Submitted to: Foods
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/23/2014
Publication Date: 5/7/2014
Citation: Maleki, S.J., Schmitt, D.A., Galeano, M.J., Hurlburt, B.K. 2014. Comparison of the digestibility of the major peanut allergens in thermally processed peanuts and in pure form. Foods. 3(2):290-303. Interpretive Summary: Peanut allergy is a major health concern in the U.S. Recently, there have been reports of different processing methods that impact the allergenicity of food proteins. Because one of the characteristics of food allergens is thought to be resistance to digestion following ingestion, the effects of different processing methods on digestion was investigated. Specifically, boiled, roasted, and fried peanuts were compared to raw peanuts using simulated digestion models in vitro. The major allergens Ara h 1 and Ara h 2 were targeted in the project. Frying and roasting the treatments with the highest heat had the greatest effect in reducing digestibility.
Technical Abstract: It has been suggested that boiling or frying of peanuts lead to less allergenic products than roasting. Here, we have compared the digestibility of the major peanut allergens in the context of peanuts subjected to boiling, frying, or roasting, and in purified form. The soluble peanut extracts and the purified allergens were digested with either trypsin or pepsin, and analyzed by gel electrophoresis and western blot. T cell proliferation was measured for the purified allergens. In most cases boiled and raw peanut proteins were similarly digestible, but the Ara h 1 protein in the boiled extracts was more resistant to digestion. Most proteins from fried and roasted peanuts were more resistant to digestion than in raw and boiled samples, and more IgE binding fragments survived digestion. High-molecular-weight fragments of Ara h 1 were resistant to digestion in fried and roasted samples. Ara h 1 and 2 purified from roasted peanuts were most resistant to digestion, but differed in their ability to stimulate T cells. The differences in digestibility and IgE binding properties of the major allergens in roasted, fried, and boiled peanuts may not explain some of the discrepancies between the prevalence of peanut allergy in different countries.