Food contact at a small scale - nanotechnology know-how
As interest in packaging materials that extend food shelf-life grows, Barry Park of the UK Nanotechnology Knowledge Transfer Network explores the potential for using nanotechnology to help reduce food waste.
Nanomaterials have a range of potential applications in the food sector that may offer benefits to both consumers and industry. These include creating foods with unaltered taste, but lower fat, salt or sugar levels, or developing packaging that enhances shelf-life, or alerts consumers when the food inside is spoilt.
Nanoparticles are generally defined as having at least one dimension in the range one to 100 nanometre (nm), where one nanometre is one billionth of a metre. Having particles of this size in a clear film, for example, adds functionality without causing any loss of clarity.
While the use of nanotechnologies in food is not widespread, there are commercial examples of application in food packaging. A report from Innovative Research and Products Inc, of Stamford, USA, notes that the worldwide nano-enabled food and beverage packaging market in 2008 was worth US$4.13bln. It was expected to grow in 2009 to US$4.21bln and is forecast to grow further to US$7.3bln in 2014.
The report, published in July 2009 on Nano-enabled Packaging for the Food and Beverage Industry, described the market in terms of ‘active packaging’, ‘intelligent packaging’ and ‘controlled release packaging’, and predicts that the greatest growth is likely to be in the intelligent segment.
It documented Europe as the smallest regional market for nano-enabled packaging for food and beverages, following far behind both the USA and Asia in market value.
The major aim of nano-enabled packaging is the reduction of spoilage, and so bakery and meat product categories have attracted the most attention. In beverages, protecting carbonated drinks and bottled water dominate.
Active technologies represent the key component of the market, with oxygen scavengers, moisture absorbers and barrier packaging the main product families. This includes polymers containing silver or zinc oxide nanoparticles for their antimicrobial properties, or packs that release antioxidants, flavours, fragrances or nutraceuticals into food or beverages to extend shelf-life or improve taste and smell.
Nanocomposites combine polymers with nanomaterials to improve flexibility, durability, temperature/moisture, stability and barrier properties.
Intelligent or smart packaging incorporate nanosensors to monitor the condition of the food contents. Nanotechnology is enabling sensor packaging to incorporate cheap radio frequency identification (RFID) tags, which are much smaller, flexible and can be printed on thin labels. This increases the tag’s versatility and thus enables much cheaper production.
Researchers at the University of Strathclyde, UK, have also been developing an oxygen-intelligent ink that is bleached colourless. On exposure to UV light, it will remain colourless until exposed to oxygen, indicating if a sealed package has been tampered with.
A further development is an ink that has a delayed reaction to oxygen. This can show how long a package has been open, and therefore how long a product is safe to eat.
Both of these inks contain nanoparticulate titanium dioxide as an active ingredient. Nanoparticulate titanium dioxide has also been included in food packaging to absorb UV light to minimise UV-induced damage to the food.
Potential health risks
Although the possible health implications of nano-enabled food products are considered minimal, concerns include potential migration of nanoparticles into food and drink. It is important, therefore, that the nanoparticles selected are non-toxic and compatible with the current legislation and do not add to concerns about waste disposal.
Governing bodies need to ensure the development of such products is well managed, and ethical challenges need to be looked at with regulations put in place.
Research conducted by the ETH Zurich Institute for Environmental Decisions in Consumer Behavior in Switzerland in 2008, found that, although people were critical of the use of nanotechnology in food, there was a relatively high acceptance of nanotechnology in food packaging.
Key to the ongoing inclusion of nanotechnology in food packaging is continued public support – the benefits need to be explained, especially given consumer concern about the amount of food that is wasted every year.
How nanomaterials are to be treated under the EU’s Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) legislation is still under discussion. This may have an impact on nanomaterials that are used in relatively small quantities.
Labelling of food and food packaging containing nanomaterials is a possibility, following the new EU Cosmetics Directive of 2010. It states that all ingredients present in cosmetic products in the form of nanomaterials should be clearly indicated in the list of ingredients by inserting the word ‘nano’ in brackets after the ingredient listing.
This requirement could apply in the future to food and food packaging. Although, just as for cosmetics, agreeing what is ‘nano’ in food related applications will present problems both to the producers and the authorities.
In partnership with Leatherhead Food International, the UK’s Nanotechnology Knowledge Transfer Network has created a Nanotechnology Food focus group to develop research funding and to communicate the needs and interests of the food industry to Government and legislation bodies. Website: www.nanoktn.com Email: email@example.com