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 Peanuts and popular processed peanut foods. Link to photo information
More than a million Americans suffer from peanut allergies, but ARS researchers are working to reduce the allergenicity. The U.S. produces about 3 to 4 billion pounds of peanuts annually; 40 percent goes into processed foods. Click the image for more information about it.

Natural Fruit Enzyme May Lessen Peanuts' Allergenic Punch

By Erin Peabody
December 21, 2005

An apple a day keeps the doctor away? Well, an enzyme naturally found in apples may at least hold the key to a less problematic peanut--which is great news for the more than one million Americans living with peanut allergies.

Agricultural Research Service (ARS) scientists have discovered that the enzyme responsible for turning apples and other fruits brown when they’re sliced also has the ability to reduce a peanut’s allergenic potency.

About 1.5 million people in the United States and many others worldwide suffer from peanut allergies. Nut allergies, like other food allergies, can be life-threatening, so several ARS researchers have been on a quest to find a safer peanut.

Si-Yin Chung, with the agency’s Southern Regional Research Center in New Orleans, La., discovered that the natural fruit enzyme called polyphenol oxidase--or PPO, for short--triggers an interesting chemical reaction when added to extracts from chopped-up peanuts.

It’s similar to what happens when a just-cut apple or banana turns brown. The slicing action releases the PPO found in some of the fruit’s tiny cells, allowing the enzyme to mix freely with compounds in the fruit’s other cells. Add oxygen from surrounding air, and the result is oxidation--and a rather unappetizing, rust-colored apple.

Peanuts don’t contain PPO, but when the enzyme is added to extracts from ground-up peanuts, it also sets off the oxidation process. This oxidation, which yields numerous volatile molecules, causes peanut proteins that were once independent and pure to link up in unusual ways.

The proteins that PPO affects are the same as those that provoke an allergic response in some people. So by shaking up the proteins’ original structure, the PPO enzyme is also altering their allergenic properties.

Chung cautions that animal studies are needed to truly confirm the enzyme’s effect on peanuts’ allergy-causing proteins. He also plans to investigate whether or not PPO affects peanuts’ flavor and shelf life.

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