Abstract:The effects of steam distillation and two-stage dual-temperature steam distillation on the removal of phthalate ester plasticizers dibutyl phthalate (DBP) and di (2-ethylhexyl) phthalate (DEHP) from edible oils were investigated. Meanwhile, the effect of operating conditions on the loss of vitamin E and the formation of trans-fatty acids (TFAs) in edible oils were discussed. The results showed that when the distillation was conducted at 240 ℃ for 100 min, the DBP content in camellia oil and soybean oil was reduced from 2.63 and 3.01 mg/kg to 0.164 and 0.232 mg/kg, respectively. When the distillation was conducted at 260 ℃ for 100 min, the content of DEHP in two oils was reduced to 0.784 and 1.226 mg/kg from 7.72 and 3.24 mg/kg, respectively. All the above DBP and DEHP content after distillation was lower than the national standards (DBP?0.3 mg/kg; DEHP?1.5 mg/kg). To reduce the DEHP content to be lower than the national standard, steam distillation at 260 ℃ for 100 min was required. Under these conditions, the loss rates of vitamin E in camellia oil and soybean oil were 40.6% and 21.4%, respectively, and the content of TFAs in soybean oil was increased to 4.75%. A two-stage dual-temperature steam distillation (190 ℃, 60 min and 260 ℃, 30 min) reduced the DBP and DEHP content to be lower than the national limits under a short high-temperature condition, and the loss of vitamin E and the content of TFAs were significantly reduced.
