Quantification of Ara h 1 in peanuts: why roasting makes a difference

• Published in: Clinical and experimental allergy 2006-06, Vol.36 (6), p.824-830
• Main Authors: Pomés, A., Butts, C. L., Chapman, M. D.
• Format: Article
• Language: English
• Subjects: allergen quantification; Allergens - analysis; Allergens - metabolism; Allergic diseases; Animals; Antibody Specificity; Antigens, Plant; Arachis; Arachis hypogaea; Biological and medical sciences; Digestive allergic diseases; Enzyme-Linked Immunosorbent Assay - methods; food allergy; Food Handling; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Glycoproteins - analysis; Glycoproteins - metabolism; Hot Temperature; Humans; immunoassay; Immunodiffusion; Immunoglobulin E - metabolism; Immunopathology; Medical sciences; peanut allergen; Peanut Hypersensitivity - immunology; Plant Proteins - analysis; Plant Proteins - metabolism
• ISSN: 0954-7894; 1365-2222
• DOI: 10.1111/j.1365-2222.2006.02490.x

Summary Background Increased allergenicity of roasted vs. raw peanut has been reported by showing higher IgE binding to roasted peanut extracts. Objective To study the effect of roasting on Ara h 1 quantification in peanut using a specific monoclonal antibody‐based ELISA, and to compare the Ara h 1 content from different kernel size peanuts from four runner cultivars. Methods Raw or oven‐roasted (177°C for 5–30 min) runner peanuts were crushed and extracted at 60°C. Inhibition ELISA was used to study binding of Ara h 1 purified from raw or roasted peanut. Runner peanuts of four different cultivars were collected, shelled, sized and roasted for 15 min at 177°C. Ara h 1 in the extracts was compared by ELISA. Results Ara h 1 levels were up to 22‐fold higher in roasted than in raw peanuts (820 vs. 37 μg/mL, in a representative experiment) with an Ara h 1 peak at 10–15 min of roasting. Inhibition ELISA indicated that this increase was not due to conformational changes in the Ara h 1 monoclonal antibody epitopes. Ara h 1 was found at lower levels in number 1 than in jumbo‐ and medium‐sized peanuts, and no differences were found among cultivars. Conclusion These results suggest that roasting increases the efficiency of Ara h 1 extraction, and/or that the monoclonal antibody binding epitopes were more accessible in roasted peanut. Expression of Ara h 1 is associated with peanut maturity.