International Journal of Applied Food Science and Nutrition
Optimization Of Sweet Potato Flour And Black Cumin Seed Blending Ratios With Wheat Flour To Produce Quality Bread
Abstract
KidanemariamTesfay Zenebe, Zenebe Tadesse Tsegay, LijalemTareke Weldeabezgi, Ftwi GebremedhinKidane and GebrehiwotGidey Gebrekrstos
This study aimed to optimize the incorporation levels of sweet potato flour and black cumin seed in wheat bread and evaluate their effects on physicochemical properties and sensory acceptability. Response Surface Methodology (RSM) coupled with Central Composite Rotatable Design (CCRD) was employed to optimize the blending ratios of sweet potato flour (8–22 g) and black cumin seed (0.59–3.89 g). A total of 13 experimental formulations were prepared and evaluated for carbohydrate content, protein content, and sensory acceptability. The results showed that the blend ratios significantly affected the nutritional and sensory qualities of the bread (p < 0.05). Increasing the level of sweet potato flour enhanced carbohydrate content, reaching a maximum value of 85.03%, whereas higher incorporation of black cumin seed improved protein content up to 8.0%. Sensory acceptability was highest (4.75) at intermediate substitution levels, indicating favorable consumer preference. The optimized formulation consisted of 11.8 g sweet potato flour and 3.49 g black cumin seed, producing bread with 82.22% carbohydrate, 7.9% protein, and an overall sensory score of 4.41. The optimized bread also showed appreciable levels of calcium, iron, and zinc. Experimental and predicted values showed no significant difference (p > 0.05), confirming the adequacy and predictive capability of the developed models. These findings demonstrate that sweet potato flour and black cumin seed can be effectively utilized to produce nutritionally improved bread with acceptable sensory quality.