The same chemicals that allow processors to market sliced apples that remain firm and don’t brown for three weeks or longer are now being sold through supermarkets to consumers who would rather preserve fruit themselves.

Westport, Conn.-based Mantrose-Haeuser Co. patented a preservative of calcium and ascorbate ions three years ago to maintain the texture, flavor, crispness and color of fresh-cut produce. A number of processors are applying the preservative in a slurry or a spray to sliced apples to extend shelf life up to six weeks (Food Engineering, September 2001). In the spring, Mantrose-Haeuser introduced NatureSeal, a low-concentration, DIY version of the coating compound that promises to arrest browning for five days. Twin packs are packaged in metalized film and carry the banner “Developed with the USDA.”

Consumers dissolve a packet of NatureSeal with four tablespoons of cold water in a plastic bag or food container, add up to five sliced apples and shake until the slices are coated. The cost of treating a pound of apples is about a dime, according to Liz Markes, national sales director. A twin pack retails for $0.99 to $1.19.

Higher concentrations of NatureSeal are being offered to school cafeterias and other foodservice outlets, Markes says. In supermarkets, the manufacturer is relying on merchanidising displays and the package itself to explain the new product to consumers. Displays are positioned in the produce department and proclaim, “Stops sliced apples from browning.” The product represents a new consumer application, but educating them hasn’t proven too difficult, Markes says, citing the case of one grocer who doubled apple sales after introducing NatureSeal.

Edible-film coatings are Mantrose-Haeuser’s core competency, and it produces coatings for jelly beans and other confections, as well as resins for fresh produce. It is a unit of RPM Inc., a specialty coatings conglomerate that includes Rustoleum. The NatureSeal line is being expanded to include products for fresh-cut potatoes, bananas, celery and carrots.