|Nanotechnology is a method of controlling matter at near-atomic scales to produce unique or enhanced materials, products and devices. The commercialization of nanocomposite materials was started by Toyota in the late 1980s. In the 1990s, research on use of nanocomposites for food packaging started using mostly montmorillonite clay as the nanocomponent in a number of polymers like polyvinyl chloride, polyethylene, nylon and starch. According to Principia Markets, the nanocomposites market will reach 1 billion pounds by 2010.
Nanotechnology research in the food industry is getting focused on food packaging. With the increasing global customer base, food retailing is transforming. However, with the move toward globalization, food packaging requires longer shelf life, along with monitoring food safety and quality based upon international standards. With a different nanostructure, the gas and water vapour permeability of plastics can be engineered to preserve fruit, vegetables, beverages, etc. With the use of nanoparticles, bottles and packaging can be made lighter and stronger with better thermal performance and less gas absorption. These properties can extend the shelf life of products, as well as reduce transportation costs involved in shipping food.
Nanotechnology has the capability to transform the nature of food packaging materials in future. Certain nanoscale innovations could bring amazing improvements to food packaging in the forms of detection of pathogens, smart and active packaging, and barrier and mechanical properties. Packaging that incorporates nano materials can be “smart,” which means that it can respond to environmental conditions or repair itself or alert a consumer to contamination and/or the presence of pathogens. It offers several extraordinary benefits to improve food packages like advancements in fundamental characteristics of food packaging materials such as antimicrobial properties, barrier properties, strength, and stability to heat and cold.
Nanocomposites are at the forefront of food packaging development. Durethan, from Bayer Polymers, is a nanocomposite film enriched with an enormous number of silicate nanoparticles which reduce entry of oxygen and other gases and the exit of moisture, thus preventing food from spoiling. Nanocor has developed nanocrystals to be used in nanocomposite plastic beer bottles. This material minimizes loss of carbon dioxide and entry of oxygen into beer bottles. The other improvements in nanotechnology for food packaging include:
• Carbon Nanotubes: They are cylinders with nanoscale diameters that can be used in food packaging to improve its mechanical properties. It has been recently discovered that they might exhibit powerful antimicrobial effects. E coli bacteria died on immediate direct contact with aggregates of carbon nanotubes.
• Nanosensors: Can easily detect pathogens, toxins and chemicals in foods. A number of research reports have described the detection methods for toxins, allergens, bacteria and viruses using nanotechnology. Scientists at the University of Pennsylvania and Monell Chemical Sciences Center have used nano-sized carbon tubes coated with DNA strands to create nanosensors that have the ability to detect odors and tastes.
• Radio Frequency Identification (RFID) tags: Could be incorporated into food packages in the future. These do not require line-of-sight for reading like bar-codes and enable registration of hundreds of tags in a second. Retail chains such as Wal-Mart are testing this technology.
Nano-wheels: Adds to the improvement in food packaging. These molecules are incorporated into plastics in order to enhance their barrier and mechanical properties.
Nanovesicles: Capable of detecting E. coli 0157:H7, Listeria monocytogenes and Salmonella spp. Liposome nanovesicles have been devised to detect peanut allergen proteins.
DNA Biochips: They have been under development for quite some time now, to detect pathogens. A carbon nanotube functions as the transmitter while a single strand of DNA function as the sensor.
Electronic tongue nano-sensors: Being developed to detect substances in parts per trillion which could be used to trigger a color changes in food packages to alert the consumer to food that has been spoiled.
Nanoscience is also being used to develop active and intelligent food packages. Antimicrobial activity can be imparted in food packages through incorporation of silver, magnesium oxide or zinc oxide nanoparticles which kill harmful microorganisms. Dirt repellent coatings for food packages are also being developed.
Another area where full fledged research work is on is in the area of biodegradable nanocomposite food packages. The packaged films can be produced with exfoliated clay layers by pumping carbohydrates and clay fillers through high shear cells. They act as effective moisture barriers by incrementing the tortuosity of the path water takes to penetrate the films. Such types of materials help achieve enough increment in film strength.
