A novel liquid chromatography-mass spectrometric method for the simultaneous determination of trimethylamine, dimethylamine and methylamine in fishery products.

A novel multianalyte method has been developed to determine the concentration of trimethylamine (TMA), dimethylamine (DMA) and methylamine (MA) in fish. The optimal points of the key parameters (pH 8, 60 °C and 60 min of reaction time) were determined for the reaction with tert-butyl bromoacetate. An HILIC column was used to elute all the compounds in only 12 min and selective quantitation of the compounds was achieved. The methodology was validated in trout, hake and Atlantic horse mackerel and was used to study the shelf life of fish under refrigeration. A good correlation with the picrate method was obtained and the proposed methodology has been proved to be robust, specific and sensible with a limit of detection of 0.08 mg N-TMA kg(-1) in freshwater fish and 1 mg N-TMA kg(-1) in marine fish. In addition, TMA has been proved to be a good spoilage indicator also in freshwater fish.

Quality changes of Atlantic horse mackerel fillets (Trachurus trachurus) packed in a modified atmosphere at different storage temperatures.

BACKGROUND: Atlantic horse mackerel (Trachurus trachurus) is an important commercial fish in Europe. Changes in microbial growth, sensory quality and chemical evolution of modified atmosphere packed (MAP) horse mackerel fillets (48% CO2/50% N2/2% O2) were monitored at different storage temperatures (2, 4, 6 and 10 °C). RESULTS: The observed sensory shelf life of MAP fish fillets was found to be approximately 7 days at 2 °C, 6 days at 4 °C, 5 at 6 °C and 3 days at 10 °C. A significant correlation was observed between all sensory attributes and two groups of bacteria [total viable count (TVC) and psychrotrophic bacteria], with sensorial rejection when the bacteria approached 106 CFU g⁻¹ at 4, 6 and 10 °C. A level of 30-50 mg total volatile basic nitrogen 100 g⁻¹ of mackerel muscle was well correlated with sensory shelf life determination at all temperatures, except for 2 °C. During the storage time, lipid oxidation did not increase at any temperature and could not be related to quality decay. The presence of acetaldehyde and butyraldehyde in the packing atmosphere was only found in fillets stored at the highest temperature studied (10 °C). CONCLUSION: In this study, key quality parameters were established to monitor the spoilage and shelf life of MAP Trachurus trachurus stored at different temperatures. In addition, these results confirm the use of modified atmosphere packaging as a mild preservation method for fillets of Atlantic horse mackerel.