Assessment of trans fatty acids in edible oils in China

Trans fatty acid (TFA) is commonly present in edible oils. TFA has been proven to have adverse effects on blood lipids, including increasing the LDL-cholesterol concentration and decreasing the HDL-cholesterol concentration. The aim of our study was to determine the levels of TFA in edible oil samples consumed in Harbin, China. In this study, 93 samples of soybean oil (SBO) (n = 29), rapeseed oil (RSO) (n = 23), sunflower oil (SFO) (n = 22), and corn oil (CO) (n = 19) were analyzed between October 2010 and January 2011, using a gas chromatograph (GC) with a flame ionization detector (FID). TFA (>2%) was detected in 17 (18%) samples, ranging from 0.14% to 4.76%. The overall TFA content was 1.15 ± 0.12% for SBO, 1.37 ± 0.23% for RSO, 1.41 ± 0.10% for SFO, and 2.01 ± 0.24% for CO. Trans C18:2 and C18:3 fatty acids were normally predominant in the investigated edible oils. The variance in the percentage of TFA in the edible oils probably resulted from differences in the quality, processing technique, and storage condition of the edible oils. The results indicated that, in China, TFA is widely present in edible oils at low levels. Therefore, it is important to assess the content of TFA in edible oils in China.