Simple methods to reduce major allergen Ara h 1 and Ana o 1/2 in peanut and cashew extracts

Authors: Chung, Si Yin; Mattison, Chris; Grimm, Casey; Reed, Shawndrika

Submitted to: Journal of Food Science and Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2017
Publication Date: 11/1/2017
Citation: Chung, S., Mattison, C.P., Grimm, C.C., Reed, S.S. 2017. Simple methods to reduce major allergen Ara h 1 and Ana o 1/2 in peanut and cashew extracts. Journal of Food Science and Nutrition. 5:1065-1071.

Interpretive Summary: Peanut allergy is common and is a major public health concern. Allergy shots or other forms of immunotherapies are being used as treatment options, but may have limitations due to safety issues and risks of side effects. The culprit is the whole peanut extract used in the treatment. A less allergenic peanut extract may be beneficial because individuals with peanut allergy may be able to tolerate a less allergenic peanut extract during immunotherapy. Our goal was to produce a peanut extract with less allergens. Also, cashew extracts with less allergens were prepared. Three simple methods were separately used to prepare less allergenic extracts: (1) a chemical (pABA) to cause precipitation and separation of major allergen(s) from a peanut or cashew extract; (2) magnetic gel-like beads to bind and separate major peanut or cashew allergens; and (3) extraction of a commercial peanut flour under a non-acidic condition. Results showed that all treatments resulted in a peanut or cashew extract lacking one or two major allergens. We conclude that a less allergenic peanut or cashew extract could be produced using such approaches.

Technical Abstract: Whole peanut extracts are usually used in immunotherapy but may have side effects. Reducing major peanut allergen(s) in the extracts may reduce the side effects. Three simple methods were evaluated to reduce major allergen Ara h 1 from a peanut extract: (1) treatment with p-aminobenzamidine (pABA); (2) treatment with magnetic 6% cross-linked agarose beads; and (3) extraction of a specific commercial peanut flour at pH 7. The first two methods were also used to reduce Ana o 1 and Ana o 2 allergens (Ana o 1/2) from a cashew extract. Method #1 involved adding an aliquot of glutaraldehyde (1%) to a mixture of pABA (20 mM) and peanut or cashew extract (0.5 mg/mL), followed by incubation for 2 hr and centrifugation/ concentration to remove precipitates and excess pABA. Method #2 involved incubation of magnetic agarose beads (1 mL) with nut extract (1 mg/mL, 1mL) for an hr, isolating the beads, and then treating the beads with 1 M NaCl. Method #3 involved stirring peanut flour in 10 mM Tris buffer, pH 7 for 40 min and centrifugation. All samples were evaluated by SDS-PAGE. pABA-treated samples were analyzed for IgE binding in western blot. We found that treatments with the above individual methods resulted in peanut extract lacking detectable Ara h 1 but containing Ara h 2/6 and cashew extract lacking Ana o 1/2, but containing Ana o 3. Consequently, reduced IgE binding was observed with the pAbA-treated extracts. We conclude that the three simple methods are useful for producing peanut extracts lacking Ara h 1 and cashew extracts lacking Ana o 1/2.