Continuous measurement of oxygen consumption during mixing of unyeasted wheat flour dough.A mixer-bioreactor has been developed. Its instrumentation allows continuous measurement of the torque and of oxygen consumption during mixing of unyeasted wheat flour dough. The oxygen consumption corresponds to 1.7 µmol . g -1 d.m. after 10 min and 3.3 µmol . g -1 d.m. after 1 h of mixing. Oxidoreductase activities are responsible for this consumption since it largely declines following treatment which denatures enzymes. Conversely, oxygen consumption increases when exogenous oxidoreductases are added to the flour. In addition, measurements of polyunsaturated fatty acids in aliquots of dough allow to show the link between their losses and the amount of oxygen consumed. An oxygen balance can be calculated. Thus, after 10 min of mixing, half of the oxygen uptake can be ascribed to the lipoxygenase system. Whereas, after 1 h, this enzyme activity explains only one third of oxygen consumption.