Volatile and nonvolatile amines in Mediterranean hake as a function of their storage temperature

The main amines in frozen and fresh hake (Merluccius merluccius) are the natural polyamines, spermine and spermidine. The levels of volatile and nonvolatile amines during storage of hake were strongly dependent on temperature. In samples stored at -20 degrees only changes in dimethylamine and agmatine were found, whereas major changes were observed in samples stored at higher temperatures. Cadaverine was the major amine formed, followed by histamine, putrescine and tyramine. The maximum levels of biogenic amines were lower than those reported for other fish species. Trimethylamine and biogenic amines related to hake spoilage showed levels higher in fresh than in frozen samples, whereas levels of natural polyamines were not statistically different.