Functional and Bioactive Characterization of Amaranth-Based Cookies: Antioxidant and Hypocholesterolemic Activities After Simulated Gastrointestinal Digestion

Abstract

This study aims to evaluate the bioaccessibility and bioactivity of proteins, phenolic compounds, and dietary fiber in cookies formulated with amaranth flour. Amaranth flour is relevant due to its high nutritional value and bioactive compounds. However, information about the effects of processing and digestion on its bioaccessibility and biological activities in bakery products remains limited. Baking promoted protein aggregation stabilized by disulfide bonds, reducing protein solubility and digestibility, while significantly increasing the extractability of phenolic compounds (281.4 mg GAE/100 g d.b. in cookies vs. 40.77 mg GAE/100 g d.b. in flour). After simulated gastrointestinal digestion (sGID), cookies showed lower proteolysis than flour but exhibited enhanced antioxidant capacity, with increases of up to 24- and 19-fold in ORAC and ABTS assays, respectively. The bioaccessible fraction also displayed bile salts binding activity mainly associated with soluble fiber, suggesting a potential hypocholesterolemic effect. These results highlight the potential of amaranth cookies as nutritional gluten-free bakery products combining sensory acceptance with biofunctional properties, supporting their application as functional foods.