Prawns slices were dried in a freeze drier (Ayela, FDU e 1200, Sl No e 11002298, Tokyo, Rikakikai Co. Ltd) and grinded into powder. X-ray diffraction patterns of control and irradiated prawn powder were obtained with a Rigaku RPT 300 PC X-ray diffractometer (Rigaku, Tokyo, Japan). An accelerating voltage and current of 30 KV and 15 m A respectively were used. The diffractograms were recorded in a varying 2q with a scanning rate of 1.0 /min and the scan range of 5e25_.