Application of electron paramagnetic resonance (EPR) spectroscopy for control of irradiated food

Abstract

AbstractFour groups of foodstuffs were irradiated in a 60Co source with doses from 0.3 to 10kGy and subsequently measured by EPR spectrometry at room temperature in air: (1) poultry bones and fins, scales and bones of carp. (2) seeds of selected fruits, (3) dehydrated mushrooms, and (4) a selected set of spices and herbs. Qualitative and, in some cases, quantitative data related to the absorbed dose of radiation were collected. In the irradiated bones from poultry and carp an asymmetric singlet (gI = 2.0030, gII =1.9973; ΔHpp = 0.85 mT) was detected which was stable at room temperature and was similar to that previously found in irradiated mammalian bones. Another stable EPR signal (g0 = 2.0024, ΔHpp = 0.56 mT) was found in the fins and scales of carp which was about five times more intense in fins than in scales. In pips of pears irradiated with a dose of 3 kGy. a signal which was about twice as intense as the endogenous signal was recorded. A multicomponent EPR signal derived from the stones of dates differed from the endogenous signal even when a low dose (0‐5 kGy) was applied. A multicomponent EPR signal is also observed in dried mushrooms irradiated with a dose of 3 kGy. In white mustard, paprika and chilli no native EPR signal exists and a radiation‐induced stable EPR signal can still be observed after a period of 3 months. The radiation‐induced EPR signal in black pepper was highly sensitive to moisture and disappeared, yet the native signal survived. The pilot experiments performed with irradiated stones of cherries, plums, lemons, apple pips, raspberries, cranberries, red currants, blackcurrants, gooseberries and tomatoes showed the induction of short‐lived EPR signals of no practical use for the control of food irradiation.