Nanotechnology in Food Safety - II

The Nano Foods

Over the last decade, the uses of nano scale structures in the food sector is increasing, where popularity, interest and activities in the area of research have greatly focused. The rapidly evolving nanotechnology will create impact on every aspect of the food system from production to processing, packaging, transportation, shelf life and bioavailability. As technology advances, nano-biotechnology devices or materials used on technology become smaller and more sensitive, whereas applicability in the areas of food packaging and food safety are exceptional. Nonetheless, food preservation using nanomaterial is expected to be promising and catch up the commercialization as fast as possible which will protect food from the moisture, lipids, gases, off-flavors, and odors, because of their unique and novel properties. The nanotechnology can be used as an excellent vehicle to deliver bioactive compounds to the target tissues, but issues on the consequences of nanotechnology need to be addressed in order to alleviate consumer concerns. As a matter of fact, the advances in nanotechnology are paving new paths day by day, yet there are many challenges and opportunities to improve the current technology. The major consumer concerns, such as transparency of safety issues and environmental impact should be thoroughly tested before they are released to the market while uniform international regulatory framework for food nanotechnology is a must.

Potential of Nanotechnology in Food Processing, Quality and Safety

Applications of nanotechnology in the food sector is continuously evolving, where nanostructured food ingredients are being developed with the claims that they offer improved taste, texture, and increased the shelf-life of different kinds of food materials. The nanotechnology also help to brought down the extent of wastage of food due to microbial infestation. Nano-encapsulation is a major area of nanotechnology application in the food sector, where nanoparticles are manufactured to encapsulate food ingredients and additives to mask their unpleasant odour, tastes or flavours. The encapsulation further control interactions of active ingredients with the food matrix, control the release of the active agents, ensure availability at a target time and specific rate, and protect them from moisture, heat, chemical, or biological degradation during processing, storage, and utilization, improve dispersion of water-insoluble food ingredients, which also exhibit the compatibility with other compounds in the system. Hence, these delivery systems possess the ability to penetrate deeply into tissues due to their smaller size and thus allow efficient delivery of active compounds to target sites in the body. Another major focus of application of nanotechnology in food processing involves the development of nanostructured food ingredients and additives, which claims that they offer improved taste, texture and consistency, enhanced bioavailability and permit mixing of previously "incompatible" ingredients in food matrix. Examples of nanostructured foodstuffs include spreads, ice cream, yoghurt, nano-salt, etc. Other indirect applications of nanotechnology in food area include the development of nano-sized agrochemicals and veterinary medicines. Nanoparticles are offering better properties for encapsulation and release than traditional encapsulation which improve the efficacy of the process.

There are various encapsulating delivery systems including synthetic and natural polymerbased have been developed for the improved bioavailability and preservation of the active food components. The nanotechnology in food processing has been considered with its role in the improvement of food products in terms of;

Food texture

Food appearance

Food taste

Nutritional value of the food

Food shelf-life

The nano-carriers are currently being utilized as delivery systems to carry food additives in food products without disturbing their basic morphology. Particle size may directly affect the delivery of any bioactive compound to various sites within the body as it was noticed that in some cell lines, only submicron nanoparticles can be absorbed efficiently but not the larger size micro-particles. An ideal delivery system is supposed to have following properties: (i) able to deliver the active compound precisely at the target place (ii) ensure availability at a target time and specific rate, and (iii) efficient to maintain active compounds at suitable levels for long periods of time (in storage condition). Nanotechnology being applied in the formation of encapsulation, emulsions, biopolymer matrices, simple solutions, and association colloids offers efficient delivery systems with all the above-mentioned qualities. Nano polymers are trying to replace conventional materials in food packaging. Nanosensors can be used to prove the presence of contaminants, mycotoxins, and microorganisms in food.

Nonetheless, nanotechnology has also enabled significant alterations in food products with novel qualities. The application of nanoparticles is not limited to antimicrobial food packaging but nanocomposite and nano-laminates have been actively used in food packaging to provide a barrier from extreme thermal and mechanical shock extending food shelf-life. In this way, the incorporation of nanoparticles into packaging materials offers quality food with longer shelf-life. The purpose of creating polymer composites is to have more mechanical and thermostable packing materials. Many inorganic or organic fillers are being used in order to achieve improved polymer composites. The incorporation of nanoparticles in polymers has allowed developing more resist packaging material with cost effectiveness. Use of inert nanoscale fillers such as clay and silicate nanoplatelets, silica (SiO₂) nanoparticles, chitin or chitosan into the polymer matrix renders it lighter, stronger, fire resistance, and better thermal properties. Antimicrobial nanocomposite films which are prepared by impregnating the fillers (having at least one dimension in the nanometric range or nanoparticles) into the polymers offer two-way benefit because of their structural integrity and barrier properties.

Nanomaterials for use in the construction of biosensors offers the high level of sensitivity and other novel attributes. In food microbiology, nanosensors or nanobiosensors are used for the detection of pathogens in processing plants or in food material, quantification of available food constituents, alerting consumers and distributors on the safety status. The nanosensor works as an indicator that responds to changes in environmental conditions such as humidity or temperature in storage rooms, microbial contamination, or products degradation. Various nanostructures like thin films, nanorods, nanoparticles and nanofibers have been examined to their possible applications in biosensors. Thin film-based optical immunosensors for detection of microbial substances or cells have led to the rapid and highly sensitive detection systems. In these immunosensors, specific antibodies, antigens, or protein molecules are immobilized on thin nano-films or sensor chips which emit signals on detection of target molecules. A dimethylsiloxane microfluidic immunosensor integrated with specific antibody immobilized on an alumina nanoporous membrane was developed for rapid detection of foodborne pathogens Escherichia coli O157:H7 and Staphylococcus aureus with electrochemical impedance spectrum. Nanotechnology can also assist in the detection of pesticides, pathogens, and toxins serving in the food quality tracking–tracing–monitoring chain.

Biosensors based on carbon nanotubes also gained much attention due to their rapid detection, simplicity and cost effectiveness and have also been successfully applied for the detection of microorganisms, toxins, and other degraded products in food and beverages. Toxin antibodies attached to these nanotubes causes a detectable change in conductivity when bound to waterborne toxins and therefore are used to detect waterborne toxins. Further, the use of electronic tongue or nose which is consists of the array of nanosensors monitor the food condition by giving signals on aroma or gases released by food items. The quartz crystal microbalance (QCM)-based electric nose can detect the interaction between various odorants and chemicals that have been coated on the crystal surface of the QCM. Many studies on small molecule detection have used quartz crystal surfaces that have been modified with different functional groups or biological molecules, such as amines, enzymes, lipids, and various polymers.