Abstract: In this paper, the contents of phthalic acid esters (PAEs) in 20 sesame seed samples collected from different areas were analyzed. The migration of PAEs into crude sesame oil during oil processing was studied. The effects of raw materials and processing technologies on PAEs migration into sesame oil were clarified in order to develop technologies for accurately preventing and controlling the risk of PAEs migration and consequently to ensure and enhance the quality and safety of sesame oil. The results showed that all samples were found to contain PAEs. Dibutyl phthalate (DBP), di(2-ethtlhexyl) phthalate (DEHP) and diisononyl ortho-phthalate (DINP), with limits set for all of them (DBP ≤ 0.3 mg/kg, DEHP ≤ 1.5 mg/kg, and DINP ≤ 9.0 mg/kg) in the Chinese national standard, were detected in 100% of the samples in the range of 0.040–0.337, 0.085–1.971 and 0.343–0.806 mg/kg with an average of 0.137, 0.560 and 0.559 mg/kg, respectively. A total of 8ΣPAEs were detected in all samples in the range of 0.209–2.828 mg/kg with an average of 1.165 mg/kg. Five and 10 percent of the samples exceeded the national standard limits for DEHP and DBP, respectively. The PAEs were gradually migrated from sesame into crude oil and accumulated during oil production. The contents of DBP, DEHP and DINP and total PAEs content of the crude pressed oil were 1.16, 1.03, 1.11 and 1.07 times higher than those of sesame seeds, respectively. The solvent extracted oil contained 1.49, 1.27, 1.24 and 1.33 times more DBP, DEHP and DINP and total PAEs than sesame seeds, respectively. The content of PAEs in the peeled sesame oil was about 20% lower than that in the whole sesame oil, and the PAEs content in the extracted oil was about 1.2 times higher than that in the pressed oil.

Key words: sesame, sesame oil, phthalic acid esters (PAEs), migration