LipidSearch‐based manual comparative analysis of long‐chain free fatty acids in thermal processed tilapia muscles: workflow, thermal processing effect and comparative lipid analysis

Abstract LipidSearch is a useful tool to analyse lipid profiles in tissues. In this work, a liquid chromatography‐mass spectrometry‐LipidSearch‐based manual comparative analysis method was built to analyse the effects of thermal processing methods (steaming, boiling and roasting) on long‐chain free fatty acid species in tilapia muscles. Then, the fatty acid profiles of raw and thermal processed tilapia muscles were analysed. About 66 fatty acid species were present in the raw, steamed, boiled and roasted tilapia muscles, and only five fatty acid species had higher sensitivity in positive ionisation mode than negative ionisation mode of mass spectrometry. Thermal processing mainly had no obvious effects on the amounts of about 60% free fatty acid species. Two, two, five and twelve fatty acid species could be the best potential biomarkers for differentiation of raw, steamed, boiled and roasted, respectively, tilapia muscles in our experiments. This work could provide a workflow of LipidSearch analysis and basic information on the effect of thermal processing on the long‐chain free fatty acid profile of foods.