Volatile amines as criteria for chemical quality assessment

Draft to be reviewed by SeaFoodPlus experts (without English correction) Volatile amines are the characteristic molecules responsible for the fishy odour and flavour present in fish several days after the catch and they are commonly used as criteria for assessing the fish quality. The nature and the formation of the volatile amines are discussed. Ammonia is present in freshly caught fish, during chilled storage it is formed by endogenous and bacterial enzymes, it is a poor indicator of fish freshness and cannot be considered as an effective marker of fish spoilage. DMA is present at very low concentration in freshly caught, about 0.2 mg/100g, it is formed from TMAO, under TMAO-ase action, an endogenous enzyme which is mainly present in gadoids; DMA-N can be considered as an effective marker of fish freshness of many white fish and it can be used to monitor the quality of frozen-stored gadoid fish. In a very fresh fish the amount of TMA-N is low, ≤ 2 mg/100g, it arises from the bacterial reduction of TMAO. TMA-N is an excellent indicator for the spoilage of gadoid fish, it is useful as a rapid means of objectively measuring the eating quality of many demersal fish specially on the medium-later phases of spoilage but it cannot be use