Cereal Chem 39:147 - 154.  |  VIEW ARTICLE

Electron Paramagnetic Resonance and Baking Studies on Gamma-Irradiated Flour.

C. C. Lee. Copyright 1962 by the American Association of Cereal Chemists, Inc. 

Irradiation of flour at its usual moisture level of 12-14% with up to 10[6] rads of Co60 gamma rays gave no observable electron paramagnetic resonance (EPR) spectrum. After reduction of the moisture content to 8 or 4%, irradiation resulted in EPR absorption indicating presence of radiation-induced free radicals. These radicals are destroyed rapidly in the presence of water vapor. With the irradiated flour kept in a sealed tube, the EPR spectrum fades with time. The fading was quite rapid for the first few days and then proceeded more slowly. For this particular flour, irradiation resulted in a moderate increase in loaf volume at fairly low radiation dosages, followed by a gradual decrease in loaf volume at higher dosages. It was also noted that the loaf volume tended to decrease as the elapsed time between irradiation and baking increased. This finding, when considered in conjunction with the fading of the EPR spectrum, indicated that the EPR- detectable free radicals in the irradiated flour did not cause a strengthening of the gluten to produce an increase in loaf volume, as these radicals disappeared on becoming stable compounds.