infusions
41
problem with polyphenols is also dependent, from the analytical angle, on the choice
of extraction solvent(s): the most powerful solvent appears acetone. On the other
side, what about the real amount of water-soluble polyphenols (Heck and De Mejia
2007; Turkmen et al. 2006), because their importance is related to the real consumption? Anyway, chlorogenic acid appears to be the most abundant polyphenol in I.
paraguariensis infusions. On the other side, it has been reported that catechins (very
common molecules in green tea) are substantially absent (Heck and De Mejia 2007).
This information has been repeatedly confirmed in the scientific literature, although
one single work reports that gallocatechin and epicatechin may jointly reach 26%
of the total organic extract in yerba mate (Schneider 2017). However, this information is not confirmed by other researchers. Consequently, the absence of analytically
detectable catechins in yerba mate has to be confirmed, also as a simple discrimination method if compared with green and black teas (Chandra and De Mejia 2004;
Hara 2001; Heck and De Mejia 2007).
In fact, the extraction of chlorogenic acid has been reported (in association with
caffeine) with a chloroform–methyl alcohol–water (for a nuclear magnetic resonance study), while the aqueous extraction appears a good option (Choi et al. 2005;
Heckman et al. 2010). The abundance of chlorogenic acid has been repeatedly
confirmed not only in yerba mate but also in other Ilex species (Filip et al. 2001;
Heckman et al. 2010). With exclusive relation to yerba mate, this compound is
reported to be approximately 42% of the organic extract (Schneider 2017). A selection of data from different papers allows knowing the amount of chlorogenic acid may
notably vary from 3.66 to 50 mg/100 ml of chimarrão and tererê extracts (Brazilian
infusions) to more than 900 mg/100 ml for roasted mate, while the maximum amount
can arrive to 1207 mg/100 ml with concern to extracts of green leaves (Butiuk et al.
2016; Croge et al. 2020; Lima et al. 2016; Mateos et al. 2018; Meinhart et al. 2010,
2018; Riachi et al. 2018; Silveira et al. 2017). Substantially, the amount of this
compound decreases from green leaves to the final product, but a number of variables—different selections, native or cultivated plants, harvesting methods, analytical
choices, etc.—are able to influence the result. The only reliable information is that
this polyphenol is the most abundant molecule for this class in yerba mate.
3.1.1.1 The Most Abundant Polyphenol in Yerba Mate: Chlorogenic
Acid
Chlorogenic acid is an important polyphenolic compound. This molecule—other
names: 3-O-caffeoylquinic acid and 3-(3,4-dihydroxycinnamoyl)quinic acid—has a
molecular weight of 354.31 Da with molecular formula: C 16 H 18 O 9 , and Chemical
Abstract Service (CAS) Number: 327-97-9, is substantially an ester obtained by
condensation between trans-caffeic acid and quinic acid. As a result, it has to be
considered as a cinnamate ester and also as tannin (Pubchem 2020a). It is a member
of the family of non-flavonoid phenolics, with caffeic and quinic acid esters, and
related isomers including 3-O-caffeoylquinic acid, 3,5-dicaffeoylquinic acid, and
4,5-dicaffeoylquinic acid (Croge et al. 2020; Heck and De Mejia 2007). Peculiar
41
problem with polyphenols is also dependent, from the analytical angle, on the choice
of extraction solvent(s): the most powerful solvent appears acetone. On the other
side, what about the real amount of water-soluble polyphenols (Heck and De Mejia
2007; Turkmen et al. 2006), because their importance is related to the real consumption? Anyway, chlorogenic acid appears to be the most abundant polyphenol in I.
paraguariensis infusions. On the other side, it has been reported that catechins (very
common molecules in green tea) are substantially absent (Heck and De Mejia 2007).
This information has been repeatedly confirmed in the scientific literature, although
one single work reports that gallocatechin and epicatechin may jointly reach 26%
of the total organic extract in yerba mate (Schneider 2017). However, this information is not confirmed by other researchers. Consequently, the absence of analytically
detectable catechins in yerba mate has to be confirmed, also as a simple discrimination method if compared with green and black teas (Chandra and De Mejia 2004;
Hara 2001; Heck and De Mejia 2007).
In fact, the extraction of chlorogenic acid has been reported (in association with
caffeine) with a chloroform–methyl alcohol–water (for a nuclear magnetic resonance study), while the aqueous extraction appears a good option (Choi et al. 2005;
Heckman et al. 2010). The abundance of chlorogenic acid has been repeatedly
confirmed not only in yerba mate but also in other Ilex species (Filip et al. 2001;
Heckman et al. 2010). With exclusive relation to yerba mate, this compound is
reported to be approximately 42% of the organic extract (Schneider 2017). A selection of data from different papers allows knowing the amount of chlorogenic acid may
notably vary from 3.66 to 50 mg/100 ml of chimarrão and tererê extracts (Brazilian
infusions) to more than 900 mg/100 ml for roasted mate, while the maximum amount
can arrive to 1207 mg/100 ml with concern to extracts of green leaves (Butiuk et al.
2016; Croge et al. 2020; Lima et al. 2016; Mateos et al. 2018; Meinhart et al. 2010,
2018; Riachi et al. 2018; Silveira et al. 2017). Substantially, the amount of this
compound decreases from green leaves to the final product, but a number of variables—different selections, native or cultivated plants, harvesting methods, analytical
choices, etc.—are able to influence the result. The only reliable information is that
this polyphenol is the most abundant molecule for this class in yerba mate.
3.1.1.1 The Most Abundant Polyphenol in Yerba Mate: Chlorogenic
Acid
Chlorogenic acid is an important polyphenolic compound. This molecule—other
names: 3-O-caffeoylquinic acid and 3-(3,4-dihydroxycinnamoyl)quinic acid—has a
molecular weight of 354.31 Da with molecular formula: C 16 H 18 O 9 , and Chemical
Abstract Service (CAS) Number: 327-97-9, is substantially an ester obtained by
condensation between trans-caffeic acid and quinic acid. As a result, it has to be
considered as a cinnamate ester and also as tannin (Pubchem 2020a). It is a member
of the family of non-flavonoid phenolics, with caffeic and quinic acid esters, and
related isomers including 3-O-caffeoylquinic acid, 3,5-dicaffeoylquinic acid, and
4,5-dicaffeoylquinic acid (Croge et al. 2020; Heck and De Mejia 2007). Peculiar