Trimethylamine oxide content and spoilage potential of New Zealand commercial fish species

Breakdown of trimethylamine oxide (TMAO) during post‐harvest storage contributes significantly to loss of seafood quality. We surveyed 51 New Zealand commercial fish species and determined white muscle tissue concentrations of TMAO and the TMAO‐derived spoilage indices: trimethylamine nitrogen (TMA‐N) and total volatile basic nitrogen (TVB‐N). There were significant differences in the TMAO concentrations between fish of various genus and species. Values ranged between 8 and 789 mg/100 g for ray‐finned fishes (Actinopterygii), and 262 and 789 mg/100 g for cartilaginous fishes. The distribution of TMAO was similar to that of Northern Hemisphere fish species. Deep water species had the highest concentrations of TMAO. Seasonal effects in tarakihi ( Nemadactylus macropterus ) and red gurnard ( Chelidonichthys kumu ) were studied and TMAO declined significantly over the summer months. TMA‐N was typically below 2 mg/100 g and TVB‐N concentrations did not exceed the limits set by the European Community (EC) Commission Regulation No. 1022/2008.