ABSTRACT
Some fish species, including hake or cod, have poor stability during frozen storage, which is reflected in a fast texture alteration, usually leading to a tougher and drier product. Much effort has been devoted to clarify the cause of this phenomenon. Almost three decades ago it was discovered that some fish species, especially those with poor freezing properties, accumulated formalde hyde (FA) and dimethylamine (DMA) during frozen storage (1). Some Japan ese workers maintained active research on the problem during the 1960s and 1970s. They surveyed a considerable number of fish species and tissues and concluded that the tissues with highest DMA and FA content were usually vis ceral organs (2-6). They also found that every time DMA was detected, FA was also present. Experiments led to the conclusion that DMA and FA were produced in equimolar amounts and that an enzyme was present in some or ganisms with the ability to breakdown trimethylamine oxide (TMAO) into DMA and FA (7, 8).
