Quantification of Ara h 1 in peanuts: why roasting makes a difference.
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 degrees C for 5-30 min) runner peanuts were crushed and extracted at 60 degrees 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 degrees 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 microg/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.


CONCLUSIONS
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.
Pomés
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A
INDOOR Biotechnologies Inc., Charlottesville, VA 22903, USA. apomes@inbio.com
Butts
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CL
Chapman
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MD
D000485:Allergens / Q000032:analysis* / Q000378:metabolism; D000818:Animals; D000918:Antibody Specificity; D052179:Antigens, Plant; D010367:Arachis; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005511:Food Handling; D006023:Glycoproteins / Q000032:analysis* / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D005779:Immunodiffusion; D007073:Immunoglobulin E / Q000378:metabolism; D008565:Membrane Proteins; D021183:Peanut Hypersensitivity / Q000276:immunology*; D010940:Plant Proteins / Q000032:analysis* / Q000378:metabolism
D000485:Allergens; D052179:Antigens, Plant; C500889:Ara h 1 protein, Arachis hypogaea; D006023:Glycoproteins; D008565:Membrane Proteins; D010940:Plant Proteins; D007073:Immunoglobulin E