Apple slices can now be preserved

29/04/05 Apple slices typically turn brown and unappealing in a few hours.

But an invisible, vitamin-and-mineral based coating that Agricultural Research Service (ARS) scientists and their corporate colleagues have developed preserves refrigerated apple slices for up to 28 days.

The dip-applied coating was patented in 1999 after exhaustive tests with sliced apples and pears. It is a key to the crunchy, delicious taste of the snack-size bags of sliced apples that you can now buy at some fast-food restaurants.

The flavorful sliced apples are also showing up in the kitchens of school cafeterias as well as in fruit salads sold at supermarket delicatessens, or in elegant selections at upscale restaurants.

Unlike lemon juice--the traditional, home-kitchen tactic to thwart browning--the apple dip doesn't change the color, taste or texture of the fruit, according to ARS research chemist Dominic W.S. Wong.

Based at the agency's Western Regional Research Center in Albany, Calif., Wong is a co-inventor of the novel dip, along with retired ARS chemists Wayne M. Camirand and Attila E. Pavlath, and colleagues at Mantrose-Haeuser, Co., Inc., Westport, Conn. The company markets the formulation under the trade "NatureSeal."

The sulfite-free coating consists of certain forms of calcium, an essential mineral, and ascorbate (vitamin C). The idea of choosing either or both of these natural compounds to retard browning isn't new. But extending shelf-life by using the specific forms prescribed by the scientists, at any of the ratios they recommended, is unique.

NatureSeal-coated apple slices are an attractive snack that might help Americans get the recommended daily servings of fruit and fight obesity.

ARS is the U.S. Department of Agriculture's chief scientific research agency.