Dough rheology and wet milling of hard waxy wheat flours

To realize the full potential of waxy wheat (Triticum aestivum L.), the wet milling properties of waxy wheat flours including their dough-mixing properties were investigated. Flours of six waxy hard wheats, one normal hard wheat ('Karl 92'), and one partial waxy hard wheat ('Trego') were fractionated by the dough-washing (Martin) process, and the yields and recoveries of starch and gluten were compared. When waxy and normal wheat starches each were blended with a wheat gluten to give a mixture containing 14.5% protein, they gave very different mixograms even though the protein was the same in those blends. Waxy wheat starch absorbed more water than normal wheat starch, which apparently retarded hydration of gluten and dough development. Higher water content had to be used for some waxy wheat flours to develop optimum dough. Washing waxy wheat flour dough under a stream of water caused dough to become slack, spread out more on the sieve, and break apart into several pieces, which when thoroughly washed, coalesced into an elastic dough like the controls. By mixing a weak dough with 2% NaCl solution or by adding hemicellulase, stickiness of the dough subsided during the washing step and thereby improved the recovery of the gluten and starch fractions.