Key aroma compounds of Chinese dry-cured Spanish mackerel (Scomberomorus niphonius) and their potential metabolic mechanisms.

The key aroma compounds of six commercially available dry-cured Spanish mackerel (Scomberomorus niphonius, DCSM) were identified using electronic nose (E-nose), gas chromatography-olfactometry (GC-O), and two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOFMS). A total of 38-55 aroma compounds were identified, and 21-26 of them, which presented high flavor dilution factors based on aroma extract dilution analysis, were quantified. Lastly, 9-14 key aroma compounds with high odor-active value, including 3-methyl-1-butanal, octanal, 1-octen-3-ol, nonanal, cis-4-decenal, ethyl caproate, (E)-2-octenal, (Z)-2-nonenal decanal, 3-methyl-1-butanol, 1-heptanol, 3-octanone, 2-octanol, and 6-methyl-5-hepten-2-one, were identified as the key aroma contributors in DCSM. Results also indicated that a longer dry-curing time would promote the generation of aroma compounds. The metabolism analysis implied that the auto-oxidation/oxidation of unsaturated fatty acids, such as oleic and linoleic acid, and the enzymatic degradation of l-leucine might be potential metabolic mechanisms.