Technical Abstract: Food allergens are a significant worldwide public health issue. Estimates for the prevalence of food allergies are around 1-2 % of the total population and up to 8 % of children; although, the prevalence may vary between populations and age groups. Peanuts are one of the most allergenic foods. The severity of peanut allergic reactions can vary from symptoms ranging from mild urticaria to potentially lethal anaphylactic shock. There are three major allergens in peanuts, Ara h1, Ara h2, and Ara h3. In addition, roasted peanuts bind higher levels of serum IgE than raw peanuts. In this study, the effects of structure of Ara h 1 from roasted and raw peanuts on IgE binding was examined using circular dichroism (CD) spectroscopy to monitor structural changes. The roasted Ara h 1 bound significantly higher IgE, the secondary structure was not significantly different from the Ara h 1 purified from raw peanut. It has been shown that IgE binds to linear epitopes, and that IgE still recognizes the linear Ara h 1 in western blots; however, here the binding to the linear Ara h 1 is significantly reduced in comparison to its folded counterpart. Our findings indicate that potential processing methods that target unfolding of Ara h 1 may be successful in reducing the allergenicity of this protein significantly.