Amino acid composition of fish meals and fish solubles prepared from putrefied sardine or mackerel was analysed in comparishon with that obtained from relatively fresh fish by the pilot plant at almost the same ocnditions. These estimations were carried out in parallel with the preceding work on the same samples used for the histamine determination.
With the putrefaction of raw fish, the amounts of total, individual, and essential amino acids decreased in the fish meal fraction, while those in the fish solubles fraction and its related products, whole meals, increased, A similar tendency was also observed in the total nitrogen content of the same samples These results indicate that the degree in the detruction of fish proteins, reflects upon the distribution pattern of the nitrogen compounds, especially amino acids, between solid fraction (meals) and liquid fraction (solubles) at the cook/press procell. Consequently, the effect of putrefaction of raw fish was not such a serious problem on the quality of fish meals. On the solubles and also on the whole meals, however, deterioration gave an antagonistic effect on the qualities by favourable increase in amino acids content and undesirable incrase in histamine and volatile basic itrogen as reported before.
