Colonic Fermentation of Coffee Melanoidins and Resulting Cardioprotective Metabolites

This article belongs to the Proceedings of International Coffee Convention 2023.

Worldwide, noncommunicable diseases accounted for 7 out of 10 deaths in 2019 (WHO), being ischemic heart disease one of the major contributors. Coffee has been implicated with several health benefits, namely the hypocholesterolemic potential, attributed to its high molecular weight compounds (e.g., polysaccharides and melanoidins) ability to affect cholesterol bioaccessibility. However, the pathways through which the nitrogen-containing brown-colored melanoidins (prevalent in many thermally processed foods) can affect cholesterol metabolism are partially unknown. In order to access coffee melanoidin’s cardioprotective potential, its colonic fermentability was simulated in vitro using human feces, employing simgi® (Dynamic Gastrointestinal Simulator). The fermentation degree was evaluated by the analysis of total carbohydrates and ammonium. The cardioprotective effect of the ferments was estimated by measuring short-chain fatty acids (SCFA) and primary and secondary bile salts (BS) after 48h of fermentation. Melanoidin total sugar content decreased due to polysaccharides fermentation, used as the primary source of energy, while ammonium production increased, owing to the degradation of the melanoidin’s proteins. SCFA production increased, as well as secondary BS, due to the microbiota activity. The conversion of primary to secondary BS (more hydrophobic) was significantly lower in the presence of melanoidins than in its absence (control). This decrease promoted by melanoidins may lower BS enterohepatic circulation, which in turn can lower cholesterol bioaccessibility and bioavailability, configuring a hypocholesterolemic effect. The in vitro colonic fermentation of coffee melanoidins, using human microbiota, yielded cardioprotective metabolites (SCFA) and decreased secondary BS, suggesting that they may regulate cholesterol homeostasis.

This work was funded by Fundação para a Ciência e a Tecnologia (FCT)/MCTES support to the research units LAQV-REQUIMTE (UIDB/50006/2020), and by the project PTDC/QUI-OUT/29373/2017 through national funds (OE), including Filipe Coreta-Gomes research contract being co-financed by the FEDER by the Operational Program of Competitiveness and Internationalization (POCI), within the PT2020 Partnership Agreement. Fernanda Machado acknowledges FCT for her PhD fellowship (2020.06768.BD). NMR data was collected at the UC-NMR facility supported in part by the FEDER European Regional Development Fund through the COMPETE Programme (Operational Programme for Competitiveness) and by National Funds through FCT through grants RECI/QEQ-QFI/0168/2012 and CENTRO-07-CT62-FEDER-002012, and also through support to Rede Nacional de Ressonância Magnética Nuclear (RNRMN) and to Coimbra Chemistry Centre through grant UID/QUI/00313/2019. This work was supported also by the project COFFEE4BGA (PID2019-111510RB-I00).

Peer reviewed