The noticeable discoveries in the field of nanotechnologies of the last years emphasized the versatility of nanoscience in many fields. New evidences demonstrated that physical and chemical properties of nanomaterials can be tuned to reduce safety issues of nanotechnology applied in food industry. In this context, and inspired by the increasing interest of industry toward nanotechnology, a novel iron oxide magnetic nanoparticle, whose synthesis was developed in our laboratory, was used in association with polyphenols to elaborate hybrid nanomaterials with interesting applications in the food industry field. The magnetic nanoparticles, presenting a size around 10 nm and constituted of stoichiometric maghemite (γ-Fe2O3), were called Surface Active Maghemite Nanoparticles (SAMNs). SAMNs show a peculiar surface chemical behavior, which is highlighted by their high water stability as colloidal suspensions, without any superficial modification or coating derivatization. In addition, SAMN production is cost-effective and eco-friendly, and these nanoparticles can be advantageously reutilized. SAMNs are able to immobilize various biomolecules and the availability of iron (III) atoms on the particle surface provides to the nanomaterial the ability to selectively bind selected molecules. Thereby, upon molecule immobilization, a core-shell complex is formed, combining the magnetism of SAMNs (the core) and the function provided by the chosen molecule (the shell). Among several other biomolecules, phenolic compounds have a high affinity for maghemite nanoparticles. This occurs because the phenolic compounds have chelating groups that react with the iron (III) sites available on the surface of SAMNs. The immobilization of phenolic compounds on the surface of SAMNs is very stable and conserved upon binding, making it possible to use the resulting complex for various purposes, such as magnetic purification, drug delivery, etc. Thus, this study proposes the development of two hybrid nanostructure by coating SAMNs with tannic acid (TA) and curcumin (CUR). Both core-shell nanostructures, SAMN@TA and SAMN@CUR, presented high stability and were deeply characterized with different techniques. SAMN@TA was successfully applied for the creation of an electrochemical sensor for the detection of polyphenol content in blueberries by square wave voltammetry. Furthermore, the antimicrobial properties of SAMN@TA were successfully tested on Listeria monocytogenes. Due to the effectiveness on reducing bacterial growth and easy removal from the system, SAMN@TA represents a possible alternative to antibiotic methods for the elimination of foodborne pathogens. Finally, the use of SAMN@CUR was proposed as a purification method to improve the extraction of pure curcumin from biological samples. The results demonstrated a sustainable and highly efficient magnetic purification process for curcumin as well as an outstanding yield of 90% and a purity > 98%. In conclusion, the reported multiple uses of SAMNs, ranging from biomolecule purification to foodborne pathogen control, offer valuable insights into the versatility of the nanomaterial and its potential applications in the food industry
