Comparison and quantification of chlorogenic acids for differentiation of green Robusta and Arabica coffee beans.

Coffea arabica and Coffea canephora (Robusta coffee) are the most commonly consumed coffee varieties globally. In this contribution, NMR was used to confirm the coffee authenticity and LC-ESI-MSn technique was employed to profile and quantify the most abundant chlorogenic acid in 54 different samples of the two coffee varieties from diverse origins. Significant variations were observed for feruloyl quinic acids, dicaffeoyl quinic acids and 5-sinapoylquinic acid while the mono-caffeoyl quinic acids showed no variation when the two coffee varieties were compared. Additionally isomer ratios were explored as a potential marker for coffee authenticity along with a thorough statistical evaluation of rather extensive data set. Robusta 5-CQA when compared with 3,4-DiCQA Robusta shows high positive correlation, similar high correlation coefficient was observed in 5-pCoQA Robusta when compared with 3-pCoQA as against the Arabica.

Badmos S ，Lee SH ，Kuhnert N 《-》

Hierarchical scheme for liquid chromatography/multi-stage spectrometric identification of 3,4,5-triacyl chlorogenic acids in green Robusta coffee beans.

Liquid chromatography/multi-stage spectrometry (LC/MS(n)) (n = 2-4) has been used to detect and characterize in green Robusta coffee beans eight quantitatively minor triacyl chlorogenic acids with seven of them not previously reported in nature. These comprise 3,4,5-tricaffeoylquinic acid (Mr 678); 3,5-dicaffeoyl-4-feruloylquinic acid, 3-feruloyl-4,5-dicaffeoylquinic acid and 3,4-dicaffeoyl-5-feruloylquinic acid (Mr 692); 3-caffeoyl-4,5-diferuloylquinic acid and 3,4-diferuloyl-5-caffeoylquinic acid (Mr 706); and 3,4-dicaffeoyl-5-sinapoylquinic acid and 3-sinapoyl-4,5-dicaffeoylquinic acid (Mr 722). Structures have been assigned on the basis of LC/MS(n) patterns of fragmentation. A new hierarchical key for the identification of triacyl quinic acids is presented, based on previously established rules of fragmentation. Fifty-two chlorogenic acids have now been characterized in green Robusta coffee beans. In this study five samples of green Robusta coffee beans and fifteen samples of Arabica coffee beans were analyzed with triacyl chlorogenic acids only found in Robusta coffee bean extracts. These triacyl chlorogenic acids could be considered as useful phytochemical markers for the identification of Robusta coffee beans.

Jaiswal R ，Kuhnert N 《-》

UHPLC-ESI-QqTOF-MS/MS characterization of minor chlorogenic acids in roasted Coffea arabica from different geographical origin.

Chlorogenic acids are relevant coffee quality markers, taste, and aroma precursors as well as important bioactive compounds. A number of mono-acyl, di-acyl, and tri-acyl quinic acid isomers were found in green coffee beans, being mono-caffeoyl, mono-feruloyl, mono-p-coumaroyl, and di-caffeoylquinic acid isomers considered as quantitatively major compounds. Roasting process increases the chemical complexity of coffee by inducing the formation of a number of lactones (quinides), shikimates, and other chlorogenic acids derivatives. So far, little attention has been paid in characterizing minor chlorogenic acids and derivatives in roasted Coffea arabica, also known as Arabica. In the present work, roasted C. arabica samples from different geographical origins (Brazil, Colombia, Costa Rica, Ethiopia, Guatemala, and India) were characterized by UHPLC-ESI-QqTOF-MS/MS. Several minor chlorogenic acid isomers were identified. In particular, HR-MS/MS provided putative identification of four dimethoxycinnamoyl-quinic acid derivatives, such as 4-dimethoxycinnamoylquinic acid, 4-dimethoxycinnamoyl-3-caffeoylquinic acid, 3-dimethoxycinnamoyl-4-feruloylquinic acid, 4-dimethoxycinnamoyl-5-feruloylquinic acid, and two caffeoyl, feruloyl quinic acid derivatives (3-caffeoyl-4-feruloylquinic acid and 3-feruloyl-4-caffeoylquinic acid). To our knowledge, these compounds were found in roasted Arabica coffee for the first time, and their presence is independent on the different geographical origins examined.

De Rosso M ，Colomban S ，Flamini R ，Navarini L ... -  《-》

Profile and characterization of the chlorogenic acids in green Robusta coffee beans by LC-MS(n): identification of seven new classes of compounds.

Jaiswal R ，Patras MA ，Eravuchira PJ ，Kuhnert N ... -  《-》

Homostachydrine (pipecolic acid betaine) as authentication marker of roasted blends of Coffea arabica and Coffea canephora (Robusta) beans.

The occurrence of pipecolic acid betaine (homostachydrine) and its biosynthetic precursor N-methylpipecolic acid was detected for the first time in green coffee beans of Robusta and Arabica species. The analyses were conducted by HPLC-ESI tandem mass spectrometry and the metabolites identified by product ion spectra and comparison with authentic standards. N-methylpipecolic acid was found at similar levels in green coffee beans of Robusta and Arabica, whereas a noticeable difference of homostachydrine content was observed between the two green coffee bean species. Interestingly, homostachydrine content was found to be unaffected by coffee bean roasting treatment because of a noticeable heat stability, a feature that makes this compound a candidate marker to determine the content of Robusta and Arabica species in roasted coffee blends. To this end, a number of certified pure Arabica and Robusta green beans were analyzed for their homostachydrine content. Results showed that homostachydrine content was 1.5±0.5mg/kg in Arabica beans and 31.0±10.0mg/kg in Robusta beans. Finally, to further support the suitability of homostachydrine as quality marker of roasted blends of Arabica and Robusta coffee beans, commercial samples of roasted ground coffee blends were analyzed and the correspondence between the derived percentages of Arabica and Robusta beans with those declared on packages by manufacturers was verified.

Servillo L ，Giovane A ，Casale R ，Cautela D ，D'Onofrio N ，Balestrieri ML ，Castaldo D ... -  《-》