Simulated gastrointestinal digestion of amaranth flour and protein isolate: Comparison of methodologies and release of antioxidant peptides.

The effect of both the simulated gastrointestinal digestion conditions and the matrix over protein hydrolysis and antioxidant peptides generation was evaluated by comparing an in-house method with COST INFOGEST-based SGD protocols. The in-house protocol was used to digest amaranth protein isolate I (Id1), while the standardized method and a modified version (similar enzyme/substrate ratio than in our lab) were used to digest I and amaranth flour F (Id3 and Fd3, Id2 and Fd2). Protein hydrolysis degree (TNBS method) was similar for the three I digested (about 60%), but lower for F digested (45 and 34% for Fd2 and Fd3, respectively).

Antioxidant effect of amaranth flour or protein isolate incorporated in high-fat diets fed to Wistar rats. Influence of dose and administration duration.

This study evaluated the effect on Wistar rat's oxidative status of incorporating amaranth flour (AF) and protein isolate (AI) in increased-fat diets. Five of the groups were fed for 4 weeks with either BD (basal diet), Chol+F (2% cholesterol, 10% porcine fat), Chol+F+E (0.005% α-tocopherol), Chol+F+AF or Chol+F+AI (25% of protein replacement) diets.