Profiling of FAHFAs in edible oils by chemical isotope labeling-assisted LC-MS: Impact of refining on FAHFA levels in rice bran oil.

Fatty acid esters of hydroxy fatty acids (FAHFAs) are bioactive lipids with promising health benefits, including anti-inflammatory, anti-diabetic, antioxidant, anti-cancer, hepatoprotective, and cardio-protective effects. Herein, the diversity and levels of FAHFAs in 16 common and exotic plant oils using the chemical isotope labeling-assisted LC-MS (CIL-LC-MS) approach revealed 236 regioisomers from 57 FAHFA families, with rice bran oil (RBO) showing the highest FAHFA content (6.12 μg/g), followed by avocado oil (AO; 2.45 μg/g) and sesame oil (SO; 2.04 μg/g), and the lowest content was found in coconut oil (3.19 ng/g). The FAHFA content profiles of 10 of these 16 oils are reported for the first time. Targeted analysis showed that OAHSA was the most abundant FAHFA family, particularly in RBO, AO, SO, and peanut oil. A careful examination of RBO refining showed substantial losses of certain FAHFAs via the chemical and miscella refining methods. However, physical refining was the optimal technique, suggesting that oil refining may affect the levels and distribution of FAHFAs. In addition, the γ-oryzanol and FAHFA levels were similarly influenced by the various refining steps. These findings deepen the knowledge of FAHFAs in edible oils and highlight their potential as a functional food ingredient for informed dietary choices or nutritional therapy against various metabolic disorders.