Variations in flavor according to fish size in rainbow trout (Oncorhynchus mykiss)

Rainbow trout are a widely consumed fish species. However, the effects of fish size on flavor have not been fully elucidated. Here, the flavor qualifies of the dorsal, tail, and abdomen of four sizes of rainbow trout (average weights 0.25, 1.14, 2.26, and 2.89 kg, respectively) were investigated by measuring fatty acids, nonvolatile compounds, and volatile compounds and by performing electronic tongue analysis. 5'-Nucleotide levels were higher in the dorsal and tail regions than in the abdomen of fish. Additionally, the heaviest fish had the highest contents of lactic acid and succinic acid, whereas fish weighing 1.14 kg had the highest levels of total free amino acids. Additionally, 0.25 and 1.14 kg fish had higher concentrations of aldehydes. t-Distributed stochastic neighborhood embedding and correlation analyses revealed that the overall flavor profiles were reflected by electronic-tongue analysis. Overall, our findings showed that fish size affected flavor in different parts of rainbow trout.