Researchers have found a way of keeping food fresher for longer while using less packaging material. The finding involves a nanotechnology-based technique to block the transport of damaging gases through a polymer, making it stronger while using less material. Scientists working at the Case Western Reserve University polymer research unit found that polyethylene oxide (PEO), when confined as nanolayers, crystallizes as a single layer, resembling very large, impermeable single crystals that reduce by 100 times the amount of gas permeability in polymer-based applications. By using a new layer-multiplying co-extrusion process that takes two polymer melts and combines them as layers, multiplies the layers to four, and doubles that again as many times as desired, the team discovered that a new structure emerges that is progressively thinner, thereby saving on material. The project is a step toward developing more flexible, optically transparent, ultra-high barrier polymers for several different applications.
A University of Warwick team claims a new process involving the layering of a polymer with silica-based nanoparticles has the potential to enhance the properties of pressure sensitive adhesive labels, water-borne coatings and biodegradable materials. The newly developed technology might be most applicable to multi-layered biodegradable packaging as it could gain more robustness and water barrier characteristics through the addition of a nanoparticle coating. The process is not detrimental to the ‘green’ profile of these bio materials as the silica-based particles are derived from sand and clay.
According to a study from iRAP, Inc. the total nano-enabled food and beverage packaging market in the year 2008 was US$4.13 bln, which is expected to grow in 2009 to US$4.21 bln and forecasted to grow to US$7.3 bln by 2014, at a CAGR of 11.65%. Active technology represents the largest share of the market, and will continue to do so in 2014, with US$4.35 bln in sales, and the intelligent segment will grow to US$2.47 bln in sales. Other highlights of the study are :
Among active technologies, oxygen scavenger, moisture absorbers and barrier packaging represent more than 80% of the current market.
Time/temperature indicators are a major share of intelligent packaging, with radio frequency identification data tags (RFIDs) forecasted to show the strongest growth in this category in the future.
In food products, bakery and meat products have attracted the most nano-packaging applications, and in beverages, carbonated drinks and bottled water dominate.
Among the regions, Asia/Pacific, in particular Japan, is the market leader in active nano-enabled packaging, with 45% of the current market, valued at US$1.86 bln in 2008 and projected to grow to US$3.43 bln by 2014, at a CAGR of 12.63%.
In the United States, Japan, and Australia, active packaging are already being successfully applied to extend shelf-life while maintaining nutritional quality and ensuring microbiological safety. Examples of commercial applications include the use of oxygen scavengers for sliced processed meat, ready-to-eat meals and beer, the use of moisture absorbers for fresh meat, poultry and fresh fish, and ethylene-scavenging bags for packaging of fruit and vegetables. In Europe, however, only a few of these systems have been developed and are being applied now. The main reasons for this are legislative restrictions and a lack of knowledge about acceptability to European consumers, as well as the efficacy of such systems and the economic and environmental impact such systems may have. The European "Actipak" project will address these issues in the near future.
Nanoclays have shown the broadest commercial viability due to their lower cost and their utility in common thermoplastics like polypropylene (PP), thermoplastic polyolefin (TPO), PET, polyethylene (PE), polystyrene (PS), and nylon.
The rapid use of nano-based packaging in a wide range of consumer products has also raised a number of safety, environmental, ethical, policy and regulatory issues. The main concerns stem from the lack of knowledge with regard to the interactions of nano-sized materials at the molecular or physiological levels and their potential effects and impacts on consumers health and the environment. Research and development in the field of active and intelligent packaging materials is very dynamic and develops in step with the search for environmentally friendly packaging solutions. In this context, the design of tailor-made packaging is a real challenge, and it implies the use of reverse engineering approaches based on food requirements and not just on the availability of packaging materials any longer. Nanotechnologies are expected to play a major role, taking into account all additional safety considerations and filling present packaging needs.