Detection of irradiated food by the changes in protein molecular mass distribution

Protein constituents were extracted from chicken drumstick and chicken whit e meat, separated according to the molecular mass (Mm), using discontinuous SDS-polyacrylamide electrophoresis (SDS-PAGE) and quantified by scanning d ensitometry. The obtained profiles were compared with the profiles correspo nding to the meat samples which were irradiated at -20. +4, and +20 degrees c. It was observed that the irradiation of chicken while meat led to prote in scission which was partially unselective (e.g. the amount of proteins wh ose Mm > 20 kDa decreased, while the amount of those whose Mm < 20 kDa incr eased), and partially selective (e.g, the appearance of Mm congruent to 16 kDa fragment). In the case of chicken drumstick meat the irradiation caused both protein scission and protein crosslinking (unselective and selective, and appearance of 16 kDa fragment). However, in the case of aerated dehydr ated egg white proteins, irradiation led only to unselective protein scissi on. The obtained results are discussed in view of possible application of d iscontinuous analytical SDS-PAGE combined with laser scanning densitometry for detection of previously irradiated foodstuff. (C) 1999 Elsevier Science Ltd. All rights reserved.