AN EPR STUDY OF FREE RADICALS GENERATED BY GAMMA‐RADIATION OF DRIED SPICES AND SPRAY‐DRIED FRUIT POWDERS

Abstract
Gamma‐radiation of powdered tumeric, black pepper, dry mustard, cinnamon and paprika, at dosage of 30 kGy, at 30°C, produced free radicals detectable by EPR. The intensities of the EPR signals were proportional to the total irradiation dose up to a saturation dose. The signal decayed most significantly in the first four‐postirradiation days, but could be detected even after 34 days. The paramagnetic signal was unaffected by the presence of oxygen, but decayed rapidly in water. Similar observations were made for spray‐dried fruit powder.