Changes in Major Peanut Allergens Under Different pH Conditions

Regional dietary habits and cooking methods affect the prevalence of specific food allergies; therefore, we determined the effects of various pH conditions on major peanut allergens. Peanut kernels were soaked overnight in commercial vinegar (pH 2.3) or acetic acid solutions at pH 1.0, 3.0, or 5.0. Protein extracts from the sera of seven patients with peanut-specific IgE levels >15 kUA/L were analyzed by SDS-PAGE and immunolabeling. A densitometer was used to quantify and compare the allergenicity of each protein. The density of Ara h 1 was reduced by treatment with pH 1.0, 3.0, or 5.0 acetic acid, or commercial vinegar. Ara h 2 remained largely unchanged after treatment with pH 5.0 acetic acid, and was decreased following treatment with pH 1.0, 2.3, or 3.0 acetic acid. Ara h 3 and Ara h 6 appeared as a thick band after treatment with pH 1.0 acetic acid and commercial vinegar. IgE-binding intensities to Ara h 1, Ara h 2, and Ara h 3 were significantly reduced after treatment with pH 1.0 acetic acid or commercial vinegar. These data suggest that treatment with acetic acid at various pH values affects peanut allergenicity and may explain the low prevalence of peanut allergy in Korea.

Effects of Cooking Methods on Peanut Allergenicity / 소아알레르기및호흡기학회지

PURPOSE: Peanut allergy is a major cause of fatal food-induced anaphylaxis. Cooking methods can affect the allergic properties of peanut proteins. The aim of this study was to determine the allergenicity of peanut according to cooking methods. METHODS: Eight kinds of peanut were included in the study: raw peanut, boiled peanut, roasted peanut (10 min, 20 min and 30 min), peanut butter, fried peanut and vinegarish peanut. The proteins were extracted with PBS and analyzed using the SDS-PAGE IgE immunoblot assay with pooled sera from 8 patients with atopic dermatitis. These patients had peanut- specific IgE levels greater than 15 kU/L, which were measured by the CAP-FEIA. RESULTS: The SDS-PAGE IgE immunoblot assay revealed more intense protein bands of Ara h 2 in roasted peanut and peanut butter than in raw, boiled, fried and vinegarish peanut. The protein band of Ara h 1 was not undetected in fried and vinegarish peanut. Ara h 3 had a stable band pattern in all samples, but there was the most prominent band at 37-40 kDa in vinegarish peanut. The IgE immunoblot assay revealed that 10 min roasted peanut had more IgE binding to Ara h 2, and there was no IgE binding to Ara h 1 in fried and vinegarish peanut. In vinegarish peanut, there was almost no IgE binding to it. CONCLUSION: The results of this study suggest that the roasted peanut may increase the allergenicity of Ara h 2 as compared to Ara h 1. Fried and vinegarish peanut may reduce the allergenicity of peanut.