Formulations with microencapsulated Fe-peptides improve in vitro bioaccessibility and bioavailability.

The bioaccessibility and the bioavailability of iron complexed to peptides (active) in microparticles forms contained in dry beverages formulations were evaluated. The peptide-iron complexes microparticles were obtained by spray drying and added in three dry formulations (tangerine, strawberry, and chocolate flavors). The peptides isolated by iron ion affinity (IMAC-Fe III) had their biological activity predicted by BIOPEP® database and were evaluated by molecular coupling. The bioaccessibility was evaluated by solubility and dialysability and the bioavalability was assessed by Caco-2 cellular model. The proportion 10:1 of peptide-iron complexes presented higher rates of bioaccessibility (49%) and bioavailability (56%). The microparticle with peptide-iron complex showed greater solubility after digestion (39.1%), bioaccessibility (19.8%), and bioavailability (34.8%) than the ferrous sulfate salt (control) for the three assays (10.2%; 12.9%; 9.7%, respectively). Tangerine and strawberry formulations contributed to the iron absorption according to the results of bioaccessibility (36.2%, 30.0% respectively) and bioavailability (80.5%, 84.1%, respectively). The results showed that iron peptide complexation and microencapsulation process improve the bioaccessibility and bioavailability when incorporated into formulations.

Microencapsulation performance of Fe-peptide complexes and stability monitoring.

Iron supplementation presents several challenges, such as low bioavailability, high reactivity and a metallic taste. Iron absorption is enhanced by complexing with organic compounds such as peptides, while microencapsulation is an alternative to protect the mineral and mask undesirable flavors. Fe-peptide complexes were obtained by reacting small whey peptides (< 5 kDa) with iron (from ferrous sulfate) under controlled conditions. Maltodextrin (MD) and polydextrose (PD) were used as the wall materials and spray dried to form particles containing the active Fe-peptide. The conditions of enzymatic hydrolysis with the bacterial endopeptidase produced from Bacillus licheniformis were optimized to achieve a high degree of cleavage (~20% degree of hydrolysis). The physicochemical and structural properties of the microparticles were evaluated during storage (365 days). The encapsulation process showed high efficiency (84%) and process yield (≥90%). The iron dialyzability and uptake by Caco-2 cells from microparticles were at least 3-fold higher than the ferrous sulfate. The water content and water activity varied from 3.0 to 5.7% and from 0.29 to 0.44, respectively, after 365 days. SEM revealed morphological stability during storage and EDX showed the presence of iron ions at the surface of the microparticles, which could be free or complexed. The microparticles can be an alternative of higher bioavailable iron besides the further protection and iron stability which the microparticles may present when compared with the Fe-peptide complexes. Future studies could demonstrate the feasibility of applying these microparticles in formulation for food supplementation, concerning bioavailability and sensory aspects.