December 16, 2004

Scientist Uses Whey to Protect Food

DAVIS, Calif. (AP) -- Oxygen, water, seeping oils - they're all out to get your food, turning sweet nuts sour and tasty confections rancid. Food scientist John Krochta is fighting back with an unlikely weapon, edible food coatings derived from whey, the dairy byproduct favored by protein-conscious athletes and Miss Muffet.

The protection, which can either come as a smooth, glossy coat or a d thin, plasticlike 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," says Krochta. "Our basic philosophy is you name the food and I'll tell you how it can benefit from an edible film or coating."

A number of foods already come to market wearing a protective coat. Fruits and vegetables often are sprayed with wax to keep them from losing moisture. Some candies are coated by "confectioner's glaze" - actually a product made from the purified secretions of a beetle.

Krochta is just one of a number of scientists looking for new and improved ways to stop spoilage.

In the east San Francisco Bay area suburb of Albany, Tara McHugh, a scientist with the USDA's Agriculture Research Service, is turning pureed fruits and vegetables into edible packaging in the form of vibrantly colored wraps.

Wrapping has the potential to prolong shelf life; apple slices wrapped in the films took longer to turn that unappetizing shade of brown. Unlike Krochta's whey protein product, which is bland, making it good for things like covering candy, McHugh's films can juice up flavor, say a steak wrapped in carrot film that could melt to a nice glaze, or hams enveloped in apple wraps.

(McHugh is also a fan of whey protein coverings, as it happens she is a former graduate student of Krochta's.)

The pureed fruit wraps are not as strong as plastic film, although they are about as tough as paper. Neither the wraps nor the 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, 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," Krochta says.

A visit to Krochta's lab in the Food Science department, part of the new Robert Mondavi Institute for Wine and Food Science at UC Davis, comes with a built-in bonus: candy tasting.

A lab worker sets the metal coating pan going and a handful of chocolate-covered nuts go swirling around in a cacophonous clatter as they pick up a coat of whey protein to provide gloss and resistance to stickiness.

Krochta and his colleagues, whose work has been supported by the California Dairy Research Foundation and Dairy Management Inc., got the idea of making a film or a coating from whey protein about 10 years ago. They established that it was a good oxygen, aroma and oil barrier and worked on creating a substance that was tough enough not to crack but flexible enough to deal with temperature variations and impacts associated with food manufacturing, shipping or use.

Then they started thinking about how the coating could be used.

Among other things, Krochta says, the edible coating could be used to cover nuts to keep them fresh in packages or to keep them from going rancid in candy bars. Other uses 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.

A novel use involves creating sealed pouches holding measured amounts of product, for instance dried buttermilk powder that bakeries could toss right in to the mixer.

The possibilities, says Krochta, are virtually endless.

"Once you explain this to people I think they generally see that it's a very natural approach, to protecting food," he says.

"It is," says Krochta, "a better way."


On the Net: http://www.ediblefilms.org