EFFECT OF GAMMA-IRRADIATION AND POSTIRRADIATION COOKING ON THIAMINE, RIBOFLAVIN AND NIACIN CONTENTS OF GRASS PRAWNS (PENAEUS-MONODON)

To determine the nutritional changes of grass prawns during ionizing r adiation processing, the effects of irradiation doses, irradiation tem peratures and the combined treatment of irradiation and cooking on thi amine, riboflavin and niacin contents of grass prawns were studied. Gr ass prawns were irradiated with different doses at refrigerated (4 deg rees C) or frozen (-20 degrees C) temperatures. A domestic cooking pro cedure then followed irradiation. Our results indicate that radiation and post-irradiation cooking result in different changes in the vitami n contents. The loss of thiamine increased with the increase of irradi ation doses and temperatures. In contrast, no significant changes were observed in either riboflavin or niacin even after irradiation doses were administered up to 7 kGy at 4 or -20 degrees C. Moreover, signifi cant destruction of thiamine occurred and there was no change in ribof lavin or niacin after post-irradiation cooking. The total loss of thia mine after the combined treatments appears to be simply the sum of the individual losses produced by the two treatments respectively. (C) 19 96 Elsevier Science Ltd.