Heat, Pressure Treatment Reduces Allergenic Proteins in Peanuts
February 10, 2014
WASHINGTON—Applying heat and pressure to roasted peanuts significantly reducing allergic reaction from the proteins in the peanuts, according to new research conducted by USDA Agricultural Research Service (ARS) scientists in New Orleans and published in the journal Food Chemistry.
Previous research by the scientists found that while people generally eat peanuts that have been roasted or boiled, the extracts that are commonly used to diagnose peanut allergies are from raw peanuts. The researchers also have shown that roasting-induced side reactions, such as browning, increased the amount of antibody that recognizes and binds to major allergenic proteins, when compared to the amount that binds to allergens from raw peanuts.
The process the researchers used to apply heat and pressure is called autoclaving, which involves a higher moisture environment—similar to steaming or boiling—than roasting. As a result, autoclaving does not initiate the browning effect that comes with roasting. The less allergenic reaction to the peanuts exposed to heat and pressure was confirmed by skin-prick tests.
The research also showed that in the autoclave-treated peanut samples, proteins became unfolded, which makes them easier to digest. Although further studies are needed to assess the clinical relevance of the findings, the researchers concluded that autoclaving at 2.56 atmospheres for 30 minutes produces a significant decrease of antibody-binding capacity of peanut allergens.
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.