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Janet Raloff
Food for Thought

Crusty Chemistry

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Want to make a piece of pizza healthier? Try using whole-wheat dough. Give it a full 2 days to rise, and then cook the tomato pie a little longer and hotter than usual. That was the recipe shared last week by researchers at the American Chemical Society meeting in Chicago.

Jeffrey Moore and Liangli Lucy Yu of the University of Maryland at College Park have been experimenting with pizza-making techniques in hopes of unleashing the full antioxidant potential of trace nutrients in wheat bran. Oxidants, generally referred to as free radicals, are biologically reactive molecular fragments that can damage cells of the body. Many diseases stem from the body's inability to keep those fragments in check. However, studies have indicated that foods rich in antioxidants can quash such free radicals and sometimes spare tissues from damage.

Most pizza makers give their yeasty dough a few hours to ferment, the chemical-biological process responsible for its rise. Working with two common wheat flours, "we found that increasing fermentation time to 48 hours doubled the amount of antioxidants called phenolic acids in the dough," Moore says. In general, values climbed from about 4 micrograms of free, or unbound, phenolic acids per gram of starting wheat to 8 µg/g. Ferulic acid proved the main contributor to this antioxidant climb.

In a different set of experiments, the food chemists tinkered with baking conditions and then ran five different test-tube assays of the crust's antioxidant activity—its ability to quash free radicals. At the meeting, they reported finding a 60 percent increase in the crust's antioxidant activity for deep-dish, "Chicago-style," pizzas that had been baked at 400 °F for 14 minutes versus 7 minutes. If the scientists instead raised the temperature to 550°F, the antioxidant activity in a pizza baked for 7 minutes increased by 80 percent.

In principle, Moore says, pizza makers should be able to increase both baking time and temperature—if they watch the pie so it doesn't burn. Deep-dish pizzas are particularly good candidates for this recipe meddling, Moore says, because they generally require longer baking times than thin-crust pizzas do.

The Maryland team focused on whole wheat crust because it has abundant fiber—a nutrient short in most U.S. diets—and includes the source of most of the grain's antioxidants. Although white flour carries fewer antioxidants, crusts made from it should also be candidates for antioxidant boosting, Moore says. Nevertheless, he suspects that the spike wouldn't be nearly as impressive as for whole-wheat crust.

The researchers have begun probing why the antioxidant increase occurs. They suspect that something in fermentation and baking processes unleash phenolic acids otherwise rendered inert by being bound to other plant materials in flour.

Moore points out that there isn't anything magical about pizza dough. A similar tinkering with baking times and temperatures should give other whole wheat bakery goods—most notably breads—boosts in their antioxidant content and activity.

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Jeffrey Moore

Department of Food Science and Nutrition

University of Maryland

0112 Skinner Bldg.

College Park, MD 20742

Liangli Lucy Yu

Department of Food Science and Nutrition

University of Maryland

0112 Skinner Bldg.

College Park, MD 20742
Further Reading

Brownlee, C. 2005. Long live the mammals: Antioxidant redirection extends mouse life span. Science News 167(May 7):292. Available at [Go to].

Cobb, K. 2002. Processing corn boosts antioxidants. Science News 162(Aug. 31):141. Available to subscribers at [Go to].

Dewanto, V. . . . and R.H. Liu. 2002. Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity. Journal of Agricultural and Food Chemistry 50(May 8):3010-3014. Abstract available at [Go to].

Raloff, J. 2001. Drink those antioxidants. Science News Online (Aug. 4). Available at [Go to].

______. 2001. Keeping antioxidants may spare gut. Science News 159(April 21):248. Available to subscribers at [Go to].

______. 2000. Panel ups RDAs for some antioxidants. Science News 157(April 15):244. Available to subscribers at [Go to].

______. 1999. Berry good protection for aging brains. Science News 156(Sept. 18):180. Available at [Go to].

______. 1998. Antioxidants preserve lung function. Science News 153(May 2):287. Available at [Go to].

______. 1997. Looking for lycopene? Tomatoes are okay, but . . . . Science News Online (July 19). Available at [Go to]" target="_blank">

Wu, C. 1997. How antioxidants defend cells. Science News 151(Feb. 15):111. Available at [Go to].

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