Effect of cinnamon beverage formulations on the bioaccessibility of polyphenols and cinnamaldehyde during in vitro gastro-pancreatic digestion

The present study was undertaken to investigate the in vitro bioaccessibility of phenolic compounds and cinnamaldehyde in cinnamon beverage and formulations during simulated gastro-pancreatic digestion. Cinnamon polyphenol bioaccessibility was 79.8% at the end of the digestion. This decline in total polyphenols was found during the gastric step of the digestion and was caused by the precipitation of cinnamon proanthocyanidins by pepsin. The addition of sweeteners increased the polyphenol bioaccessibility to value near 90% decreasing the interaction between pepsin and tannins. The addition of bovine milk gave rise to an immediate decrease in cinnamon polyphenol concentration and negatively affect their post-pancreatic bioaccessibility. Quercetin-3-rhamnoside, syringic and coumaric acids were find to be poor bioaccessible whereas kaempferol and cinnamaldehyde were stable during digestion. The addition of sweeteners did not affect the bioaccessibility of these compounds. Milk addition caused an immediate decrease in the concentration of monomeric phenolic compounds partially due to the interaction with milk protein as probed by fluorescence spectroscopy. The final bioaccessibility was affected by milk only for cinnamaldehyde. The present study demonstrates that cinnamon beverage provide a significant source of dietary bioaccessible polyphenols and that the modality of consuming cinnamon could represent a crucial factor since the addition of sweeteners improve their bioaccessibility whereas milk negatively affect it.