title: Determination of thermally induced trans-fatty acids in soybean oil by attenuated total reflectance fourier transform infrared spectroscopy and gas chromatography analysis.
abstract: The intake of edible oil containing trans-fatty acids has deleterious effects mainly on the cardiovascular system. Thermal processes such as refining and frying cause the formation of trans-fatty acids in edible oil. This study was conducted to investigate the possible formation of trans-fatty acids because of the heat treatment of soybean oil. The types of trans-fatty acids in heated soybean oil are determined by attenuated total reflectance Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry methods. The effects of the heating temperature on the trans-fatty acids in soybean oil were evaluated using gas chromatography flame ionization detection analysis. Results show that heat treatment at 240 °C causes the formation of trans-fatty acids in soybean oil and the amount of trans-fatty acids increases with heating time. The only peak observed at 966 cm(-1) of the samples indicates the formation of nonconjugated trans isomers in the heated soybean oil. The major types of trans-fatty acids formed were trans-polyunsaturated fatty acids. Significant increases (P < 0.05) in the amounts of two trans-linoleic acids (C18:2-9c,12t and C18:2-9t,12c) and four trans-linolenic acids (C18:3-9c,12c,15t, C18:3-9t,12c,15c, and C18:3-9t,12t,15c/C18:3-9t,12c,15t) in soybean oil heated to temperatures exceeding 200 °C were compared with those of the control sample. The heating temperature and duration should be considered to reduce the formation of trans-fatty acids during thermal treatment.
authors.affiliation: Institute of Agro-products Processing Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: An
authors.initials: A
authors.lastname: Li
authors.forename: Yiming
authors.initials: Y
authors.lastname: Ha
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Weiming
authors.initials: W
authors.lastname: Li
authors.forename: Qingpeng
authors.initials: Q
authors.lastname: Li
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D013024:Soybean Oil / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D044242:Trans Fatty Acids / Q000032:analysis*
chemical_list: D044242:Trans Fatty Acids; D013024:Soybean Oil