Technical Talk – October 2007

Nano’s Here…and Growing by Leaps and Bounds

Question: What is nanotechnology, and what effect will it have in the baking industry?

Answer: Nanotechnology is the practice of investigating, modifying or developing materials that are at the size of molecular or atomic level. The word is derived from the Greek “nano,” meaning dwarf, and referring to the very small scale of particles that this technology deals with. In general, it deals with particles in the range of 10 – 100 nm (nanometres) in size – or less, and in some cases, down to 1 nm.  In order to put this in perspective, consider that a nano-metre is one billionth of a metre. The interest in dealing with particles that small is because at that level the properties and behaviour of materials change significantly. Particles of that size can appear completely transparent, or remain in suspension, in a food system indefinitely. This is particularly very important for the development of certain beverages and fortified waters. These properties are also very important in the development of food packaging and plastic food containers, as well as in the formulation of many foods.

It is almost certain that nanotechnology will have a significant impact on food structure, processing and production.  Major food companies, such as Kraft, Unilever and Nestlé, are involved in nanotechnology research project applications in foods.  Experts estimate that the value of the application of nanotechnology in foods will exceed $20 billion by 2010. The leading countries involved in nanotechnology research and development are currently the United States, Japan, and China.

Already traditional food processing practices deal with nanoscale food components.  Many of the proteins, fats, and carbohydrates often range in size from tens to hundreds of nanometres. For example, when starch thickens as a result of heating, the crystals that form are particles in the nano range (three-dimensional nanostructures). The problem with these practices is we do not fully understand why they work. The science of nanotechnology, by enabling us to investigate and manipulate materials at the nano scale, will help us gain better understanding of the processes, and thereby provide tools for better selection of raw materials, and help to apply improved processes to food manufacture. For example, an understanding of structures at the nanoscale will help us improve the way we control the quality of foams and emulsions. Foams and emulsions are a few molecules thick, and behave similarly to nanomaterials. They play a significant role in the form-ulation of many foods and beverages, ranging from beer to baked goods.

Understanding protein functionality at the molecular level (and particularly protein interactions and their role in stabilizing food foams and emulsions) can help us develop better methods of stabilization of protein networks, that can improve food products for the baking and dairy industries, as well as beverage industry. 

Another aspect of the application of nanoparticles to food systems is that of improved bioavailability and absorption of certain functional ingredients by the human body. The nanoparticles are considered as alternatives to encapsulated and controlled-release functional ingredients in order to enhance their bioavailability. This is very important for the development of functional foods and nutraceuticals. For example, nanoparticles of carotenoids can be dispersed in water, and thus, can be added to drinks, providing an increased bioavailability. Similarly, a synthetic lycopene of nanoparticle size has undergone toxicity testing, and gained “GRAS affirmed” (Generally Recognized As Safe) status with the U.S. FDA (Food and Drug Administration).  Nanoencapsulation of vitamins, minerals, and phytochemicals have been developed, where nanodrops of oil envelops these healthy components for better delivery in the human body.

Another area of the application of nanotechnology affecting food products, including baked goods, is packaging.  Nanoscale titanium dioxide (TiO2) is available, and can be incorporated into plastic packaging material. It can be transparent, and provide resistance to UV light. However, there is some controversy with regard to the safety of nanoscale TiO2 crystals. Due to its transparency and resistance to UV light, it has been used in sunscreens and lotions, and has been considered to be safe. Traditional use of titanium dioxide (not at the nanoparticle size) in foods has been in confectionery products, such as sugar coatings, and as a clouding agent in beverages. Currently, the safety of nanoscale TiO2 as a direct additive to foods, or as incorporated into food packaging materials, is still being debated.

Incorporation of nanoparticles of antimicrobial compounds into packaging materials in the food system is currently used and being researched. There is the potential ability for this new technology to detect dangerous pathogenic micro-organisms in foods.

Nanoparticle technology is being used in the development of catalyst systems to keep frying oil fresher for a longer period of time. The catalyst is made up of ceramic nanoparticles that hugely increase the surface area, and, it is claimed, significantly increase the shelf life of the frying oil. This may offer the cost advantage needed in the transition to healthier frying oils from the partially hydrogenated ones containing high amounts of trans fats.  Other applications of nanotechnology in foods include the coating of foods with nanoparticles of certain compounds to prevent oxidation or provide antimicrobial activity. Such nanofilms can be applied directly onto foods, such as candy (to prevent stickiness) or cookies (to extend their shelf life). These coatings provide the necessary function without interfering with the texture and mouth feel of the food product.

As the evolution of nanoparticles progresses, we will see increasing applications in the food industry, including the baked goods and cereals manufacturing. Due to the modification of these compounds from normal size to nanoparticles, concerns are being raised about their safety, not only from the ingestion point, but also in terms of migration from packaging materials into foods. It is therefore important that a proper evaluation and risk assessment be carried out prior to introduction in the market.

For more information, or fee for service help with product or process development needs, please contact the GFTC at 519-821-1246, by fax at 519-836-1281 or by e-mail at gftc@gftc.ca.

This column is written by Dr. John Michaelides of the Guelph Food Technology Centre, 519-821-1246, www.gftc.ca