Impact of in-vitro gastro-pancreatic digestion on polyphenols and cinnamaldehyde bioaccessibility and antioxidant activity in stirred cinnamon-fortified yogurt

In this study, cinnamon powder was supplemented into yogurt as a functional ingredient. The total phenolic compounds, individual phytochemicals and radical scavenging activity of the yogurts were measured and compared with a cinnamon water extract treated in the same way as the fortified yogurt. Cinnamon-fortified yogurt displayed higher total phenolic content (P < 0.05) and higher radical scavenging activity (P < 0.05) compared to plain yogurt. Phenolic acids, flavonols and cinnamaldehyde were identified in the cinnamon-fortified yogurt. Results showed that only the 34.7% of the total phenolic compounds present in the cinnamon water extract were found in the cinnamon-fortified yogurt, the remaining being bound to milk proteins. A low recovery was also found for the individual phytochemicals. However, in-vitro digestion of the cinnamon-fortified yogurt resulted in the release of phenolic compounds from milk proteins so that at the end of the digestion the amount of phenolic compounds recovered in the cinnamon-fortified yogurt was higher than that found in the digested cinnamon water extract (P < 0.05). These results clearly showed that yogurt matrix enhance the gastro-intestinal stability and the bioaccessibility of cinnamon polyphenols. Cinnamon-fortified yogurt can be considered an important source of dietary bioaccessible polyphenols.