Development of active low-density polyethylene (LDPE) antioxidant packaging films: Controlled release effect of modified mesoporous silicas

Abstract

Active LDPE antioxidant packaging films were developed by incorporating α-tocopherol loaded mesoporous silicas, in which the mesoporous silica materials were modified by (3-aminopropyl) triethoxysilane, trimethylchlorosilane, and n-octytrimethoxysilane before being loaded with α-tocopherol. The assemblies were characterized by infrared spectroscopy, nitrogen adsorption/desorption isotherms, thermal gravimetric analyzer and powder X-ray diffraction. Controlled release effect of the films were investigated by conducting migration tests in fatty food simulant at 40℃. Diffusion coefficients of α-tocopherol in films were obtained and the release kinetics were also studied. Besides the experimental studies, interactions between α-tocopherol molecules and the pore wall of modified mesoporous silicas were calculated after molecular dynamics simulations, thus to help understand the controlled release mechanism of modified mesoporous silicas on molecular level. The results showed that all three kinds of modified mesoporous silicas had enhanced slow release effect as compared with their non-modified counterpart. Among them, the aminopropyl grafted mesoporous silica showed the best slow release effect, which caused the diffusion coefficient of α-tocopherol in films decreased by ∼32 % as compared with trimethylsilyl grafted mesoporous silica. Interaction energies results proved that the enhanced slow release effect could be attributed to stronger interactions between the adsorbates and adsorbents. These results demonstrate that mesoporous silicas modified with different functional groups in antioxidant packaging film matrixes have the application potential to offer protection for packaged fatty food with different antioxidant requirements.