H. R. Azarbad - Faculty of Food Science and Technology, Ferdowsi University of Mashhad, Islamic Republic of Iran.
M. Mazaheri Tehrani - Department of Food Science and Technology, Faculty of Food Science and Technology, Ferdowsi University of Mashhad, Islamic Republic of Iran.
H. Rashidi - Food Industries Department, Khorasan Razavi Agricultural and Natural Resources Research and Education Center, AREEO, Mashhad, Islamic Republic of Iran.

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 ۶۷.۱۸% SF, ۱۷.۸۲% RF and ۱۵% MF with combined desirability equals to ۰.۷۹۱. 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.

Celiac, Desirability function, Optimum formulation, Organoleptic evaluation., نان فاقد گلوتن, طرح مخلوط دی اپتیمال, آرد برنج, آرد سورگوم, آرد ارزن