Whey-based film promises cost and environmental savings
byproducts to preserve fresh foods, a discovery that could save
money and lead to less packaging waste. Anthony Fletcher
reports.
University of California food scientist John Krochta has developed an edible foodcoating derived from the dairy byproduct whey. He believes that the protection, which can either come as a smooth, glossy coat or a thin, plastic-like film, can be used to make all kinds of foods spoilage resistant, reducing the amount of packaging needed and finding a use for a byproduct that now ends up mostly in low value products or is thrown away.
"The result is a very natural approach to protecting food," said Krochta. "Our basic philosophy is you name the food and I'll tell you how it can benefit from an edible film or coating."
He believes that his edible whey coating could be used to cover nuts to keep them fresh in packages or to keep them from going rancid in chocolate bars. Other uses might include coating fragile foods such as breakfast cereals and sealing foods like salmon or sliced turkey, possibly with the addition of a natural anti-bacterial agent.
Krochta is just one of a number of scientists looking for new and improved ways to stop spoilage - indeed research into biodegradable packaging has taken off as scientists look for a cost-effective alternative to polystyrene-based products.
Scientists at Oregon State University's department of Food Science and Technology for example have already designed an edible film made from natural ingredients that protects foods coated in the material from spoiling. The film can also hold vitamins and other nutrients within it to boost the nutritional value of the food.
The scientists combined chitosan, a fibre found in crab and shrimp shells, which is also a raw material for nutraceutical products, and the protein from egg whites, lysozyme, to create an anti-microbial food wrap. The product looks like a sandwich wrap yet is thin enough to have no effect on the texture of the food it covers.
In addition Tara McHugh, a scientist with the USDA's Agriculture Research Service (ARS), is turning pureed fruits and vegetables into edible packaging in the form of vibrantly-coloured wraps.
The pureed fruit wraps are not as strong as plastic film, although they are about as tough as paper. Neither the wraps nor Krochta's whey coating are intended to replace packaging altogether; food would still have to be protected by another barrier, such as a bag or box, to keep things hygienic.
However, there is an undeniable opportunity to improve the environmental profile of the food industry. The food processing sector is a major contributor to industrial waste - in the UK for example, the Environment Agency has estimated that the food and drink sector produces between seven and eight million tonnes of waste per year, second only to the construction industry.
Edible films could cut down on the amount of packaging required, such as the bag-in-box or plastic-plus-foil approaches used now.
"Our concept is rather than putting the oxygen barrier in the package, put it on the product so that you can get away with a simpler package that uses less material and is cheaper," said Krochta.
Indeed, a major attraction of edible film is the fact that it could prove to be economically competitive. Manufacturers of edible film have a selection of different starches - such as wheat, potato or corn - to choose from, giving them a fair degree of purchasing flexibility. That flexibility could help them keep their prices competitive with polystyrene items.
Indeed, 2004 was largely an unsatisfactory year for manufacturers of plastics packaging and packaging films. Raw material cost increases for plastics, which have been rising for an unusually long period of time, have made polystyrene - and other plastics - an expensive commodity. Limited raw material supply, container shortages and rising oil prices have exacerbated the problem.
