Effect of varying protein content and glutenin-to-gliadin ratio on the functional properties of wheat dough

Gluten, starch, lipids, and water-soluble material were separated from seve n wheat samples with a range of protein contents and breadmaking quality. T he isolated glutens were further partitioned into gliadin- and glutenin-ric h fractions using pH precipitation. Protein content and glutenin-to-gliadin ratio were systematically altered by blending these fractions into the ori ginal flours in calculated amounts. Mixing properties, extension-tester par ameters, and baking performance of composite flours were determined using s mall-scale techniques. Results of dough testing with blends of constant glu tenin-to-gliadin ratio showed increases in the mixing time, mixograph peak resistance, maximum resistance to extension, extensibility, and loaf volume as the protein content increased. At constant protein content, increases i n glutenin-to-gliadin ratio were associated with increases in mixing time, mixograph peak resistance, maximum resistance to extension, and loaf volume , and with decreases in extensibility. Thus,total protein content and glute nin-to-gliadin ratio independently affected dough and baking properties. Th e results have allowed the separation of the effects of flour protein quant ity and composition on breadmaking properties.