Evaluation of the chemical, antinutritional and antioxidant properties of composite flour comprising native and modified acha (digitaria exilis stapf) flour supplemented with mango kernel seed and soy cake flours

Abstract

Gluten-free flours that are nutritionally balanced with appropriate functional characteristics were developed by supplementation of native and modified acha flours with protein, dietary fiber and antioxidants-rich mango kernel and soy cakes flours. Acha flour was subjected to chemical and enzymatic modifications. The proximate, mineral compositions, bioactive and antinutrients properties of the composite flours were evaluated. The water content of the composite flours with native and chemically modified acha flour was between 7.62 and 9.30%, while that of enzymatic acha flour was between 10.12 and 10.79%. However, samples made with 20 and 30% incorporated mango kernel flour had around 13 and 19% increase in the protein content respectively, others including sample with enzymatically modified acha flour had lower protein content. On the other hand, all samples with enzymatically modified acha flour had between 83 and 100% increase in fibre content. The Na/K ratio of all the samples were less than one, as nutritionally required. Samples with enzymatically modified acha flour had best total flavonoid (0.03–0.77 mgGAE/g), total phenol (2.35–11.99 mgTAE/g) and DPPH radical scavenging activities (58.29–94.02%) contents. In addition, samples with enzymatically modified acha flour had the least antinutritional values. Although all the samples had values that were significantly (p ≥ 0.05) different, the samples had significant protein, dietary fiber, minerals and antioxidants contents, while the antinutritional contents were well lower than the standard.