Shelves are lined with more and more drinks packed in clear bottles and filled with natural and functional ingredients but these are precisely the trends that make light exposure a major concern for brands. In the third installment of our four-part special edition on shelf life, we consider what damage light can inflict on products and how best to mitigate it.
What is affected?
Exposure to light can damage the colors, vitamins, lipids, and flavours in beverages, cutting short shelf life and eating into product value.
Although some synthetic dyes like FD&C blue #1 and artificial flavours like aspartame are vulnerable to light, Carol Zweep, manager of packaging and nutrition labelling services at Guelph Food Technology Centre, said natural ingredients are particularly vulnerable.
Carotenoids, anthocyanins and chlorophyll are all groups of natural colours that can degrade and create undesirable shades when exposed to light. Some citrus flavours can also degrade, creating off-flavours.
As formulators look to make more natural products, this can prove to be a headache.
Another trend that is forcing companies to consider light damage is fortification as many vitamins can degrade with light exposure, reducing nutritional value and causing unpleasant sensory changes.
Light can also accelerate the oxidation and degradation of lipids and fatty acids. This makes milk, especially long-life milk, one of the most light sensitive beverages. Light exposure causes chemical reactions that can modify the proteins and fats in milk, and yoghurts, damaging flavour and vitamin content.
What to consider
So when deciding how best to protect products from light damage, what factors should manufacturers consider.
Zweep said it is important to think about the nature of the light that products are exposed to. She said a lot of brands focus on UV light when products spend much of their life before reaching the customer under flurescent lighting. It can therefore be important to consider how exposure to visible light will affect product quality.
But before even thinking about the nature of the light hitting product packaging, it is important to consider the nature of the product itself.
Morag Girdwood, global brand development manager, at ColorMatrix said beverage brands promoting the high vitamin content of their products should pay close attention to the impact of light. This is not only because light can affect the vitamin content but because of the consequences for taste if light is allowed to degrade the vitamins.
Another important consideration is the shelf life that companies are looking to achieve. If they want to sell a product with an extra long shelf, such as a long-life milk, then more protection will be needed.
For a milk product, Girdwood warned that there is some compromise between length of shelf life and the ‘whiteness’ of the bottle that is achievable.
Another potential aesthetic compromise relates to bottle transparency. Beverage brands want to show off the content of their products but Zweep from Guelph Food Technology Centre said this makes it difficult to protect products from light.
Girdwood claimed that ColorMatrix has developed a solution to this problem with the creation of a light protection technology that is added to the colour rather than the resin of the bottle.
There are in fact a range of options open to brands looking for light protection, with the decision as to which one to go for dependent on their mix of priorities. Options include the addition of a white colorant or a UV additive, and the use of a multilayer bottle or a full body shrink sleeve.
To help companies decide which option to go for, testing services are available. Niama Boutroy, a spokesperson from Sidel, which runs a packaging testing service in France for sensitive beverages, said they map out different options and see how they perform against the desired shelf life in the expected environmental conditions, on a worst case scenario basis.
As for the next steps in light protection, Girdwood from ColorMatrix said the company is working on combining different technologies and meeting sustainability requirements. This could mean combining oxygen and light protection while allowing manufacturers to continue reducing the weight of their bottles.