NEW ORLEANS—Molecular differences between raw and heat-treated nuts in terms of their inherent peptides has helped to account in part for the increased allergenic properties observed in roasted peanuts, according to a new study published in the journal Molecular Nutrition and Food Research.
U.S. Department of Agriculture (USDA) scientists studied how the peanut-roasting process alters how well an allergic individual's immunoglobulin E (IgE) binds to peanut allergens to determine whether heat-treating can increase the risk of an allergic reaction.
The major allergenic proteins (or allergens) of peanuts are known as "Ara h 1," "Ara h 2" and "Ara h 3." The team compared the reaction by human IgE antibody to the heated and unheated forms of Ara h 1.
The study showed that roasting-induced side reactions, such as browning, increased the amount of IgE that recognizes and binds to Ara h 1—when compared to the amount that binds to Ara h 1 from raw peanuts, showing allergenic properties are increased in roasted peanuts.
An estimated 1.2% to 1.4% of Americans are allergic to peanuts, tree nuts or both; and the prevalence of allergies keeps rising, especially in children. In a recent study, only 50% of patients with nut allergies could identify which specific nut types. Peanuts were the most commonly identified item, and the shell made a significant difference—almost 95% of participants correctly identified peanuts in a shell, compared to 80.5% who could identify a peanut outside the shell.