水産物の腐敗に關する研究

(第1報)サメ肉に於けるアンモニア生成の機構並にその特異性に就いて

抄録

In the present work, we have been led to a conclusion that a large amount of ammonia found in the shark muscle which has lost off its freshness, must, at least at the first stage of the storage, be originated from urea contained in the muscle, and that breaking down of the urea into ammonia may be due mainly to the action of urease secreted from micro. organisms such as urobacteria. We could not find any appreciable amount of native urease in the shark muscles. The speed of the development of ammonia became dull at the point of 400-500mg % of its nitroge? and after a while the second rising of ammonia amount was observed with true putrefactiv? odour. The urea increased its amount in the shark muscles that were preserved from micro-organisms or stored at a low temperature. It may be considered, therefore, that in a shark urea is composed even in the muscle as well as in the liver.