Abstract: Lipid oxidation and degradation in instant meatballs stored for different periods of time (0, 1, 2, 3, 4 and 5 days) were investigated by measuring peroxide value (POV), thiobarbituric acid reactive substances (TBARS) value, carbonyl value and diene value. The changes in the fatty acid composition of instant meatballs during storage were analyzed by gas chromatography-mass spectrometry (GC-MS). The evolution of volatile flavor compounds was studied by headspace-solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) combined with calculation of odor activity value (OAV) and sensory evaluation. The results showed that eating quality attributes such as flavor and texture continued to decline during storage. Off-flavor appeared on the 4th day, and then quality deterioration was accelerated. The POV increased significantly during the early stage (0–3 days), but did not change significantly at the later stage (3–5 days). The TBARS value first increased slowly (0–4 days) and then dramatically (4–5 days). The carbonyl and diene values showed an upward trend during storage, indicating an increase in the degree of lipid oxidation. During storage, the proportion of unsaturated fatty acids (UFA) especially polyunsaturated fatty acids (PUFA) was significantly reduced. A total of 36 volatile flavor compounds with OAV ≥ 0.1 were detected. Among of them, the number (15) of aldehydes was highest. The OAVs of aldehydes and alcohols accounted for a high proportion (79.73%–87.58% and 10.15%–16.64%, respectively) of the total. Four and two classes of odor-active compounds were significantly correlated with lipid oxidation and sensory score for flavor, respectively.

Key words: instant meatballs; headspace-solid phase microextraction gas chromatography-mass spectrometry; lipid oxidation and degradation; fatty acid; volatile flavor compounds