Looking for the physiological role of anthocyanins in the leaves of Coffea arabica.

The aim of this study was to determine which anthocyanins are related to the purple coloration of young leaves in Coffea arabica var. Purpurascens and assess their impact on photosynthesis as compared to C. arabica var. Catuaí, with green leaves. Two delphinidin glicosides were identified and histological cross-sections showed they were located throughout the adaxial epidermis in young leaves, disappearing as the leaves mature. Regardless the irradiance level, the photosynthetic performance of Purpurascens leaves did not differ from that observed in leaves of the Catuaí variety, providing no evidence that anthocyanins improve photosynthetic performance in coffee plants. To analyze the photoprotective action of anthocyanins, we evaluated the isomerization process for chlorogenic acids (CGAs) in coffee leaves exposed to UV-B radiation. No differences were observed in the total concentration of phenolic compounds in either variety before or after the UV treatment; however, we observed less degradation of CGA isomers in the Purpurascens leaves and a relative increase of cis-5-caffeoylquinic acid, a positional isomer of one of the most abundant form of CQA in coffee leaves, trans-5-caffeoylquinic acid, suggesting a possible protective role for anthocyanins in this purple coffee variety.

Domingues Júnior AP ，Shimizu MM ，Moura JC ，Catharino RR ，Ramos RA ，Ribeiro RV ，Mazzafera P ... -  《-》

Distribution of p-coumaroylquinic acids in commercial Coffea spp. of different geographical origin and in other wild coffee species.

Quantitative analyses of mono-p-coumaroylquinic acids (pCoQAs) and total chlorogenic acids (CGAs) in green coffee commercial lots of C. arabica, C. canephora and C. liberica from different geographical origins and eight wild Coffea species were carried out. Among the commercial lots, pCoQAs average content of C. arabica (0.67 mg/g) is higher than that of C. canephora (0.40 mg/g) being C. liberica intermediate (0.58 mg/g). As far as the analyzed wild Coffea species is concerned, C. pseudozanguebariae is characterized by the lower pCoQAs content (0.12 mg/g) whereas C. sessiliflora is by far the richest source of pCoQAs (2.18 mg/g). Effect of the roasting process on the mono-p-coumaroylquinic acids profile was evaluated for the economically exploited species C. arabica and C. canephora. For the first time distribution of mono-p-coumaroylquinic acid isomers in wild coffee species by fast and accurate UHPLC-DAD analyses using authentic standards previously synthetized, is reported.

Gutiérrez Ortiz AL ，Berti F ，Solano Sánchez W ，Navarini L ，Colomban S ，Crisafulli P ，Forzato C ... -  《-》

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 《-》

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 ... -  《-》

Botanical and geographical characterization of green coffee (Coffea arabica and Coffea canephora): chemometric evaluation of phenolic and methylxanthine contents.

Alonso-Salces RM ，Serra F ，Reniero F ，Héberger K ... -  《-》