Study on radiation-induced radicals giving rise to stable EPR signal suitable for the detection of irradiation in L-sorbose-containing fruits

Ionizing radiation is useful for the conservation and disinfestation of fresh and dried fruits. The treatment of fruits with gamma-rays or beams of accelerated electrons has been carefully tested and was recommended by FAO/WHO Codex Alimentarius Commission for the common use as an effective and safe preservation method [1]. It was found earlier that the ionizing radiation produces stable EPR signals in dried fruits, presumably derived from sugar radicals which are trapped in crystalline sugars [2, 3]. Radiation-induced EPR signals in dried fruits are relatively intense while their complexity (multiline spectrum) and broadness show conclusively that several radicals are involved. It is in contrast to the native EPR signals observed in non-irradiated dried fruits, which are weak single EPR lines. Radiation-induced EPR signal in dried fruit represents a broad, multiline spectrum in contrast to the native EPR signal observed in non-irradiated fruits, which is a weak single line or does not appear. Thus, the distinction in EPR between non-irradiated and irradiated fruit is very simple. The detection of a specifi c, complex EPR signal in fruits provides evidence for the radiation treatment of the latter [4, 5]. The EPR detection of dried fruits treated with ionizing radiation has been tested in several interlaboratory exercises with Study on radiation-induced radicals giving rise to stable EPR signal suitable for the detection of irradiation in L-sorbose-containing fruits Grzegorz P. Guzik, Wacław Stachowicz