Abstract: The odor-active compounds of stewed marinated beef stored for different periods of time (0, 3, 6, 9 and 12 months) were analyzed by purge & trap-thermal desorption-gas chromatography-olfactometry-mass spectrometry (P&T-TDS-GC-O-MS) and odor activity value (OAV), and sensory evaluation was conducted to identify the compounds responsible for the characteristic off-flavor. The results showed that 52 odor-active compounds with OAV ≥ 0.1 were detected. Among them, the number (13) of aldehydes was the highest. Aldehydes and alcohols accounted for a high proportion (34.53%–70.55% and 27.72%–57.91%, respectively) of the total OAV. During storage, the color of stewed marinated beef became darker and its elasticity decreased. At the later storage period, the aroma became weak, and the off-flavor intensively increased, leading to decreased acceptability. Meanwhile, principal component analysis (PCA) showed good separation among samples with different storage periods. The correlation analysis demonstrated that 16 and 12 odor-active compounds were significantly correlated with sensory flavor score and storage time, respectively. According to GC-O identification, 1-octene-3-ol, heptanal, octanal, nonanal, decanal, E,E-2,4-decanodienal, 2-nonanone, and octanoic acid may be the major source of stewed marinated beef off-flavor.

Key words: stewed marinated beef; purge and trap-thermal desorption-gas chromatography-olfactometry-mass spectrometry; odor-active compounds; off-flavor