Nanofood

The nearly new field of nanotechnology is impacting on the food industry. Food giants like Nestlé, Heinz, Kraft and Unilever are researching the potential of nanotechnology to improve their food safety, packaging and nutritional content. Current estimates from Cientifica are that nanotechnologies in the food industry will grow from $410 million in 2006 to about 5.8 billion in 2012. This is a huge growth forecast for a six-year period.

Nanotechnology is already evident in the packaging area, in both 'smart' and 'active' packaging. Oxygen scavenging layers in plastic bottles are a classic example of 'active' packaging; the pack itself acts to improve the condition of the contents and the shelf life of the product increases. 'Smart' packaging reacts to the internal or external environment and alerts the consumer. One example is the ripeness indicators placed on some fruit packs; another is packaging film which changes colour when it is in the presence of E.Coli 0157.

West Australian company Advanced Nanotechnology has recently been awarded a grant of $1.948 million under the Australian government's Commercial Ready Program. The grant will fund, on a dollar-for-dollar basis for two and half years, the development of a range of advanced coatings and films (transparent functional coatings) which incorporate nanopowders to show enhanced properties. Products that will be developed include transparent coatings and films that exhibit long-life UV protection, combined UV and abrasion resistance, high conductivity/anti-static properties, tuneable refractive index, enhanced pearlescence, and films with UV and antimicrobial properties.

Nanopowders of zinc oxide, alumina, zirconium oxide and ceria, manufactured by Advanced Nano using its proprietary platform technologies, will provide the key ingredients for these products.

Dr Paul McCormick, Advanced Nano's CEO, stated: "The company has identified transparent functional coatings as an important strategic growth area for its nanopowders and nanoingredients."

A specific example of a product to be commercialised by this project is transparent food packaging film. Existing chemical UV absorbers (used to prevent product deterioration and extend product shelf life) are known to migrate out of thin plastic films and, in some cases, into the contents of the packaging. Replacing the chemical absorbers with dispersed zinc oxide nanoparticles provides the required UV protection and product stability, while remaining transparent, inert and stable within the film. In addition, zinc oxide nanoparticles can provide added benefits of antimicrobial behaviour, controlled gas permeability, as well as increased strength and toughness, all properties currently being sought by the food packaging industry in order to improve and lengthen the shelf life of the product.

Transparent food packaging film is a multi-billion dollar global market.

It is within food itself that there are some rather exciting prospects for nanotechnology. The technology can be used to improve emulsification. Products like mayonnaise will be able to have a lower fat content, the same mouthfeel and be shelf-stable. Ice-creams will be able to have a fuller, richer mouthfeel by using nanotechnology to control the fat particle size.

However, even greater potential lies in the synergy between the food, pharmaceutical and health industries. The small scale of nanoparticles means they can be used to deliver water- or oil-soluble ingredients through the food and then across cell membranes into the consumers' cells. Nutraceuticals and functional foods that have traditionally been quite difficult to incorporate into foodstuffs because of solubility concerns will have a vehicle right into the cell. Bioactive ingredients, flavours, colours and antioxidants will be encapsulated into nanoparticles and incorporated into foods which will be promoted as having a health benefit.

There is more work that needs to be done before it can be assumed that these technologies will all benefit the consumer. Currently there is no framework to assess the toxicity of nanomaterials. The consequences of nanomaterials entering the human body are an under-researched area and there is concern that encapsulating nutrients in nanoscale spheres could enhance the biological activity of dietary supplements. It is conceivable that toxicity may have to be redefined to include information about surface area:volume ratios rather than just being weight based. There is even a competition in progress right now to design a 'nanohazard' warning sign.

However, the fact that these concerns are in open discussion is a good sign. It is in everyone's interest to ensure that the technology enhances the safety and quality of the food we eat.