A novel chiral stationary phase LC-MS/MS method to evaluate oxidation mechanisms of edible oils

作者：Ito Junya; Shimizu Naoki; Kobayashi Eri; Hanzawa Yasuhiko; Otoki Yurika; Kato Shunji; Hirokawa Takafumi; Kuwahara Shigefumi; Miyazawa Teruo; Nakagawa Kiyotaka

来源：Scientific Reports, 2017, 7(1): 10026.

DOI：10.1038/s41598-017-10536-2

The elucidation of lipid oxidation mechanisms of food is vital. In certain lipids, characteristic lipid hydroperoxide isomers are formed by different oxidation mechanisms (i.e., photo-oxidation or auto-oxidation). For example, linoleic acid is photo-oxidized to 13-9Z, 11E-hydroperoxyoctadecadienoic acid (HPODE), 12-9Z, 13E-HPODE, 10-8E, 12Z-HPODE and 9-10E, 12Z-HPODE, whereas 13-9Z, 11E-HPODE, 13-9E, 11E-HPODE, 9-10E, 12Z-HPODE and 9-10E, 12E-HPODE are formed by auto-oxidation. Therefore, we considered that oxidation mechanisms could be evaluated by analyzing these characteristic positional and cis/trans lipid hydroperoxide isomers. In this study, we developed a novel chiral stationary phase LC-MS/MS (CSP-LC-MS/MS) method to analyze the positional and cis/trans isomers of HPODE, with the use of a chiral column and sodium ion. Also, as an application of the method, either light-exposed or heated edible oils were treated with lipase to hydrolyze triacylglycerols. The resultant fatty acids including HPODE isomers were analyzed with the developed method. As a result, HPODE isomers characteristic to photo-oxidation were certainly detected in light-exposed edible oils. On the other hand, in heated edible oils, the HPODE isomers characteristic to auto-oxidation were largely increased. Thus, the combination of the developed CSP-LC-MS/MS method with lipase proves to be a powerful tool to evaluate the involvement and mechanisms of lipid oxidation in the process of food deterioration.

• 出版日期2017-8-30