Optimization of Gluten-Free Bread Formulation Using Sorghum, Rice, and Millet Flour by D-Optimal Mixture Design Approach

There is an increasing interest in Gluten-Free (GF) products as the prevalence of celiac disease. Sorghum, millet, and rice flours are the most suitable cereal flours for GF products. The objective of this study was to optimize mixtures of Sorghum Flour (SF), Rice Flour (RF), and Millet Flour (MF) for production of GF bread based on D-optimal mixture design approach. The characteristics of flours including moisture, proteins, fat, ash, fiber, and pH were measured. GF bread quality parameters such as specific volume, hardness, crumb structure, image characteristics and organoleptic evaluation were also analyzed. Our results revealed that three flour blends (SF, RF, and MF) had remarkable effect on physical and organoleptic properties of GF bread. Increasing MF and SF together with decreasing RF increased specific volume and mean cell area and produced GF breads with a softer texture. Color and taste improved with incorporation of RF, SF, and MF at high levels. The organoleptic evaluation of texture was correlated to instrumental texture analysis. The optimum formulation obtained according to organoleptic evaluation, specific volume, hardness, and crumb structure contained 67.18% SF, 17.82% RF and 15% MF with combined desirability equals to 0.791. In general, the results of the present study indicate that RF, SF, and MF can be used as a substitute for wheat flour in producing high quality GF bread. The data presented in this study could be useful in producing GF bread for celiac patients.