Vinson and Michael Coco, Jr., a chemistry student at the university, analyzed four commercial brands of popcorn, including two air-popped and two microwave varieties.
They evaluated antioxidants known as polyphenols. These compounds are found in a wide variety of plants. Antioxidants undo the damage that can be done by unstable molecules known as ''free radicals."
"Everyone knows plant foods have antioxidants," Vinson tells WebMD. "But nobody has even looked at what is in popcorn with respect to these compounds."
Vinson and Coco ground up the hull and the ''fluffy stuff," Vinson says, and checked the polyphenol levels.
Most of the polyphenols -- about 90% -- were in the hull, Vinson says.
The four brands tested had slightly different serving sizes, from a little under an ounce to a little over. The antioxidants per serving ranged from about 242-363 milligrams (mg).
In comparison, they found that a serving of many fruits has about 160 mg of polyphenols.
Popcorn's polyphenols are not as diluted with water as those are in fruit, Vinson says."Popcorn starts out about 15% water and ends up a couple percent."
He calls popcorn "a wonderful high-fiber snack," but like other experts, he warns that adding too much butter and other oil can quickly ruin popcorn's healthy image. He presented the study, which was partially funded by Weaver Popcorn Company, today in San Diego at the American Chemical Society's annual meeting.
Antioxidants in Popcorn: Study Details
The study is a good first step, but it wasn't designed to measure health benefits, says Jeffrey B. Blumberg, PhD, professor of nutrition at Tufts University and senior scientist and director of Tufts' Antioxidants Research Laboratory.