Identification of irradiated fruit from the pectin-derived EPR signal

An EPR method based upon the observation of an unidentified multiline spectrum has been reported for the detection of irradiated fruit (dried papaya, banana, dates). A similar long-lived EPR spectrum after irradiation of dried amorphous apple pectin (BDH, 6% methyl ester) suggesting that pectin might be the origin of the signal in the dried fruit. Compositions of pectins vary greatly according to source and also with the age of the fruit itself. Therefore, a series of pectins of citrus fruit and potato tuber origin have been investigated to examine the effects of different levels of esterification on the irradiation-induced EPR signal. (author)