γ‐IRRADIATION OF 5′‐INOSINIC ACID IN FISH MEAT CAKE

The radiolysis of 5′‐inosinic acid (5′‐IMP) was studied to evaluate the wholesomeness of γ‐irradiated fish meat cake. 5′‐IMP in a phosphate buffer (pH 6.5) decomposed at 3.12 of G(‐M) by ′‐irradiation to hypoxanthine. Hypoxanthine, purine base, decomposed almost at the same rate as 5′‐IMP. Protein and unsaturated fatty acid had a markedly protective effect on 5′‐IMP against γ‐irradiation, and metal ions like iron were somewhat protective. In an actual fish meat cake, Kamaboko, 5′‐IMP was kept stable even at a high dose of γ‐ray. The solvent extract from irradiated Kamaboko with 5′‐IMP and hypoxanthine or without them showed no mutagenecity in the mutation assay using Salmonella typhimurium.