Trimethylamine Oxide and Its Decomposition in the Bloody Muscle of Fish-II

In a previous report, it was observed that the bloody muscle of 16 species of fish contained DMA as well as TMA. In this experiment, the bloody and ordinary muscles of different species of fish were kept separately but under similar conditions with the intention to examine changes in the amount of TMA, DMA and formaldehyde during storage. The results obtained are as follows: 1) No measurable increase of TMA and DMA was observed in the ordinary muscle during storage for up to 25 days at 0°C, but a fairly rapid increase of these amines was observed in the bloody muscle of all samples. 2) At -6°C, TMA amount was somewhat smaller than that produced at 0°C, however, a rather slow but continuous increase of DMA was observed. 3) The rate of formation of TMA and DMA during storage seemed to differ according to the species of fish. The fish forming more TMA also formed more DMA and a correlation was assumed to exist between the amounts of TMA and DMA produced. 4) Since the formation of these amines in the bloody muscle was considered to be caused by enzymic action, the amount of the amines may be used for practical purposes as an index of freshness of fish before they get spoiled by bacterial growth.