Physico-chemical characteristics and sensory evaluation of wheat bread partially substituted with sweet potato (Ipomoea batatas L.) flour

Purpose The purpose of this paper is to investigate the effect of partial substitution of wheat flour with sweet potato flour on the nutrient composition and sensory properties of bread. Design/methodology/approach Sweet potato flour was blended with wheat flour at 5, 10, 15, 20 and 25 percent levels of substitution for bread production. Proximate, minerals and antinutritional factors of the breads were investigated using AOAC methods. Sensory evaluation was carried out by a panel of 50 consumers. Data were subjected to analysis of variance and means were separated by Tukey’s comparison test at p <0.05. Results were reported as mean ± SD. Findings The nutritional and sensory quality of bread made from wheat flour supplemented with sweet potato flour at 5, 10, 15, 20 and 25 percent was investigated. Blending of sweet potato flour with wheat flour had significantly decreased the protein content (4.76–7.78 percent) while the ash (1.35–3.07 percent), crude fiber (0.24–1.03), carbohydrate contents (88.39–90.45 percent), iron, zinc, phosphorus and vitamin A contents were significantly increased ( p<0.05) with increasing sweet potato flour in the formulations. The tannin and phytate contents of the composite breads were low. Sensory evaluation of the breads revealed a mild reduction of the bread’s general acceptability with increase in the substitution level by sweet potato flour. Originality/value This study showed that the wheat flour used in making breads could be substituted with up to 15 percent sweet potato flour without compromising its nutritional quality, with only a mild reduction in sensory quality.