## 3 Edible Coatings
### Active Edible Packaging
#### 3.4.4 Nanoparticles and Nanomaterials as Active Compounds  
The growing demand is due to consumers' concerns about food safety and quality, and the so-called \"ecological films\" involve using nanotechnology to improve their properties. In contrast, nanotechnology in food coatings plays an important role in developing a new generation of coatings with improved properties. Biodegradable and environmentally friendly biopolymers have gained enormous potential in food packaging, which, to improve barrier and mechanical properties, are used in combination with nanoparticles, defined as particles of 1 to 100 nm. In active packaging, bioactive agents (antimicrobial agents, enzymes, antioxidants) are used as components of polymer-based packaging that destroy microbes (bacteria, fungi, protozoa) or inhibit their penetration. For this reason, nanocomposites play a key role due to their antimicrobial properties [150]. The migration of nanometres from nanocomposites depends on many factors, including size, concentration, solubility, diffusion, type of food, pH, or interaction time. Some studies confirm the lack of migration of nanomaterials to food products after appropriate encapsulation of the polymer used. The main advantages of nanomaterials include high absorption and bioavailability, dispersion, solubility, and improved stability during food processing, improving efficiency during production, and reducing waste and financial burden [151]. The use of nanoparticles in packaging aims to improve the mechanical, thermal (stability), and barrier properties by introducing them into a polymer matrix. In addition, the packaging material influences the conditions inside the package. A significant role is played by the interaction of the material from which the packaging is made--with the food product or with the atmosphere in the packaging, affecting the quality of the food. The ability to monitor changes in packaging conditions should also be considered. The most commonly used nanoparticles in food packaging are nanoparticles of metals or their oxides, such as silver, gold, copper, zinc, or magnesium [152, 153]. [PERSON] et al. [154] studied films containing red apple pomace and TiO\({}_{2}\) nanoparticles. The research that was conducted shows that the addition of nanoparticles significantly improved the water vapour barrier properties, mechanical properties, and thermal stability of the film. The film's excellent antioxidant and antibacterial properties were also observed, which may be a potential strategy for transforming apple processing waste into active packaging materials. An important aspect is the legal regulations regarding food packaging materials, which may be accepted in one country and not in another. These discrepancies result from the classification of edible films and coatings as food ingredients, food products, substances that come into direct contact with food, as well as food additives or packaging substances, by the provisions of American and European directives. Edible coatings, defined as an integral ingredient of food, must meet several food standards, including should not alter the taste, smell, colour, or texture of the food, must be made by manufacturing practice, and must not hurt the composition of the food or pose a risk to human health. However, Regulation (EC) No 1935/2004 does not specify the safety assessment of nanoparticles in packaged food and the biological effects [64]. The addition of functional compounds to film-forming solutions, e.g., phenolic compounds, is recognised as safe (GRAS) and can be practiced to improve the functionality of edible coatings and films by the FDA Regulation 2019 [3]. In addition, guidelines and protocols for risk assessment in the aspect of nanotechnology are developed by the International Organisation for Standardisation (ISO), and the characterisation and identification of nanomaterials have been included by the European Food Safety Authority [155].