Allergenic Properties of Roasted Peanut Allergens May Be Reduced by Peroxidase

Abstract

Peanut allergy is a public health issue. The culprits are the peanut allergens. Reducing the allergenic properties of these allergens or proteins will be beneficial to allergic individuals. In this study, the objective was to determine if peroxidase (POD), which catalyzes protein cross-linking, reduces the allergenic properties of peanut allergens. In the experiments, protein extracts from raw and roasted defatted peanut meals at pH 8 were incubated with and without POD in the presence of hydrogen peroxide at 37 degrees C for 60 min. The POD-treated and untreated samples were then analyzed by SDS-PAGE, western blots, and competitive inhibition ELISA. IgE binding or allergenicity was determined in blots and ELISA. Results showed that POD treatment had no effect on raw peanuts with respect to protein cross-linking. However, a significant decrease was seen in the levels of the major allergens, Ara h 1 and Ara h 2, in roasted peanuts after POD treatment. Also, polymers were formed. Despite this, a reduction in IgE binding was observed. It was concluded that POD induced the cross-linking of mainly Ara h 1 and Ara h 2 from roasted peanuts and that, due to POD treatment, IgE binding was reduced. The finding indicates that POD can help reduce the allergenic properties of roasted peanut allergens.

Peanut proteins: Applications, ailments and possible remediation

“…Ara h 1 purified from peanuts heated at different temperatures exhibited IgE binding properties similar to those found for native Ara h 1, indicating that the allergenicity of Ara h 1 is heat-stable [32]. The allergenic potency of peanut allergens can be reduced by using various enzymes like peroxidase [21,33] and also using phytic acid [34] or treatment with activated charcoal [35].…”

Effects of food processing on food allergens

“…The investigators suggested that wet heat processing may denature some peanut allergens but such protein denaturation may not be adequate for the management and prevention of the peanut allergy risk. Chung et al [27] and Chung et al [28] reported that peroxidase treatment of peanuts reduced allergenicity of Ara h 1 and Ara h 2 in roasted but not in raw peanuts. The authors suggested that the oxidation products of PPO-catalyzed reactions lead to protein -protein cross-linking with subsequent formation of large crosslinked protein aggregates resulting in reduced accessibility of immunoreactive epitopes.…”

Enzymatic and Chemical Modifications of Food Allergens

“…Acting on phenolic compounds POD generate o-quinones, which further react with other phenolics, amino, or sulfhydryl compounds in proteins to form cross-linked products. In their study Chung et al (Chung et al, 2004) have treated protein extracts from raw and roasted defatted peanut meals with POD in the presence of hydrogen. While POD treatment had no effect on raw peanuts, a significant cross-linking and decrease in the levels of the major allergens, Ara h 1 and Ara h 2, in roasted peanuts (Fig.7) was observed in imunoblots and IgE ELISA.…”