ORIGINAL PAPER: 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: Pomes, A, Butts, CL, Chapman, MD
• Format: Article
• Language: English
• Subjects: Arachis hypogaea
• ISSN: 0954-7894; 1365-2222
• DOI: 10.1111/j.1365-2222.2006.02490.x

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 degree C for 5-30 min) runner peanuts were crushed and extracted at 60 degree 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 degree 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 mu g-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.