New material may improve packaged food shelf life
March 28, 2011
by Keith Nunes
ANAHEIM, CALIF. – Researchers from Texas A&M University have identified a new material they call “nano-bricks” that may improve the shelf life of packaged foods. The research findings were presented at the National Meeting and Exposition of the American Chemical Society that is taking place this week in Anaheim.
The researchers said the new material, which would be applied in the form of a coating, has the capability of slowing the loss of carbon dioxide from carbonated beverage packaging and extend the shelf life of military M.R.E.s (Meal, Ready to Eat).
The new film combines particles of montmorillonite clay, a soil ingredient used to make bricks, with a variety of polymer materials. The resulting film is about 70% clay and contains a small amount of polymer, making it more eco-friendly than current plastics, according to the researchers. The film is less than 100 nanometers thick — or thousands of times thinner than the width of a single human hair — and transparent to the naked eye.
“This is a new, ‘outside of the box’ technology that gives plastic the superior food preservation properties of glass,” said Jaime Grunlan, an associate professor in the department of mechanical engineering at Texas A&M, College Station, who reported on the research. “It will give consumers tastier, longer lasting foods and help boost the food packaging industry.”
When layered onto existing plastic packaging, the new material adds strength and provides an improved barrier to oxygen, he said. Dr. Grunlan demonstrated in lab studies that the film is 100 times less permeable to oxygen than existing silicon oxide coatings. This means that it’s also likely to be a better oxygen barrier than a metal coating, whose permeability is similar to that of silicon oxide.
Dr. Grunlan said when the material is viewed under an electron microscope it looks like bricks and mortar, which is why they are calling it “nano-bricks.”
“Others have added clay to polymer to reduce (gas) permeability, but they are thousands of times more permeable than our film,” Dr. Grunlan said. “We have the most organized structure — a nano-brick wall — which is the source of this exceptional barrier. This is truly the most oxygen impermeable film in existence.”
Dr. Grunlan is trying to improve the quality of the film to make it more appealing to packaging manufacturers, which includes making it more resistant to moisture. He envisions that manufacturers will dip plastics in the coating or spray the coating onto plastics. In the future, he hopes to develop nano-brick films that block sunlight and contain antimicrobial substances to enhance packaging performance.