McHugh, with the U.S. Department of Agriculture's Agricultural Research Service in Albany, Calif., says the edible wraps are more environment-friendly than plastic wrap and aluminum foil. In addition to covering sandwiches, she says the new wraps can protect meat in home freezers. And they also add to a healthful diet because each wrap is equal to a serving of a fruit or a vegetable.
"Another advantage of these wraps," she explains, "is that they can provide a glaze or a sauce for cooking. You can use a tomato or ketchup-flavored wrap to hamburgers when you freeze them and then when you defrost the meat you can cook the whole thing, wrap and all."
The wraps come in a wide variety of flavors, including broccoli, carrot, tomato, mango, peach, pear, apple, papaya and strawberry. The fact that they are biodegradable, unlike plastic and aluminum products, is compatible with the goals of green chemistry, which works to improve the environment or prevent harm to the land and water, according to McHugh.
McHugh's work is featured in the April 2003 issue of the quarterly magazine, ChemMatters, published by the American Chemical Society, the world's largest scientific society. The magazine is designed for high school chemistry students and features articles about chemistry in everyday life.
A food wrap is an edible film cut in pre-formed sheets or into envelope-like shapes. It looks like a piece of paper, except that it's made from a highly concentrated puree of a fruit or a vegetable, not from a tree. While a wrap made entirely from fruit or vegetables keeps air from reaching the food, it isn't very water-resistant. This is good because it will dissolve in your mouth. But you don't want it dissolving into your food in the freezer.
To make them more water-resistant, McHugh says she adds lipids, namely vegetable oils, to the wraps. Lipids are naturally water repellent, she explains.
Because the wraps can be made from off-grade produce, she says they could create a new market for farmers. Despite their many advantages, however, McHugh emphasizes that the edible wraps are not a replacement for all other food wraps.
In addition to the wraps, McHugh and her colleagues have created a snack bar that is 100 percent fruit. Fruit bars normally contain other ingredients besides the fruit, she says. "The 100 percent fruit bar has no sodium, fat or preservatives and has 140 calories. It's just available on the West Coast at this point," according to McHugh.
McHugh says the edible wraps are expected to be available in stores by the end of the year.
To access the ChemMatters article (April 2003 issue), "Edible Wraps, Safe, Strong, and Delicious," go to: http://www.chemistry.org/portal/a/c/s/1/acsdisplay.html?DOC=education\\curriculum\\chemmatt.html