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Reaction pathway mechanism of thermally induced isomerization of 9,12‐linoleic acid triacylglycerol
Author(s) -
Guo Qin,
Jiang Fan,
Deng Zhaoxuan,
Li Qingpeng,
Jin Jing,
Ha Yiming,
Wang Feng
Publication year - 2017
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.7988
Subject(s) - chemistry , isomerization , linoleic acid , conjugated linoleic acid , organic chemistry , derivatization , fatty acid , polyunsaturated fatty acid , ampoule , chromatography , catalysis , high performance liquid chromatography
BACKGROUND To clarify the formation mechanism of trans linoleic acid isomers in edible oils during the heating process, trilinolein and trilinoelaidin, as representative oils, were placed in glass ampoules and sealed before heating at 180, 240 and 320 °C. The glass ampoules were removed at regular time intervals, and the contents were analyzed by infrared spectroscopy. The samples were then subjected to derivatization into their methyl esters for gas chromatographic analysis. RESULTS Analysis results show that 9 c ,12 c and 9 t ,12 t fatty acids from trilinolein and trilinoelaidin molecules undergo chemical bond rotation, migration and degradation, leading to the formation of non‐conjugated linoleic acids ( NLAs ), conjugated linoleic acids ( CLAs ) and aldehydes. The formation rate of isomers from the 9 c ,12 c fatty acid is higher than that of the 9 t ,12 t fatty acid. The production of aldehydes increases with heating temperature and time. The isomerization pathways involved in the formation of NLAs and CLAs during heating are clearly presented. CONCLUSION These findings suggest possible pathways of NFA and CFA formation from heated trilinolein and trilinoelaidin, complement the mechanistic studies previously published in the literature, and provide a theoretical basis for future control of the quality and safety of fats and oils. © 2016 Society of Chemical Industry