Planta Med 2015; 81 - PM_219
DOI: 10.1055/s-0035-1565596

Bioaccessibility and bioavailability in vitro of antioxidants from powdered green coffee beans

U Gawlik-Dziki 1, M Świeca 1, Ł Pecio 2, D Dziki 3
  • 1Department of Biochemistry and Food Chemistry, University of Life Sciences, Lublin, Poland
  • 2Department of Biochemistry and Crop Quality, Institute of Soil Science and Plant Cultivation, State Research Institute, Puławy, Poland
  • 3Thermal Engineering Department, University of Life Sciences, Puławy, Lublin, Poland

Green coffee (Coffea arabica) beans (GCB) derived from Ethiopia, Kenya, Brazil and Colombia were studied. Phenolics profile and caffeine content were determined using UPLC-MS technique. Potentially bioaccessible and bioavailable phytochemicals were released during digestion in the simulated human gastrointestinal tract. Antiradical activity (AA), reducing power (RP), chelating ability (CHEL) and ability to prevent lipids against oxidation (LPO) were estimated.

The dominant compound identified in all analyzed samples was 5-caffeoylquinic acid. Significant amounts of other phenolic acids (3-caffeoylquinic acid; 4-caffeoylquinic acid; 3-feruloylquinic acid; 5-caffeoylquinic acids and 3,5-dicaffeoylquinic acid) were determined. Caffeine content averaged from 4.36 mg/g dw to 4.99 mg/g dw. Digestion in vitro released chelating and reductive agents, free radical scavengers and lipid-preventers. The highest capacity for metal ions chelation was found for Brazilian GCB (EC50= 2.07 mg dw/mL), whereas the lowest for GCB from Ethiopia (EC50= 7.01 mg dw/mL). Importantly, the activity of extracts obtained after absorption in vitro was significantly higher than that determined for samples obtained after simulated digestion. Particularly noteworthy is the fact that GCBs were an excellent source of potentially bioaccessible reductive compounds. The AA activity of samples obtained after digestion in vitro averaged about 4 mg dw/mL. The potential bioavailability of antiradical compounds differed significantly. The highest activity was found for Brazilian GCB whereas the lowest was found for GCB from Colombia. The LPO activity of bioaccessible in vitro phytochemicals was relatively low. Probably, this is because lipophilic compounds are less extractable in the gastrointestinal model system. Most importantly, the potential bioavailability of these phytochemicals was surprisingly high.

Acknowledgement: The study was financed by the Polish National Science Centre (grant 2013/09/B/NZ9/01801).