UV light may be harmful for PET
not be ignored by makers of beverages and food products packaged in
PET according to research studies by the Belgium-based Milliken
& Company.
"When examining the variety of threats to consumer products packaged in PET, the effect of UV light is one of the least studied, least understood and most complex, throughout the various consumer category segments and regions of the world," said Michael Purcell a market manager with Milliken Chemical, a division of Milliken & Company and provider of high-performance plastic additives.
"As global brand owners pursue continued growth through the development of new products and packages that create and cater to new consumption occasions, we are just beginning to understand the challenge ahead presented by the damaging effect that UV light can have on beverages, food and personal care products," he said.
"From our research, we have discovered that the interaction of UV light and various beverage components is extremely complex and can negatively impact the vital brand elements of colour, flavour and nutritional value, often in unexpected ways."
Purcell's comments were delivered at Barrier PET Packaging and Shrink Sleeves Conference, held earlier this week in Brussels, Belgium. During his presentation, Purcell reported on ongoing research by Milliken Chemical, which has conducted extensive testing on the impact of UV light on beverages packaged in PET containers.
Using accelerated UV exposure testing in refrigerated UV chambers, Milliken scientists simulated retail store environments and explored the impact of UV light on beverages at various levels of light exposures and at various levels of UV protection.
"One of the most important discoveries from this work is an appreciation of the extreme complexity of the impact of UV light on beverages," Purcell said. "Not only does UV light impact colour, flavour and nutritional ingredients individually, there is also a matrix effect in which the impact of light on a given component can cause it to react with other beverage components in a series of events."
For example, citric acid together with trace metals under UV exposure can destabilise colour; while vitamin B12 is quite stable alone, it is degraded when in combination with vitamin C and UV light.
Another important research finding has been that taste and nutritional content are much more fragile under UV light than colour.
"While changes in colour caused by UV light exposure are the most dramatic and most easily documented, colour is often not the most fragile beverage component," Purcell said. "Our studies have shown that taste is actually the most fragile component when exposed to UV light, followed by vitamins and then colour."
Milliken's research has also demonstrated that the level of UV protection in a PET container can be critically important in determining whether the product will be adequately protected for colour, taste and nutritional value during extended shelf life and use in the home.
"As a new area of inquiry, the industry has not yet established a general standard for UV protection in PET containers," he said. "While some PET additives provide UV absorption through the 370 nanometers (nm) range, our studies have shown that only at the 390 nanometer protection level are you achieving complete protection against the impact of harmful UV light. By 390 protection, I mean packaging that allows only 5 per cent of 390 nm wavelength light to pass through the walls of the package."Milliken's research studies have demonstrated that there is a significant difference between 370 and 390 UV protection of colour, taste and vitamins.
"From our studies, we determined that some color, taste and nutritional components are damaged significantly by UV light in the higher ranges, above 370," he said. "For many product components, going from 370 to 390 protection is not 10 per cent better, it is often 100 percent better because of the greater sensitivity of the ingredients to light of wavelengths between 370 and 390."
The company says that these research studies have been instrumental to the development of ClearShield, a homogenous polymer additive that provides UV protection at the 390 level. ClearShield is FDA compliant for beverage and food applications and can be effectively integrated with PET containers at either the resin or the container forming stages.
According to Purcell, the use of UV protection is likely to grow as consumer packaged goods companies throughout Europe begin to understand the impact of UV light on products in PET packaging, including speciality beverages and foods with unique natural flavours or nutritional components. This growth in UV protection will provide profitable growth opportunities for the makers of consumer products, as well as the resin producers and container manufacturers who support them with PET packaging options, he said.
"UV protection for PET containers is essential to assuring extended shelf life and the protection of UV-sensitive formulations, such as beverages with unique tastes, nutritional benefits and colour," Purcell said. "A PET container with UV absorbers at the 390 level can assure a consistent consumer experience and protect the significant investments that branded products companies make in bringing a product to market.
"Additionally, the use of PET containers with UV protection provides increased flexibility in product formulation, allowing for the expanded use of UV-sensitive ingredients, eliminating the need for stabilising beverage additives and reducing the need for over-loading a product with UV-sensitive components," he said.
Milliken & Company is headquartered in Spartanburg, South Carolina and is one of the world's largest privately held chemical and textile companies. Milliken Chemical is a market leader in additives for plastics.
