抄録
In order to clarify the substances responsible for the offensive odor in fish, volatile fatty acids, which play an important role as a biochemical oxygen demand (BOD) substance, were examined by gas chromatography. It was proved that the concentration of volatile fatty acids was high in the river water and in the bottom mud where the fish with offensive odor lived. Such acids were also found in a high concentration in the muscles and digestive organs of the fish with offensive odor, but was not detected in their liver, or in the fish in breeding ponds and in river ayu living in Nagara Bridge basin. Therefore, fish were kept in a tank with constant concentration of volatile fatty acids and the taste of fish was examined at regular intervals. At the same time, concentration of volatile fatty acids in the internal organs of the fish was analyzed. Accumulation of volatile fatty acids was recognized in internal organs except in the liver, and the offensive odor appeared on the 37 th day. At that time, a total of 73.7 ppm of total fatty acids was detected in the muscles. This value agreed with the concentration of fatty acids in the fish with offensive odor. These results suggested that volatile fatty acids were responsible as a substance giving the offensive odor to fishes.
