A study on the oxidative stability and comprehensive lipidomics of specialty nut oils from Northeast China

To comprehensively evaluate the oxidation stability of specialty nut oils from Northeast China, this study examined hazelnut oil (HO), almond oil (AO), shiny-leaved yellowhorn oil (SYO), walnut oil (WO), and pine nut oil (PO). Using the Schaal oven accelerated oxidation method, we dynamically monitored changes in their oxidation indicators and antioxidant capacity, and conducted an evaluation through principal component analysis. The results indicated that HO exhibited excellent oxidation stability. Further analysis of fatty acid changes revealed that HO maintained a monounsaturated/polyunsaturated fatty acid (MUFA/PUFA) ratio as high as 7.66. In contrast, the PUFA in the other four oils degraded significantly faster during oxidation, further validating its superior stability. Based on untargeted lipidomics technology utilizing ultra-high-performance liquid chromatography-Quadrupole-Exactive Orbitrap mass spectrometry (UHPLC-QE-Orbitrap/MS/MS), a total of 789 lipid molecules from 23 subclasses were identified. Among these, triacylglycerol (TG) was the most abundant lipid subclass (relative abundance > 90%). 176 significantly differential lipids were successfully identified through chemometrics, serving as potential biomarkers for distinguishing between each other. Unsaturation analysis of differential lipids revealed that the content of polyunsaturated lipids in HO was significantly lower than in other oils, intrinsically explaining the origin of its superior stability. This study employs multidimensional analysis to not only provide comprehensive information on the lipid composition of Northeast China's specialty nuts but also systematically reveal the differences in their oxidative stability and underlying causes. It lays a solid scientific foundation for the high-value development, quality control, and industrial application of specialty oilseed resources.