Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2009
Publication Date: 1/7/2010
Citation: Schmitt, D., Nesbit, J.B., Hurlburt, B.K., Cheng, H., Maleki, S.J. 2010. Processing can alter the properties of peanut extract preparations. Journal of Agricultural and Food Chemistry. 58(2):1138-1143.
Interpretive Summary: Allergy to peanuts is an increasing public health risk, affecting over 1% of the U.S. and U.K. school children. As avoidance is the only treatment for peanut allergy, it is important that methods and reagents for accurate diagnosis of food allergy, and detection of allergenic foods are reliable and consistent. Most current kits used for detection and diagnosis rely on the identification of a particular form of the allergenic peanut proteins. Because most peanuts are ingested in the processed form, e.g. boiled or roasted, we investigated the effect that heating had on the form of the peanut proteins. We found that, indeed, heating caused alterations in two of the major peanut proteins responsible for allergic reactions, resulting in increased allergenicity. Additionally, these changes could account for some of the inconsistent results obtained in some of the commonly accepted methods used in detection tests, and to diagnose peanut allergic individuals.
Technical Abstract: As peanut allergy is an increasing public health risk, affecting over 1% of the United States and United Kingdom school children; it is important that methods and reagents for accurate diagnosis of food allergy, and detection of allergenic foods are reliable and consistent. Given that most current experimental, diagnostic, and detection tests rely on the presence of soluble allergens in food extracts, we investigated the effects of thermal processing on the solubility and IgE binding of the major peanut allergens, Ara h 1 and Ara h 2. The soluble and insoluble fractions of peanuts that were boiled, fried, and roasted were subjected to electrophoresis and Western blot analysis using anti-Ara h 1, and anti-Ara h 2 antibodies and serum IgE from peanut allergic individuals. Overall protein solubility is reduced with processing and IgE binding increases in the insoluble fractions, due mostly to the increase in the amount of insoluble proteins, with increased time of heating in all processes tested; therefore, it can be concluded that thermal processing of peanuts alters solubility, and the differences in protein solubility within various extract preparations may contribute to inconsistent skin prick test and immunoassay results, particularly, when nonstandardized reagents are used.