ESR detection of irradiated broad bean (Vicia faba L.) and kinetics of the radiation induced free radical and Mn2+ signals

Polat M., Korkmaz M.

INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY, vol.38, no.6, pp.641-651, 2003 (SCI-Expanded) identifier identifier


An ESR (Electron Spin Resonance) investigation on irradiated dry broad bean gave a spectrum which was composed of an equally spaced sextet and a single resonance line. These lines appeared at g = 2.0045 (+/-0.0005) and originated from Mn2+ ions and radiation induced radicals, respectively. Ground broad bean was used throughout the work to avoid any artefacts arising from a microwave cavity filling factor. Free radical signal intensity was observed to increase exponentially in relation to the increase in absorbed dose over the dose range 1.25-15 kGy. Although the Mn2+ signal increases below room temperature, the signal due to the natural and radiation induced radicals decreases. Above room temperature, they both decreased and these decreases were irreversible. The kinetics of these decreases were studied in detail over a temperature range of 308-373 K by annealing samples at different temperatures for various times.