Hydration and rheological properties of amaranth-wheat flour dough: influence of germination of amaranth seeds

Abstract

The objective of this work was to analyze wheat dough combined with amaranth flour to predict dough behavior during breadmaking. Blends with wheat and amaranth flours from germinated (GA) and non-germinated (A) seeds at 5%, 15% and 25% were formulated. The dry gluten content, as measurement of the amount of insoluble protein of blends, was determined. Besides, the hydration (moisture-Mcont, water absorption-Wabs, molecular mobility-λ, water activity-aw) and rheological (texture and viscoelasticity) properties of dough were also determined. Dough with 25% of amaranth flour (A25, GA25) showed higher moisture but had lowed less λ than the compared to wheat dough. Moreover, A25 was a bit harder compared to wheat dough though it presented less relaxation of the matrix polymers but a viscous behavior higher than the elastic one (>tan δ). The major difference was detected for GA25 dough, which exhibited a structure with the lowest consistency and with the highest G"/G′ ratio due to the modification of proteins during germination, since these proteins contribute to dough elasticity through the stabilization of polymeric gluten proteins.