Free fatty acids profiling in cold-pressed rapeseed oil pretreated by microwave

摘要

This study proposed a strategy based on simple chemical derivatization cou-pled with neutral loss scan tandem to electrospray ionization source of mass spectrome-ter (NLS-ESI-MS/MS) for rapid and sensitive detection of free fatty acids (FFAs) in cold-pressed rapeseed oils without sample purification and enrichment. The method was applied to investigate contents of FFAs and their changes in cold-pressed rapeseed oil pretreated by microwave. Results showed that main FFAs in rapeseed oil control samples were myris-tic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2) and linolenic acid (C18:3). The highest content of C18:1 was 7163.69 nmol/g and C18:2 was 5221.18 nmol/g among 8 oil samples. FFAs generally increased after microwave pretreatment except C14:0 in oil sample of 'Xinyou 17' and 'Suyou 6'. C18:1 and C18:2 significantly changed (P<0.05) after microwave pretreatment. With this established simple, practical and reliable analysis approach, changes of FFAs would be monitored to ensure safety and quality of edible oils. A powerful tool is provided for thermal degradation mecha-nism research of edible oils.