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Nanotechnology: ensuring ideas result in safe food products

1st April 2013


With nanotechnology, the scientific world is delving even deeper into us as well as into the environment around us. This calls for new expertise and instrumentation capable of working on samples many times smaller than before.

Prior to the arrival of nanotechnology, mankind had to content itself with how nature arranged its materials. Now, the possibility exists to manipulate atoms, the basic building blocks of the physical world, to create entirely new materials and structures.

But the effect of nanoparticles on humans is of great concern because they can work their way deeper into parts of the body than scientists have experienced before. This calls for a great deal of complex research to turn principles into safe products.

To find out what demands this places on researchers and scientists and what might result, European Food Scientist spoke to academicians and researchers in several countries.

In the USA, Rutgers is believed to be the first university to hire a professor of food nanotechnology, Qingrong Huang, who is assistant professor in the Department of Food Science. He sees two chief areas of research interest: tailored delivery of nutrients and nanoscale sensors.

“We are looking at bioengineering or biotechnology rather than pure food science,“ he says. “This area is a totally new concept and there are a lot of challenges. It is unique in that it requires more interdisciplinary contact than any other branch of science. The result will be that food will move from being a commodity onto a value-added basis with specific attributes of quality and functionality designed to meet consumer demand.“

Professor Huang expects to take an interdisciplinary approach to his research, working with microbiologists, chemists, chemical engineers, bioengineers and biochemists.

“In my opinion, this is one technology that will have profound implications for the food industry, even though they're not very clear to a lot of people at the moment,“ he says. “The problem for the industry before it advances much further is to define the challenges, identify the benefits and decide how to deliver them. There are so many areas to investigate and the human body is so complex but there is only so much research money in the world. Scientists have to decide what and how to deliver what people want.“

He is keen, for example, to see biosensors that identify pathogens at an early stage so any undesirable side effects from nanotechnology developments can be quickly dealt with. He is also interested in packaging that responds to changes in its contents and can sense when they are spoiling and alert the consumer. He also sees great promise in food-borne nutraceuticals that could use proteins to deliver drugs to targeted areas of the body.

Nanopatterning

In the Department of Chemical Engineering at the University of Birmingham, Professor Peter Fryer is investigating modified surfaces that are non-stick and easy to clean. These could be created by engineering nano-patterns on the surface. His team is using micromanipulation to measure the adhesive and cohesive strength of deposits on a stainless steel surface.

Professor Fryer says: “Nanoscientists have to be prepared to research outside the area of their first degree. It is essential to use the knowledge of other disciplines to fully understand all the aspects of nanotechnology. At the moment, no-one really knows what the core discipline of this subject is. One point to understand is that the terms of standard physics do not cover the performance of very small particles.

“Researchers may also need to co-operate on the use of equipment. Further developments in nanotechnology depend on the level of equipment available and atomic level instrumentation is hugely expensive and not used every day of the year. In addition to the huge capital cost, maintenance, updating and running costs are also expensive. And, at the moment, there are more ideas to research than there is equipment to support them. It would make sense to have some sort of sharing system.“

Professor Fryer says nanoencapsulation is a popular area of research just now. Encapsulating flavours for release at different times during eating, for example, can provide a novel experience. But all these techniques are relatively expensive and so the pharmaceutical industry will probably lead in implementing developments with the food industry following as costs drop.

Open minded

In the Netherlands, Dr Holger Schönherr, on the staff of the Department of Materials Science and Technology of Polymers University at the University of Twente in the Netherlands, says, “Nanoscientists need a new, open-minded outlook to obtain the best results from their research. Key to this is a realisation that the borders between disciplines are starting to vanish. The nanoscientist needs an understanding of chemistry, biology and physics as well as the area of material science, which is often attached to other disciplines and rarely stands alone.

“Individual disciplines are losing their definition in the face of their greater interaction. But, as a result of working at nano-dimensions, I have been surprised at how much chemistry in particular there is in life. Personally I have found great motivation to research nanotechnology. There is still a great deal to learn and we will be hearing about nanotechnology for a long time to come.“

Dr Schönherr's research interests are in the area of soft organic and polymeric surfaces and interfaces, and, in particular, in the surface and interface physics and chemistry of these soft materials. He points out that the study of nanotechnology needs a wealth of sophisticated instrumentation including atomic, chemical and scanning force microscopes and force spectroscopes. Techniques include scanning probe lithography, polymer crystallisation, confinement, ultra thin films and self-assembled monolayers.

He says: “Nanotechnology currently has to be defined according to the area of research, with work to be done both on individual particles and on ensembles. The difference is similar to analysing an individual person as opposed to investigating the population of a nation. Both are complex areas.“

One area of research that Dr Schönherr is involved in is the developments of additives to prevent flocculation in liquids. If particles with a strong Brownian movement are introduced into a liquid and powder mix, for example, they can prevent settlement of the solid element and maintain an even dispersal of particles throughout the liquid medium without the need for mechanical mixing. An advantage that would benefit both the commercial food processor and the home mixing of powders and liquids.

Nanoconsortium

On the commercial side, Kraft Foods started the first, and possibly the only, nanotechnology laboratory among the big food companies in 1999. Its NanoteK research consortium was established in January2000 with 15 universities in several countries and national research labs carrying out research that may yield cutting-edge food technology.

Dr Manuel Marquez-Sanchez, research director, admits this is to maintain the company's leadership in food science. But he says: “We also want to know how to use this technology both for food safety and quality. The company's key focus is customisation and personalisation of food products. Potentially we could develop products that recognise people's profiles such as allergies or nutritional deficiencies.

“The consortium is free of food scientists because Kraft has plenty of those. Instead, the company funds the work of physicists, engineers and molecular chemists. Several of the groups are studying nanoparticles that encapsulate certain flavours, colours or nutrients and can be selectively zapped to release their payload.

“Nanotechnology will play an important and prominent role in food safety and this includes the development of nanosensors that can be placed in food production, distribution and packaging to detect the presence of organisms from E.coli and listeria to Campylobacter and salmonella. One version would fluoresce in different colours in the presence of even minute traces of harmful pathogens.“

Marquez and his team have found a way to create nanoparticles by forcing two flows of liquid through tiny jets so that one stream fully encloses the other. As the jet stream breaks up, droplets form and are hardened into capsules just 50nanometres wide.

Kraft Foods itself hopes to achieve fresher tastes, stronger aromas and a higher absorption rate for food nutrients through use of these supersmall capsules.

Other scientists in the consortium include materials scientist David Weitz of Harvard, who is studying colloidosomes: micron-sized hollow spheres with selectively permeable membranes that allow controlled release of the shell's contents.

Gustavo Larsen, assistant professor of chemical engineering at the University of Nebraska, is working on smart filters based on cellulose coated with an inorganic compound that can be imprinted with the shapes of certain molecules.

Greg Sotzing, associate professor of chemistry at the University of Connecticut, is developing an electronic tongue that detects minute amounts of a huge range of chemicals, using tiny electrodes coated with a conductive polymer.

The consensus of opinion is that nanotechnology in the food sector is here to stay but we are only just starting to see the first of the opportunities. It seems the next step for those involved is to create definitions: what is the core discipline; what should be researched first; and what are the safety considerations.





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