Lipidomics and volatilomics reveal lipid oxidation mechanisms in foxtail millet flour during storage

Foxtail millet is rich in unsaturated lipids and is susceptible to oxidative deterioration during storage. In this study, foxtail millet flour was stored at 50 °C and 60% relative humidity for 0-8 weeks to trace lipid remodeling and volatile formation. Unsaturated fatty acids declined markedly, with linoleic acid decreasing from 547.06 ± 1.11 to 383.73 ± 3.13 mg/g. Lipidomics identified 72 lipid species, with TGs as the predominant class, and showed depletion of structural lipids represented by PC 18:2_18:2 and MGDG 18:2_18:2, together with accumulation of oxidized lipids such as FA 18:2;O. Volatilomics detected 51 volatiles, among which 1-dodecanol, 1-undecanol, and nonanal were storage-related markers. These results suggest that storage-induced lipid deterioration involved the disruption of structural lipids, hydrolysis of triacylglycerols, and oxidation of unsaturated acyl chains, ultimately promoting the formation of aldehydes and alcohols associated with flavor deterioration.