Quality and cost evaluation of bread produced from blends of wheat and partially defatted soy flours

Abstract

Background: This study was necessitated by the need to improve the nutritional quality of baked products, ensure their acceptability and the baker's profitability.

Objective: The aim of the study therefore was to evaluate the quality and cost of bread produced from composite flours of wheat and partially defatted soy.

Materials and Methods: Blends of wheat and partially defatted soy flours were processed into bread according to the following ratios: 97.5:2.5; 95:5; 92.5:7.5 and 90:10; with 100% wheat flour as control. The proximate composition, physical properties, sensory evaluation and cost analysis of the bread samples were determined using standard methods of analysis.

Results: Bread produced from the flour blends had significantly (p < 0.05) higher protein content 10.94% - 13.13%, than the control (8.60%). While the moisture content increased significantly (p < 0.05) with increase in soy flour from 38.00% to 44.00%; carbohydrate content decreased from 44.99% to 38.85% with increase in soy flour supplementation, with concomitant decrease in energy from 251.62 to 224.55 kcal/100g. Loaf volume, specific loaf volume and loaf height decreased significantly p < 0.05 from 796.70 to 553.30 cm³/g, and 7.00 to 3.39 cm³ respectively; while loaf weight increased significantly p < 0.05 from 169.20 to 184.51g. The general acceptability of the bread decreased with increase in soy flour supplementation.

Conclusion: The most acceptable bread was from the 97.50:2.50 blends. Cost analysis indicated that baking with soy flour was more profitable than 100% wheat flour.

Keywords: Partially defatted soy flours, wheat flour, bread,  supplementation, cost