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

The migration of α-tocopherol (α-T) from low density polyethylene (LDPE) films, added with 20 (film A) and 40 mg g−1 (film B) to corn oil for 12 weeks at 5, 20 and 30 °C was determined. A LDPE film added with no α-T was used as control (film C). Diffusion coefficient (D) values for the film A system were 1.4 × 10−11, 7.1 × 10−11 and 30.3 × 10−11 cm2 s−1 at 5, 20 and 30 °C, respectively. Meanwhile, D values for the film B system were 1.3 × 10−11, 9.6 × 10−11 and 51.1 × 10−11 cm2 s−1 at the same temperatures. The activation energy (Ea) for the diffusion of α-T was 126.5 (film A) and 105.9 kJ mol−1 (film B). The effect of the migration of α-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 α-T resulted suitable to maintain the oxidative stability of the oil for about 16 weeks at 30 °C, compared to 12 weeks for the oil in contact with the film C.