Key Laboratory of Synthetic and Natural Functional Molecule of Ministry of Education, College of Chemistry and Materials Science, National Demonstration Center for Experimental Chemistry Education, Northwest University, Xi'an, Shaanxi 710127, China; State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Department of Municipal and Environmental Engineering, Xi'an University of Technology, Xi'an, Shaanxi 710048, China.
Key Laboratory of Synthetic and Natural Functional Molecule of Ministry of Education, College of Chemistry and Materials Science, National Demonstration Center for Experimental Chemistry Education, Northwest University, Xi'an, Shaanxi 710127, China.
Food Res Int. 2024 Sep;191:114695. doi: 10.1016/j.foodres.2024.114695. Epub 2024 Jun 27.
Roasting walnut kernel significantly improves the oxidative stability and sensory properties of its oil. However, the effect of roasting temperatures on the molecular change of main components and micronutrients in walnut oil is still unclear. Herein, lipidomics and metabolomics were integrated to comprehensively profile the walnut oil obtained at different roasting temperatures (30 °C, 120 °C, 140 °C, 160 °C, and 180 °C). Lipidomics showed that the content of glycerolipids, sphingolipids, and glycerophospholipids decreased with roasting temperatures, while the oxidized fatty acids and triglycerides increased. Ratios of linoleic acid and linolenic acid varied with roasting temperatures and were most close to 4-6:1 at 140 °C, 160 °C, and 180 °C. Major classes of micronutrients showed a tendency to increase at the roasting temperature of 120 °C and 140 °C, then decrease at 160 °C and 180 °C. Liposoluble amino acids identified for the first time in walnut oil varied with roasting temperatures. Correlation analysis demonstrated that the higher contents of liposoluble amino acids and phenolics are positively associated with enhanced oxidative stability of walnut oil obtained at 140 °C. Furthermore, glutamine and 5-oxo-D-proline were expected to be potential biomarkers to differentiate the fresh and roasted walnut oil. The study is expected to provide new insight into the change mechanism of both major lipids and micronutrients in walnut oil during the roasting process.
烘烤核桃仁显著提高了其油的氧化稳定性和感官特性。然而，烘烤温度对核桃油中主要成分和微量营养素的分子变化的影响尚不清楚。在此，采用脂质组学和代谢组学相结合的方法，全面分析了在不同烘烤温度（30°C、120°C、140°C、160°C 和 180°C）下获得的核桃油。脂质组学表明，甘油磷脂、鞘脂和甘油磷酯的含量随烘烤温度的升高而降低，而氧化脂肪酸和三酰基甘油的含量增加。亚油酸和亚麻酸的比例随烘烤温度而变化，在 140°C、160°C 和 180°C 时最接近 4-6:1。主要类别的微量营养素在 120°C 和 140°C 的烘烤温度下呈增加趋势，然后在 160°C 和 180°C 时减少。首次在核桃油中鉴定出的脂溶性氨基酸随烘烤温度而变化。相关性分析表明，脂溶性氨基酸和酚类的含量越高，140°C 下获得的核桃油的氧化稳定性越强。此外，谷氨酰胺和 5-氧-D-脯氨酸有望成为区分新鲜和烘烤核桃油的潜在生物标志物。该研究有望为烘烤过程中核桃油中主要脂质和微量营养素的变化机制提供新的见解。
