Physico-chemical and Sensory Properties of Bread Prepared from Wheat and Orange-Fleshed Sweet Potato (Flour, Starch and Non-Starch Residue Flour) Blends

Abstract

Bread was produced from wheat (Trititum spp) orange flesh sweet potato (Ipomoea batatas L.) flour, starch and non-starch residue blends. The orange-fleshed sweet potatoes were washed, peeled, sliced, dried and milled to flour. The starch and non-starch residue were also produced from the orange-fleshed sweet potatoes. Different proportions of wheat and flour, wheat and starch and wheat and non-starch residue of orange-fleshed sweet potato with increasing level of orange-fleshed sweet potato at 10, 20, 30 and 40% addition in wheat were prepared. Control samples were 100% wheat flour (A0), 100% orange-fleshed sweet potato flour (A1), 100% orange-fleshed sweet potato starch (B1) and 100% orange-fleshed sweet potato non-starch residue (C1). Breads from these different proportions were formulated. The proximate, mineral, vitamin, physical properties and sensory attributes of the bread samples and their composites were determined. The GENSTAT Statistical Software (version 17.0) was used for data analyses. The Proximate compositions of the bread ranges as follows; moisture 26.30-36.21%, protein 0.85-7.89%, fat 6.33-8.93%, fiber 0.82-4.92%, ash 0.56-2.11% and carbohydrates 41.26-64.84%. The physical properties of the breads ranged from 210.60-254.00 g, 0.05-2.40 mm, 317.60-440.60 cm3 and 1.25-2.10 for loaf weight, oven spring, loaf volume and specific volume respectively. Mineral and vitamin composition for breads samples ranged respectively thus for calcium 18.45-33.21 zinc 0.92-6.27, magnesium 0.28-19.33, phosphorus 31.00-319.60 and potassium 56.30-352.60, vitamin B1, 0.10-0.37, vitamin B2, 0.07-1.23, vitamin B6, 0.09-1.25, vitamin B12 0.04-1.13 mg/100 g, vitamin C 0.12-14.17 mg/100 g and vitamin A 0.00-8193 µg/100 g.The sensory evaluation results indicated that up to 20% substitution of wheat flour with orange-fleshed sweet potato flour, starch and non-starch residue flours was acceptable in bread formulation.