EVALUATION OF ELECTRON-SPIN-RESONANCE TECHNIQUE FOR THE DETECTION OF IRRADIATED MANGO (MANGIFERA-INDICA L) FRUITS

The electron spin resonance (ESR) technique was examined as a method f or the detection of irradiated mango fruits. A symmetric ESR signal at g = 1.988 was detected in the hard seed cover (endocarp), the dry epi dermal layer (testa) surrounding the kernel, and the soft kernel porti ons of the seed from four mango cultivars. The amplitude of the signal in the epidermal layer and seed cover showed a dose-dependent increas e over control values. Qualitatively, however, no new signal was obser ved following irradiation, except that line width increased by 50%. Me thyl cellosolve washing greatly reduced the intensity of the endogenou s and radiation (1.0kGy)-induced ESR signals in the seed cover; result s suggest phenolic substances as the source of free radicals. The simi larity of naturally occurring ESR signals to that induced by irradiati on seems to restrict the practical utility of this method in irradiate d mangoes.