Chemical studies on the herring (Clupea Harengus). I.—Trimethylamine oxide and volatile amines in fresh, spoiling and cooked herring flesh

Gas chromatography was applied to a study of the production of volatile amines and ammonia in herring flesh under various conditions. Fresh flesh contained ammonia and a small quantity of trimethylamine, but no monomethylamine, dimethylamine or higher amines in the range ethylamine to pentylamine were detected. The trimethylamine oxide content varied according to the season, being higher in winter than in summer. During storage at 10–13°. ammonia and trimethylamine were formed, and also smaller quantities of di‐ and mono‐methylamine. No higher amines were detected after 4 days. The trimethylamine oxide content dropped over the period. Cooking in sealed glass tubes at 120° resulted in breakdown of trimethylamine oxide, and formation of ammonia, tri‐, di‐ and mono‐methylamine (trace). No higher volatile amines were detected in the cooked flesh. The possible significance of the results in relation to the development of flavour in canned herring is discussed.