Copper release from nano‑copper/polypropylene composite films to food and the forms of copper in food simulants

The influences of temperature, exposure time, different types of polypropylene (PP), (3-Aminopropyl) triethoxysilane (KH550) used as coupling agent, sterilizing conditions on copper migration from nano‑copper/PP composite films into food/ food simulants were explored. Results showed that copper migrated more easily from polypropylene (PPH) films with a maximum rate of 34.51%, compared to those from copolymer polypropylene (PPR) and block copolymer polypropylene (PPB) to 3% acetic acid ( w / v ). Gamma (γ) irradiation could significantly increase the copper migration ( P  < 0.05). Different forms of copper were found in different simulants. Copper crystals were found in 10% ethyl alcohol and identified by scanning electron microscopy and energy dispersed analysis of X-rays (SEM-EDX). The hydroxylation (%) of nano‑copper/PP films was less than 100%. These films had certain antioxidant and antimicrobial properties which could extend the shelf life of packaged food. The migration amount of copper into rice vinegar was the largest, with a maximum of 0.65 mg/ kg. Industrial relevance Although nanomaterials are potentially beneficial for food packaging, migration of nanoparticles to the packaged food can be harmful to the human body. Therefore, it is very important to determine the presence and characterize the morphology of nanoparticles in food. In this paper, we have developed a new and effective packaging material containing nanoparticles and have explored the migration form and morphology in food simulants. In conjunction with the results of current study, nano‑copper/PP packaging material can be suggested for maintaining the product quality and has commercial potential.