Qualitative changes in each part of yellowtail Seriola quinqueradiata flesh during cold storage

To evaluate the important odor components in raw yellowtail, volatiles from each part of stored yellowtail flesh were analyzed using gas chromatography-mass spectrometry (GC–MS) and olfactometry (GC–O). The principal component analysis (PCA) results from GC–MS of 88 volatiles showed that PC1 separated the data into two groups [the dark muscle (DM) long storage] and [the ordinary muscle (OM) + DM no storage + DM short storage]. Eleven compounds, including 2,3-butanedione, in 24 kinds of odors were identified or tentatively estimated using GC–O analysis. The numbers of odors perceived at the maximum split ratio (243) in GC–O analysis were 8 and 12 from OM and DM, respectively, irrespective of storage time. Kovats retention index 1387 (unknown compound, fishy and plastic odor) had the strongest odor in both muscles before and after storage. GC–O analysis showed that DM odors were more intense than those from dorsal OM. Moreover, their intensities increased during storage. Sensory evaluation revealed that DM had a stronger odor than OM throughout the storage period. These findings suggested that odor components, which showed small thresholds, as well as other identified components from DM, such as 2,3-butanedione, contributed to the yellowtail meat odor before and after storage.