The effect of plantain and tigernut flours substitution on the antioxidant, physicochemical and pasting properties of wheat-based composite flours

Wheat based composite flour was substituted with plantain and tigernut flours in order to enhance its protein, fibre, minerals, antioxidants and resistant starch contents. The proximate and compositions were optimized using optimal model design of response surface methodology. The independent variables were wheat flour (60–77%), plantain flour (92–37%) and tigernut flour (3–10%). The optimum blends, that is, blends with overall best protein, fibre and minerals contents were chosen for subsequent analyses (functional properties, amylose and amylopectin contents, resistant starch, dietary fibre, pasting characteristics and antioxidant properties). The control was 100% wheat flour. From the results, the optimum blends obtained were runs 2 (70% wheat, 20% plantain and 10% tigernut flours), 13 (77% wheat, 20% plantain and 3% tigernut flours) and 15 (65.66% wheat, 29% plantain and 5.33% tigernut flours) with overall best ash, fibre, protein and mineral contents. Substitution of wheat flour with plantain and tigernut flours reduces the swelling capacity and foaming capacity while there are no significant (p ≤ 0.05) differences in the oil absorption capacity at all levels of substitution. Substitution of wheat flour with plantain and tigernut however increases the water absorption capacity. In addition, substitution of wheat flour with plantain and tigernut flour above 30% significantly (p ≤ 0.05) increases the antioxidant properties and insoluble dietary fibre. However, 100% wheat flour had better pasting characteristics. The study therefore showed that substitution of wheat flour with plantain and tigernut flour (30% and above) greatly enhanced its nutritional quality while the 100% wheat flour was better in terms of pasting characteristics.