Changes in immunoreactivity of allergen-reduced peanuts due to post-enzyme treatment roasting

The objective of this study was to evaluate the effect of enzyme treatment and post-enzyme treatment roasting on allergenicity of raw peanut kernels. Raw peanuts were treated by single- and two-enzyme treatments, respectively. Enzyme-treated raw peanuts were dry roasted. Reductions of four major allergens (Ara h 1, 2, 3, and 6) and in vitro allergenicity of peanuts were evaluated. Quantitative measurements show that enzyme treatment of raw peanuts reduced Ara h 1, 2, 3 and 6 in raw peanuts by 99-100%, 95-99%, 35-46% and 85-88%, respectively. Roasting of enzyme-treated peanuts significantly reduced the total soluble protein (P < 0.05), Ara h 3 and 6 (P < 0.0001), slightly increased Ara h 1 in the extracts (P < 0.05), but did not significantly affect Ara h 2. Immunoblot shows that the IgE-bindings of both soluble and insoluble proteins of enzyme-treated peanuts were slightly enhanced by roasting but still tremendously lower than that of untreated peanuts.