Analysis of the trend of volatile compounds by HS-SPME-GC-MS and the main factors affecting the formation of rancid odor during the oxidation process of infant nutrition package.

In this study, headspace solid-phase micro-extraction (HS-SPME) coupled with GC-MS was used to analyze the trend of volatile compounds in fresh and oxidative infant nutrition package. Among the volatile compounds, aldehydes and ketones, alcohols, lipids, cycloalkenes, alkanes, alkenes, aromatic hydrocarbons, oxygenated compound were identified. A total of 65 volatile compounds were detected in the fresh nutrition package, whereas 9 new volatile compounds were detected during the accelerated oxidation process, which was oxidized at 45 °C for 4 weeks. The main components of the rancid flavor formed and the relative content of volatile substances gradually changed during the accelerated oxidation process. The volatile substances hexanal, nonanal, and 2-pentylfuran substantially increased. Linalool, α-terpineol, d-limonene, and 1-methoxy-nonane presented an evidently downward trend. The relative content of the newly formed compound 3-hydroxy-2-methylpyran-4-one during the oxidation process was always large, its relative content initially increased, then decreased, and finally increased again. The formation of rancid flavor of the nutrient package was speculated to have been formed by the interaction of hexanal, nonanal, 2-pentylfuran, and 3-hydroxy-2-methylpyran-4-one.