EFFECTS OF GAMMA-IRRADIATION AND COOKING ON VITAMIN-B(6) AND VITAMIN-B(12) IN GRASS PRAWNS (PENAEUS-MONODON)

The effects of irradiation doses, irradiation temperature and a combin ed treatment of irradiation and cooking on the vitamin B6 and B12 cont ents of grass prawns have been studied. Grass prawns were irradiated a t refrigerated (4-degrees-C) or frozen (-20-degrees-C) temperatures wi th different doses. A domestic cooking procedure was followed after ir radiation. The changes in vitamins B6 and B12 of both raw and cooked g rass prawns were evaluated. Results showed no significant changes of v itamin B6 and B12 in grass prawns with a radiation dose up to 7 kGy at either 4-degrees-C or -20-degrees-C. Irradiation at 4-degrees-C cause d more destruction of vitamin B12 but not vitamin B6 than did irradiat ion at -20-degrees-C in grass prawns. There was significant destructio n of both vitamins B6 and B12 in unirradiated samples during cooking. The introduction of the irradiation process before cooking had no effe ct on either vitamin. These results indicate that the loss of vitamins B6 and B12 in the combined treatments was caused mainly by thermal de struction.