Effect of tempering moisture of wheat on grinding energy, middlings and flour size distribution, and gluten and dough mixing properties

Abstract

The effect of tempering moisture on milling performance, energy consumption during grinding, granulometric composition (of both middlings and flour) and baking quality of flour for hard and medium-hard wheat grain were tested. The baking quality of flour was determined on the basis of water absorption and rheological properties of wet gluten and bread dough. Samples of wheat were tempered to 12%, 14%, 16% or 18% moisture content. An increase in the moisture content of grains due to pre-milling tempering increased both the specific grinding energy and the grinding efficiency index. An increase in the moisture content of hard wheat grains results in a decrease in flour yield, with the proportion of fractions forming the flour being maintained. In addition, it contributes to a decrease in the protein content of flour, which also results in a reduced amount of gluten, and a shortened period of dough development. An increase in the moisture level of the grain contributed to the mechanical strengthening of the gluten network and an enhancement of its sorption capacity. The positive effect of the moistening treatment is connected with the formation of bread dough with increased water absorption and much more stable consistency during kneading.