Effect of potato-maize blending ratio and fermentation time on the quality of wheat-based composite bread

Bread is a widely consumed fermented and baked food traditionally produced from wheat flour. In Ethiopia, strong dependence on imported wheat and significant postharvest losses of potato, estimated at 20–40%, highlight the need for alternative flour blends that enhance nutrition and reduce waste. This study examined how different proportions of potato and maize, combined with varying fermentation periods, affect the quality of wheat-based composite bread. Three formulations—BR1 (5% maize, 70% wheat, 25% potato), BR2 (15% maize, 70% wheat, 15% potato), and BR3 (25% maize, 70% wheat, 5% potato)—were evaluated with fermentation times of 1:40, 2:00, and 2:20 hours using a 3 × 3 factorial design with triplicates. A 100% wheat bread served as the control. Nutritional analysis showed that BR2 had the highest protein content (12.34%), while BR3 recorded the greatest fat (3.76%) and fiber (2.00%). In baked breads, the 2:20-hour control yielded the highest protein (14.61%). BR3 had the highest fiber (1.87%), and BR1 had the highest ash level (4.44%). BR1 also contained the most carbohydrates (52.66%), whereas BR2 provided the greatest energy value (271.80 kcal/100 g). Mineral results indicated that BR3 was richest in iron (18.98 mg/100 g), while BR2 had the highest calcium (63.33 mg/100 g) and zinc (7.29 mg/100 g). Sensory evaluation showed good acceptability for all breads, with BR2 fermented for 2:00 hours receiving the highest preference. Microbial analysis confirmed that all samples were safe. The study concludes that using 15% maize and 15% potato with a fermentation time of 2 hours results in nutritionally improved and acceptable composite bread.