Oxidative Lipidomics to Unravel the Glycerol Core Aldehydes of Three Typical Unsaturated Triglycerides under Simulated Heating Conditions

Glycerol core aldehydes (GCAs) are significant nonvolatile aldehyde compounds generated in heated edible oils, which may pose potential health risks. Utilizing the complementary CID and EAD mass spectrometry data, this study introduced a predict-to-hit strategy, identifying 42 types of GCAs from oxidized OOO, LLL, and LnLnLn. Structural analysis revealed that oxidation occurred at both the sn-2 and sn-1/3 positions of triglyceride (TG), with the Sn-1/3 position exhibiting greater susceptibility as the degree of TG unsaturation increased. As the temperature increases, the concentration of saturated GCAs steadily rises, while unsaturated GCAs exhibit an initial increase, followed by a decrease. During further oxidation, GCAs tend to convert into hydroxyl compounds, monocyclic epoxides, dicyclic epoxides, and polycyclic epoxides, with epoxy groups predominantly forming at the 9,10 positions. These observations enhance our understanding of the formation of GCAs and promote the search for strategies to delay or prevent oxidation.