In the future, Maraschino cherries could be as red as a radish -- literally.
The brilliantly colored cherries skewered in drinks and topping ice cream sundaes actually lose their natural tint as they soak in a microbe-killing bath during processing. To restore their carmine hue, manufacturers resort to synthetic dyes, especially one known both as FD&C Red No. 40 and as Allura Red. Consumers tend to prefer natural colorants, but food scientists have had trouble duplicating the pure, deep red that No. 40 offers.
Researchers at Oregon State University have begun testing scarlet pigments isolated from the skins of radishes, especially a cultivar known as Fuego. These anthocyanin pigments not only impart an intense red color, they resist fading. Maraschinos stained with cherry pigments begin losing their color within a month of bottling.
Oregon State's Ronald E. Wrolstad, a food chemist, decided to investigate the radish's potential after reading about the acylated structure of the red pigment in their skins, which he suspected would make them resistant to color-altering chemical reactions.
The trick has been getting enough pigment. It took 65 pounds of radishes to garner the first 0.3 ounce of purified pigment. Oregon State horticulturists are now trying to increase radish yields per acre or pigment yields per radish. Because the roots redden with maturity, harvesting them long after they become ripe can dramatically increase their pigment yield. But overripe radishes are unappetizing, except perhaps to livestock, whereas ripe radish flesh can be marketed for processed foods.
In experiments, the radish pigments yield a brilliant Maraschino. However, Wrolstad notes, the color remains true for only about 6 months (somewhat longer if refrigerated), compared to years for Red No. 40. Still, he says, that should prove long enough for use in at least some products.
Wrolstad says he's also investigating a potential role for radish pigments in confectionery products. But don't tell your kids, or they'll try to convince you that M&Ms colored with this all-natural red should qualify as one of their five servings of vegetables for the day.
Photo: Radishes being washed before their pigmented skins are harvested . Credit: L. Ketchum, OSU.
Maraschinos appear to derive their name from the Balkan marasca cherry that has served for centuries as the main ingredient of a liqueur-soaked preserved fruit.
Some well-heeled Americans were vacationing in Yugoslavia around the turn of the century, so the story goes, when they encountered these brandied cherries and promptly fell in love with them. Though they purchased a case to take home with them, the cherries were gone -- totally consumed -- by the time the ship arrived in the United States.
The vacationers promptly started importing the cherries as a commercial venture. Eventually, U.S. growers decided it would behoove them to develop a domestic Maraschino industry -- sans the liqueur.
Retired Oregon State food scientist Robert Cain, an expert on preserved cherries, has a book on his desk, printed in Michigan circa 1912, that describes how to make Maraschinos. Even then, they were soaked in a bisulfite-based solution, he notes. Unfortunately, this briny bath robs cherries of their color and most of their taste, so processors must season the treated fruit with almond oil and dye them with commercial colorants.
Those early Maraschinos were an unreliable lot, notes Carl Payne of the Oregon Cherry Growers in Salem, a major producer of preserved cherries. The recipes didn't always yield a tasty product -- which is where Ernest Wiegand, founder of Oregon State's food science department, enters the picture. Some 70 years ago, Wiegand was looking for a way to salvage surplus cherries, a major cash crop in the Willamette Valley.
The big market for these cherries was back East. In an era that predated refrigerated freight cars, however, any cherries shipped there tended to arrive a fermented mess. So he tinkered with the Maraschino recipe, adding a critical new ingredient: calcium. It kept the brined cherries from going mushy as they soaked. It also yielded a more commercially reliable process, one that serves as the basis for domestic Maraschinos today.
Roughly 35 percent of U.S. sweet cherries -- close to 50,000 tons of fruit -- are preserved in brine, notes Cain. Roughly half of these become Maraschinos, including some 8,000 tons of Oregon cherries. Though many Maraschinos start out as Royal Annes, even the nearly black Bing cherry can be used.
Photo: Maraschino cherries tinted with radish-derived dye, shown in background flasks. Credit: L. Ketchum, OSU.
To provide a year-round supply, cherry processors hold their fruit in vats of brine until needed. At that point, they wash out the preservative by soaking the cherries in running water for up to 6 hours. They boil the fruit in water for 15 minutes on as many as three separate occasions to remove any remaining sulfur dioxide residues. Then the cherries are drained and gradually sweetened with syrup. Finally, the tint is added and the fruit bottled.
A week later, the cherries could be speared and swizzling a child's Shirley Temple or garnishing her uncle's banana split.
Giusti, M.M., and R.E. Wrolstad. 1996. Characterization of red radish anthocyanins. Journal of Food Science 61(July-August):322.
___. 1996. Radish anthocyanin extract as a natural red colorant for Maraschino cherries. Journal of Food Science 61(March-April):688.
Schmitz, J. 1995. Rooting for red. Oregon's Agricultural Progress 41(Fall):8.
Ronald E. Wrolstad
Department of Food Science and Technology
Oregon State University
Corvallis, OR 97331-6602
Oregon Cherry Growers
P.O. Box 7357
Salem, OR 97303
Oregon's Agricultural Progress
Oregon State University
Administrative Services A422
Corvallis, OR 97331-2119
This week's Food for Thought is prepared by Janet Raloff, senior editor of Science News.