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 ... -  《-》

Quantification of Coffea arabica and Coffea canephora var. robusta in roasted and ground coffee blends.

This study reports direct quantification of arabica in roasted and ground coffee blends of Coffea arabica and Coffea canephora var. robusta. (1)H-NMR analysis of water extracts of coffee blends were combined with multivariate statistical analysis to obtain an OPLS model with high predictive capability. This approach allowed to evaluate the composition of coffee blends of unknown arabica and robusta content, on the basis of multiple chemical components. Differences in geographical origin of the analyzed samples did not affected the compositional determination of coffee blends. This approach represents a valid tool in authentication procedures of arabica and robusta blends of roasted and ground coffee.

Cagliani LR ，Pellegrino G ，Giugno G ，Consonni R ... -  《-》

Heat-induced formation of N,N-dimethylpiperidinium (mepiquat) in Arabica and Robusta coffee.

N,N-dimethylpiperidinium (mepiquat) is a new process-induced compound formed from natural constituents during the cooking process. Mepiquat was first found in coffee and cereal products, but its formation mechanism in coffee is still unclear. In the current study, Arabica and Robusta coffee beans were roasted at different temperatures (215, 220, and 230 °C) to study the effect of roasting process on mepiquat formation. The highest mepiquat content, 1,020 µg/kg, was found in dark roast (230 °C) Indonesia Wahana, while 430 µg/kg of mepiquat was detected in medium roast (220 °C) Vietnam Robusta. At the same roasting temperature, higher level of mepiquat was observed in Arabica than in Robusta. In both species, substances related to mepiquat formation, including betaine, choline, trigonelline, lysine, carnitine, pipecolic acid (PipAc), pipecolic acid betaine (PipBet), were also detected. The lysine-based Maillard reaction and decarboxylation in Arabica and Robusta promoted mepiquat formation through the degradation of choline and trigonelline, and the formation of intermediate products. Results from both the model system and selected commercial beans showed that choline and trigonelline had a significant correlation (P < 0.01) with mepiquat formation in Arabica. PRACTICAL APPLICATION: Mepiquat is considered as a new process-induced compound resulting from typical roasting conditions, but its formation mechanism in coffee is still unclear. This work demonstrates the formation mechanism of mepiquat by many precursor substances contained in Arabica and Robusta. It is very important to figure out how mepiquat is ''naturally" present in daily diets, especially in those processed at high temperatures.

Li X ，Zhang X ，Tan L ，Yan H ，Yuan Y ... -  《-》

Melatonin and serotonin profiles in beans of Coffea species.

A high-performance liquid chromatography (HPLC) and an electrospray ionization mass spectrometry (LC/ESI-MS) methods were applied to quantify the profiles of melatonin and serotonin (5-HT) in green and roasted beans of Coffea canephora (robusta) and Coffea arabica (arabica). Both melatonin and 5-HT were detected in green coffee beans (5.8±0.8μg/g dry weight (DW), 10.5±0.6μg/g DW) and also in roasted beans of C. canephora (8.0±0.9μg/g DW, 7.3±0.5μg/g DW). Melatonin (3.0±0.6μg/50mL) and 5-HT (4.0±0.7μg/50mL) were detected in coffee brew. In C. arabica, 5-HT was high in green beans (12.5±0.8μg/g DW) compared with roasted beans (8.7±0.4). The levels of melatonin were higher (9.6±0.8μg/g DW) in roasted beans compared with green beans (6.8±0.4μg/g DW). Both melatonin (3.9±0.2μg/50mL) and 5-HT (7.3±0.6μg/50mL) were detected in coffee brew. Because of the relevance of indoleamines as bioactive molecules with implications for food, nutritional sciences and human health, it was of interest to explore their levels in coffee, an important universal beverage.

Ramakrishna A ，Giridhar P ，Sankar KU ，Ravishankar GA ... -  《-》

Rapid authentication of coffee blends and quantification of 16-O-methylcafestol in roasted coffee beans by nuclear magnetic resonance.

Schievano E ，Finotello C ，De Angelis E ，Mammi S ，Navarini L ... -  《-》