Migration of α-tocopherol from LDPE films to corn oil and its effect on the oxidative stability

The migration of a-tocopherol (alpha-T) from low density polyethylene (LOPE) films, added with 20 (film A) and 40 mg g(-1) (film B) to corn oil for 12 weeks at 5,20 and 30 degrees C was determined. A LOPE film added with no alpha-T was used as control (film C). Diffusion coefficient (D) values for the film A system were 1.4 x 10(-11), 7.1 x 10(-11) and 30.3 x 10(-11) cm(2) s(-1) at 5, 20 and 30 degrees C, respectively. Meanwhile, D values for the film B system were 1.3 x 10(-11), 9.6 x 10(-11) and 51.1 x 10(-11) cm(2) s(-1) at the same temperatures. The activation energy (E-a) for the diffusion of alpha-T was 126.5 (film A) and 105.9 kJ mol(-1) (film B). The effect of the migration of alpha-T on the oxidative stability of corn oil was evaluated by monitoring hexanal content by solid phase micro-extraction (SPME) and gas chromatography. The hexanal content in the oil showed that both films added with alpha-T resulted suitable to maintain the oxidative stability of the oil for about 16 weeks at 30 degrees C, compared to 12 weeks for the oil in contact with the film C. (C) 2010 Elsevier Ltd. All rights reserved.