There is an increasing emphasis on the consumption of whole grain products, moreover, unconventional and underutilized grains such as Amaranth and Acha are reported to have tremendous health benefits, and their incorporation into whole wheat flour could significantly modify the functionality of flour or its product(s). In this study, bread, an important dietary staple food; was produced from blends of whole-grain wheat, amaranth and acha flours, combined in different ratios (70:30:0, 70:0:30, 70:20:10, 70:10:20 and 70:15:15 represented by MM1, MM2, MM3, MM4 and MM5 respectively). Rheology and pasting properties of the flour blends, quality attributes, antioxidant properties, α-amylase and α-glucosidase inhibition, as well the glycaemic indices (GI) of the multigrain breads were evaluated using standard methods. Whole wheat flour supplementation with amaranth flour and/or acha flour, modified the rheology and pasting properties of composite flours, increased the ash, fibre and protein contents of bread while reducing the carbohydrate content. Multigrain breads also exhibited significant hydroxyl (OH) radical scavenging ability, Fe2+ chelation and inhibit of Fe2+- induced lipid peroxidation. Bread with greater amaranth flour substitution (MM1B and MM4B) have higher α-amylase (IC50 = 1.90, 1.41 mg/mL) and α-glucosidase (IC50 = 0.83, 1.39 mg/mL) inhibitory abilities, while multigrain breads generally possessed low GI (42–51) value whereas, white flour bread (control) had intermediate GI (65). The synergistic properties contributed by the grains may have conferred on the bread its potential as a dietary product for better health maintenance, thus, multigrain bread is of greater dietary and health importance than white bread.
