The objective of this investigation was to evaluate the effects generated by amaranth flour (AF)-of different particle sizes (PS) added to white wheat flour from 0% to 20%-on the proximate composition, dough rheological behavior, and bread technological parameters. The reduction of particle size led to an increased hydration capacity of the wheat-amaranth composite flour, while bulk density decreased. Increasing the amount of AF and decreasing the PS led to a significant increase in protein, lipids, and ash contents, while the moisture and carbohydrates of the composite flour decreased. Increasing AF addition led to an increase in dough tenacity and a decrease in dough extensibility, while the PS had an irregular trend. The large particle size, at 15% and 20% levels of AF in wheat flour, increased significantly (p < 0.001) the dough tenacity and hardness, bread firmness, but decreased bread volume, porosity, and elasticity, while medium and small particles at 5-15% addition levels improved porosity and elasticity of the composite bread. Significant correlations (p < 0.05) were found between proximate composition, dough rheological characteristics, and bread quality for the wheat-amaranth composite flours. The results of this study are an important basis for the development of innovative wheat-amaranth bread recipes.
Keywords: amaranth; bread; composite flour; dough; particle size; rheology.