Having food or beverages stay fresher and last longer on the shelf is one ideal that everyone in the food and beverage industries should invest in. The CSIRinvented a way for this ideal to become a reality, with proven success.
During the normal course of the research process at the CSIR’s encapsulation and delivery research group, new polymer systems with special properties are created. It was the special nature of these newly created polymer systems that led researcher Dr Philip Labuschagne and his team to discover new uses for it. What they found was a very handy new technology specifically geared towards the food and beverages industries.
Their invention, which is now patented, is an oxygen barrier technology. It has the potential to considerably lengthen the shelflife of food and beverages stored in plastic containers.
Labuschagne explains how the invention happened: “We regularly use a process called inter-polymer complexation in our drug delivery research. The result is a polymeric product with unique properties – one of which is that the polymer has a high density (or a close-knit polymer network formed by hydrogen bonds). This property led us to investigate its effect on the permeability of gasses.”
Not letting oxygen through
His group did several trials on various inter-polymer complexation systems until a system was found that reduces oxygen permeability by a factor of about 20 (for polyester-based plastics) and by a factor of around 150 (for polyolefin-based plastics).
“The consequence is that you can increase the shelf-life of any oxygen-sensitive beverage in plastic containers by up to 150 times,” he says.
“Another advantage of this technology is that it is a polymer solution that can easily be applied to a plastic surface, such as a beverage container, using a simple dip-coating process. The polymers used are also suitable for pharmaceutical use, thus they are completely non-toxic,” he says. Beverages that are typically sensitive to oxygen are beer or ciders, juices and any tomato based products. Traditionally these products are stored in glass containers to ensure sufficient shelf-life. However, with this barrier technology, new opportunities for plastic packaging are possible. Plastic packaging is desirable because it reduces the enormous cost (and carbon emissions) resulting from the transport of heavy materials, such as glass.
An external coating
Labuschagne continues: “The coating is applied on the outside ofthe container using a dip-coating process. Because it has some degree of moisture susceptibility,a second protective UV-curable overcoat is applied over the barrier coating. Both these layers have achieved approval for use as external coating on food containers by the American Food and Drug
Cost-wise, the barrier technology compares favourably to other barrier technologies, but is superior to them in certain aspects. For example, metal-oxide coatings are expensive and suffer from brittleness; oxygen scavenger technology has a limited life span; and multi-layer technology is not only prone to delamination, but also difficult to recycle. “The containers can also be produced locally which can lead to considerable cost savings,” says Labuschagne.
With local inventions such as this barrier technology, it is just a matter of time before we will be able to buy fruit juices that can stay in the fridge for at least a month. Or beer sold in plastic recyclable bottles rather than glass.“The food processing sector is the country’s largest manufacturing sector in employment terms with some 160 000 employees. South Africa has a competitive advantage in a number of fruit and beverage sub-sectors which, if fully exploited, could place it among the top 10 export producers in high-value agricultural products. I believe that the oxygen barrier technology has the potential to improve the competitiveness of this sector,” concludes Labuschagne.