In the food industry, nanomaterials are used in a variety of aims to improve quality, deliver nutrients, and increase packaging and storage efficiency. zinc oxide (ZnO) nanoparticles (NPs), for example, are widely added to food as a Zn supplement to increase absorption of Zn. Nanomaterials with a dimension in range of 1-100 nm have a large surface area to volume ratio, increasing their reactivity with other materials. Accordingly, nanomaterials can lead unexpected biological or toxic effects because they have different physicochemical properties compared with bulk one. Many studies have reported that the toxic effect may vary depending on size, shape, surface charge, solubility or other physicochemical properties of nanomaterials. Therefore, it is important to identify the physicochemical properties of nanomaterials in order to evaluate the in biological response and toxicity of nanomaterials. Also, nanomaterials with highly reactivity can interact with other components such as proteins and lipids to form protein-nanoparticle corona, resulting in changes in their physicochemical properties. Since food additives nanomaterials are added to foods, there may be interactions between nanomaterials and food components, which can physicochemical properties of nanomaterials and affect toxicity and absorption rates. So, the interaction between nanomaterials and food components should be considered,
In the present study, the interactions between ZnO NPs and food components, such as casein, albumin, zein or glucose, were investigated by measuring changes in hydrodynamic radius and zeta potential values. Dissolution properties were also evaluated ZnO NPs in DW, cell culture media, artificial lysosomal fluids and in vitro 3 step digestion model. The interactions between food proteins and ZnO NPs were evaluated by fluorescence quenching ratio. The effects of the interaction with proteins on biological responses were investigated in terms of cytotoxicity, membrane damage, ROS generation, cellular uptake and intestinal transport mechanism. SDS-PAGE was also performed to confirm the stability of primary structure of proteins and digestion efficiency affected by interactions.
The results demonstrated that physicochemical properties of ZnO NPs were influenced by food component type. The dissolution properties varied depending on the solvent conditions, and were not affected by the interaction between ZnO NPs and food components in DW and in vitro 3 step digestion fluids. However, the interactions affected cell proliferation, membrane damage, ROS generation, cellular uptake, and intestinal transport but did not affect the primary structure of proteins and digestion efficiency. In conclusion, toxicological responses can be affected by the interactions between ZnO NPs and food protein. These studies provide basic information about the safety of NPs added to food matrices.