Comparative Bioaccesibility Study of Cereal-Based Nutraceutical Ingredients Using INFOGEST Static, Semi-Dynamic and Dynamic In Vitro Gastrointestinal Digestion

Efficient development of effective functional foods and nutraceuticals requires adequate estimation methods of the bioaccessibility of their bioactive compounds. Specially grain-based nutraceuticals and functional ingredients are often enriched in bound/low bioavailable bioactive phytochemicals. The objective of this work was to evaluate the differences in applying static or dynamic digestion models for the estimation of bioaccessibility of antioxidants present in cereal grain-based/fiber-rich ingredients produced using enzymatic hydrolysis and sprouting processes. Main liberated phenolic compounds, antioxidant activity (ABTS^•+ and ORAC) and ferric reducing capacity were evaluated in the samples following three digestion protocols with differences based on their dynamism: static, semi-dynamic and dynamic. The samples digested with the dynamic method showed higher antioxidant and reducing capacities than those digested with the static and semi-dynamic protocols. The results obtained from the digests with the dynamic model showed a total phenol content (TPs) ranging from 1068.22 to 1456.65 μmol GAE 100 g^-1 and antioxidant capacity values from 7944.62 to 15,641.90 μmol TE 100 g^-1 (ORAC) and from 8454.08 to 11,002.64 μmol TE 100 g^-1 (ABTS^•+), with a reducing power ranging from 2103.32 to 2679.78 mmol Fe reduced 100 g^-1 (FRAP). The dynamic character of the protocols used for developing bioactive cereal-based foods significantly affects the estimation of their bioaccessibility, probably giving a better approach to their potential bioavailability in in vivo systems.