1.5 Nanocoating Applications in Food Industry
Food coating can be described as a thin film of an edible composite material to prevent mass transfer. Such coatings can serve as barriers to moisture and gases. Coatings are added directly and formed by applying a fluid film-forming solution or liquid compounds on the food component. Edible surface materials may be classified into two categories: soluble polysaccharides and lipids. Alginates, cellulose, pectin, starch, chitosan, and other polysaccharides are suitable polysaccharides. Many lipid compounds have been used for producing culinary films and clothes such as animal or vegetable fats, waxes, acylglycerols, and fatty acids, which can act as an appropriate lipid. Lipid films have outstanding moisture trapping properties or as binding agents for gloss applying to chocolate. Waxes are widely used to cover fruit and vegetables to slow ventilation and to prevent moisture loss [46].
Edible coatings are used in a broad variety of products from nuts, herbs, poultry, sweets, cheese, candies, bakery, and fried food. Few research work has documented nanoparticles being incorporated into coating films to enhance their physical properties by enhancing the release of oxygen; montmorillonite clay was applied to pectins. Similarly, gelatin and montmorillonite-derived nanocomposites have been used to greatly change physical properties. There was also a considerable increase in chitosan/layered nanocomposites stability. Nanoparticles can be used as antimicrobial and additive carriers. It can also be used to stabilize additives and control their diffusion effectively in food and the various regions, e.g. surface vs. bulk of the food system. This control may be useful for long-term food storage or for conveying certain desired characteristics like flavor to a food system. In this way, the United States has also produced an edible antibacterial nanocoating that can be applied directly to baking products, released by the Sono-Tec Corporation [46–49].
The three main applications of nanomaterials in food packaging were also described as research trends in food packaging using nanotechnology, where nanoreinforcement, active nanocomposite packaging, and intelligent nanocomposite packaging are the main issues for food packaging. The presence of nanoparticles in the polymer matrix products increases the properties of the commodity in better packaging. In addition to barrier properties, strength, rigidity, dimensional stability, and material heat tolerance may be strengthened by inserting nanoclays or SiO2 nanoparticles. Nanoparticles are specially developed for applications of antimicrobial packaging in active packaging as active agents, silver, gold, and metal–oxygen nanoparticles with the antimicrobial function being the most studied nanoparticles with silver nanoparticles already present in several commercial applications. This is suitable for other fields of active packaging such as ethylene layer removers. Nanoparticles may be used as reactive particles in packaging materials for smart packaging to warn about the quality of the drug packed. To interact and to classify the drug, the so-called nanosensors can respond to external stimulation adjustments to ensure its consistency and health. Recent developments in polymer nanomaterials are oxygen indicators, freshness indicators, and pathogenic in smart food packaging.
1.6 Nanocoats Used in Food Manufacturing
Edible coatings are either applied to or formed directly on foods, whereas edible films are self-supporting structures used to wrap food products and also located in between two food components. It is a fact that such coatings may act as a barrier to heat, moisture, and gas. Coatings are added and formulated either by applying a liquid film-forming solution or directly on the food component with molten compounds. Edible coatings may be divided into two categories: polysaccharides and lipids and both of these categories are hydro-soluble. The best lipids are waxes, acylglycerols, and fatty acids, and among them, lipid films have excellent moisture capture properties and are used to color gloss on candy products as coloring agents. On the other side, waxes are commonly used to cover fruit and vegetables to delay breathing and rising moisture shortages [50].
Today, an edible coating is used for a large range of foodstuffs including nuts, potatoes, poultry, candy, dairy, cookies, pastry, and French fried products. Nonetheless, few research studies have identified nanoparticles in coating films to enhance their physical properties. Montmorillonite clay has been applied to pectins to reduce oxygen diffusion. Also, nanocomposites prepared for gelatin and montmorillonite have been used to improve physical properties. The efficiency of chitosan-layered nanocomposites was also greatly improved [51].
1.7 Importance of Nanolamine in Food Business
Nanolamines offer food scientists with various directions to manufacture modern food industry nanolaminate films. A nanoclay consists of two or more layers of physically or chemically connected nanometer-like content. One of the most efficient nanolamine methods is based on a layer deposition technique that covers loaded surfaces with interfacial films composed of several nanolayers of different materials. Nanolaminates have some benefits over conventional manufacturing methods for edible coatings and films and can also be used for several essential applications in the food and milk field.
Specific layers of adsorbing substances can be created, such as proteins, polysaccharides, lipids, and colloidal particles. Films are prepared with some active functional agents, such as antioxidants, antibrowning agents, enzymes, flavorings, and colors. These nanolaminated lacquerings could be entirely produced with the same nanocoating by simple processes such as dipping or washing from edible ingredients. The composition, thickness, structure, and properties of the laminate formed around the object depends on the dipping and coating process. These include changes in the adsorbed substances type in dipping solutions, the total number of dipping steps used, the order in which the item is introduced through the various dipping solutions, the solution, and the environmental conditions used [51].
1.8 Antimicrobial Films Used in Food Industry
There is currently substantial focus given to the use in packaging products of antimicrobial substances (such as silver nanoparticles and silver coatings). Antimicrobial films may help monitor the production and spoilage of pathogenic microorganisms. According to the accepted structural stability and barrier characteristics, the nanomaterials and the antimicrobial characteristics of the antimicrobials impregnated in the image; it is highly beneficial to create an antimicrobial photo. This film allows nanomaterials to add more powerful copies of biological molecules.
A layer-by-layer incorporation of antimicrobial peptides such as nisin may also contribute to the creation of antimicrobial films. Nisin acts as a depolarizing agent in bacterial membranes and creates pores in lipid bilayers. Nanofilm multilayer peptides intercalated different peptides charged at neutral pH, which was much more stable than when peptide film only stabilized electrostatic interactions.
There have also been records of nanoscale chitosan antibacterial action. A potential antimicrobial pathway includes interactions between the positive and the negative chitosan cell membranes, raising the membrane permeability and eventually contributing to the breakdown and leakage of intracellular content. The ineffectiveness of both rough chitosan and engineered nanoparticles at pH levels above 6 is consistent with observation given the lack of protonated amino groups [52].
1.9 Nano-scavenging Oxygen Film Used in Food or Eating Substances
Oxygen (O2) is responsible either directly or indirectly for the deterioration of many foods. For example, direct oxidation reactions lead to fruit browning and vegetable oils rancidity. Degradation of food by indirect action of O2 includes aerobic microorganism food spoilage. The inclusion of O2 scavengers in the food kit will also hold O2 rates very small, which are beneficial for many purposes because they will increase the food's life.
Successful production of oxygen scavenger films was achieved by applying titanium nanoparticles (TiO2) to different polymers, which are used to pack a wide range of oxygen-sensitive products. In particular, the emphasis was on the