Jaiswal R. and Kuhnert N. Department of Chemistry, Jacobs University Bremen, Bremen, Germany. E-mail: r.jaiswal@jacobs-university.de
Coffee is the third most consumed beverage in the world. Roasted coffee contains more than 300 derivatives of chlorogenic acids
(CGAs) which contribute to the coffee flavour and possess fascinating biological properties [1]. We used LC-MSn for the identification and characterization of seven new C1- acylated chlorogenic acids in roasted coffee.
All of them are reported for the first time from this source. These CGAs comprise 1-O-caffeoyl-3-O-feruloylquinic acid 1, 1-O-caffeoyl-4-O-feruloylquinic acid 2, 1-O-caffeoyl-4-O-dimethoxycinnamoylquinic acid 3, 1-O-caffeoyl-3-O-sinapoylquinic acid 4, 1- O-feruloyl-4-O-sinapoylquinic acid 5, 1-O-feruloyl-3-O-sinapoylquinic acid 6 and 1-O-caffeoyl-3-O- trimethoxycinnamoylquinic acid 7.
The regiochemistry assignment of these CGAs was based on their unique fragmentation patterns in negative ion mode MS and their HPLC retention times [2, 3].
OH OH O OH O O
6 5OH
HOOC 1 4 R3 23
R1 R2 Quinic Acid (R1=R2=R3=H)
Chlorogenic Acids:
(1) R1=Caffeoyl, R2=Feruloyl, R3=H (2) R1=Caffeoyl, R2=H, R3=Feruloyl (3) R1=Caffeoyl, R2=H, R3=Dimethoxycinnamoyl (4) R1=Caffeoyl, R2=Sinapoyl, R3=H (5) R1=Feruloyl, R2=H, R3=Sinapoyl (6) R1=Feruloyl, R2=Sinapoyl, R3=H (4) R1=Caffeoyl, R2=trimethoxycinnamoyl, R3=H
O OH Caffeic Acid
O OH Ferulic Acid
O OH
Dimethoxycinnamic Acid
OH O OOOO
OOH OOH Sinapic Acid Trimethoxycinnamic Acid
References
[1] Jaiswal, R. et al. Understanding the fate of chlorogenic acids in roasting using mass spectrometry based targeted and non-targeted analytical strategies. Food Funct. 2012, 3, 976-984.
[2] Clifford, M.N. et al. Hierarchical scheme for LC-MSn identification of chlorogenic acids. J. Agric. Food Chem. 2003, 51, 2900-2911.
[3] Jaiswal, R. et al. Hierarchical scheme for liquid chromatography/multi-stage spectrometric identification of 3,4,5-triacyl chlorogenic acids in green Robusta coffee beans. Rapid Commun. Mass Spectrom. 2010, 24, 2283-2294.
