Widely targeted lipidomics reveal the effects of roasting on Torreya grandis kernel oil: oxidative stability and lipid alteration

Roasting Chinese torreya ( Torreya grandis cv. Merrillii ) kernels significantly influences the quality of oil. However, the changes of oxidative stability of T. grandis kernel oil are still unclear. Herein, oxidative stability index (OSI) was conducted to investigate the oil obtained at different roasting temperatures (60°C, 90°C, 120°C, and 150°C) and duration (25, 50, 75, 100 and 125 minutes). Furthermore, Maillard reaction, antioxidant compounds, microstructure and widely targeted lipidomics analysis were integrated to analyze the changes of kernels and oils roasted at 150°C. Roasting kernels at 150°C for 25 min resulted in the highest oil yield and disrupted the cellular structure, facilitating the release of tocopherols. 150°C, 25 min roasting had a pronounced effect on the lipid composition, particularly on phosphatidylcholines (PCs) and lyso-phosphatidylcholines (LPCs). A total of 26 lipids emerged as potential markers for distinguishing T. grandis kernel oils with varying roasting intensities, primarily associated with glycerophospholipid metabolism. Pearson correlation showed that the increase of tocopherols and LPC (LPC (22:5), P173) may contribute to enhanced OSI (8.13 h). These findings provide new insight into the change mechanism of oxidative stability in T. grandis oil obtained from high-temperature pretreatment.