Chemical Studies on the Substance of Fish Smell III. Investigation on the Components of Mucilaginous Substances of Salmon

Abstract

By adding picrolonic acid to the mucilage obtained from the skin of salmon we can gain the picrolonate. Under the microscope we have determined the shape of its crystal-and its melting point, and compared the present compound with synthesized sample. In this experiment we found that the present compound has the same character as a picrolonate which is produced from δ-aminovaleric acid and the reaction product of pyridine and acetaldehyde. In the same experiment it was found that the present compound contains another two kinds of picrolonate of certain amine. On the course of our experiment to synthesize the liquid which give off fishy smell, we have found the following results: the smell of fresh fish consists from piperidine, and the reaction product of piperidine and acetaldehyde. The condensed mixture of above substances give off smell of freshwater fish and when trimethylamine is added to this mixture, we feel sea-fish-smell. In the smell of fish whose freshness is slightly reduced, δ-aminovaleric acid is contained besides above mixture, and if the freshness of fish still more reduced, methylmeriucaptan and indole are contained.