Aroma-active compounds in skipjack tuna sauce

Volatile compounds in skipjack tuna (Katsuwonus pelanis) viscera (STV) and tuna sauce (TS) made from STV were analyzed by vacuum simultaneous distillation-solvent extraction/gas chromatography/mass spectrometry/olfactometry and aroma extract dilution analysis. Predominant odorants in STV were lipid-derived compounds, such as (E,E)-2,4-heptadienal (stale/peanut-like), (E,Z)-2,6-nonadienal (cucumber-like), (E,E)-2,4-decadienal (fatty/rancid fat-like), (E)-2-nonenal (stale, bitter), and (Z)-4-heptenal (fishy/rancid), and unidenified compounds having grassy, fresh fish-like odors. In contrast to STV, potent odorants in TS were mostly thermally generated compounds such as 3-(methylthio)propanal (baked potato-/soy sauce-like), dimethyl trisulfide (cooked cabbage-like), and 3-methylbutanal (dark chocolate-like). Additional potent odorants in TS were (E,E)-2,4-heptadienal, (E)-2-nonenal, phenylacetaldehyde (honeysuckle-like), and two unidentified compounds having nutty, baked potato-, vitamin-, and cooked rice-like odors. Two amino acids, glutamic acid and aspartic acid, were predominant in both samples.