Migration of Ti and Zn from Nanoparticle Modified LDPE Films into Food Simulants

Nanoparticle modified films (NMFs) were prepared by blending low-density polyethylene (LDPE) with nano-TiO2 or nano-ZnO. Migration of Ti or Zn into four kinds of food simulants were performed under 40 degrees C for 1, 4 and 7 d, as well as 70 degrees C for 2 h. Furthermore, the effect of microwave or ultraviolet treatment on migration was investigated. Results showed that Ti or Zn migration increased with time, and the highest migration occurred in acid simulant, whereas the least occurred in fatty simulant. Temperature promoted the migration process. The amounts of Ti migrated into food simulants ranged from 0.0046 mg kg(-1) to 0.61 mg kg(-1). For Zn, the amounts were from 0.52 mg kg(-1) to 14.17 mg kg(-1). Microwaves facilitated the migration of nanoparticles, while ultraviolet did not. These results indicated that nano-TiO2 modified LDPE films might be safe commercial food packaging films, while nano-ZnO modified LDPE films might require further investigation.