Treating peanuts with heat and pressure might help reduce allergic reactions to proteins in this popular legume, recent research suggests. Autoclaving peanuts for 30 minutes resulted in a significant decrease in the capacity of peanut allergens to bind to immunoglobulin-E (IgE), an international team of researchers reported.
In separate work, researchers led by Soheila J. Maleki, PhD, of the Food Processing and Sensory Quality Research Unit of the USDA Agricultural Research Service (ARS), Southern Regional Research Center, in New Orleans, La., found that, in roasted peanuts, an important allergen binds higher levels of serum IgE than in raw peanuts.
Working with numerous collaborators, Dr. Maleki and others at ARS have explored different facets of peanut allergenicity with the hope of reducing allergic reactivity in peanut products.
With first author Beatriz Cabanillas and colleagues at the Hospital Universitario 12 de Octubre in Madrid, Spain, Dr. Maleki assessed immunoreactivity to raw and autoclaved peanut extracts using several methods, including clinical tests. Laboratory work showed that unfolding of proteins occurred in autoclaved samples, making them more susceptible to digestion.
She speculates that a combination approach to processing might help to reduce peanut allergenicity while maintaining the familiar character of popular peanut-containing foods.
“Consumers love the flavor of roasted peanuts,” she says. “The peanuts in peanut butter and many other foods are roasted. But IgE binds better to proteins in roasted peanuts than raw peanuts. Something that would be interesting to try, but that we have not done yet, would be to take these autoclaved peanuts with reduced immunogenicity and roast them, to see if we can get the texture and flavor so that consumers and the industry would be open to using this process.”
Researchers have identified 12 allergens, with different levels of immunogenicity, in peanuts, Dr. Maleki notes. Genetic methods are being using to explore ways to potentially reduce the allergic reactivity of peanuts, she says. By concentrating on the allergens that are most important for allergic reactivity, the researchers hope to find ways to make peanuts less allergenic.
“We have screened thousands of peanut varieties, and we’ve found significant differences in levels of different allergens and in their capability of binding to IgE, which is elevated in allergic individuals,” Dr. Maleki says.
“Our philosophy is not to genetically modify plants,” she says, “but we have identified one naturally occurring mutation that reduced the binding of IgE to the most reactive of the 12 allergens from 56 to 90 percent, depending on the patient tested.”