Lipid oxidation and lipidomic profiles of raw and thermal-extracted yak fat under hydroxyl radical-induced oxidative stress

The lipid profiles in raw fat (RF) and thermal-extracted fat (TF) from yak under hydroxyl radical-induced oxidative stress were investigated. Both hydroxyl radical and thermal extraction accelerated lipid oxidation. A total of 1168 lipids were identified and classified into 18 lipid categories. The top eight classes of lipids included PCs, PEs, TGs, SMs, CERs, PSs, FAs and PAs. Furtherly, 432 differentially abundant lipids were detected in TF samples compared to RF samples. RF and TF samples displayed a complete distinction in lipidomic profiles, and some lipids in both RF and TF samples demonstrated remarkable differences in abundance with the increasing of H₂O₂ concentration. RF samples demonstrated a relatively higher abundance of PCs, PEs, PSs, PGs and PIs, while TF samples exhibited a higher level of PAs, TGs, FAs and CERs. These findings indicated that radical attack and thermal extraction severely affected lipid oxidation and lipid metabolomics.