## 1 Introduction  
In recent years, the integration of nanotechnology into food science has leaned toward the use of nanoscale structures to take advantage of these nanostructures' physical, chemical, optical, and mechanical properties in food systems. The incorporation of nanomaterials is intended to solve technological challenges in the food industry; among them is the extension of the shelf life of food, the use of additives to improve sensory and techno-functional properties, the use of antimicrobial ingredients, and the development of active packaging [1, 2]. The combination of these two disciplines has resulted in the implementation of nanostructures such as nanoparticles, nanofibers, nanosheets, and nanotubes, among others, synthesized from organic (proteins, peptides, biopolymers, and lipids) and inorganic (metals, metal oxides, and synthetic polymers) compounds. Their optical, electronic, and surface properties are responsible for the desired effects in various applications. For example, the effect of decreasing antimicrobial activity is given by the chemical reactivity on the surface of the nanomaterial and the adhesion mechanisms of the microorganism [3, 4]; as a consequence of this feature, submicroscopic organisms are deactivated, for example, _Salmonella enterica_, _Escherichia coli_, and _Listeria innocua_, due to the potential surface charge of engineered water nanostructures (EWNS) [5]. However, the antimicrobial effect is all-encompassing regarding the physicochemical interactions between bacteria and nanostructures. The surface charge (which generates electrostatic repulsions that confer thermodynamic stability on the system) and the droplet size in a nanoemulsion will influence the bioavailability and release of the compound [6]; furthermore, mechanical and migration properties are being studied as determinants of the use of nanostructures (nanoclays and nanoparticles) in active packaging [1]. Nanomaterial characteristics depend on the material's application and can have a positive or negative effect; however, two points of control to warrant nanomaterials' safe use in the food industry are their biological effect and potential toxicity [7]. Thinking on this, the method to obtain a nanomaterial can offer some advantages concerning toxicity. There are chemical, physical, and green synthesis methods. Nowadays, green synthesis is convenient in food and medicinal applications due to its minimal use of harmful and hazardous synthetic chemicals [8]. Despite these advantages, an illustrative comparison of the function of different methods' components and synthesis conditions, which affect the size, morphology, and crystallinity allows for the understanding of these formation mechanisms. At the same time, characterization techniques provide information that describes the mechanical, optical, electrical, and thermal nanomaterial properties that make classification possible [9; 10]. Therefore, understanding in-depth the phenomena that occur at the interface of a food matrix and a nanostructure, as well as knowing some parameters involved in determining the antimicrobial effect, the barrier properties of packaging, and delivery systems to improve the compound's bioavailability, is of the utmost importance. With this in mind, regarding the potential of nanostructured materials, this review aims to frame the daily interrelationship between nanotechnology and food science by reviewing the classification, synthesis methods, and characterization of nanomaterials; highlighting the physicochemical properties involved in the interactions between a nanomaterial and a biomolecule of interest; and obtaining nanomaterials that, according to their properties, can be used in applications that meet the needs of the food industry (Figure 1).  
Figure 1: Summary of the nanostructures, characterization, and nanotechnology application in food science.