According to a report presented at the 2000 International Chemical Congress of Pacific Basin Societies, edible film wraps made from broccoli, oranges, carrots, strawberries and other fruits and vegetables can be good – and tasty – oxygen barriers.
Tara McHugh, Ph.D., a research food technologist with the U.S. Department of Agriculture, described the technology for the first time, including specific findings, such as how an apple wrap can significantly extend the shelf life of fresh-cut apple slices.
‘If you look at the film alone, it looks a lot like a sheet of paper – opaque and orange, if it’s made from carrots, for example. Strawberry is red and broccoli is green’ said McHugh. ‘But in contrast to other edible films, it’s very flexible without having to add plasticizers like glycerol.’ She believes that’s due to the naturally occurring sugars in the fruits and vegetables.
The idea is to make preformed sheets of the films into envelope-like wraps. Other produce, baked goods, confectioneries and perhaps even meat would be tucked inside.
The USDA is currently looking to sign cooperative agreements with industry to develop the technology further, says McHugh. Meanwhile, a patent has been filed and ideas keep coming in, she claims.
McHugh also claims that the new films are as good as synthetic films at keeping out oxygen because of the tightly packed polymer chains. Puree films work best in low humidity, she noted, because they are soluble in water – including saliva, a necessary feature to eating them easily.
McHugh has tested fresh-cut apple slices by dipping them in liquid apple puree and by wrapping them in a puree sheet. After 12 days, the dipped slices lost nearly as much moisture as those simply left exposed: 48 percent and 50 percent, respectively. In contrast, the wrapped slices lost only 30 percent of their moisture.