Wheat bread enriched with green coffee - In vitro bioaccessibility and bioavailability of phenolics and antioxidant activity.

The potential bioaccessibility and bioavailability of phenolics, caffeine and antioxidant activity of wheat bread enriched with green coffee were studied. Supplementation enhanced nutraceutical potential by improving phenolic content and lipid protecting capacity. The simulated-digestion-released phenolics (mainly caffeic acid, syringic acid and vanillic acid) from bread, also caused significant qualitative changes (chlorogenic acids were cleaved and significant amounts of caffeic acid and ferulic acid were determined). Compared to the control, for the bread with 1% and 5% of the functional component the contents of phenolics were 1.6 and 3.33 times higher. Also, an approximately 2.3-fold increase in antioxidant activity was found in bread containing 5% of the supplement. The compounds responsible for antioxidant potential have high bioaccessibility but poor bioavailability. The qualitative composition of the phenolic fraction has a key role in developing the antioxidant potential of bread; however, caffeine and synergism between antioxidants are also important considerations.